Overview|V4.6.0|OceanBase Database| docs|Distributed Database

Variable	Description
validate_password_check_user_name	Specifies whether the password can be the same as the username.
validate_password_length	Specifies the minimum length of the password.
validate_password_mixed_case_count	Specifies the minimum number of uppercase and lowercase letters in the password.
validate_password_number_count	Specifies the minimum number of digits in the password.
validate_password_policy	Specifies the password check policy.
validate_password_special_char_count	Specifies the minimum number of special characters in the password.
ob_tcp_invited_nodes	Specifies the IP address whitelist of the tenant. You can specify the %, _, and IP addresses. Multiple IP addresses are separated with commas. You can match the IP address list, the mask, or the IP address with wildcards.
default_password_lifetime	Specifies the password expiration time.
block_encryption_mode	Specifies the encryption algorithm to be used in the aes_encrypt and aes_decrypt functions.
sql_safe_updates	Specifies whether to enable the SQL safe mode of 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 provided only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. The setting does not take effect and no error is returned.
pid_file	Queries the path of the file that stores the process ID of the server.
port	Specifies the TCP/IP port number to be listened on when an OBServer node is deployed.
socket	Queries the name of the `Socket` file for local client connections.

Variable	Description
ap_query_cost_threshold	Specifies the cost threshold for adaptive selection of columnar replicas.
ap_query_route_policy	Controls the adaptive selection strategy for AP query replicas.
ap_query_replica_fallback	Controls whether to fall back to a non-columnar replica for queries when no columnar replicas are available, when the automatic query routing feature is enabled.

Variable name	Description
version_comment	Displays the version information of the OBServer node.
version	Displays the server version number.
ob_last_schema_version	Sets the latest schema version used in the current session.
ob_proxy_global_variables_version	Sets the latest version information of global variables to be returned by the OBServer node to the OBProxy node.
ob_enable_transmission_checksum	Specifies whether to enable packet checksum verification between the OBProxy node and the OBServer node. This setting takes effect immediately.
ob_compatibility_control	Controls the behavior mode when there are compatibility conflicts 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 this setting after the tenant is created.
old_alter_table	Specifies whether to enable the syntax and operation mode of the old ALTER TABLE statement. 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 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 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.
ob_global_debug_sync	Sets a synchronization point during debugging. This variable affects all sessions.

Variable name	Description
lower_case_table_names	Specifies whether to enable case sensitivity.

