Overview|V4.4.2|OceanBase Database| docs|Distributed Database

This topic lists system variables of OceanBase Database based on their functions.

Global level

Security

Variable	Description
validate_password_check_user_name	Specifies whether the user password can be the same as the username.
validate_password_length	Specifies the minimum length of the user password.
validate_password_mixed_case_count	Specifies the minimum number of uppercase and lowercase letters in the user password.
validate_password_number_count	Specifies the minimum number of digits in the user password.
validate_password_policy	Specifies the password check strategy.
validate_password_special_char_count	Specifies the minimum number of special characters in the user password.
ob_tcp_invited_nodes	Specifies the IP address whitelist for the tenant. You can use a wildcard character (%), an underscore (_), or an IP address. You can separate multiple IP addresses with commas. You can match the IP addresses in the list, by mask, or by wildcard.
default_password_lifetime	Specifies the password expiration time.
block_encryption_mode	Specifies the encryption algorithm used in the aes_encrypt and aes_decrypt functions.
sql_safe_updates	Specifies whether to enable the SQL safe mode in MySQL. The default value is OFF.
super_read_only	Controls the read/write permissions of the database. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
pid_file	Queries the path name of the file in which the server writes the process ID.
port	Specifies the TCP/IP port number for the server when you deploy the OBServer node.
socket	Queries the name of the `Socket` file for local client connections.

Variable name	Description
version_comment	Displays the version information of an OBServer node.
version	Displays the server version.
ob_last_schema_version	Sets the latest schema version used in the current session.
ob_proxy_global_variables_version	Sets the latest version of global variables to be returned by an OBServer node to an OBProxy node.
ob_enable_transmission_checksum	Sets whether to enable packet checksum verification between an OBProxy node and an OBServer node. The setting takes effect immediately.
ob_compatibility_control	Controls the behavior when compatibility conflicts occur between MySQL 5.7 and MySQL 8.0.
ob_compatibility_version	Controls the OceanBase Database version compatible with the feature that changes the product behavior.
ob_security_version	Controls the OceanBase Database version compatible with the security feature. You can specify the compatible version when you create a tenant. You cannot modify the compatible version after the tenant is created.
old_alter_table	Sets whether to enable the syntax and operation mode of the old ALTER TABLE statement. The default value is `OFF`. Note This variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting does not take effect.

Variable name	Description
debug	Sets the debug options. The default value is `d:t:i:o,/tmp/mysqld.trace`. Note This variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting does not take effect.
ob_global_debug_sync	Sets the synchronization point during debugging. This variable affects all sessions.

Variable name	Description
lower_case_table_names	Sets whether to enable case sensitivity.

Variable	Description
query_cache_size	Specifies the size of memory allocated for storing the results of queries that are not yet executed.
query_cache_type	Specifies the query cache type.
ob_query_timeout	Specifies the query timeout.
is_result_accurate	When a query contains the `TOPK` hint, `is_result_accurate` specifies whether the query result is accurate.
net_buffer_length	Specifies the maximum size of an SQL query that an OBServer node can accept.
read_only	Specifies whether a tenant is in read-only mode.
ob_read_consistency	Specifies the read consistency level.
ob_max_read_stale_time	Specifies the maximum delay threshold (us) for weak-consistency reads.
net_read_timeout	Specifies the number of seconds to wait for other data before interrupting a read.
net_write_timeout	Specifies the number of seconds to wait for a block to be written before interrupting a write.
ob_enable_index_direct_select	Specifies whether to allow users to directly query index tables.
ob_enable_aggregation_pushdown	Specifies whether to allow aggregation operations to be pushed down.
ob_enable_jit	Specifies the JIT execution engine mode.
sql_throttle_network	Specifies the request queuing time. If the queuing time exceeds this value, the query cannot be executed.
parallel_servers_target	Specifies the queuing conditions for large queries on each server.
cte_max_recursion_depth	Specifies the maximum recursion depth for common table expressions (CTEs). The server terminates the execution of any operation exceeding this CTE value.
regexp_stack_limit	Specifies the maximum available memory for the internal stack used in regular expression matching operations.
regexp_time_limit	Specifies the time limit for regular expression matching operations.
long_query_time	Specifies the threshold for slow queries.

Variable	Description
event_scheduler	Specifies whether the event scheduler is enabled and running on the server.

Variable	Description
ob_create_table_strict_mode	Specifies the strict mode for table creation.
ob_default_replica_num	Specifies the default number of replicas for each table in a cluster.
master_info_repository	Specifies whether to record metadata to the mysql table in the InnoDB system database or to store it as a file in the data directory. The default value is `FILE`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
replication_optimize_for_static_plugin_config	Specifies whether to enable shared locks to improve the performance of semi-synchronous replication. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
replication_sender_observe_commit_only	Specifies whether to enable limited callbacks to improve the performance of semi-synchronous replication. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
rpl_semi_sync_slave_enabled	Specifies whether to enable semi-synchronous replication on a replica. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
rpl_semi_sync_slave_trace_level	Specifies the debug tracing level for semi-synchronous replication on a replica. The default value is `32`, which indicates the network waiting level. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
rpl_stop_slave_timeout	Specifies the time to wait before a STOP SLAVE statement times out, in seconds. The default value is `31536000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_checkpoint_group	Specifies the maximum number of transactions that can be processed by multi-threaded replication before a checkpoint operation is called to update the progress status. The default value is `512`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_checkpoint_period	Specifies the maximum time allowed between checkpoint operations to update the status of multi-threaded replication, in milliseconds. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_compressed_protocol	Specifies whether to use the compression of the source or replica protocol when both the source and replica support compression. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_exec_mode	Specifies how replication threads resolve conflicts and errors during replication. Setting it to `IDEMPOTENT` suppresses errors for duplicate and missing keys; setting it to `STRICT` does not suppress these errors. The default value is `STRICT`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_max_allowed_packet	Specifies the maximum size of data packets for replication SQL and I/O threads, in bytes. The default value is `1073741824`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_net_timeout	Specifies the time to wait for more data or a heartbeat signal from the source before the replica assumes the connection is disconnected and aborts reading and attempts to reconnect, in seconds. The default value is `60`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_parallel_type	Specifies the type of parallel execution for replication transactions when multi-threaded replication is enabled. The default value is `DATABASE`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_parallel_workers	Specifies the number of threads to execute replication transactions in parallel. The default value is `0`, which indicates that parallel execution of replication transactions is disabled. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_pending_jobs_size_max	Specifies the maximum length of the work queue for storing unapplied events for multi-threaded replication. The unit is bytes. The default value is `16777216`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_preserve_commit_order	Specifies whether to commit transactions in the order they appear in the relay log for multi-threaded replication. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_rows_search_algorithms	Specifies the algorithms for searching and finding related rows for replication. The default value is `TABLE_SCAN,INDEX_SCAN`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_sql_verify_checksum	Specifies whether to verify data using the checksum read from the relay log for the SQL thread of replication. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_transaction_retries	Specifies the number of times the system automatically retries a transaction that fails due to a deadlock or because the transaction execution time exceeds the value specified by the `innodb_lock_wait_timeout` variable. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_type_conversions	Specifies the type conversion mode for row-based replication. The default value is empty, indicating that type conversion between the source and replica is disabled. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
sql_slave_skip_counter	Specifies the number of events to be skipped from the source for the replica. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
skip_slave_start	Specifies whether to skip starting the replication thread when the replica server starts. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
slave_load_tmpdir	Specifies the directory name for creating temporary files for the replica. The default value is empty. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
slave_skip_errors	Specifies which errors to skip during replication. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
sync_master_info	The effect of this variable on the replica depends on whether the `master_info_repository` parameter is set to FILE or TABLE. The default value is `10000`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
init_slave	This variable is similar to init_connect. It specifies the string to be executed by the replica when the replication SQL thread starts. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
log_slow_slave_statements	Specifies whether to record slow SQL statements executed by the replication thread to the slow query log if the slow query log is enabled on the replica. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
report_host	Specifies the hostname or IP address of the replica to be reported to the source during registration. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
report_password	Specifies the password of the replication user account to be reported to the source during registration. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
report_port	Specifies the TCP/IP port number for connecting to the replica to be reported to the source during registration. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
report_user	The username of the account to which the replica is registered. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log	The name of the relay log. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_basename	The name and full path of the relay log. The default value is `/usr/local/mysql/data/obrd-relay-bin`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_index	The name of the relay log index file. The default value is `/usr/local/mysql/data/obrd-relay-bin.index`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_info_file	The name of the file that records information about the relay log. The default value is `relay-log.info`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_recovery	If this variable is enabled, the relay log is automatically recovered after the replica is started. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_space_limit	The maximum capacity of all relay logs, in bytes. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.

Variable name	Description
rpl_semi_sync_master_enabled	Specifies whether to enable semi-synchronous replication on the source. The default value is `OFF`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_timeout	Specifies the time in milliseconds that the source waits for confirmation from the replicas after a transaction is committed. The default value is `10000`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_trace_level	Specifies the debug tracing level for semi-synchronous replication on the source. The default value is `32`, which indicates the network waiting level. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_wait_for_slave_count	Specifies the number of replicas that must confirm a transaction before the source continues. The default value is `1`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_wait_no_slave	Specifies whether the source waits for the timeout (set by the `rpl_semi_sync_master_timeout` variable) even if the number of replicas is less than the value specified by the `rpl_semi_sync_master_wait_for_slave_count` variable. The default value is `OFF`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_wait_point	Specifies the point at which the semi-synchronous source waits for confirmation from the replicas before returning the status to the client that submitted the transaction. The default value is `AFTER_SYNC`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.

Variable name	Description
recyclebin	Specifies whether to enable the recycle bin.
ob_enable_truncate_flashback	Specifies whether to enable flashback for table truncation.

Variable name	Description
ob_enable_plan_cache	Specifies whether to enable the plan cache.
ob_plan_cache_percentage	Specifies the percentage of memory allocated to the plan cache relative to the tenant's memory.
ob_plan_cache_evict_high_percentage	Specifies the percentage of memory at which the plan cache is evicted relative to the memory limit.
ob_plan_cache_evict_low_percentage	Specifies the percentage of memory at which the plan cache eviction stops relative to the memory limit.
ob_bnl_join_cache_size	Specifies the amount of data cached in the Batch Nest Loop Join cache for each batch.
stored_program_cache	Specifies the number of stored procedures and functions to cache. The default value is `256`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
table_definition_cache	Specifies the number of memory spaces allocated to cache table definitions. The default value is `-1`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
table_open_cache_instances	Specifies the number of table cache instances to open. The default value is `16`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Functions

Variable name	Description
interactive_timeout	Specifies the number of seconds the server waits for activity before closing an interactive connection.
wait_timeout	Specifies the number of seconds the server waits for activity before closing a noninteractive connection.
group_concat_max_len	Specifies the maximum length of the result of the `GROUP_CONCAT()` function.

InnoDB storage engine

Variable	Description
innodb_change_buffering_debug	The debug level for setting the change buffer of InnoDB. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_compress_debug	The debug level for adjusting and controlling the compression behavior. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_disable_resize_buffer_pool_debug	Whether to enable the size adjustment of the InnoDB buffer pool. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_fil_make_page_dirty_debug	The debug level for dirtying the specified number of pages in InnoDB. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_limit_optimistic_insert_debug	The number of records per B-tree page. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_merge_threshold_set_all_debug	The percentage of full pages of an index. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_saved_page_number_debug	The number of pages saved in InnoDB for debugging. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_trx_purge_view_update_only_debug	The debug level for controlling whether to only update the purge view during transaction cleanup. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_trx_rseg_n_slots_debug	The number of slots in a transaction rollback segment. Each slot stores the rollback information of a transaction. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_stats_persistent	Whether to persist the statistics of InnoDB indexes to the disk.
innodb_force_recovery	The crash recovery mode for repairing the data of the InnoDB storage engine. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
innodb_replication_delay	The extended time of replication threads on the replica server when the value of the `innodb_thread_concurrency` variable is reached. The unit is milliseconds. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_large_prefix	Whether to allow an index key prefix longer than 767 bytes (up to 3072 bytes) for an InnoDB table that uses the DYNAMIC or COMPRESSED row format. The default value is `ON`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_sort_buffer_size	The size of the buffer for sorting operations. The default value is `1048576`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
default_tmp_storage_engine	The default temporary table storage engine. The default value is `InnoDB`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_tmpdir	The directory for storing temporary files of InnoDB. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
mecab_rc_file	The path of the MeCab configuration file. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
innodb_temp_data_file_path	The path for temporary data files used by InnoDB. The default value is `ibtmp1:12M:autoextend`, which indicates that InnoDB will use a temporary data file named ibtmp1 with an initial size of 12 MB, and this file will automatically expand as needed to store additional temporary data. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_data_file_path	The path and filename for InnoDB data files. The default value is `ibdata1:12M:autoextend`, which indicates that InnoDB will use a temporary data file named ibdata1 with an initial size of 12 MB, and this file will automatically expand as needed to store additional temporary data. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_data_home_dir	The root directory for InnoDB data files. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_read_only	Whether to start InnoDB in read-only mode. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_rollback_on_timeout	Whether to abort and roll back the entire transaction when a transaction times out. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_api_disable_rowlock	Whether to disable row locks when InnoDB memcached executes DML operations. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_autoinc_lock_mode	The locking mode for generating auto-increment values. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
low_priority_updates	Whether to control the priority of INSERT, UPDATE, DELETE, and REPLACE statements. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
max_error_count	The maximum number of errors, warnings, and notifications that can be stored in the diagnostic context. The default value is `64`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
max_insert_delayed_threads	The maximum number of threads for executing INSERT DELAYED statements. The default value is `20`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_disable	This variable acts as a switch to control which metrics counters to disable. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_enable	This variable acts as a switch to control which metrics counters to enable. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_reset	This variable acts as a switch to control which metrics counters to reset to 0. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_reset_all	This variable acts as a switch to control which metrics counters to reset to 0. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_old_blocks_pct	The approximate percentage of the old data blocks in the InnoDB buffer pool. The default value is `37`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_old_blocks_time	The time that a block must stay in the old sublist after its first access before it can be moved to the new sublist, in milliseconds. The default value is `1000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_purge_batch_size	The number of undo log pages to parse and process at a time from the history list. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_purge_rseg_truncate_frequency	This variable specifies how often to truncate rollback segments. The default value is `128`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_random_read_ahead	This variable specifies whether to enable random read-ahead for InnoDB I/O. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_read_ahead_threshold	This variable specifies the number of pages that must be read sequentially from a segment before asynchronous reads from the next segment are initiated. The default value is `56`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_rollback_segments	This variable specifies the number of rollback segments used to generate undo records. The default value is `128`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_spin_wait_delay	This variable specifies the interval between spin lock waits. The default value is `6`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_status_output	This variable specifies whether to enable or disable the regular output of the standard InnoDB monitor. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_status_output_locks	This variable specifies whether to enable or disable InnoDB lock monitoring. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_sync_spin_loops	This variable specifies the number of times a thread waits before being suspended when an InnoDB mutex is released. The default value is `30`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
internal_tmp_disk_storage_engine	This variable specifies the storage engine for temporary tables on disk. The default value is `INNODB`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_fast_shutdown	This variable specifies the shutdown mode for the InnoDB engine. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_io_capacity	This variable specifies the approximate number of IOPS that can be executed by background tasks per second. The default value is `200`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_io_capacity_max	This variable specifies the maximum number of IOPS that can be executed by background tasks per second in an emergency. The default value is `2000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_thread_concurrency	This variable specifies the maximum number of threads allowed in InnoDB. The default value is `0`, which indicates no limit. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_thread_sleep_delay	This variable specifies the time in microseconds that an InnoDB thread sleeps before being added to the InnoDB wait queue. The default value is `10000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_adaptive_hash_index_parts	This variable specifies the number of partitions in the adaptive hash index search system. The default value is `8`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
innodb_numa_interleave	This variable specifies whether to enable the NUMA interleaving memory policy for allocating buffer pool memory. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
innodb_open_files	This variable specifies the maximum number of files that can be opened at a time. The default value is `2000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
innodb_page_cleaners	The number of threads for flushing dirty pages in the buffer pool. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_purge_threads	The number of background threads for purging. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_read_io_threads	The number of I/O threads for reading. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_sync_array_size	The size of the mutex/lock wait array. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_use_native_aio	Whether to use the Linux asynchronous I/O subsystem. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_write_io_threads	The number of I/O threads for writing. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_api_enable_binlog	Whether to allow the InnoDB Memcached plugin to be used with MySQL binlogs. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_locks_unsafe_for_binlog	This variable affects how InnoDB uses gap locks for searches and index scans. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_buffer_size	The size of the InnoDB transaction log buffer, in bytes. The default value is `16777216`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_files_in_group	The number of log files in the log group. The default value is `2`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_file_size	The size of each log file in the log group, in bytes. The default value is `50331648`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_group_home_dir	The directory path for InnoDB redo logs. The default value is `./`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_undo_directory	The directory for the undo tablespaces created by InnoDB. The default value is `./`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_undo_tablespaces	The number of undo tablespaces available to InnoDB. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.