Variable name	Description
query_cache_size	Specifies the amount of memory allocated for storing the results of queries that have not been executed.
query_cache_type	Specifies the query cache type.
ob_query_timeout	Specifies the query timeout.
is_result_accurate	When a query has the `topk` hint, `is_result_accurate` indicates whether the result is accurate.
net_buffer_length	Specifies the maximum size of an SQL query that can be accepted by an OBServer node.
read_only	Specifies whether the tenant is in read-only mode.
ob_read_consistency	Specifies the read consistency level.
ob_max_read_stale_time	Specifies the maximum delay threshold (in microseconds) 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 request queuing time is greater than or equal to 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 that exceeds 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 name	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 settings will not take effect.
replication_optimize_for_static_plugin_config	Controls 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 settings will not take effect.
replication_sender_observe_commit_only	Controls whether to enable restricted 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 settings will not take effect.
rpl_semi_sync_slave_enabled	Controls whether to enable semi-synchronous replication on the 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 settings will not take effect.
rpl_semi_sync_slave_trace_level	Specifies the debug trace level of semi-synchronous replication on the replica. The default value is `32`, which indicates the network wait 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 settings will not take effect.
rpl_stop_slave_timeout	Specifies the time to wait before a STOP SLAVE operation 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 settings 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 settings will not take effect.
slave_checkpoint_period	Specifies the maximum time allowed before a checkpoint operation is called 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 settings will not take effect.
slave_compressed_protocol	When both the source and replica support compression, specifies whether to use compression in the source or replica protocol. 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.
slave_exec_mode	Specifies how replication threads resolve conflicts and errors during replication. If you set this variable to `IDEMPOTENT`, duplicate key and not found key errors are suppressed. If you set this variable to `STRICT`, duplicate key and not found key errors are not suppressed. 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 settings 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 settings will not take effect.
slave_net_timeout	The time to wait for more data or a heartbeat signal from the source before the replica considers the connection to be disconnected, 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 settings 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 settings will not take effect.
slave_parallel_workers	Specifies the number of threads for parallel execution of replication transactions. 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 settings will not take effect.
slave_pending_jobs_size_max	For multi-threaded replication, specifies the maximum length of the work queue that stores unapplied events, in bytes. The default value is `16777216`. 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.
slave_preserve_commit_order	For multi-threaded replication, specifies whether to commit transactions in the order they appear in the relay log. 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. However, the setting does not take effect.
slave_rows_search_algorithms	Specifies the algorithms that the replica uses to search for related rows. The default value is `TABLE_SCAN,INDEX_SCAN`. 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.
slave_sql_verify_checksum	Specifies whether to verify data by using the checksum read from the relay log. 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. However, the setting does not take effect.
slave_transaction_retries	Specifies the number of times the system automatically retries a transaction when the replication SQL thread fails to execute it due to a deadlock or 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 features are not supported. You can query and set this variable. However, the setting does not take effect.
slave_type_conversions	Specifies the type conversion mode on the replica 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 features are not supported. You can query and set this variable. However, the setting does not take effect.
sql_slave_skip_counter	Specifies the number of events from the source to be skipped by the replica. 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.
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 features are not supported. You can query this variable, but cannot set it.
slave_load_tmpdir	Specifies the directory name for temporary files created by the replica. The default value is empty. 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.
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 features are 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 of the replica 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 features are not supported. You can query and set this variable. However, 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 features are not supported. You can query and set this variable. However, 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 replica has the slow query log enabled. 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. However, the setting does not take effect.
report_host	The hostname or IP address reported to the source during replica registration. The default value is `null`. 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.
report_password	The password of the replication user account reported to the source during replica registration. The default value is `null`. 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.
report_port	The TCP/IP port number for connecting to the replica, reported to the source during replica registration. The default value is `null`. 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.
report_user	The username of the account to which the replica reports 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.
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 you enable this variable, the relay log is automatically recovered when the replica 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.
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 only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the settings do not take effect and no error is returned.
rpl_semi_sync_master_timeout	Specifies the time in milliseconds that the source waits for the replica to return an acknowledgment after a transaction is committed. 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 and set this variable. However, the settings do not take effect and no error is returned.
rpl_semi_sync_master_trace_level	Specifies the debug trace level for semi-synchronous replication on the source. The default value is `32`, which indicates the network wait 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. However, the settings do not take effect and no error is returned.
rpl_semi_sync_master_wait_for_slave_count	Specifies the number of replicas that must return an acknowledgment for each transaction before the source continues. 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. However, the settings do not take effect and no error is returned.
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 set for the `rpl_semi_sync_master_wait_for_slave_count` variable. 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. However, the settings do not take effect and no error is returned.
rpl_semi_sync_master_wait_point	Specifies the point at which the source waits for the replica to return an acknowledgment for a transaction before returning the status to the client that submitted the transaction. The default value is `AFTER_SYNC`. 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 settings do not take effect and no error is returned.

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 that can be used for the plan cache.
ob_plan_cache_evict_high_percentage	Specifies the percentage of memory that triggers the eviction of the plan cache.
ob_plan_cache_evict_low_percentage	Specifies the percentage of memory at which the eviction of the plan cache stops.
ob_bnl_join_cache_size	Specifies the amount of data to cache for each batch in a Batch Nest Loop Join.
stored_program_cache	Specifies the number of stored procedures and functions to cache. The default value is `256`. 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 settings do not take effect and no error is returned.
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. However, the settings do not take effect and no error is returned.
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 this variable, but you cannot set it.

Variable name	Description
interactive_timeout	Specifies the number of seconds that the server waits for activity before closing an interactive connection.
wait_timeout	Specifies the number of seconds that 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.