Variable name	Description
json_float_full_precision	Controls the precision mode for parsing JSON numbers.

Variable	Description
ob_capability_flag	Indicates the capabilities of an OBServer node. This variable is used for capability negotiation with the Proxy. It specifies which features are supported and which are not supported by the OBServer node.
ob_compatibility_mode	Specifies the compatibility mode of a tenant.
ob_route_policy	Specifies the routing policy for selecting data replicas within an OBServer node.
performance_schema	Specifies whether to support queries for performance information. The default value is `OFF`. Note This variable is for compatibility with MySQL 8.0. The related features are not supported. You can query and set this variable, but the settings do not take effect.
resource_manager_plan	Activates the resource management plan. Different plans use different CPU quotas to limit user activities in resource groups.
license	Displays the type of the license.
ob_proxy_partition_hit	Specifies whether to send SQL requests for data to the OBServer node where the data leader partition is located.
ob_org_cluster_id	Specifies the `CLUSTER_ID` of the OceanBase cluster.
server_uuid	Displays the UUID of the OBServer node.
default_storage_engine	Displays the default storage engine of the OBServer node.
slave_allow_batching	Specifies whether to enable batch updates for the replication thread. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.

Variable	Description
datadir	Displays the local disk path for storing data.
plugin_dir	Displays the path for storing plugin DLLs.
secure_file_priv	Specifies the path that can be accessed when importing or exporting data to a file.
ob_enable_hash_group_by	Specifies whether to enable the Hash Group by feature.

MyISAM storage engine

Variable	Description
delay_key_write	Specifies whether to delay the write of index keys for MyISAM tables. The default value is `ON`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_buffer_size	Specifies the size of the key buffer for the MyISAM storage engine. The default value is `8388608`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_cache_age_threshold	Specifies the threshold for degrading a buffer from the hot sub-list to the warm sub-list in the key cache. A lower value means a faster degradation. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_cache_block_size	Specifies the size of a single block in the MyISAM key cache. The default value is `1024`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_cache_division_limit	Specifies the division limit for the MyISAM key cache. The default value is `100`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
max_seeks_for_key	Specifies the maximum number of seek operations in a MyISAM query. The default value is `18446744073709551615`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
skip_external_locking	Specifies whether to disable the external locking mechanism for MyISAM tables. The default value is `ON`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Temporary files

Variable	Description
max_tmp_tables	Specifies the maximum number of temporary tables that can be held in a user session. The default value is `32`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.

Memory

Variable	Description
ob_sql_work_area_percentage	Specifies the percentage of memory allocated for SQL execution.
ob_sql_audit_percentage	Specifies the percentage of memory allocated for SQL audit.
ob_reserved_meta_memory_percentage	Specifies the percentage of memory reserved for tenants, primarily for storing meta-related structures.
ob_temp_tablespace_size_percentage	Specifies the percentage of memory allocated for temporary tablespaces in the tenant's disk.

NDB storage engine

Variable name	Description
ndb_allow_copying_alter_table	Specifies whether to allow the `ALTER TABLE` statement and other DDL statements to use copy operations on tables. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_autoincrement_prefetch_sz	Specifies the number of auto-increment values to be prefetched. This value can affect the performance and concurrent access capability of auto-increment columns. The default value is `1`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_blob_read_batch_bytes	Specifies the size of BLOB data to be read in batches in an NDB Cluster. The unit is bytes. The default value is `65536`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_blob_write_batch_bytes	Specifies the size of BLOB data to be written in batches in an NDB Cluster. The unit is bytes. The default value is `65536`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_cache_check_time	Specifies the interval, in milliseconds, at which to check whether the cache needs to be refreshed on each NDB node. The default value is `0`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_clear_apply_status	Specifies whether to clear the application status. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_data_node_neighbour	Defines the neighbor relationships of data nodes. The default value is `0`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_default_column_format	Defines the default column format for tables, whether to store them in fixed-length or variable-length format. The default value is `FIXED`, indicating fixed-length storage. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_deferred_constraints	Controls whether to delay constraint checks on tables. The default value is `0`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_distribution	Specifies the default distribution method for NDB tables, whether to partition by hash key values or by linear hash. The default value is `KEYHASH`, indicating hash key value partitioning. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_eventbuffer_free_percent	Specifies the percentage of free space in the event buffer of an NDB Cluster. The default value is `20`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_eventbuffer_max_alloc	Specifies the maximum size of memory that can be allocated for the event buffer, in bytes. The default value is `0`, indicating no limit. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_extra_logging	Specifies whether to log specified NDB storage engine information to the MySQL error log. The default value is `1`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_force_send	Specifies whether to immediately send the cache to NDB without waiting for other threads. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_fully_replicated	Specifies whether to fully replicate new tables. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_index_stat_enable	Specifies whether to enable the NDB index statistics collection feature. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_index_stat_option	Specifies the options for generating NDB index statistics. The default value is `loop_checkon=1000ms,loop_idle=1000ms,loop_busy=100ms,update_batch=1,read_batch=4,idle_batch=32,check_batch=32,check_delay=1m,delete_batch=8,clean_delay=0,error_batch=4,error_delay=1m,evict_batch=8,evict_delay=1m,cache_limit=32M,cache_lowpct=90`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_join_pushdown	Specifies whether to enable the join pushdown optimization feature in the storage engine. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_binlog_index	Specifies whether to insert the mapping of epochs to binlog positions into the ndb_binlog_index table. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_empty_epochs	Specifies whether to write unchanged epoch transactions to the binlog. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_empty_update	Specifies whether to write unchanged update transactions to the binlog. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_exclusive_reads	Specifies whether to use an exclusive lock for reading primary keys. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_update_as_write	Specifies whether to write updates to the binlog as updates (OFF) or writes (ON). The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_update_minimal	Specifies the log recording behavior of NDB Cluster. If the value is `ON`, NDB Cluster records only the minimal information of update operations. If the value is `OFF`, NDB Cluster records the entire row changes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_updated_only	Specifies whether to write only the updated rows or the entire rows to the binlog when Mysqld writes updates to the binlog. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_optimization_delay	Specifies the wait time between groups of rows when using the OPTIMIZE TABLE statement on an NDB table, in microseconds. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_read_backup	Specifies whether to allow reading data from any fragment of any NDB table created after this variable is set. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_recv_thread_activation_threshold	Specifies the activation threshold for receive threads. The default value is `8`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_recv_thread_cpu_mask	Specifies the CPU mask for receive threads. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_report_thresh_binlog_epoch_slip	Specifies the maximum allowed size of a binlog timestamp jump before a report is generated. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_report_thresh_binlog_mem_usage	Specifies the percentage threshold of the remaining available memory for binlog before a report is sent. When the remaining available memory for binlog is less than this value, a report is sent. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_row_checksum	Specifies the checksum value for table rows. When the value is `1`, the checksum values for all rows are calculated and saved. When the value is `0`, the checksum detection for table rows is not performed. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_show_foreign_key_mock_tables	Specifies whether to display mock tables for foreign key dependencies. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_slave_conflict_role	Specifies the role of the node in a circular replication (master-master) setup. The default value is `NONE`, indicating that the role is undefined or not configured. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_table_no_logging	Controls the logging behavior for NDB tables. When the value is `ON`, all tables created or modified using the NDB storage engine are in a no-logging state. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_table_temporary	Specifies the behavior of temporary tables when using the NDB storage engine. When the value is `ON`, NDB tables are not written to disk. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_use_exact_count	Specifies whether to force NDB to use record counts to accelerate `SELECT count(*)` queries. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_use_transactions	Controls whether to enable NDB transaction support. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_max_bytes	Only for testing and debugging. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_max_rows	Only for testing and debugging. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_offline	Specifies whether to set the `ndbinfo` database to offline mode. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_show_hidden	Specifies whether to display the underlying internal tables of the `ndbinfo` database in the MySQL client. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_data_pointer_size	Specifies the default pointer size, in bytes, for MyISAM tables created without the `MAX_ROWS` option. The default value is `6`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_max_sort_file_size	Specifies the maximum size of the temporary files allowed during MyISAM index recreation (in `REPAIR TABLE`, `ALTER TABLE`, or `LOAD DATA` operations), in bytes. The default value is `9223372036853720064`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_repair_threads	Specifies the number of concurrent threads for repairing MyISAM tables. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_sort_buffer_size	The size of the buffer allocated for sorting MyISAM indexes during the REPAIR TABLE operation or when creating indexes with CREATE INDEX (or ALTER TABLE), in bytes. The default value is `8388608`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
myisam_stats_method	The method for calculating NULL values when collecting statistical information about the distribution of index values in MyISAM tables. The default value is `nulls_unequal`, which treats NULL values as regular values and handles them the same as other values. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
myisam_use_mmap	Whether to use memory mapping for reading and writing MyISAM tables. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
server_id_bits	The number of least significant bits in the 32-bit server_id that actually identify the server. The default value is `32`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Full-text index

Variable	Description
innodb_ft_enable_diag_print	Enables or disables diagnostic output for InnoDB full-text indexes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_num_word_optimize	Specifies the minimum number of words to optimize during an OPTIMIZE TABLE operation. The default value is `2000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_result_cache_limit	Specifies the size of the InnoDB full-text index result cache. The default value is `2000000000`, in bytes. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_server_stopword_table	Specifies the server stopword table for InnoDB full-text indexes. The default value is `NULL`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_optimize_fulltext_only	Controls the behavior of the OPTIMIZE TABLE statement on InnoDB tables with FULLTEXT indexes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_cache_size	Specifies the size of the InnoDB full-text index cache. The default value is `8000000`, in bytes. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.
innodb_ft_sort_pll_degree	Specifies the number of parallel threads for full-text index sorting. The default value is `2`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.
innodb_ft_total_cache_size	Specifies the total size of the InnoDB full-text index cache. The default value is `640000000`, in bytes. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.
ft_stopword_file	Specifies the file path for stopword processing. The default value is `built-in`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.

Runtime Filter

Variable	Description
runtime_filter_type	Specifies the Runtime Filter type at the tenant level.
runtime_filter_wait_time_ms	Specifies the maximum wait time for Runtime Filters.
runtime_filter_max_in_num	Specifies the number of distinct values (NDV) for Runtime In Filters.
runtime_bloom_filter_max_size	Specifies the maximum memory usage for Runtime Bloom Filters, in bytes.

Upgrade

Variable	Description
avoid_temporal_upgrade	Manages the upgrade behavior for temporal data (such as dates and times). The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.

Time zones and dates

Name	Description
time_zone	The time zone used by the current tenant session. The value can be specified in offset format, such as `'+08:00'`, or region format, such as `Asia/Shanghai`.
timestamp	`TIMESTAMP` is a timestamp in seconds, and it affects the result of `SELECT NOW(6)`.
system_time_zone	Specifies the system time zone for the server.
error_on_overlap_time	Specifies whether to return an error if a timestamp is ambiguous in a time zone with overlapping daylight saving time changes.
nls_language	The default language in the database's internationalization (NLS) settings, used for prompts, dates, month names, and as the default value for `NLS_SORT` and `NLS_DATE_LANGUAGE`.
nls_territory	The current territory, which is used in conjunction with `nls_language`.
nls_date_language	Specifies the default language for dates in the database's internationalization support.
nls_calendar	Used to specify the calendar system to be used by the database.
ob_timestamp_service	Specifies the timestamp service to use.

Transactions and transaction logs

Variable name	Description
autocommit	Specifies whether to auto-commit a transaction.
tx_isolation	Specifies the transaction isolation level.
ob_proxy_set_trx_executed	Specifies whether a user sends the `START TRANSACTION` statement to the OBServer through the ODP.
ob_early_lock_release	This variable specifies whether to enable the early lock release (ELR) feature. Note This variable is deprecated starting from V2.2.30. The ELR feature is now controlled by the tenant-level parameter `enable_early_lock_release`.
ob_trx_idle_timeout	The transaction idle timeout. After an interval exceeds the timeout value, it is considered that the transaction is idle and the transaction is considered to be timed out.
transaction_isolation	Sets the transaction isolation level.
transaction_read_only	Specifies whether a read-only transaction is allowed.
ob_trx_lock_timeout	Used to set the wait timeout for transactions.
tx_read_only	Specify whether a transaction is read-only.
ob_trx_timeout	This variable specifies the transaction timeout.
ob_trace_info	This variable is used to pass trace information, which will ultimately be persistently written to the REDO log.
gtid_executed	Stores the set of committed transactions and the GTID specified by the statement. The default value is `NULL`. Note This variable is retained for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot modify its value.
gtid_owned	This variable stores the list of GTID values of current transactions and the IDs of the threads that own them. The default value is `NULL`. Note This variable is compatible with MySQL 5.7 only. You can query its value but cannot set it.

Name	Description
ob_enable_sql_audit	Specifies whether to enable SQL Audit for the current tenant.

Data types

Variable	Description
nls_length_semantics	Specifies the length semantics of the CHAR and VARCHAR2 data types.
nls_nchar_conv_excp	Specifies whether to return an error when data is lost during the conversion between NCHAR/NVARCHAR2 and CHAR/VARCHAR2 data types.
nls_numeric_characters	Specifies the decimal and thousand separators used during the conversion between numbers and strings.
nls_currency	Specifies the local currency symbol for the `L` element in the number format.
nls_iso_currency	Specifies the local currency symbol for the `C` element in the number format.
nls_dual_currency	Specifies the local currency symbol for the `U` element in the number format.
nls_date_format	Specifies the format for converting a date to a string and for implicitly converting a string to a date.
nls_timestamp_format	Specifies the format for converting a TIMESTAMP or TIMESTAMP_LTZ value to a string and for implicitly converting a string to a TIMESTAMP or TIMESTAMP_LTZ value.
nls_timestamp_tz_format	Specifies the format for converting a TIMESTAMP_TZ value to a string and for implicitly converting a string to a TIMESTAMP_TZ value.
explicit_defaults_for_timestamp	Specifies whether to enable nonstandard behavior for the TIMESTAMP data type when handling default values and NULL values.
log_row_value_options	Specifies whether to enable partial updates for LOB data.
ob_default_lob_inrow_threshold	Specifies the default in-row storage threshold for LOB fields when creating a table.

Variable	Description
connect_timeout	Specifies the connection timeout.
ob_pl_block_timeout	Specifies the maximum timeout for PL.
cursor_sharing	Specifies whether to parameterize SQL statements.
have_profiling	Indicates whether to enable query performance analysis. The default value is `NO`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
profiling	Specifies whether to enable statement analysis. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
profiling_history_size	Specifies the number of query performance records to be saved. The default value is `15`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
innodb_strict_mode	Specifies the SQL syntax check mode.
max_connections	Specifies the maximum number of connections for a tenant.
sql_mode	Specifies the SQL mode. Different SQL modes have a significant impact on behaviors such as insertions.
sql_quote_show_create	Specifies whether to enable quoting identifiers in `SHOW CREATE TABLE` and `SHOW CREATE DATABASE` statements.
ob_enable_rich_error_msg	Specifies whether to display information such as svr_ip, time, and trace_id when an error occurs during SQL execution.
sql_throttle_current_priority	Specifies the throttling priority. Requests from sessions where `sql_throttle_current_priority` is less than `sql_throttle_priority` will be throttled.
sql_throttle_priority	Specifies the throttling priority.
sql_throttle_rt	Specifies the RT value.
max_allowed_packet	Specifies the maximum size of a network packet.
max_user_connections	Specifies the maximum number of connections that a single user can establish with an OBServer node. A value of `0` indicates no limit.
max_sp_recursion_depth	Specifies the maximum number of nested calls to a specified stored procedure.
sql_select_limit	Specifies the maximum number of rows that a SELECT query can return.
max_connections	Specifies the maximum number of connections for a tenant.
ob_enable_blk_nestedloop_join	Specifies whether to enable block nested loop joins.
parallel_max_servers	Specifies the maximum number of threads in the parallel execution (PX) thread pool on each server.
sql_transpiler	Specifies whether to enable the SQL Transpiler feature. Note This variable is available starting with V4.4.2 of OceanBase Database V4.4.x.
plsql_can_transform_sql_to_assign	Specifies whether to allow `select into from dual` statements in PL/SQL to be rewritten as `assign` statements.

System logs

Variable	Description
binlog_row_image	Controls whether to record full-column logs.
ob_enable_show_trace	Specifies whether to use trace logs.
ob_log_level	Specifies the log level at the session level. If not specified, the system log level is used.
tracefile_identifier	Specifies the content to be added to the log to facilitate the filtering of row iteration trace logs.
master_verify_checksum	Specifies whether to enable checksum verification. The default value is `OFF`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting does not take effect.
log_statements_unsafe_for_binlog	Specifies whether to record error code 1592 information to the error log. The default value is `1`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting does not take effect.
binlog_gtid_simple_recovery	Controls how the server iterates through binlog files during GTID search when it starts or restarts. The default value is `1`, which means that the values of `gtid_executed` and `gtid_purged` are calculated based on the values of `previous_gtids_log_event` in the latest and oldest binlog files at startup. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
log_bin_basename	The full path of the binlog file. The default value is `null`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
log_bin_index	The name and path of the binlog index file. The default value is `null`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
log_slave_updates	Specifies whether the replica server records updates received from the primary server's binlog to its own binlog. The default value is `OFF`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Server variables

Variable name	Description
preload_buffer_size	The size of the buffer used for preloading indexes. The unit is bytes. The default value is `32768`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
read_buffer_size	The size of the buffer used for reading data. The unit is bytes. The default value is `131072`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
read_rnd_buffer_size	The size of the buffer used for reading data from MyISAM tables and for multi-range read optimization for any storage engine. The unit is bytes. The default value is `262144`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
sync_frm	Whether to synchronize the metadata of InnoDB tables to the `.frm` files on the disk. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
keep_files_on_create	When you do not use the `DATA DIRECTORY` or `INDEX DIRECTORY` option to specify the location of data files or index files, this variable specifies whether to retain existing files in the corresponding directory when you create a MyISAM table. The default value is `OFF`, which indicates to overwrite existing files. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
max_heap_table_size	The maximum size to which a memory table can grow. The unit is bytes. The default value is `16777216`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
bulk_insert_buffer_size	The size of the buffer used for bulk insert operations. The unit is bytes per thread. The default value is `8388608`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
general_log_file	The name of the file to store general query logs. The default value is `host_name.log`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
host_cache_size	The size of the host cache. The default value is `279`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_error_verbosity	The level of detail to include in error logs. The default value is `3`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_output	The output destination for general query logs and slow query logs. The default value is `FILE`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_queries_not_using_indexes	Whether to record queries that do not use indexes to the slow query log. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_slow_admin_statements	Whether to record slow administrative statements such as ALTER TABLE, ANALYZE TABLE, CHECK TABLE, CREATE INDEX, DROP INDEX, OPTIMIZE TABLE, and REPAIR TABLE to the slow query log. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_syslog	Whether to record error logs to the system log. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_syslog_facility	The tool for writing error logs to the system log. The default value is `daemon`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_syslog_include_pid	Whether to write the process ID of the service process in the error log output to the system log. The default value is `1`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_syslog_tag	The label to be added to the server identifier in the error log output written to the system log. The default value is `null`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_throttle_queries_not_using_indexes	The maximum number of statements written to the slow query log per minute. The default value is `0`, indicating no limit. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_timestamps	The timezone for the timestamps of error logs, general logs, and slow query logs written to files. The default value is `UTC`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_warnings	The record level for additional warning information in the error log. The default value is `2`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
max_delayed_threads	The maximum number of threads that can be created to process INSERT DELAYED statements. The default value is `20`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
offline_mode	Whether to set the server to offline mode. The default value is `0`, indicating that the server is not set to offline mode. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
require_secure_transport	Whether to use a secure transport for the connection between the client and the server. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
slow_launch_time	The time in seconds that a thread takes to create. If this time exceeds the value of this variable, the value of the Slow_launch_threads status variable increases. The default value is `2`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
sql_log_off	Whether to enable (OFF) or disable (ON) the general query log for the current session. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_cache_size	The maximum number of threads that can be cached. The default value is `9`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_high_priority_connection	Whether to reserve idle threads for high-priority connections in the thread pool. The default value is `0`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_max_unused_threads	The maximum number of unused threads in the thread pool. The default value is `0`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_prio_kickup_timer	The time in milliseconds that a statement waits before being moved to the high-priority queue. The default value is `1000`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_stall_limit	The time in 10 milliseconds that a statement must complete after it starts execution. The default value is `6`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
have_statement_timeout	Whether to enable the statement timeout feature. The default value is `ON`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it.
old	A compatibility variable for resolving compatibility issues. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
version_tokens_session_number	An internal variable. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
back_log	The maximum number of connections that can be stored in the connection request queue when the server is processing connection requests. The default value is `80`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
basedir	The path of the installation root directory. The default value is `/usr/local/mysql/`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
bind_address	The IP address to which the server binds when it listens for TCP/IP client connections. The default value is `*`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
core_file	Whether to generate a core file before the server exits when a fatal error occurs. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
have_compress	Whether the zlib compression library required for the COMPRESS() and UNCOMPRESS() functions is available. The default value is `ON`, indicating that it is available. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
ignore_db_dirs	A comma-separated list of names that are not considered database directories in the data directory. The default value is `null`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
init_file	The name of a file that contains SQL statements to be executed when the server starts. The default value is `null`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
large_files_support	Whether the server supports handling large files. The default value is `1`, indicating that it supports handling large files. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
large_pages	Whether to enable support for large pages. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
large_page_size	If large page support is enabled, this variable specifies the size of memory pages in bytes. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
locked_in_memory	Whether the server is locked in memory. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
log_error	The output destination of the error log file. The default value is `./obrd.16c.vd3-s2h6-n3.err`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
named_pipe	Whether to allow clients to connect to the server using named pipes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
named_pipe_full_access_group	When named pipe connections are supported, the Windows user group that has permission to use named pipe connections. The default value is `empty string`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
open_files_limit	The number of file descriptors available to the server. The default value is `655360`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
shared_memory	Specifies whether to allow clients to connect by using shared memory. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
shared_memory_base_name	Specifies the name of the shared memory used for shared memory connections. The default value is `MYSQL`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
skip_name_resolve	Specifies whether to resolve hostnames during client connection checks. The default value is `OFF`, which means that hostnames must be resolved. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
skip_networking	Specifies whether to allow TCP/IP connections. The default value is `OFF`, which means that TCP/IP connections are disabled. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_handling	Specifies the thread model used by the server to handle client connections. The default value is `one-thread-per-connection`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_pool_algorithm	Specifies the algorithm used by the thread pool plugin. The default value is `0`, which means that the conservative low-concurrency algorithm is used. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_pool_size	Specifies the number of thread groups in the thread pool. The default value is `16`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_stack	Specifies the size of the stack for each thread. The default value is `262144`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
tls_version	Specifies the protocols that the server allows for encrypted connections. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.

X Plugin

Variable name	Description
mysqlx_bind_address	Specifies the network address on which the X plugin listens for TCP/IP connections. The default value is `*`, which means that all TCP/IP connections from all server hosts are accepted. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_port	Specifies the network port on which the X plugin listens for TCP/IP connections. The default value is `33060`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_port_open_timeout	Specifies the time in seconds that the X plugin waits for a TCP/IP port to become idle. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_socket	Specifies the path to the Unix socket file used by the X plugin. The default value is `/tmp/mysqlx.sock`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_ca	Specifies the path to the SSL certificate authority (CA) file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_capath	Specifies the directory path to the SSL certificate authority (CA) certificate file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_cert	Specifies the path to the SSL certificate file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_cipher	Specifies the list of encryption algorithms used for SSL encryption by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_crl	Specifies the filename of the certificate revocation list (CRL) file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_crlpath	Specifies the directory path to the certificate revocation list (CRL) file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_key	Specifies the path to the SSL certificate key file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.

Performance schema

Variable name	Description
performance_schema_accounts_size	Specifies the number of rows in the `accounts` table. The default value is `-1`, indicating automatic scaling. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_digests_size	Specifies the maximum number of rows in the `events_statements_summary_by_digest` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_stages_history_long_size	Specifies the number of rows in the `events_stages_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_stages_history_size	Specifies the number of rows for each thread in the `events_stages_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_statements_history_long_size	Specifies the number of rows in the `events_statements_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_statements_history_size	Specifies the number of rows for each thread in the `events_statements_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_transactions_history_long_size	Specifies the number of rows in the `events_transactions_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_transactions_history_size	Specifies the number of rows for each thread in the `events_transactions_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_waits_history_long_size	Specifies the number of rows in the `events_waits_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_waits_history_size	Specifies the number of rows for each thread in the `events_waits_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_hosts_size	Specifies the number of rows in the `hosts` table. The default value is `-1`, indicating automatic scaling. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_cond_classes	Specifies the maximum number of condition collectors. The default value is `80`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_cond_instances	Specifies the maximum number of condition objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_digest_length	Specifies the maximum length of a standardized SQL statement in bytes when it is stored in the performance schema. The default value is `1024`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_file_classes	Specifies the maximum number of file collectors. The default value is `80`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_file_handles	The maximum number of file objects that can be opened. The default value is `32768`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_file_instances	The maximum number of file objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_index_stat	The maximum number of indexes in the statistics maintained by the Performance Schema. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_memory_classes	The maximum number of memory collectors. The default value is `320`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_metadata_locks	The maximum number of metadata lock collectors. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_mutex_classes	The maximum number of mutex collectors. The default value is `200`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_mutex_instances	The maximum number of mutex objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_prepared_statements_instances	The maximum number of rows in the `prepared_statements_instances` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_program_instances	The maximum number of stored programs in the statistics maintained by the Performance Schema. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_rwlock_classes	The maximum number of rwlock collectors. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_rwlock_instances	The maximum number of rwlock objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_socket_classes	The maximum number of socket collectors. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_socket_instances	The maximum number of socket objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_sql_text_length	The maximum length of SQL statements that can be stored in the `SQL_TEXT` column of the `events_statements_current`, `events_statements_history`, and `events_statements_history_long` statement event tables, in bytes. The default value is `1024`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_stage_classes	The maximum number of stage collectors. The default value is `150`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_statement_classes	The maximum number of statement collectors. The default value is `193`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_statement_stack	The maximum depth of nested stored program calls in the statistics maintained by the Performance Schema. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_table_handles	The maximum number of table objects that can be opened. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_table_instances	The maximum number of table objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_table_lock_stat	The maximum number of tables in lock statistics maintained by the Performance Schema. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_thread_classes	The maximum number of thread collectors. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_thread_instances	The maximum number of thread objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_session_connect_attrs_size	The preallocated memory size, in bytes, for storing connection attribute key-value pairs for each thread. The default value is `512`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_setup_actors_size	The number of rows in the `setup_actors` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_setup_objects_size	The number of rows in the `setup_objects` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_users_size	The number of rows in the `users` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.

Variable	Description
metadata_locks_cache_size	The size of the metadata lock cache. The default value is `1024` bytes. Note This variable is available only for MySQL 5.7 compatibility. The related features are not supported. You can query the variable but cannot set it.
metadata_locks_hash_instances	The number of instances of the metadata lock hash table. The default value is `8`. Note This variable is available only for MySQL 5.7 compatibility. The related features are not supported. You can query the variable but cannot set it.

Variable	Description
foreign_key_checks	Specifies whether to check foreign key constraints in DML/DDL operations.

Variable	Description
mview_refresh_dop	Specifies the default refresh parallelism for materialized views.

Variable	Description
optimizer_use_sql_plan_baselines	Specifies whether to use the Plan Baseline plan.
optimizer_capture_sql_plan_baselines	Specifies whether to automatically capture new plans to the Plan Baseline.
parallel_degree_policy	Specifies the parallelism selection strategy.
parallel_degree_limit	Specifies the upper limit of the parallelism selected by the optimizer when the Auto DOP strategy is used.
parallel_min_scan_time_threshold	Specifies the minimum evaluation execution time for parallel processing of base table scans.
optimizer_dynamic_sampling	Specifies the level of dynamic sampling.
optimizer_features_enable	Enables the optimizer features of different OceanBase Database versions.
ob_enable_transformation	Specifies whether to enable the rewrite feature of the SQL optimizer.
ob_table_access_policy	Controls the optimizer to prioritize a specific storage format when generating base table plans.