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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings do not take effect and no error is returned.
innodb_compress_debug	The debug level for adjusting and controlling the compression behavior. The default value is `0`. 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 do not take effect and no error is returned.
innodb_disable_resize_buffer_pool_debug	Whether to enable the buffer pool size adjustment of InnoDB. 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 and set this variable, but the settings do not take effect and no error is returned.
innodb_fil_make_page_dirty_debug	The debug level for making the specified number of pages dirty in InnoDB. The default value is `0`. 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 do not take effect and no error is returned.
innodb_limit_optimistic_insert_debug	The number of records on each B-tree page. The default value is `0`. 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 do not take effect and no error is returned.
innodb_merge_threshold_set_all_debug	The percentage of full pages for an index. The default value is `50`. 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 do not take effect and no error is returned.
innodb_saved_page_number_debug	The number of pages saved in InnoDB for debugging. The default value is `0`. 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 do not take effect and no error is returned.
innodb_trx_purge_view_update_only_debug	The debug level for controlling whether to update only the purge view during transaction cleanup. The default value is `0`. 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 do not take effect and no error is returned.
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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings do not take effect and no error is returned.
innodb_stats_persistent	Whether to persist the statistics of InnoDB indexes to disk.
innodb_force_recovery	The crash recovery mode for repairing data of the InnoDB storage engine. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable, but you cannot set it.
innodb_replication_delay	The extended time of replication threads on the replication 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings do not take effect and no error is returned.
innodb_large_prefix	Whether to allow an index key prefix longer than 767 bytes (up to 3072 bytes) for InnoDB tables that use the DYNAMIC or COMPRESSED row format. The default value is `ON`. 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 do not take effect and no error is returned.
innodb_sort_buffer_size	The size of the buffer for sorting operations. The default value is `1048576`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings do not take effect and no error is returned.
innodb_tmpdir	The directory for storing temporary files of InnoDB. 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 do not take effect and no error is returned.
mecab_rc_file	The path of the MeCab configuration file. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable, but you cannot set it.
innodb_temp_data_file_path	Specifies the storage path for temporary data files used by InnoDB. The default value is `ibtmp1:12M:autoextend`, indicating that InnoDB will use a temporary data file named ibtmp1 with an initial size of 12MB, which will automatically expand as needed to store additional temporary data. 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.
innodb_data_file_path	Specifies the storage path and filename for InnoDB data files. The default value is `ibdata1:12M:autoextend`, indicating that InnoDB will use a temporary data file named ibdata1 with an initial size of 12MB, which will automatically expand as needed to store additional temporary data. 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.
innodb_data_home_dir	Specifies the root directory for InnoDB data files. 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.
innodb_read_only	Specifies 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 features are not supported, so you can query it but cannot set it.
innodb_rollback_on_timeout	Specifies 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 features are not supported, so you can query it but cannot set it.
innodb_api_disable_rowlock	Specifies 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 features are not supported, so you can query it but cannot set it.
innodb_autoinc_lock_mode	Specifies 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 features are not supported, so you can query it but cannot set it.
low_priority_updates	Specifies 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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
max_error_count	Specifies 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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
max_insert_delayed_threads	Specifies 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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
innodb_old_blocks_pct	Specifies the approximate percentage of the old data block sublist in the InnoDB buffer pool. The default value is `37`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
innodb_old_blocks_time	Specifies how long 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 features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
innodb_purge_batch_size	Specifies the number of undo log pages to parse and process at once from the history list. The default value is `300`. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported, so you can query and set it. Setting it does not produce an error but has no effect.
innodb_purge_rseg_truncate_frequency	Controls how often rollback segments are truncated. 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 does not take effect.
innodb_random_read_ahead	Enables or disables 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 does not take effect.
innodb_read_ahead_threshold	Controls the linear read-ahead behavior of the InnoDB storage engine. The default value is `56`, which means that InnoDB must read at least 56 pages from a segment in sequence to initiate asynchronous reads from the next segment. 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 does not take effect.
innodb_rollback_segments	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 does not take effect.
innodb_spin_wait_delay	The time interval for each spin lock wait. 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 does not take effect.
innodb_status_output	Enables or disables the periodic 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 does not take effect.
innodb_status_output_locks	Enables or disables 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 does not take effect.
innodb_sync_spin_loops	The number of times a thread waits for an InnoDB mutex to be released before it is suspended. 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 does not take effect.
internal_tmp_disk_storage_engine	Specifies the storage engine for internal 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 does not take effect.
innodb_fast_shutdown	The shutdown mode of 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 does not take effect.
innodb_io_capacity	An approximate value of the IOPS that the InnoDB engine can perform per second for background tasks. 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 does not take effect.
innodb_io_capacity_max	The maximum IOPS that the background tasks can perform 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 does not take effect.
innodb_thread_concurrency	The maximum number of threads allowed in the InnoDB engine. 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 does not take effect.
innodb_thread_sleep_delay	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 does not take effect.
innodb_adaptive_hash_index_parts	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 you cannot set it.
innodb_numa_interleave	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 you cannot set it.
innodb_open_files	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 you cannot set it.
innodb_page_cleaners	The number of threads for flushing dirty pages from the buffer pool. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you cannot set it.
innodb_purge_threads	The number of background threads for purge operations. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you cannot set it.
innodb_read_io_threads	The number of I/O threads for read operations. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you 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 this variable, but you 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 this variable, but you cannot set it.
innodb_write_io_threads	The number of I/O threads for write operations. The default value is `4`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you cannot set it.
innodb_api_enable_binlog	Whether to allow the use of the InnoDB Memcached plugin with MySQL binlogs. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you 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 this variable, but you 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 this variable, but you cannot set it.
innodb_log_files_in_group	The number of log files in a log group. The default value is `2`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you cannot set it.
innodb_log_file_size	The size of each log file in a log group, in bytes. The default value is `50331648`. Note This variable is available only for compatibility with MySQL 5.7. You can query this variable, but you 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 this variable, but you 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 this variable, but you 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 this variable, but you cannot set it.