Variable	Description
auto_increment_increment	Specifies the auto-increment step size. This variable is available only for MySQL clients.
auto_increment_offset	Specifies the starting value of the `AUTO_INCREMENT` column.
last_insert_id	Returns the last auto-increment value inserted in the current session.
identity	`identity` and the `last_insert_id` variable are synonyms. You can query `identity` by executing the `select @@identity` statement.
sql_auto_is_null	Specifies whether to retrieve the auto-increment value of the last inserted row.
auto_increment_cache_size	Specifies the number of auto-increment values cached.
div_precision_increment	Specifies the increment of the precision of the result of a division operation based on the precision of the dividend. This is a MySQL compatibility feature.

Character sets and strings

Variable name	Description
character_set_client	The character set for statements sent from the client.
character_set_connection	The character set to be converted after receiving a statement.
character_set_database	The character set for the default database.
character_set_results	The character set to be converted before sending the result set or error message back to the client.
character_set_server	The character set for the server.
character_set_system	The character set used by the server.
collation_connection	The character set and collation for the connection.
collation_database	The default character set and collation for the database.
collation_server	The default character set and collation for the server.
character_set_filesystem	The character set type for the file system.
sql_warnings	Whether to generate information strings for single-row INSERT statements when warnings occur.
init_connect	The string to be executed by the server for each client connection, consisting of one or more SQL statements separated by semicolons.
nls_sort	The collation for string values.
nls_comp	The comparison rule for string values.
nls_characterset	The default character set for data types such as CHAR, VARCHAR2, and CLOB in the database.
nls_nchar_characterset	The default character set for data types such as NCHAR, NVARCHAR2, and NCLOB.

Group replication

Variable name	Description
group_replication_allow_local_disjoint_gtids_join	Specifies whether to allow a server to join a group if it has local transactions not present in the group. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_allow_local_lower_version_join	Specifies whether to allow a server to join a group if the MySQL Server version on the server is lower than that on other members of the group. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_auto_increment_increment	Specifies the increment value for the auto-increment column of each member in the replication group. This ensures that the auto-increment column values are ordered and do not overlap in a multi-primary group. The default value is `7`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_bootstrap_group	Specifies whether to use the current server to bootstrap the group. This variable can only be set on one server and can only be set when bootstrapping the group for the first time or re-bootstrapping the group. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_components_stop_timeout	Specifies the timeout in seconds for each component during group replication shutdown. The default value is `2`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_compression_threshold	Specifies the threshold for message compression between group members. Messages will be compressed if the threshold is exceeded. The default value is `1000000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_enforce_update_everywhere_checks	Specifies whether to enable or disable strict consistency checks for multi-primary updates at any time. The default value is `OFF`, which disables the checks. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_exit_state_action	Specifies the behavior of group replication when a server instance leaves the group due to an exception. The default value is `READ_ONLY`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_flow_control_applier_threshold	Specifies the number of transactions waiting in the application queue that triggers flow control. The default value is `25000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_flow_control_certifier_threshold	Specifies the number of transactions waiting in the certifier queue that triggers flow control. The default value is `25000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_flow_control_mode	Specifies the mode for flow control. The default value is `QUOTA`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_force_members	Specifies the list of member addresses in the format `host1:port1,host2:port2`. This variable is used to forcibly establish a new group. After setting this variable, excluded members (those not specified in the variable) will not receive new view messages and will be blocked (write operations will be blocked). The default value is empty. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_group_name	Specifies the name of the group replication group to which the current server belongs. The default value is empty. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_group_seeds	Specifies the list of seed member addresses in the format `host1:port1,host2:port2`. The default value is empty. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_gtid_assignment_block_size	The number of consecutive GTIDs to be reserved for each member. The default value is `1000000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_ip_whitelist	The list of hosts (IP addresses or host names) that are allowed to connect to the group. The allowed hosts are called the whitelist. The default value is `AUTOMATIC`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_local_address	The network address used by a group replication member to provide access to other members in the group. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_member_weight	The percentage weight of a group member, which affects the chance of the member being selected as the primary node during a failover (only applicable to groups in single-primary mode). In a group in single-primary mode, when the primary node leaves the group, the member with the higher weight is prioritized to be selected as the new primary node. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_poll_spin_loops	The number of times the group replication communication thread waits for the communication engine mutex to be released before waiting for more incoming network messages. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_complete_at	The strategy for applying cached transactions after the status transmission is completed in a distributed recovery. The default value is `TRANSACTIONS_APPLIED`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_reconnect_interval	The interval, in seconds, between reconnection attempts to find an available donor when a new server cannot find an available donor during distributed recovery. The default value is `60`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_retry_count	The number of times to retry connecting to find an available donor when a new server cannot find an available donor during distributed recovery. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_ca	The path to the file containing the list of trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_capath	The directory path to the trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_cert	The name of the SSL certificate file for establishing a secure connection for distributed recovery. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_cipher	The list of allowed encryption algorithms for SSL encryption. The available encryption algorithms depend on the version of the SSL library used to compile the MySQL Server. Different SSL libraries support different encryption algorithms. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_crl	The name of the file containing the certificate revocation list. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_crlpath	The directory path containing the certificate revocation list files. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_key	The name of the SSL key file for establishing a secure connection for distributed recovery. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_verify_server_cert	Specifies whether to verify the server common name in the donor certificate during distributed recovery. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_recovery_use_ssl	Specifies whether to use SSL for the connection channel used in distributed recovery by group replication members. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_single_primary_mode	Specifies whether to run group replication in single-primary mode, where one server is automatically selected to handle read/write workloads. If set to `ON`, only one readable/writable primary node exists, and all other group members are secondary nodes. If set to `OFF`, single-primary mode is disabled, and multi-primary mode is enabled, where all group members are readable/writable primary nodes. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_ssl_mode	Specifies the security status of SSL connections between group replication members. The default value is `DISABLED`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_start_on_boot	Specifies whether to start group replication when the server starts. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_transaction_size_limit	Specifies the maximum size of a transaction that can be received in group replication, in bytes. The default value is `150000000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_unreachable_majority_timeout	Specifies the waiting time before a group member leaves the group when it is disconnected from the majority of the group members due to a network partition. The unit is seconds. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.

Session level

Version information

Variable name	Description
ob_last_schema_version	Specifies the latest schema version used in the current session.
old_alter_table	Specifies whether to enable the syntax and operation mode of the ALTER TABLE statement in earlier versions. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.

Debug

Variable name	Description
debug	Specifies the debug options. The default value is `d:t:i:o,/tmp/mysqld.trace`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.

Read/Write and query

Variable name	Description
is_result_accurate	When a query is specified with the `topk` hint, `is_result_accurate` indicates whether the result is accurate.
long_query_time	Specifies the threshold for slow queries.

Replica

Variable name	Description
master_info_repository	Specifies whether to record metadata in the mysql table of the system database InnoDB or as a file in the data directory. The default value is `FILE`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.

Cache

Variable name	Description
table_definition_cache	Specifies the number of memory spaces for caching table definitions. The default value is `-1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
table_open_cache_instances	Specifies the number of table cache instances. The default value is `16`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query, but cannot set this variable.

Cluster

Variable name	Description
ob_capability_flag	Specifies the capabilities provided by the OBServer node. It is used for capability negotiation with the Proxy to inform the Proxy of the supported and unsupported features of the current OBServer node.
ob_proxy_partition_hit	Specifies whether to send SQL statements to the OBServer node where the data master partition is located.
ob_org_cluster_id	Specifies the `CLUSTER_ID` of the OceanBase cluster.

Variable name	Description
ndb_allow_copying_alter_table	Specifies whether to allow the `ALTER TABLE` statement and other DDL statements to use copy operations on tables. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_autoincrement_prefetch_sz	Specifies the number of auto-increment values to be prefetched. This value can affect the performance and concurrent access capability of auto-increment columns. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_blob_read_batch_bytes	Specifies the size of batch reads of BLOB data in NDB Cluster, in bytes. The default value is `65536`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_blob_write_batch_bytes	Specifies the size of batch writes of BLOB data in NDB Cluster, in bytes. The default value is `65536`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_deferred_constraints	Specifies whether to delay constraint checks on tables. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_fully_replicated	Specifies whether to fully replicate new tables. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_index_stat_enable	Specifies whether to use the NDB index statistics collection feature. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_index_stat_option	Specifies the options for generating NDB index statistics. The default value is `loop_checkon=1000ms,loop_idle=1000ms,loop_busy=100ms,update_batch=1,read_batch=4,idle_batch=32,check_batch=32,check_delay=1m,delete_batch=8,clean_delay=0,error_batch=4,error_delay=1m,evict_batch=8,evict_delay=1m,cache_limit=32M,cache_lowpct=90`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_join_pushdown	Specifies whether to enable the join pushdown optimization feature in the storage engine. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_log_binlog_index	Specifies whether to insert the mapping of epochs to binlog positions into the ndb_binlog_index table. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_log_exclusive_reads	Specifies whether to use an exclusive lock to record primary key reads. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_row_checksum	Specifies the checksum value for table rows. If the value is `1`, the checksum values of all rows are calculated and saved. If the value is `0`, no checksum checks are performed on table rows. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_use_exact_count	Specifies whether to force NDB to use record counts to accelerate `SELECT count(*)` queries. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_use_transactions	Specifies whether to enable NDB transaction support. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndbinfo_max_bytes	This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
ndbinfo_max_rows	This variable is available starting with yyy. It is used for testing and debugging. The default value is `10`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `10`.
ndbinfo_show_hidden	Specifies whether to display the internal tables of the `ndbinfo` database in the MySQL client. The default value is `OFF`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_repair_threads	Specifies the number of concurrent threads for repairing MyISAM tables. The default value is `1`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_sort_buffer_size	Specifies the size of the buffer allocated for sorting MyISAM indexes during the REPAIR TABLE operation or when creating indexes using CREATE INDEX (or ALTER TABLE). The unit is bytes. The default value is `8388608`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_stats_method	Specifies the method for calculating NULL values when collecting statistical information about the distribution of index values in MyISAM tables. The default value is `nulls_unequal`, which treats NULL values as regular values and handles them like other values. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_use_mmap	Specifies whether to use memory mapping for reading and writing MyISAM tables. The default value is `OFF`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.

Variable	Description
have_profiling	Indicates whether query performance analysis is supported. The default value is `NO`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
profiling	Indicates whether the statement analysis feature is enabled or disabled. The default value is `0`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
profiling_history_size	Specifies the number of query performance records to be saved. The default value is `15`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
enable_sql_plan_monitor	Specifies whether to record SQL statements into the SQL plan monitor for the current session.
sql_transpiler	Controls whether to enable the SQL Transpiler feature. Note This variable is available starting with V4.4.2 in V4.4.x.

Variable	Description
ob_enable_show_trace	Specifies whether to use the trace log.
tracefile_identifier	Specifies the content to be added to the log for filtering row iteration trace logs.

Variable	Description
pseudo_slave_mode	Specifies whether to convert the server to a pseudo slave mode. The default value is `OFF`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
pseudo_thread_id	Specifies the ID of the session thread. The default value is `2147483647`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
rbr_exec_mode	Specifies the mode of the session thread, either IDEMPOTENT or STRICT. The default value is `STRICT`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
preload_buffer_size	Specifies the cache size for preloading indexes, in bytes. The default value is `32768`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
read_buffer_size	Specifies the cache size for reading data, in bytes. The default value is `131072`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
read_rnd_buffer_size	Specifies the cache size for reading data from MyISAM tables, and for multi-range read optimization for any storage engine, in bytes. The default value is `262144`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
keep_files_on_create	When the `DATA DIRECTORY` or `INDEX DIRECTORY` option is not used to specify the location for storing data files or index files, this variable specifies whether to retain existing files in the corresponding directory when creating a MyISAM table. The default value is `OFF`, which means to overwrite existing files. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
max_heap_table_size	Specifies the maximum size to which user-created memory tables can grow, in bytes. The default value is `16777216`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
bulk_insert_buffer_size	Specifies the cache size for bulk insert operations, in bytes per thread. The default value is `8388608`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.

Time zone and date

Variable name	Description
timestamp	`TIMESTAMP` is the timestamp in seconds. This variable affects the result of `select now(6)`.
nls_language	The default language of the database for internationalization. This language is used for prompts, dates, month names, and the default values of `NLS_SORT` and `NLS_DATE_LANGUAGE`.

Transaction and transaction log

Variable name	Description
ob_proxy_set_trx_executed	Specifies whether to send the `START TRANSACTION Syntax` statement to OBServer through obproxy.
ob_trace_info	Specifies the trace information, which can be persisted to the REDO log.

Vector

Variable name	Description
ob_hnsw_ef_search	Specifies the number of neighbor points to search in each layer of the graph for the HNSW algorithm during vector index queries.
ob_ivf_nprobes	Specifies the number of nearest cluster centers to search during vector index queries. This variable affects the performance and recall rate of IVF queries: a larger value increases the recall rate but also increases the search time.

Optimizer

Variable name	Description
ob_table_access_policy	Controls the optimizer to prioritize specific storage formats when generating base table plans.

Auto-increment column

Variable name	Description
last_insert_id	Returns the value of the auto-increment column inserted in the last session.

Group replication variables

Variable name	Description
group_replication_force_members	Specifies the list of member addresses in the format `host1:port1,host2:port2`. This variable is used to forcibly create a new group. After setting this variable, excluded members (those not specified in this variable) will not receive new view messages and will be blocked (write operations will be blocked). The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_group_name	Specifies the name of the group to which the current server belongs. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_gtid_assignment_block_size	Specifies the number of consecutive GTIDs to be reserved for each member. The default value is `1000000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_ip_whitelist	Specifies the list of hosts (IP addresses or hostnames) allowed to connect to the group. These allowed addresses are referred to as white-listed addresses. The default value is `AUTOMATIC`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_local_address	The network address used by group replication members to provide access to other members in the group. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_ca	Specifies the path to the file containing the list of trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_capath	Specifies the directory path for the certificates issued by trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_cert	Specifies the name of the SSL certificate file required to establish a secure connection for distributed recovery. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_cipher	Specifies the list of allowed encryption algorithms for SSL encryption. The available encryption algorithms depend on the version of the SSL library used when compiling MySQL Server. Different SSL libraries support different encryption algorithms. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_crl	Specifies the file name containing the certificate revocation list. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_crlpath	Specifies the directory path containing the certificate revocation list files. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_key	Specifies the name of the SSL key file required to establish a secure connection for distributed recovery. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.

This topic lists system variables of OceanBase Database based on their functions.

Global level

Security

Variable	Description
validate_password_check_user_name	Specifies whether the user password can be the same as the username.
validate_password_length	Specifies the minimum length of the user password.
validate_password_mixed_case_count	Specifies the minimum number of uppercase and lowercase letters in the user password.
validate_password_number_count	Specifies the minimum number of digits in the user password.
validate_password_policy	Specifies the password check strategy.
validate_password_special_char_count	Specifies the minimum number of special characters in the user password.
ob_tcp_invited_nodes	Specifies the IP address whitelist for the tenant. You can use a wildcard character (%), an underscore (_), or an IP address. You can separate multiple IP addresses with commas. You can match the IP addresses in the list, by mask, or by wildcard.
default_password_lifetime	Specifies the password expiration time.
block_encryption_mode	Specifies the encryption algorithm used in the aes_encrypt and aes_decrypt functions.
sql_safe_updates	Specifies whether to enable the SQL safe mode in MySQL. The default value is OFF.
super_read_only	Controls the read/write permissions of the database. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
pid_file	Queries the path name of the file in which the server writes the process ID.
port	Specifies the TCP/IP port number for the server when you deploy the OBServer node.
socket	Queries the name of the `Socket` file for local client connections.