Variable	Description
ob_capability_flag	Indicates the capabilities provided by the OBServer node. This variable is used to negotiate capabilities 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 the tenant.
ob_route_policy	Specifies the routing strategy for selecting data replicas within the OBServer node.
performance_schema	Specifies whether to support queries for Performance information. The default value is `OFF`. Note This variable is only for compatibility with MySQL 8.0. 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.
resource_manager_plan	Activates the resource management plan. Different plans use different CPU quotas to limit user activities within resource groups.
license	Displays the type of license.
ob_proxy_partition_hit	Specifies whether to send SQL statements to the OBServer node where the data partitions are 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 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.

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 accessible paths for importing or exporting files.
ob_enable_hash_group_by	Specifies whether to enable Hash Group by.

Variable	Description
delay_key_write	Specifies whether to delay writing index keys to MyISAM tables. 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. However, the settings do 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 available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the settings do not take effect.
key_cache_age_threshold	Specifies the threshold for degrading a buffer from the hot sublist to the warm sublist in the key cache. The lower the value, the faster the degradation. The default value is `300`. 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 settings do 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 available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the settings do 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 available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, the settings do not take effect.
max_seeks_for_key	Specifies the maximum number of address operations in a MyISAM query. The default value is `18446744073709551615`. 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 settings do 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 available only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it.

Variable	Description
max_tmp_tables	Specifies the maximum number of temporary tables that a user session can hold. 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 and set this variable. However, the settings do not take effect.

Variable	Description
ob_sql_work_area_percentage	Specifies the percentage of tenant memory allocated for SQL execution.
ob_sql_audit_percentage	Specifies the percentage of tenant memory allocated for SQL audit.
ob_reserved_meta_memory_percentage	Specifies the percentage of tenant memory reserved for storing Meta-related structures.
ob_temp_tablespace_size_percentage	Specifies the percentage of tenant disk space allocated for temporary tablespaces.