Variable name	Description
version_comment	Displays the version information of an OBServer node.
version	Displays the server version.
ob_last_schema_version	Sets the latest schema version used in the current session.
ob_proxy_global_variables_version	Sets the latest version of global variables to be returned by an OBServer node to an OBProxy node.
ob_enable_transmission_checksum	Sets whether to enable packet checksum verification between an OBProxy node and an OBServer node. The setting takes effect immediately.
ob_compatibility_control	Controls the behavior when compatibility conflicts occur between MySQL 5.7 and MySQL 8.0.
ob_compatibility_version	Controls the OceanBase Database version compatible with the feature that changes the product behavior.
ob_security_version	Controls the OceanBase Database version compatible with the security feature. You can specify the compatible version when you create a tenant. You cannot modify the compatible version after the tenant is created.
old_alter_table	Sets whether to enable the syntax and operation mode of the old ALTER TABLE statement. The default value is `OFF`. Note This variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting does not take effect.

Variable name	Description
debug	Sets the debug options. The default value is `d:t:i:o,/tmp/mysqld.trace`. Note This variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting does not take effect.
ob_global_debug_sync	Sets the synchronization point during debugging. This variable affects all sessions.

Variable name	Description
lower_case_table_names	Sets whether to enable case sensitivity.

Variable	Description
query_cache_size	Specifies the size of memory allocated for storing the results of queries that are not yet executed.
query_cache_type	Specifies the query cache type.
ob_query_timeout	Specifies the query timeout.
is_result_accurate	When a query contains the `TOPK` hint, `is_result_accurate` specifies whether the query result is accurate.
net_buffer_length	Specifies the maximum size of an SQL query that an OBServer node can accept.
read_only	Specifies whether a tenant is in read-only mode.
ob_read_consistency	Specifies the read consistency level.
ob_max_read_stale_time	Specifies the maximum delay threshold (us) for weak-consistency reads.
net_read_timeout	Specifies the number of seconds to wait for other data before interrupting a read.
net_write_timeout	Specifies the number of seconds to wait for a block to be written before interrupting a write.
ob_enable_index_direct_select	Specifies whether to allow users to directly query index tables.
ob_enable_aggregation_pushdown	Specifies whether to allow aggregation operations to be pushed down.
ob_enable_jit	Specifies the JIT execution engine mode.
sql_throttle_network	Specifies the request queuing time. If the queuing time exceeds this value, the query cannot be executed.
parallel_servers_target	Specifies the queuing conditions for large queries on each server.
cte_max_recursion_depth	Specifies the maximum recursion depth for common table expressions (CTEs). The server terminates the execution of any operation exceeding this CTE value.
regexp_stack_limit	Specifies the maximum available memory for the internal stack used in regular expression matching operations.
regexp_time_limit	Specifies the time limit for regular expression matching operations.
long_query_time	Specifies the threshold for slow queries.

Variable	Description
event_scheduler	Specifies whether the event scheduler is enabled and running on the server.

Variable	Description
ob_create_table_strict_mode	Specifies the strict mode for table creation.
ob_default_replica_num	Specifies the default number of replicas for each table in a cluster.
master_info_repository	Specifies whether to record metadata to the mysql table in the InnoDB system database or to store it as a file in the data directory. The default value is `FILE`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
replication_optimize_for_static_plugin_config	Specifies whether to enable shared locks to improve the performance of semi-synchronous replication. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
replication_sender_observe_commit_only	Specifies whether to enable limited callbacks to improve the performance of semi-synchronous replication. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
rpl_semi_sync_slave_enabled	Specifies whether to enable semi-synchronous replication on a replica. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
rpl_semi_sync_slave_trace_level	Specifies the debug tracing level for semi-synchronous replication on a replica. The default value is `32`, which indicates the network waiting level. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
rpl_stop_slave_timeout	Specifies the time to wait before a STOP SLAVE statement times out, in seconds. The default value is `31536000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_checkpoint_group	Specifies the maximum number of transactions that can be processed by multi-threaded replication before a checkpoint operation is called to update the progress status. The default value is `512`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_checkpoint_period	Specifies the maximum time allowed between checkpoint operations to update the status of multi-threaded replication, in milliseconds. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_compressed_protocol	Specifies whether to use the compression of the source or replica protocol when both the source and replica support compression. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_exec_mode	Specifies how replication threads resolve conflicts and errors during replication. Setting it to `IDEMPOTENT` suppresses errors for duplicate and missing keys; setting it to `STRICT` does not suppress these errors. The default value is `STRICT`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_max_allowed_packet	Specifies the maximum size of data packets for replication SQL and I/O threads, in bytes. The default value is `1073741824`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_net_timeout	Specifies the time to wait for more data or a heartbeat signal from the source before the replica assumes the connection is disconnected and aborts reading and attempts to reconnect, in seconds. The default value is `60`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_parallel_type	Specifies the type of parallel execution for replication transactions when multi-threaded replication is enabled. The default value is `DATABASE`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_parallel_workers	Specifies the number of threads to execute replication transactions in parallel. The default value is `0`, which indicates that parallel execution of replication transactions is disabled. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
slave_pending_jobs_size_max	Specifies the maximum length of the work queue for storing unapplied events for multi-threaded replication. The unit is bytes. The default value is `16777216`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_preserve_commit_order	Specifies whether to commit transactions in the order they appear in the relay log for multi-threaded replication. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_rows_search_algorithms	Specifies the algorithms for searching and finding related rows for replication. The default value is `TABLE_SCAN,INDEX_SCAN`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_sql_verify_checksum	Specifies whether to verify data using the checksum read from the relay log for the SQL thread of replication. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_transaction_retries	Specifies the number of times the system automatically retries a transaction that fails due to a deadlock or because the transaction execution time exceeds the value specified by the `innodb_lock_wait_timeout` variable. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
slave_type_conversions	Specifies the type conversion mode for row-based replication. The default value is empty, indicating that type conversion between the source and replica is disabled. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
sql_slave_skip_counter	Specifies the number of events to be skipped from the source for the replica. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
skip_slave_start	Specifies whether to skip starting the replication thread when the replica server starts. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
slave_load_tmpdir	Specifies the directory name for creating temporary files for the replica. The default value is empty. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
slave_skip_errors	Specifies which errors to skip during replication. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
sync_master_info	The effect of this variable on the replica depends on whether the `master_info_repository` parameter is set to FILE or TABLE. The default value is `10000`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
init_slave	This variable is similar to init_connect. It specifies the string to be executed by the replica when the replication SQL thread starts. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
log_slow_slave_statements	Specifies whether to record slow SQL statements executed by the replication thread to the slow query log if the slow query log is enabled on the replica. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting does not take effect.
report_host	Specifies the hostname or IP address of the replica to be reported to the source during registration. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
report_password	Specifies the password of the replication user account to be reported to the source during registration. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
report_port	Specifies the TCP/IP port number for connecting to the replica to be reported to the source during registration. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
report_user	The username of the account to which the replica is registered. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log	The name of the relay log. The default value is `null`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_basename	The name and full path of the relay log. The default value is `/usr/local/mysql/data/obrd-relay-bin`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_index	The name of the relay log index file. The default value is `/usr/local/mysql/data/obrd-relay-bin.index`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_info_file	The name of the file that records information about the relay log. The default value is `relay-log.info`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_recovery	If this variable is enabled, the relay log is automatically recovered after the replica is started. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.
relay_log_space_limit	The maximum capacity of all relay logs, in bytes. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it.

Variable name	Description
rpl_semi_sync_master_enabled	Specifies whether to enable semi-synchronous replication on the source. The default value is `OFF`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_timeout	Specifies the time in milliseconds that the source waits for confirmation from the replicas after a transaction is committed. The default value is `10000`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_trace_level	Specifies the debug tracing level for semi-synchronous replication on the source. The default value is `32`, which indicates the network waiting level. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_wait_for_slave_count	Specifies the number of replicas that must confirm a transaction before the source continues. The default value is `1`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_wait_no_slave	Specifies whether the source waits for the timeout (set by the `rpl_semi_sync_master_timeout` variable) even if the number of replicas is less than the value specified by the `rpl_semi_sync_master_wait_for_slave_count` variable. The default value is `OFF`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
rpl_semi_sync_master_wait_point	Specifies the point at which the semi-synchronous source waits for confirmation from the replicas before returning the status to the client that submitted the transaction. The default value is `AFTER_SYNC`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.

Variable name	Description
recyclebin	Specifies whether to enable the recycle bin.
ob_enable_truncate_flashback	Specifies whether to enable flashback for table truncation.

Variable name	Description
ob_enable_plan_cache	Specifies whether to enable the plan cache.
ob_plan_cache_percentage	Specifies the percentage of memory allocated to the plan cache relative to the tenant's memory.
ob_plan_cache_evict_high_percentage	Specifies the percentage of memory at which the plan cache is evicted relative to the memory limit.
ob_plan_cache_evict_low_percentage	Specifies the percentage of memory at which the plan cache eviction stops relative to the memory limit.
ob_bnl_join_cache_size	Specifies the amount of data cached in the Batch Nest Loop Join cache for each batch.
stored_program_cache	Specifies the number of stored procedures and functions to cache. The default value is `256`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
table_definition_cache	Specifies the number of memory spaces allocated to cache table definitions. The default value is `-1`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
table_open_cache_instances	Specifies the number of table cache instances to open. The default value is `16`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Functions

Variable name	Description
interactive_timeout	Specifies the number of seconds the server waits for activity before closing an interactive connection.
wait_timeout	Specifies the number of seconds the server waits for activity before closing a noninteractive connection.
group_concat_max_len	Specifies the maximum length of the result of the `GROUP_CONCAT()` function.

InnoDB storage engine

Variable	Description
innodb_change_buffering_debug	The debug level for setting the change buffer of InnoDB. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_compress_debug	The debug level for adjusting and controlling the compression behavior. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_disable_resize_buffer_pool_debug	Whether to enable the size adjustment of the InnoDB buffer pool. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_fil_make_page_dirty_debug	The debug level for dirtying the specified number of pages in InnoDB. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_limit_optimistic_insert_debug	The number of records per B-tree page. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_merge_threshold_set_all_debug	The percentage of full pages of an index. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_saved_page_number_debug	The number of pages saved in InnoDB for debugging. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_trx_purge_view_update_only_debug	The debug level for controlling whether to only update the purge view during transaction cleanup. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_trx_rseg_n_slots_debug	The number of slots in a transaction rollback segment. Each slot stores the rollback information of a transaction. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_stats_persistent	Whether to persist the statistics of InnoDB indexes to the disk.
innodb_force_recovery	The crash recovery mode for repairing the data of the InnoDB storage engine. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
innodb_replication_delay	The extended time of replication threads on the replica server when the value of the `innodb_thread_concurrency` variable is reached. The unit is milliseconds. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_large_prefix	Whether to allow an index key prefix longer than 767 bytes (up to 3072 bytes) for an InnoDB table that uses the DYNAMIC or COMPRESSED row format. The default value is `ON`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_sort_buffer_size	The size of the buffer for sorting operations. The default value is `1048576`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
default_tmp_storage_engine	The default temporary table storage engine. The default value is `InnoDB`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
innodb_tmpdir	The directory for storing temporary files of InnoDB. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.
mecab_rc_file	The path of the MeCab configuration file. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
innodb_temp_data_file_path	The path for temporary data files used by InnoDB. The default value is `ibtmp1:12M:autoextend`, which indicates that InnoDB will use a temporary data file named ibtmp1 with an initial size of 12 MB, and this file will automatically expand as needed to store additional temporary data. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_data_file_path	The path and filename for InnoDB data files. The default value is `ibdata1:12M:autoextend`, which indicates that InnoDB will use a temporary data file named ibdata1 with an initial size of 12 MB, and this file will automatically expand as needed to store additional temporary data. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_data_home_dir	The root directory for InnoDB data files. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_read_only	Whether to start InnoDB in read-only mode. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_rollback_on_timeout	Whether to abort and roll back the entire transaction when a transaction times out. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_api_disable_rowlock	Whether to disable row locks when InnoDB memcached executes DML operations. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
innodb_autoinc_lock_mode	The locking mode for generating auto-increment values. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it.
low_priority_updates	Whether to control the priority of INSERT, UPDATE, DELETE, and REPLACE statements. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
max_error_count	The maximum number of errors, warnings, and notifications that can be stored in the diagnostic context. The default value is `64`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
max_insert_delayed_threads	The maximum number of threads for executing INSERT DELAYED statements. The default value is `20`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_disable	This variable acts as a switch to control which metrics counters to disable. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_enable	This variable acts as a switch to control which metrics counters to enable. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_reset	This variable acts as a switch to control which metrics counters to reset to 0. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_monitor_reset_all	This variable acts as a switch to control which metrics counters to reset to 0. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_old_blocks_pct	The approximate percentage of the old data blocks in the InnoDB buffer pool. The default value is `37`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_old_blocks_time	The time that a block must stay in the old sublist after its first access before it can be moved to the new sublist, in milliseconds. The default value is `1000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_purge_batch_size	The number of undo log pages to parse and process at a time from the history list. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. The setting will not take effect, but no error will be returned.
innodb_purge_rseg_truncate_frequency	This variable specifies how often to truncate rollback segments. The default value is `128`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_random_read_ahead	This variable specifies whether to enable random read-ahead for InnoDB I/O. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_read_ahead_threshold	This variable specifies the number of pages that must be read sequentially from a segment before asynchronous reads from the next segment are initiated. The default value is `56`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_rollback_segments	This variable specifies the number of rollback segments used to generate undo records. The default value is `128`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_spin_wait_delay	This variable specifies the interval between spin lock waits. The default value is `6`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_status_output	This variable specifies whether to enable or disable the regular output of the standard InnoDB monitor. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_status_output_locks	This variable specifies whether to enable or disable InnoDB lock monitoring. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_sync_spin_loops	This variable specifies the number of times a thread waits before being suspended when an InnoDB mutex is released. The default value is `30`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
internal_tmp_disk_storage_engine	This variable specifies the storage engine for temporary tables on disk. The default value is `INNODB`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_fast_shutdown	This variable specifies the shutdown mode for the InnoDB engine. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_io_capacity	This variable specifies the approximate number of IOPS that can be executed by background tasks per second. The default value is `200`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_io_capacity_max	This variable specifies the maximum number of IOPS that can be executed by background tasks per second in an emergency. The default value is `2000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_thread_concurrency	This variable specifies the maximum number of threads allowed in InnoDB. The default value is `0`, which indicates no limit. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_thread_sleep_delay	This variable specifies the time in microseconds that an InnoDB thread sleeps before being added to the InnoDB wait queue. The default value is `10000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
innodb_adaptive_hash_index_parts	This variable specifies the number of partitions in the adaptive hash index search system. The default value is `8`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
innodb_numa_interleave	This variable specifies whether to enable the NUMA interleaving memory policy for allocating buffer pool memory. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
innodb_open_files	This variable specifies the maximum number of files that can be opened at a time. The default value is `2000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
innodb_page_cleaners	The number of threads for flushing dirty pages in the buffer pool. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_purge_threads	The number of background threads for purging. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_read_io_threads	The number of I/O threads for reading. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_sync_array_size	The size of the mutex/lock wait array. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_use_native_aio	Whether to use the Linux asynchronous I/O subsystem. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_write_io_threads	The number of I/O threads for writing. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_api_enable_binlog	Whether to allow the InnoDB Memcached plugin to be used with MySQL binlogs. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_locks_unsafe_for_binlog	This variable affects how InnoDB uses gap locks for searches and index scans. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_buffer_size	The size of the InnoDB transaction log buffer, in bytes. The default value is `16777216`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_files_in_group	The number of log files in the log group. The default value is `2`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_file_size	The size of each log file in the log group, in bytes. The default value is `50331648`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_log_group_home_dir	The directory path for InnoDB redo logs. The default value is `./`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_undo_directory	The directory for the undo tablespaces created by InnoDB. The default value is `./`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.
innodb_undo_tablespaces	The number of undo tablespaces available to InnoDB. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. You can query the variable but cannot set it.