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. The setting will not be reported as an error but will not take effect.
ndb_autoincrement_prefetch_sz	Specifies the number of auto-increment values to prefetch. This value can affect the performance and concurrency 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. The setting will not be reported as an error but will not take effect.
ndb_blob_read_batch_bytes	Specifies the size of BLOB data to read in batches in an 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. The setting will not be reported as an error but will not take effect.
ndb_blob_write_batch_bytes	Specifies the size of BLOB data to write in batches in an 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. The setting will not be reported as an error but will not take effect.
ndb_cache_check_time	Specifies the interval at which to check each NDB node for cache refreshes, in milliseconds. 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. The setting will not be reported as an error but will not take effect.
ndb_clear_apply_status	Specifies whether to clear the application status. 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. The setting will not be reported as an error but will not take effect.
ndb_data_node_neighbour	Defines the neighbor relationships of data nodes. 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. The setting will not be reported as an error but will not take effect.
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 only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. The setting will not be reported as an error but will not take effect.
ndb_deferred_constraints	Controls 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. The setting will not be reported as an error but will not take effect.
ndb_distribution	Specifies the default distribution method for NDB tables, whether to partition by hash key or linear hash. The default value is `KEYHASH`, indicating hash key partitioning. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. The setting will not be reported as an error but will not take effect.
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 only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. The setting will not be reported as an error but will not take effect.
ndb_eventbuffer_max_alloc	Specifies the maximum amount of memory that can be allocated for the event buffer, in bytes. The default value is `0`, indicating no limit. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. The setting will not be reported as an error but will not take effect.
ndb_extra_logging	Specifies whether to log information about the specified NDB storage engine to the MySQL error log. 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. The setting will not be reported as an error but will not take effect.
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 only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. The setting will not be reported as an error but will not take effect.
ndb_fully_replicated	Specifies whether new tables are fully replicated. 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. The setting will not be reported as an error but will not take effect.
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 from 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 exclusive locks to record primary key reads. 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 updates on the source are written 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 logging behavior of NDB Cluster. If the value is `ON`, NDB Cluster records only the minimal information for update operations. If the value is `OFF`, NDB Cluster records changes to the entire row. 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 Mysqld writes only updated rows or the entire row to the binlog when writing updates. 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 later. 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 below this value, a report is sent. 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. Setting this variable does not generate an error but has no effect.
ndb_row_checksum	Specifies the checksum value for table rows. When the value is `1`, checksums are calculated and saved for each row of data. When the value is `0`, checksum checks are not performed for table rows. The default value is `1`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
ndb_use_exact_count	Specifies whether to force NDB to use record counts to accelerate `SELECT count(*)` queries during query planning. 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. Setting this variable does not generate an error but has no effect.
ndb_use_transactions	Controls whether to enable transaction support for NDB. 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. Setting this variable does not generate an error but has no effect.
ndbinfo_max_bytes	For testing and debugging purposes only. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
ndbinfo_max_rows	For testing and debugging purposes only. 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. Setting this variable does not generate an error but has no effect.
ndbinfo_offline	Specifies whether to put the `ndbinfo` database in an offline state. 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. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
myisam_max_sort_file_size	Specifies the maximum size in bytes of the temporary file allowed during MyISAM index recreation (during `REPAIR TABLE`, `ALTER TABLE`, or `LOAD DATA` operations). The default value is `9223372036853720064`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
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 feature is not supported. You can query and set this variable. Setting this variable does not generate an error but has no effect.
myisam_sort_buffer_size	The size of the buffer allocated for sorting MyISAM indexes during REPAIR TABLE or when creating indexes using 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 settings will not take effect.
myisam_stats_method	The method used by the server to calculate NULL values when collecting statistics on 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 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.
myisam_use_mmap	Whether to use memory-mapped files 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 settings will not take effect.
server_id_bits	The number of least significant bits in a 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.

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. You can query and set this variable, but the setting will not take effect.
innodb_ft_num_word_optimize	Specifies the minimum number of words to be optimized 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. You can query and set this variable, but the setting will not take effect.
innodb_ft_result_cache_limit	Sets the size of the result cache for InnoDB full-text indexes. The default value is `2000000000` bytes. 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.
innodb_ft_server_stopword_table	Sets 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. You can query and set this variable, but the setting 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. You can query and set this variable, but the setting will not take effect.
innodb_ft_cache_size	Sets the size of the InnoDB full-text index cache. The default value is `8000000` bytes. 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.
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. You can query, but cannot set this variable.
innodb_ft_total_cache_size	Sets the total cache size for InnoDB full-text indexes. The default value is `640000000` bytes. 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.
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. You can query, but cannot set this variable.

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

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. You can query and set this variable, but the setting will not take effect.

Variable name	Description
time_zone	Used to specify the session timezone for the current tenant. It can be set to the offset format (`'+08:00'`) or the region format (`Asia/Shanghai`).
timestamp	`TIMESTAMP` is the timestamp in seconds and affects the result of `select now(6)`.
system_time_zone	Specifies the system time zone of the server.
error_on_overlap_time	Specifies whether to return an error when the times of day in a summer time overlap zone are ambiguous.
nls_language	Specifies the default language for internationalization in the database. This setting is used for prompts, dates, month names, and the default values of `NLS_SORT` and `NLS_DATE_LANGUAGE`.
nls_territory	Specifies the current territory for internationalization in the database. Used together with `nls_language`.
nls_date_language	Specifies the default language of the date for internationalization support.
nls_calendar	Specifies the calendar system used by the database.
ob_timestamp_service	Specifies the timestamp service.