Variable name	Description
json_float_full_precision	Controls the precision mode for parsing JSON numbers.

Variable	Description
ob_capability_flag	Indicates the capabilities of an OBServer node. This variable is used for capability negotiation with the Proxy. It specifies which features are supported and which are not supported by the OBServer node.
ob_compatibility_mode	Specifies the compatibility mode of a tenant.
ob_route_policy	Specifies the routing policy for selecting data replicas within an OBServer node.
performance_schema	Specifies whether to support queries for performance information. The default value is `OFF`. Note This variable is for compatibility with MySQL 8.0. The related features are not supported. You can query and set this variable, but the settings do not take effect.
resource_manager_plan	Activates the resource management plan. Different plans use different CPU quotas to limit user activities in resource groups.
license	Displays the type of the license.
ob_proxy_partition_hit	Specifies whether to send SQL requests for data to the OBServer node where the data leader partition is located.
ob_org_cluster_id	Specifies the `CLUSTER_ID` of the OceanBase cluster.
server_uuid	Displays the UUID of the OBServer node.
default_storage_engine	Displays the default storage engine of the OBServer node.
slave_allow_batching	Specifies whether to enable batch updates for the replication thread. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect.

Variable	Description
datadir	Displays the local disk path for storing data.
plugin_dir	Displays the path for storing plugin DLLs.
secure_file_priv	Specifies the path that can be accessed when importing or exporting data to a file.
ob_enable_hash_group_by	Specifies whether to enable the Hash Group by feature.

MyISAM storage engine

Variable	Description
delay_key_write	Specifies whether to delay the write of index keys for MyISAM tables. The default value is `ON`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_buffer_size	Specifies the size of the key buffer for the MyISAM storage engine. The default value is `8388608`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_cache_age_threshold	Specifies the threshold for degrading a buffer from the hot sub-list to the warm sub-list in the key cache. A lower value means a faster degradation. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_cache_block_size	Specifies the size of a single block in the MyISAM key cache. The default value is `1024`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
key_cache_division_limit	Specifies the division limit for the MyISAM key cache. The default value is `100`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
max_seeks_for_key	Specifies the maximum number of seek operations in a MyISAM query. The default value is `18446744073709551615`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
skip_external_locking	Specifies whether to disable the external locking mechanism for MyISAM tables. The default value is `ON`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Temporary files

Variable	Description
max_tmp_tables	Specifies the maximum number of temporary tables that can be held in a user session. The default value is `32`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.

Memory

Variable	Description
ob_sql_work_area_percentage	Specifies the percentage of memory allocated for SQL execution.
ob_sql_audit_percentage	Specifies the percentage of memory allocated for SQL audit.
ob_reserved_meta_memory_percentage	Specifies the percentage of memory reserved for tenants, primarily for storing meta-related structures.
ob_temp_tablespace_size_percentage	Specifies the percentage of memory allocated for temporary tablespaces in the tenant's disk.

NDB storage engine

Variable name	Description
ndb_allow_copying_alter_table	Specifies whether to allow the `ALTER TABLE` statement and other DDL statements to use copy operations on tables. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_autoincrement_prefetch_sz	Specifies the number of auto-increment values to be prefetched. This value can affect the performance and concurrent access capability of auto-increment columns. The default value is `1`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_blob_read_batch_bytes	Specifies the size of BLOB data to be read in batches in an NDB Cluster. The unit is bytes. The default value is `65536`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_blob_write_batch_bytes	Specifies the size of BLOB data to be written in batches in an NDB Cluster. The unit is bytes. The default value is `65536`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_cache_check_time	Specifies the interval, in milliseconds, at which to check whether the cache needs to be refreshed on each NDB node. The default value is `0`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_clear_apply_status	Specifies whether to clear the application status. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_data_node_neighbour	Defines the neighbor relationships of data nodes. The default value is `0`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_default_column_format	Defines the default column format for tables, whether to store them in fixed-length or variable-length format. The default value is `FIXED`, indicating fixed-length storage. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_deferred_constraints	Controls whether to delay constraint checks on tables. The default value is `0`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_distribution	Specifies the default distribution method for NDB tables, whether to partition by hash key values or by linear hash. The default value is `KEYHASH`, indicating hash key value partitioning. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_eventbuffer_free_percent	Specifies the percentage of free space in the event buffer of an NDB Cluster. The default value is `20`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_eventbuffer_max_alloc	Specifies the maximum size of memory that can be allocated for the event buffer, in bytes. The default value is `0`, indicating no limit. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_extra_logging	Specifies whether to log specified NDB storage engine information to the MySQL error log. The default value is `1`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_force_send	Specifies whether to immediately send the cache to NDB without waiting for other threads. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_fully_replicated	Specifies whether to fully replicate new tables. The default value is `OFF`. Note This variable is available starting with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_index_stat_enable	Specifies whether to enable the NDB index statistics collection feature. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_index_stat_option	Specifies the options for generating NDB index statistics. The default value is `loop_checkon=1000ms,loop_idle=1000ms,loop_busy=100ms,update_batch=1,read_batch=4,idle_batch=32,check_batch=32,check_delay=1m,delete_batch=8,clean_delay=0,error_batch=4,error_delay=1m,evict_batch=8,evict_delay=1m,cache_limit=32M,cache_lowpct=90`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_join_pushdown	Specifies whether to enable the join pushdown optimization feature in the storage engine. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_binlog_index	Specifies whether to insert the mapping of epochs to binlog positions into the ndb_binlog_index table. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_empty_epochs	Specifies whether to write unchanged epoch transactions to the binlog. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_empty_update	Specifies whether to write unchanged update transactions to the binlog. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_exclusive_reads	Specifies whether to use an exclusive lock for reading primary keys. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_update_as_write	Specifies whether to write updates to the binlog as updates (OFF) or writes (ON). The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_update_minimal	Specifies the log recording behavior of NDB Cluster. If the value is `ON`, NDB Cluster records only the minimal information of update operations. If the value is `OFF`, NDB Cluster records the entire row changes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_log_updated_only	Specifies whether to write only the updated rows or the entire rows to the binlog when Mysqld writes updates to the binlog. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_optimization_delay	Specifies the wait time between groups of rows when using the OPTIMIZE TABLE statement on an NDB table, in microseconds. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_read_backup	Specifies whether to allow reading data from any fragment of any NDB table created after this variable is set. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_recv_thread_activation_threshold	Specifies the activation threshold for receive threads. The default value is `8`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_recv_thread_cpu_mask	Specifies the CPU mask for receive threads. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_report_thresh_binlog_epoch_slip	Specifies the maximum allowed size of a binlog timestamp jump before a report is generated. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_report_thresh_binlog_mem_usage	Specifies the percentage threshold of the remaining available memory for binlog before a report is sent. When the remaining available memory for binlog is less than this value, a report is sent. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_row_checksum	Specifies the checksum value for table rows. When the value is `1`, the checksum values for all rows are calculated and saved. When the value is `0`, the checksum detection for table rows is not performed. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_show_foreign_key_mock_tables	Specifies whether to display mock tables for foreign key dependencies. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_slave_conflict_role	Specifies the role of the node in a circular replication (master-master) setup. The default value is `NONE`, indicating that the role is undefined or not configured. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_table_no_logging	Controls the logging behavior for NDB tables. When the value is `ON`, all tables created or modified using the NDB storage engine are in a no-logging state. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_table_temporary	Specifies the behavior of temporary tables when using the NDB storage engine. When the value is `ON`, NDB tables are not written to disk. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_use_exact_count	Specifies whether to force NDB to use record counts to accelerate `SELECT count(*)` queries. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndb_use_transactions	Controls whether to enable NDB transaction support. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_max_bytes	Only for testing and debugging. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_max_rows	Only for testing and debugging. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_offline	Specifies whether to set the `ndbinfo` database to offline mode. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
ndbinfo_show_hidden	Specifies whether to display the underlying internal tables of the `ndbinfo` database in the MySQL client. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_data_pointer_size	Specifies the default pointer size, in bytes, for MyISAM tables created without the `MAX_ROWS` option. The default value is `6`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_max_sort_file_size	Specifies the maximum size of the temporary files allowed during MyISAM index recreation (in `REPAIR TABLE`, `ALTER TABLE`, or `LOAD DATA` operations), in bytes. The default value is `9223372036853720064`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_repair_threads	Specifies the number of concurrent threads for repairing MyISAM tables. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
myisam_sort_buffer_size	The size of the buffer allocated for sorting MyISAM indexes during the REPAIR TABLE operation or when creating indexes with CREATE INDEX (or ALTER TABLE), in bytes. The default value is `8388608`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
myisam_stats_method	The method for calculating NULL values when collecting statistical information about the distribution of index values in MyISAM tables. The default value is `nulls_unequal`, which treats NULL values as regular values and handles them the same as other values. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
myisam_use_mmap	Whether to use memory mapping for reading and writing MyISAM tables. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect.
server_id_bits	The number of least significant bits in the 32-bit server_id that actually identify the server. The default value is `32`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Full-text index

Variable	Description
innodb_ft_enable_diag_print	Enables or disables diagnostic output for InnoDB full-text indexes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_num_word_optimize	Specifies the minimum number of words to optimize during an OPTIMIZE TABLE operation. The default value is `2000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_result_cache_limit	Specifies the size of the InnoDB full-text index result cache. The default value is `2000000000`, in bytes. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_server_stopword_table	Specifies the server stopword table for InnoDB full-text indexes. The default value is `NULL`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_optimize_fulltext_only	Controls the behavior of the OPTIMIZE TABLE statement on InnoDB tables with FULLTEXT indexes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.
innodb_ft_cache_size	Specifies the size of the InnoDB full-text index cache. The default value is `8000000`, in bytes. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.
innodb_ft_sort_pll_degree	Specifies the number of parallel threads for full-text index sorting. The default value is `2`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.
innodb_ft_total_cache_size	Specifies the total size of the InnoDB full-text index cache. The default value is `640000000`, in bytes. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.
ft_stopword_file	Specifies the file path for stopword processing. The default value is `built-in`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. You cannot set it.

Runtime Filter

Variable	Description
runtime_filter_type	Specifies the Runtime Filter type at the tenant level.
runtime_filter_wait_time_ms	Specifies the maximum wait time for Runtime Filters.
runtime_filter_max_in_num	Specifies the number of distinct values (NDV) for Runtime In Filters.
runtime_bloom_filter_max_size	Specifies the maximum memory usage for Runtime Bloom Filters, in bytes.

Upgrade

Variable	Description
avoid_temporal_upgrade	Manages the upgrade behavior for temporal data (such as dates and times). The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it without errors. However, the settings will not take effect.

Time zones and dates

Name	Description
time_zone	The time zone used by the current tenant session. The value can be specified in offset format, such as `'+08:00'`, or region format, such as `Asia/Shanghai`.
timestamp	`TIMESTAMP` is a timestamp in seconds, and it affects the result of `SELECT NOW(6)`.
system_time_zone	Specifies the system time zone for the server.
error_on_overlap_time	Specifies whether to return an error if a timestamp is ambiguous in a time zone with overlapping daylight saving time changes.
nls_language	The default language in the database's internationalization (NLS) settings, used for prompts, dates, month names, and as the default value for `NLS_SORT` and `NLS_DATE_LANGUAGE`.
nls_territory	The current territory, which is used in conjunction with `nls_language`.
nls_date_language	Specifies the default language for dates in the database's internationalization support.
nls_calendar	Used to specify the calendar system to be used by the database.
ob_timestamp_service	Specifies the timestamp service to use.

Transactions and transaction logs

Variable name	Description
autocommit	Specifies whether to auto-commit a transaction.
tx_isolation	Specifies the transaction isolation level.
ob_proxy_set_trx_executed	Specifies whether a user sends the `START TRANSACTION` statement to the OBServer through the ODP.
ob_early_lock_release	This variable specifies whether to enable the early lock release (ELR) feature. Note This variable is deprecated starting from V2.2.30. The ELR feature is now controlled by the tenant-level parameter `enable_early_lock_release`.
ob_trx_idle_timeout	The transaction idle timeout. After an interval exceeds the timeout value, it is considered that the transaction is idle and the transaction is considered to be timed out.
transaction_isolation	Sets the transaction isolation level.
transaction_read_only	Specifies whether a read-only transaction is allowed.
ob_trx_lock_timeout	Used to set the wait timeout for transactions.
tx_read_only	Specify whether a transaction is read-only.
ob_trx_timeout	This variable specifies the transaction timeout.
ob_trace_info	This variable is used to pass trace information, which will ultimately be persistently written to the REDO log.
gtid_executed	Stores the set of committed transactions and the GTID specified by the statement. The default value is `NULL`. Note This variable is retained for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot modify its value.
gtid_owned	This variable stores the list of GTID values of current transactions and the IDs of the threads that own them. The default value is `NULL`. Note This variable is compatible with MySQL 5.7 only. You can query its value but cannot set it.

Name	Description
ob_enable_sql_audit	Specifies whether to enable SQL Audit for the current tenant.

Data types

Variable	Description
nls_length_semantics	Specifies the length semantics of the CHAR and VARCHAR2 data types.
nls_nchar_conv_excp	Specifies whether to return an error when data is lost during the conversion between NCHAR/NVARCHAR2 and CHAR/VARCHAR2 data types.
nls_numeric_characters	Specifies the decimal and thousand separators used during the conversion between numbers and strings.
nls_currency	Specifies the local currency symbol for the `L` element in the number format.
nls_iso_currency	Specifies the local currency symbol for the `C` element in the number format.
nls_dual_currency	Specifies the local currency symbol for the `U` element in the number format.
nls_date_format	Specifies the format for converting a date to a string and for implicitly converting a string to a date.
nls_timestamp_format	Specifies the format for converting a TIMESTAMP or TIMESTAMP_LTZ value to a string and for implicitly converting a string to a TIMESTAMP or TIMESTAMP_LTZ value.
nls_timestamp_tz_format	Specifies the format for converting a TIMESTAMP_TZ value to a string and for implicitly converting a string to a TIMESTAMP_TZ value.
explicit_defaults_for_timestamp	Specifies whether to enable nonstandard behavior for the TIMESTAMP data type when handling default values and NULL values.
log_row_value_options	Specifies whether to enable partial updates for LOB data.
ob_default_lob_inrow_threshold	Specifies the default in-row storage threshold for LOB fields when creating a table.