Variable	Description
autocommit	Used to specify whether to automatically commit transactions.
tx_isolation	For specifying transaction isolation levels.
ob_proxy_set_trx_executed	Specifies whether to send the `START TRANSACTION` statement to the OBServer through the ODP.
ob_early_lock_release	Enables or disables the early lock release (ELR) feature for a transaction. Note This variable is deprecated starting from V2.2.30. The ELR behavior is now controlled by the tenant-level parameter `enable_early_lock_release`.
ob_trx_idle_timeout	Used to set the transaction idle timeout. When the time interval between two consecutive statements in a transaction exceeds this value, the transaction will time out.
transaction_isolation	Sets the transaction isolation level.
transaction_read_only	Whether to allow only read-only transactions.
ob_trx_lock_timeout	The transaction wait timeout specifies how long a transaction waits to acquire a lock.
tx_read_only	Specifies whether to enable read-only transactions.
ob_trx_timeout	Sets the transaction timeout period.
ob_trace_info	Used to transmit trace information. The information can eventually be persisted to the REDO logs.
gtid_executed	The set of transactions that have been committed and the GTID set by statements. Default value: `NULL`. Note This variable is available for compatibility with MySQL 5.7. The related functionality is not supported, which means you can query the variable, but cannot set it.
gtid_owned	This variable stores the lists of all GTIDs being used and the IDs of the threads that own them. The default value is `NULL`. Note This variable is available for MySQL 5.7 compatibility. It cannot be set, although it can be queried.

Variable name	Description
ob_enable_sql_audit	Indicates whether to enable the SQL Audit feature for the current tenant.

Variable name	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 conversion between NCHAR/NVARCHAR2 and CHAR/VARCHAR2.
nls_numeric_characters	Specifies the characters used as the decimal separator and thousand separator in string-to-number and number-to-string conversion.
nls_currency	Specifies the local currency symbol for the `L` format element.
nls_iso_currency	Specifies the local currency symbol for the `C` format element.
nls_dual_currency	Specifies the local currency symbol for the `U` format element.
nls_date_format	Specifies the format for converting a DATE value to a string and for implicitly converting a string to a DATE value.
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 non-standard 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 period.
ob_pl_block_timeout	Specifies the maximum timeout period for PL.
cursor_sharing	Specifies whether to parameterize SQL statements.
have_profiling	Specifies whether to support query performance analysis. The default value is `NO`. Note This variable is for MySQL 5.7 compatibility only. The related features are not supported. You can query the variable, but cannot set it.
profiling	Specifies whether to enable or disable statement analysis. The default value is `0`. Note This variable is for MySQL 5.7 compatibility only. The related features are not supported. You can query and set the variable. However, setting the variable 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 for MySQL 5.7 compatibility only. The related features are not supported. You can query and set the variable. However, setting the variable does not take effect.
innodb_strict_mode	Specifies the SQL syntax check mode.
max_connections	Specifies the maximum number of connections for the entire tenant.
sql_mode	Specifies the SQL mode. Different SQL modes have a significant impact on operations such as insertions.
sql_quote_show_create	Specifies whether to enable quote identifiers for the `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. Only requests from sessions where `sql_throttle_current_priority` is less than `sql_throttle_priority` are 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. If the value is set to `0`, no limit is imposed.
max_sp_recursion_depth	Specifies the maximum number of levels for recursive calls to any 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 the entire 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.
ob_enable_pl_async_commit	Specifies whether to enable PL asynchronous commit optimization.
sql_transpiler	Specifies whether to enable the SQL Transpiler feature. Note For V4.4.x versions, this variable is available starting from V4.4.2. For V4.6.x versions, this variable is available starting from V4.6.0.

Variable	Description
binlog_row_image	Specifies whether to record full column logs.
ob_enable_show_trace	This system variable specifies whether to enable trace logs.
ob_log_level	Used to set the log level for the session. If not specified, the system default log level is used.
tracefile_identifier	You can set this variable to a specified value that allows you to filter the lines in the trace log.
master_verify_checksum	Controls whether to enable checksum verification. The default value is `OFF`. Note This variable is introduced only for compatibility with MySQL 5.7. The feature is not supported and can be queried and set. Changes to this variable do not take effect.
log_statements_unsafe_for_binlog	Specifies whether to log error code 1592 to the error log. The default value is `1`. Note This variable is for compatibility with MySQL 5.7 and is not supported. You can query and set it without any error, but the setting has no effect.
binlog_gtid_simple_recovery	Controls how the server iterates over binlog files when searching for GTID during startup or restart. The default value is `1`, indicating that the values of `gtid_executed` and `gtid_purged` will be calculated based on the latest and oldest binlog files' `previous_gtids_log_event` values upon startup. Note This variable is for MySQL 5.7 compatibility only. It does not support any of the related functions and cannot be modified, although it can be queried.
log_bin_basename	binlog file path. The default value is `null`. Note This variable is used for compatibility with MySQL 5.7. You can query this variable but cannot set a value for it.
log_bin_index	The name and path of the binlog index file. Its default value is `null`. Note This variable is for MySQL 5.7 compatibility. The associated feature is not supported, so you can only query this variable, but cannot set it.
log_slave_updates	Specifies whether to log updates received from the master server to the binlog of the replica server. The default value is `OFF`. Note This variable is for MySQL 5.7 compatibility. The related functionality is not supported. You can query this variable but cannot set it.