Variable	Description
connect_timeout	Specifies the connection timeout.
ob_pl_block_timeout	Specifies the maximum timeout for PL.
cursor_sharing	Specifies whether to parameterize SQL statements.
have_profiling	Indicates whether to enable query performance analysis. The default value is `NO`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
profiling	Specifies whether to enable statement analysis. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
profiling_history_size	Specifies the number of query performance records to be saved. The default value is `15`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
innodb_strict_mode	Specifies the SQL syntax check mode.
max_connections	Specifies the maximum number of connections for a tenant.
sql_mode	Specifies the SQL mode. Different SQL modes have a significant impact on behaviors such as insertions.
sql_quote_show_create	Specifies whether to enable quoting identifiers in `SHOW CREATE TABLE` and `SHOW CREATE DATABASE` statements.
ob_enable_rich_error_msg	Specifies whether to display information such as svr_ip, time, and trace_id when an error occurs during SQL execution.
sql_throttle_current_priority	Specifies the throttling priority. Requests from sessions where `sql_throttle_current_priority` is less than `sql_throttle_priority` will be throttled.
sql_throttle_priority	Specifies the throttling priority.
sql_throttle_rt	Specifies the RT value.
max_allowed_packet	Specifies the maximum size of a network packet.
max_user_connections	Specifies the maximum number of connections that a single user can establish with an OBServer node. A value of `0` indicates no limit.
max_sp_recursion_depth	Specifies the maximum number of nested calls to a specified stored procedure.
sql_select_limit	Specifies the maximum number of rows that a SELECT query can return.
max_connections	Specifies the maximum number of connections for a tenant.
ob_enable_blk_nestedloop_join	Specifies whether to enable block nested loop joins.
parallel_max_servers	Specifies the maximum number of threads in the parallel execution (PX) thread pool on each server.
sql_transpiler	Specifies whether to enable the SQL Transpiler feature. Note This variable is available starting with V4.4.2 of OceanBase Database V4.4.x.
plsql_can_transform_sql_to_assign	Specifies whether to allow `select into from dual` statements in PL/SQL to be rewritten as `assign` statements.

System logs

Variable	Description
binlog_row_image	Controls whether to record full-column logs.
ob_enable_show_trace	Specifies whether to use trace logs.
ob_log_level	Specifies the log level at the session level. If not specified, the system log level is used.
tracefile_identifier	Specifies the content to be added to the log to facilitate the filtering of row iteration trace logs.
master_verify_checksum	Specifies whether to enable checksum verification. The default value is `OFF`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting does not take effect.
log_statements_unsafe_for_binlog	Specifies whether to record error code 1592 information to the error log. The default value is `1`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting does not take effect.
binlog_gtid_simple_recovery	Controls how the server iterates through binlog files during GTID search when it starts or restarts. The default value is `1`, which means that the values of `gtid_executed` and `gtid_purged` are calculated based on the values of `previous_gtids_log_event` in the latest and oldest binlog files at startup. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
log_bin_basename	The full path of the binlog file. The default value is `null`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
log_bin_index	The name and path of the binlog index file. The default value is `null`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.
log_slave_updates	Specifies whether the replica server records updates received from the primary server's binlog to its own binlog. The default value is `OFF`. Note This variable is used only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it.

Server variables

Variable name	Description
preload_buffer_size	The size of the buffer used for preloading indexes. The unit is bytes. The default value is `32768`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
read_buffer_size	The size of the buffer used for reading data. The unit is bytes. The default value is `131072`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
read_rnd_buffer_size	The size of the buffer used for reading data from MyISAM tables and for multi-range read optimization for any storage engine. The unit is bytes. The default value is `262144`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
sync_frm	Whether to synchronize the metadata of InnoDB tables to the `.frm` files on the disk. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
keep_files_on_create	When you do not use the `DATA DIRECTORY` or `INDEX DIRECTORY` option to specify the location of data files or index files, this variable specifies whether to retain existing files in the corresponding directory when you create a MyISAM table. The default value is `OFF`, which indicates to overwrite existing files. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
max_heap_table_size	The maximum size to which a memory table can grow. The unit is bytes. The default value is `16777216`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
bulk_insert_buffer_size	The size of the buffer used for bulk insert operations. The unit is bytes per thread. The default value is `8388608`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
general_log_file	The name of the file to store general query logs. The default value is `host_name.log`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
host_cache_size	The size of the host cache. The default value is `279`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_error_verbosity	The level of detail to include in error logs. The default value is `3`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_output	The output destination for general query logs and slow query logs. The default value is `FILE`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_queries_not_using_indexes	Whether to record queries that do not use indexes to the slow query log. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_slow_admin_statements	Whether to record slow administrative statements such as ALTER TABLE, ANALYZE TABLE, CHECK TABLE, CREATE INDEX, DROP INDEX, OPTIMIZE TABLE, and REPAIR TABLE to the slow query log. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_syslog	Whether to record error logs to the system log. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
log_syslog_facility	The tool for writing error logs to the system log. The default value is `daemon`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_syslog_include_pid	Whether to write the process ID of the service process in the error log output to the system log. The default value is `1`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_syslog_tag	The label to be added to the server identifier in the error log output written to the system log. The default value is `null`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_throttle_queries_not_using_indexes	The maximum number of statements written to the slow query log per minute. The default value is `0`, indicating no limit. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_timestamps	The timezone for the timestamps of error logs, general logs, and slow query logs written to files. The default value is `UTC`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
log_warnings	The record level for additional warning information in the error log. The default value is `2`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
max_delayed_threads	The maximum number of threads that can be created to process INSERT DELAYED statements. The default value is `20`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
offline_mode	Whether to set the server to offline mode. The default value is `0`, indicating that the server is not set to offline mode. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
require_secure_transport	Whether to use a secure transport for the connection between the client and the server. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
slow_launch_time	The time in seconds that a thread takes to create. If this time exceeds the value of this variable, the value of the Slow_launch_threads status variable increases. The default value is `2`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
sql_log_off	Whether to enable (OFF) or disable (ON) the general query log for the current session. The default value is `OFF`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_cache_size	The maximum number of threads that can be cached. The default value is `9`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_high_priority_connection	Whether to reserve idle threads for high-priority connections in the thread pool. The default value is `0`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_max_unused_threads	The maximum number of unused threads in the thread pool. The default value is `0`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_prio_kickup_timer	The time in milliseconds that a statement waits before being moved to the high-priority queue. The default value is `1000`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
thread_pool_stall_limit	The time in 10 milliseconds that a statement must complete after it starts execution. The default value is `6`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
have_statement_timeout	Whether to enable the statement timeout feature. The default value is `ON`. Note This variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it.
old	A compatibility variable for resolving compatibility issues. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
version_tokens_session_number	An internal variable. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect and no error is returned.
back_log	The maximum number of connections that can be stored in the connection request queue when the server is processing connection requests. The default value is `80`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
basedir	The path of the installation root directory. The default value is `/usr/local/mysql/`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
bind_address	The IP address to which the server binds when it listens for TCP/IP client connections. The default value is `*`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
core_file	Whether to generate a core file before the server exits when a fatal error occurs. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
have_compress	Whether the zlib compression library required for the COMPRESS() and UNCOMPRESS() functions is available. The default value is `ON`, indicating that it is available. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
ignore_db_dirs	A comma-separated list of names that are not considered database directories in the data directory. The default value is `null`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
init_file	The name of a file that contains SQL statements to be executed when the server starts. The default value is `null`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
large_files_support	Whether the server supports handling large files. The default value is `1`, indicating that it supports handling large files. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
large_pages	Whether to enable support for large pages. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
large_page_size	If large page support is enabled, this variable specifies the size of memory pages in bytes. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
locked_in_memory	Whether the server is locked in memory. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
log_error	The output destination of the error log file. The default value is `./obrd.16c.vd3-s2h6-n3.err`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
named_pipe	Whether to allow clients to connect to the server using named pipes. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
named_pipe_full_access_group	When named pipe connections are supported, the Windows user group that has permission to use named pipe connections. The default value is `empty string`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
open_files_limit	The number of file descriptors available to the server. The default value is `655360`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
shared_memory	Specifies whether to allow clients to connect by using shared memory. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
shared_memory_base_name	Specifies the name of the shared memory used for shared memory connections. The default value is `MYSQL`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
skip_name_resolve	Specifies whether to resolve hostnames during client connection checks. The default value is `OFF`, which means that hostnames must be resolved. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
skip_networking	Specifies whether to allow TCP/IP connections. The default value is `OFF`, which means that TCP/IP connections are disabled. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_handling	Specifies the thread model used by the server to handle client connections. The default value is `one-thread-per-connection`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_pool_algorithm	Specifies the algorithm used by the thread pool plugin. The default value is `0`, which means that the conservative low-concurrency algorithm is used. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_pool_size	Specifies the number of thread groups in the thread pool. The default value is `16`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
thread_stack	Specifies the size of the stack for each thread. The default value is `262144`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
tls_version	Specifies the protocols that the server allows for encrypted connections. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.

X Plugin

Variable name	Description
mysqlx_bind_address	Specifies the network address on which the X plugin listens for TCP/IP connections. The default value is `*`, which means that all TCP/IP connections from all server hosts are accepted. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_port	Specifies the network port on which the X plugin listens for TCP/IP connections. The default value is `33060`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_port_open_timeout	Specifies the time in seconds that the X plugin waits for a TCP/IP port to become idle. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_socket	Specifies the path to the Unix socket file used by the X plugin. The default value is `/tmp/mysqlx.sock`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_ca	Specifies the path to the SSL certificate authority (CA) file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_capath	Specifies the directory path to the SSL certificate authority (CA) certificate file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_cert	Specifies the path to the SSL certificate file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_cipher	Specifies the list of encryption algorithms used for SSL encryption by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_crl	Specifies the filename of the certificate revocation list (CRL) file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_crlpath	Specifies the directory path to the certificate revocation list (CRL) file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.
mysqlx_ssl_key	Specifies the path to the SSL certificate key file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query it but cannot set it.

Performance schema

Variable name	Description
performance_schema_accounts_size	Specifies the number of rows in the `accounts` table. The default value is `-1`, indicating automatic scaling. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_digests_size	Specifies the maximum number of rows in the `events_statements_summary_by_digest` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_stages_history_long_size	Specifies the number of rows in the `events_stages_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_stages_history_size	Specifies the number of rows for each thread in the `events_stages_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_statements_history_long_size	Specifies the number of rows in the `events_statements_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_statements_history_size	Specifies the number of rows for each thread in the `events_statements_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_transactions_history_long_size	Specifies the number of rows in the `events_transactions_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_transactions_history_size	Specifies the number of rows for each thread in the `events_transactions_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_waits_history_long_size	Specifies the number of rows in the `events_waits_history_long` table. The default value is `10000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_events_waits_history_size	Specifies the number of rows for each thread in the `events_waits_history` table. The default value is `10`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_hosts_size	Specifies the number of rows in the `hosts` table. The default value is `-1`, indicating automatic scaling. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_cond_classes	Specifies the maximum number of condition collectors. The default value is `80`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_cond_instances	Specifies the maximum number of condition objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_digest_length	Specifies the maximum length of a standardized SQL statement in bytes when it is stored in the performance schema. The default value is `1024`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_file_classes	Specifies the maximum number of file collectors. The default value is `80`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.
performance_schema_max_file_handles	The maximum number of file objects that can be opened. The default value is `32768`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_file_instances	The maximum number of file objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_index_stat	The maximum number of indexes in the statistics maintained by the Performance Schema. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_memory_classes	The maximum number of memory collectors. The default value is `320`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_metadata_locks	The maximum number of metadata lock collectors. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_mutex_classes	The maximum number of mutex collectors. The default value is `200`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_mutex_instances	The maximum number of mutex objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_prepared_statements_instances	The maximum number of rows in the `prepared_statements_instances` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_program_instances	The maximum number of stored programs in the statistics maintained by the Performance Schema. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_rwlock_classes	The maximum number of rwlock collectors. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_rwlock_instances	The maximum number of rwlock objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_socket_classes	The maximum number of socket collectors. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_socket_instances	The maximum number of socket objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_sql_text_length	The maximum length of SQL statements that can be stored in the `SQL_TEXT` column of the `events_statements_current`, `events_statements_history`, and `events_statements_history_long` statement event tables, in bytes. The default value is `1024`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_stage_classes	The maximum number of stage collectors. The default value is `150`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_statement_classes	The maximum number of statement collectors. The default value is `193`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_statement_stack	The maximum depth of nested stored program calls in the statistics maintained by the Performance Schema. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_max_table_handles	The maximum number of table objects that can be opened. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_table_instances	The maximum number of table objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_table_lock_stat	The maximum number of tables in lock statistics maintained by the Performance Schema. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_thread_classes	The maximum number of thread collectors. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_max_thread_instances	The maximum number of thread objects that can be collected. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_session_connect_attrs_size	The preallocated memory size, in bytes, for storing connection attribute key-value pairs for each thread. The default value is `512`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_setup_actors_size	The number of rows in the `setup_actors` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_setup_objects_size	The number of rows in the `setup_objects` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.
performance_schema_users_size	The number of rows in the `users` table. The default value is `-1`, indicating automatic scaling. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable but cannot set it.

Variable	Description
metadata_locks_cache_size	The size of the metadata lock cache. The default value is `1024` bytes. Note This variable is available only for MySQL 5.7 compatibility. The related features are not supported. You can query the variable but cannot set it.
metadata_locks_hash_instances	The number of instances of the metadata lock hash table. The default value is `8`. Note This variable is available only for MySQL 5.7 compatibility. The related features are not supported. You can query the variable but cannot set it.

Variable	Description
foreign_key_checks	Specifies whether to check foreign key constraints in DML/DDL operations.

Variable	Description
mview_refresh_dop	Specifies the default refresh parallelism for materialized views.

Variable	Description
optimizer_use_sql_plan_baselines	Specifies whether to use the Plan Baseline plan.
optimizer_capture_sql_plan_baselines	Specifies whether to automatically capture new plans to the Plan Baseline.
parallel_degree_policy	Specifies the parallelism selection strategy.
parallel_degree_limit	Specifies the upper limit of the parallelism selected by the optimizer when the Auto DOP strategy is used.
parallel_min_scan_time_threshold	Specifies the minimum evaluation execution time for parallel processing of base table scans.
optimizer_dynamic_sampling	Specifies the level of dynamic sampling.
optimizer_features_enable	Enables the optimizer features of different OceanBase Database versions.
ob_enable_transformation	Specifies whether to enable the rewrite feature of the SQL optimizer.
ob_table_access_policy	Controls the optimizer to prioritize a specific storage format when generating base table plans.

Variable	Description
auto_increment_increment	Specifies the auto-increment step size. This variable is available only for MySQL clients.
auto_increment_offset	Specifies the starting value of the `AUTO_INCREMENT` column.
last_insert_id	Returns the last auto-increment value inserted in the current session.
identity	`identity` and the `last_insert_id` variable are synonyms. You can query `identity` by executing the `select @@identity` statement.
sql_auto_is_null	Specifies whether to retrieve the auto-increment value of the last inserted row.
auto_increment_cache_size	Specifies the number of auto-increment values cached.
div_precision_increment	Specifies the increment of the precision of the result of a division operation based on the precision of the dividend. This is a MySQL compatibility feature.

Character sets and strings

Variable name	Description
character_set_client	The character set for statements sent from the client.
character_set_connection	The character set to be converted after receiving a statement.
character_set_database	The character set for the default database.
character_set_results	The character set to be converted before sending the result set or error message back to the client.
character_set_server	The character set for the server.
character_set_system	The character set used by the server.
collation_connection	The character set and collation for the connection.
collation_database	The default character set and collation for the database.
collation_server	The default character set and collation for the server.
character_set_filesystem	The character set type for the file system.
sql_warnings	Whether to generate information strings for single-row INSERT statements when warnings occur.
init_connect	The string to be executed by the server for each client connection, consisting of one or more SQL statements separated by semicolons.
nls_sort	The collation for string values.
nls_comp	The comparison rule for string values.
nls_characterset	The default character set for data types such as CHAR, VARCHAR2, and CLOB in the database.
nls_nchar_characterset	The default character set for data types such as NCHAR, NVARCHAR2, and NCLOB.

Group replication

Variable name	Description
group_replication_allow_local_disjoint_gtids_join	Specifies whether to allow a server to join a group if it has local transactions not present in the group. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_allow_local_lower_version_join	Specifies whether to allow a server to join a group if the MySQL Server version on the server is lower than that on other members of the group. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_auto_increment_increment	Specifies the increment value for the auto-increment column of each member in the replication group. This ensures that the auto-increment column values are ordered and do not overlap in a multi-primary group. The default value is `7`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_bootstrap_group	Specifies whether to use the current server to bootstrap the group. This variable can only be set on one server and can only be set when bootstrapping the group for the first time or re-bootstrapping the group. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_components_stop_timeout	Specifies the timeout in seconds for each component during group replication shutdown. The default value is `2`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_compression_threshold	Specifies the threshold for message compression between group members. Messages will be compressed if the threshold is exceeded. The default value is `1000000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_enforce_update_everywhere_checks	Specifies whether to enable or disable strict consistency checks for multi-primary updates at any time. The default value is `OFF`, which disables the checks. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_exit_state_action	Specifies the behavior of group replication when a server instance leaves the group due to an exception. The default value is `READ_ONLY`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_flow_control_applier_threshold	Specifies the number of transactions waiting in the application queue that triggers flow control. The default value is `25000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_flow_control_certifier_threshold	Specifies the number of transactions waiting in the certifier queue that triggers flow control. The default value is `25000`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_flow_control_mode	Specifies the mode for flow control. The default value is `QUOTA`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_force_members	Specifies the list of member addresses in the format `host1:port1,host2:port2`. This variable is used to forcibly establish a new group. After setting this variable, excluded members (those not specified in the variable) will not receive new view messages and will be blocked (write operations will be blocked). The default value is empty. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_group_name	Specifies the name of the group replication group to which the current server belongs. The default value is empty. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_group_seeds	Specifies the list of seed member addresses in the format `host1:port1,host2:port2`. The default value is empty. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect and will not generate an error.
group_replication_gtid_assignment_block_size	The number of consecutive GTIDs to be reserved for each member. The default value is `1000000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_ip_whitelist	The list of hosts (IP addresses or host names) that are allowed to connect to the group. The allowed hosts are called the whitelist. The default value is `AUTOMATIC`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_local_address	The network address used by a group replication member to provide access to other members in the group. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_member_weight	The percentage weight of a group member, which affects the chance of the member being selected as the primary node during a failover (only applicable to groups in single-primary mode). In a group in single-primary mode, when the primary node leaves the group, the member with the higher weight is prioritized to be selected as the new primary node. The default value is `50`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_poll_spin_loops	The number of times the group replication communication thread waits for the communication engine mutex to be released before waiting for more incoming network messages. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_complete_at	The strategy for applying cached transactions after the status transmission is completed in a distributed recovery. The default value is `TRANSACTIONS_APPLIED`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_reconnect_interval	The interval, in seconds, between reconnection attempts to find an available donor when a new server cannot find an available donor during distributed recovery. The default value is `60`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_retry_count	The number of times to retry connecting to find an available donor when a new server cannot find an available donor during distributed recovery. The default value is `10`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_ca	The path to the file containing the list of trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_capath	The directory path to the trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_cert	The name of the SSL certificate file for establishing a secure connection for distributed recovery. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_cipher	The list of allowed encryption algorithms for SSL encryption. The available encryption algorithms depend on the version of the SSL library used to compile the MySQL Server. Different SSL libraries support different encryption algorithms. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_crl	The name of the file containing the certificate revocation list. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_crlpath	The directory path containing the certificate revocation list files. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_key	The name of the SSL key file for establishing a secure connection for distributed recovery. The default value is an empty string. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
group_replication_recovery_ssl_verify_server_cert	Specifies whether to verify the server common name in the donor certificate during distributed recovery. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_recovery_use_ssl	Specifies whether to use SSL for the connection channel used in distributed recovery by group replication members. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_single_primary_mode	Specifies whether to run group replication in single-primary mode, where one server is automatically selected to handle read/write workloads. If set to `ON`, only one readable/writable primary node exists, and all other group members are secondary nodes. If set to `OFF`, single-primary mode is disabled, and multi-primary mode is enabled, where all group members are readable/writable primary nodes. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_ssl_mode	Specifies the security status of SSL connections between group replication members. The default value is `DISABLED`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_start_on_boot	Specifies whether to start group replication when the server starts. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_transaction_size_limit	Specifies the maximum size of a transaction that can be received in group replication, in bytes. The default value is `150000000`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.
group_replication_unreachable_majority_timeout	Specifies the waiting time before a group member leaves the group when it is disconnected from the majority of the group members due to a network partition. The unit is seconds. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported.

Session level

Version information

Variable name	Description
ob_last_schema_version	Specifies the latest schema version used in the current session.
old_alter_table	Specifies whether to enable the syntax and operation mode of the ALTER TABLE statement in earlier versions. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.

Debug

Variable name	Description
debug	Specifies the debug options. The default value is `d:t:i:o,/tmp/mysqld.trace`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.

Read/Write and query

Variable name	Description
is_result_accurate	When a query is specified with the `topk` hint, `is_result_accurate` indicates whether the result is accurate.
long_query_time	Specifies the threshold for slow queries.

Replica

Variable name	Description
master_info_repository	Specifies whether to record metadata in the mysql table of the system database InnoDB or as a file in the data directory. The default value is `FILE`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.

Cache

Variable name	Description
table_definition_cache	Specifies the number of memory spaces for caching table definitions. The default value is `-1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect.
table_open_cache_instances	Specifies the number of table cache instances. The default value is `16`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query, but cannot set this variable.

Cluster

Variable name	Description
ob_capability_flag	Specifies the capabilities provided by the OBServer node. It is used for capability negotiation with the Proxy to inform the Proxy of the supported and unsupported features of the current OBServer node.
ob_proxy_partition_hit	Specifies whether to send SQL statements to the OBServer node where the data master partition is located.
ob_org_cluster_id	Specifies the `CLUSTER_ID` of the OceanBase cluster.

Variable name	Description
ndb_allow_copying_alter_table	Specifies whether to allow the `ALTER TABLE` statement and other DDL statements to use copy operations on tables. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_autoincrement_prefetch_sz	Specifies the number of auto-increment values to be prefetched. This value can affect the performance and concurrent access capability of auto-increment columns. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_blob_read_batch_bytes	Specifies the size of batch reads of BLOB data in NDB Cluster, in bytes. The default value is `65536`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_blob_write_batch_bytes	Specifies the size of batch writes of BLOB data in NDB Cluster, in bytes. The default value is `65536`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_deferred_constraints	Specifies whether to delay constraint checks on tables. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_fully_replicated	Specifies whether to fully replicate new tables. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_index_stat_enable	Specifies whether to use the NDB index statistics collection feature. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_index_stat_option	Specifies the options for generating NDB index statistics. The default value is `loop_checkon=1000ms,loop_idle=1000ms,loop_busy=100ms,update_batch=1,read_batch=4,idle_batch=32,check_batch=32,check_delay=1m,delete_batch=8,clean_delay=0,error_batch=4,error_delay=1m,evict_batch=8,evict_delay=1m,cache_limit=32M,cache_lowpct=90`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_join_pushdown	Specifies whether to enable the join pushdown optimization feature in the storage engine. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_log_binlog_index	Specifies whether to insert the mapping of epochs to binlog positions into the ndb_binlog_index table. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_log_exclusive_reads	Specifies whether to use an exclusive lock to record primary key reads. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_row_checksum	Specifies the checksum value for table rows. If the value is `1`, the checksum values of all rows are calculated and saved. If the value is `0`, no checksum checks are performed on table rows. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_use_exact_count	Specifies whether to force NDB to use record counts to accelerate `SELECT count(*)` queries. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndb_use_transactions	Specifies whether to enable NDB transaction support. The default value is `OFF`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors.
ndbinfo_max_bytes	This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
ndbinfo_max_rows	This variable is available starting with yyy. It is used for testing and debugging. The default value is `10`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `10`.
ndbinfo_show_hidden	Specifies whether to display the internal tables of the `ndbinfo` database in the MySQL client. The default value is `OFF`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_repair_threads	Specifies the number of concurrent threads for repairing MyISAM tables. The default value is `1`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_sort_buffer_size	Specifies the size of the buffer allocated for sorting MyISAM indexes during the REPAIR TABLE operation or when creating indexes using CREATE INDEX (or ALTER TABLE). The unit is bytes. The default value is `8388608`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_stats_method	Specifies the method for calculating NULL values when collecting statistical information about the distribution of index values in MyISAM tables. The default value is `nulls_unequal`, which treats NULL values as regular values and handles them like other values. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.
myisam_use_mmap	Specifies whether to use memory mapping for reading and writing MyISAM tables. The default value is `OFF`. Note This variable is available starting with yyy. It is used for testing and debugging. The default value is `0`.

Variable	Description
have_profiling	Indicates whether query performance analysis is supported. The default value is `NO`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it.
profiling	Indicates whether the statement analysis feature is enabled or disabled. The default value is `0`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
profiling_history_size	Specifies the number of query performance records to be saved. The default value is `15`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
enable_sql_plan_monitor	Specifies whether to record SQL statements into the SQL plan monitor for the current session.
sql_transpiler	Controls whether to enable the SQL Transpiler feature. Note This variable is available starting with V4.4.2 in V4.4.x.

Variable	Description
ob_enable_show_trace	Specifies whether to use the trace log.
tracefile_identifier	Specifies the content to be added to the log for filtering row iteration trace logs.

Variable	Description
pseudo_slave_mode	Specifies whether to convert the server to a pseudo slave mode. The default value is `OFF`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
pseudo_thread_id	Specifies the ID of the session thread. The default value is `2147483647`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
rbr_exec_mode	Specifies the mode of the session thread, either IDEMPOTENT or STRICT. The default value is `STRICT`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
preload_buffer_size	Specifies the cache size for preloading indexes, in bytes. The default value is `32768`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
read_buffer_size	Specifies the cache size for reading data, in bytes. The default value is `131072`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
read_rnd_buffer_size	Specifies the cache size for reading data from MyISAM tables, and for multi-range read optimization for any storage engine, in bytes. The default value is `262144`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
keep_files_on_create	When the `DATA DIRECTORY` or `INDEX DIRECTORY` option is not used to specify the location for storing data files or index files, this variable specifies whether to retain existing files in the corresponding directory when creating a MyISAM table. The default value is `OFF`, which means to overwrite existing files. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
max_heap_table_size	Specifies the maximum size to which user-created memory tables can grow, in bytes. The default value is `16777216`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.
bulk_insert_buffer_size	Specifies the cache size for bulk insert operations, in bytes per thread. The default value is `8388608`. Note This variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the setting does not take effect.

Time zone and date

Variable name	Description
timestamp	`TIMESTAMP` is the timestamp in seconds. This variable affects the result of `select now(6)`.
nls_language	The default language of the database for internationalization. This language is used for prompts, dates, month names, and the default values of `NLS_SORT` and `NLS_DATE_LANGUAGE`.

Transaction and transaction log

Variable name	Description
ob_proxy_set_trx_executed	Specifies whether to send the `START TRANSACTION Syntax` statement to OBServer through obproxy.
ob_trace_info	Specifies the trace information, which can be persisted to the REDO log.

Vector

Variable name	Description
ob_hnsw_ef_search	Specifies the number of neighbor points to search in each layer of the graph for the HNSW algorithm during vector index queries.
ob_ivf_nprobes	Specifies the number of nearest cluster centers to search during vector index queries. This variable affects the performance and recall rate of IVF queries: a larger value increases the recall rate but also increases the search time.

Optimizer

Variable name	Description
ob_table_access_policy	Controls the optimizer to prioritize specific storage formats when generating base table plans.

Auto-increment column

Variable name	Description
last_insert_id	Returns the value of the auto-increment column inserted in the last session.

Group replication variables

Variable name	Description
group_replication_force_members	Specifies the list of member addresses in the format `host1:port1,host2:port2`. This variable is used to forcibly create a new group. After setting this variable, excluded members (those not specified in this variable) will not receive new view messages and will be blocked (write operations will be blocked). The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_group_name	Specifies the name of the group to which the current server belongs. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_gtid_assignment_block_size	Specifies the number of consecutive GTIDs to be reserved for each member. The default value is `1000000`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_ip_whitelist	Specifies the list of hosts (IP addresses or hostnames) allowed to connect to the group. These allowed addresses are referred to as white-listed addresses. The default value is `AUTOMATIC`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_local_address	The network address used by group replication members to provide access to other members in the group. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_ca	Specifies the path to the file containing the list of trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_capath	Specifies the directory path for the certificates issued by trusted SSL certificate authorities for distributed recovery connections. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_cert	Specifies the name of the SSL certificate file required to establish a secure connection for distributed recovery. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_cipher	Specifies the list of allowed encryption algorithms for SSL encryption. The available encryption algorithms depend on the version of the SSL library used when compiling MySQL Server. Different SSL libraries support different encryption algorithms. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_crl	Specifies the file name containing the certificate revocation list. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_crlpath	Specifies the directory path containing the certificate revocation list files. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.
group_replication_recovery_ssl_key	Specifies the name of the SSL key file required to establish a secure connection for distributed recovery. The default value is an empty string. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and no errors will be reported.

Customer Stories

Documentation

Overview

Security

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Version-related variables

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Debug-related variables

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Case sensitivity-related variables

Read/write and query-related

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Variables related to the source

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Variables related to the recycle bin

Variables related to caching

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Functions

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