Variable name	Description
preload_buffer_size	The size of the buffer used for preloading indexes, in bytes. The default value is `32768`. 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 will not take effect.
read_buffer_size	The size of the buffer used for reading data, in bytes. The default value is `131072`. 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 will not take effect.
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, in bytes. The default value is `262144`. 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 will not take effect.
sync_frm	Whether to synchronize the metadata information 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 features are not supported. You can query and set this variable, but the settings will not take effect.
keep_files_on_create	When the `DATA DIRECTORY` or `INDEX DIRECTORY` option is not used to specify the storage location of 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 available 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.
max_heap_table_size	The maximum size to which a user-created memory table can grow, in bytes. The default value is `16777216`. 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 will not take effect.
bulk_insert_buffer_size	The size of the buffer used for bulk inserts, in bytes per thread. 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 settings will not take effect.
general_log_file	The name of the general query log file. The default value is `host_name.log`. 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 will not take effect.
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 features are not supported. You can query and set this variable, but the settings will not take effect.
log_error_verbosity	The level of detail for writing error, warning, and comment information to the error log. The default value is `3`. 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 will not take effect.
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 features are not supported. You can query and set this variable, but the settings will not take effect.
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 features are not supported. You can query and set this variable, but the settings will not take effect.
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 features are not supported. You can query and set this variable, but the settings will not take effect.
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 features are not supported. You can query and set this variable, but the settings will not take effect.
log_syslog_facility	The tool for writing error logs to the system log. The default value is `daemon`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting will not take effect and no error will be reported.
log_syslog_include_pid	Whether to write the service process ID to the system log. 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 and set this variable. However, the setting will not take effect and no error will be reported.
log_syslog_tag	The tag to add to the server identifier in the error log output written to the system log. The default value is `null`. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting will not take effect and no error will be reported.
log_throttle_queries_not_using_indexes	The maximum number of statements to write to the slow query log per minute. The default value is `0`, indicating no limit. Note This variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting will not take effect and no error will be reported.
log_warnings	The record level for additional warning information to be recorded in the error log. 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. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting will not take effect and no error will be reported.
require_secure_transport	Whether secure transport is required for the connection between the client and the server. 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. However, the setting will not take effect and no error will be reported.
slow_launch_time	The time in seconds that a thread creation takes to increase the value of the Slow_launch_threads status variable. 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. However, the setting will not take effect and no error will be reported.
sql_log_off	Whether to enable (OFF) or disable (ON) general query log recording for the current session. 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. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting will not take effect and no error will be reported.
thread_pool_prio_kickup_timer	The time in milliseconds that a statement must wait before it is moved to the high-priority queue. 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 this variable. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, 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 only for compatibility with MySQL 5.7. The related functionality is not supported. You can query, but cannot set this variable.
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 queued while 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 the library 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 the server 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 large page 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 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 the value, but you 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 the value, but you cannot set it.
skip_name_resolve	Specifies whether to resolve the host name when a client connects. The default value is `OFF`, which indicates that the host name must be resolved. Note This variable is available only for compatibility with MySQL 5.7. You can query the value, but you cannot set it.
skip_networking	Specifies whether to allow TCP/IP connections. The default value is `OFF`, which indicates that TCP/IP connections are disabled. Note This variable is available only for compatibility with MySQL 5.7. You can query the value, but you cannot set it.
thread_handling	Specifies the thread model used for handling 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 the value, but you cannot set it.
thread_pool_algorithm	Specifies the algorithm used by the thread pool plugin. The default value is `0`, which indicates the conservative low-concurrency algorithm. Note This variable is available only for compatibility with MySQL 5.7. You can query the value, but you 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 the value, but you cannot set it.
thread_stack	Specifies the stack size of each thread. The default value is `262144`. Note This variable is available only for compatibility with MySQL 5.7. You can query the value, but you 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 the value, but you cannot set it.

Variable name	Description
mysqlx_bind_address	Specifies the network address to which the X plugin listens for TCP/IP connections. The default value is `*`, which means that all TCP/IP connections from all servers are accepted. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query it, but cannot set it.
mysqlx_port	Specifies the network port to 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. You can query it, but cannot set it.
mysqlx_port_open_timeout	Specifies the time in seconds that the X plugin waits for the TCP/IP port to be free. 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 it, but cannot set it.
mysqlx_socket	Specifies the path of 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. You can query it, but cannot set it.
mysqlx_ssl_ca	Specifies the path of 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. You can query it, but cannot set it.
mysqlx_ssl_capath	Specifies the directory path of 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. You can query it, but cannot set it.
mysqlx_ssl_cert	Specifies the path of 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. 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. You can query it, but cannot set it.
mysqlx_ssl_crl	Specifies the name of the file containing the certificate revocation list used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query it, but cannot set it.
mysqlx_ssl_crlpath	Specifies the directory path of the certificate revocation list file used by the X plugin. Note This variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query it, but cannot set it.
mysqlx_ssl_key	Specifies the path of 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. You can query it, but cannot set it.

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 it, 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 it, 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 it, 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 it, 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 it, 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 it, 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 it, 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 it, 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 it, 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 it, 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 it, 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 it, but cannot set it.
performance_schema_max_cond_instances	Specifies the maximum number of condition objects to 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 it, but cannot set it.
performance_schema_max_digest_length	Specifies the maximum length of a normalized SQL statement stored in the performance schema, in bytes. 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 it, 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 it, but cannot set it.
performance_schema_max_file_handles	Specifies 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 features are not supported. You can query this variable but cannot set it.
performance_schema_max_file_instances	Specifies the maximum number of file objects that can be collected. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_index_stat	The maximum number of indexes in the statistics maintained by the Performance Schema. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_memory_classes	Specifies 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 features are not supported. You can query this variable but cannot set it.
performance_schema_max_metadata_locks	Specifies the maximum number of metadata lock collectors. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_mutex_classes	Specifies 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 features are not supported. You can query this variable but cannot set it.
performance_schema_max_mutex_instances	Specifies the maximum number of mutex objects that can be collected. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_prepared_statements_instances	Specifies the maximum number of rows in the `prepared_statements_instances` table. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_program_instances	The maximum number of stored programs in the statistics maintained by the Performance Schema. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_rwlock_classes	Specifies 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 features are not supported. You can query this variable but cannot set it.
performance_schema_max_rwlock_instances	Specifies the maximum number of rwlock objects that can be collected. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_socket_classes	Specifies 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 features are not supported. You can query this variable but cannot set it.
performance_schema_max_socket_instances	Specifies the maximum number of socket objects that can be collected. The default value is `-1`, which indicates automatic scaling. 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.
performance_schema_max_sql_text_length	Specifies the maximum length of an SQL statement that can be stored in the `SQL_TEXT` column of the `events_statements_current`, `events_statements_history`, and `events_statements_history_long` tables, in bytes. The default value is `1024`. 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.
performance_schema_max_stage_classes	Specifies 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 features are not supported. You can query this variable but cannot set it.
performance_schema_max_statement_classes	Specifies 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 features are 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 features are 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. The related feature is not supported. 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. The related feature is not supported. 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. The related feature is not supported. 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. The related feature is not supported. 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. The related feature is not supported. You can query this variable but cannot set it.
performance_schema_session_connect_attrs_size	The size of the preallocated memory for storing connection attribute key-value pairs for each thread, in bytes. The default value is `512`. 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_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. The related feature is not supported. 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. The related feature is not supported. 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. The related feature is not supported. You can query this variable but cannot set it.

Variable name	Description
metadata_locks_cache_size	Sets the size of the metadata lock cache. The default value is `1024` bytes. Note This variable is for MySQL 5.7 compatibility. The related feature is not supported. You can query this variable, but you cannot set it.
metadata_locks_hash_instances	Specifies the number of instances of the metadata lock hash table. The default value is `8`. Note This variable is for MySQL 5.7 compatibility. The related feature is not supported. You can query this variable, but you cannot set it.

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

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

Variable name	Description
optimizer_use_sql_plan_baselines	Specifies whether to use Plan Baseline plans.
optimizer_capture_sql_plan_baselines	Specifies whether to automatically capture new plans to 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 estimated 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	Specifies the storage format to be prioritized when the optimizer generates a base table plan.

Variable name	Description
auto_increment_increment	Sets the auto-increment step size. This variable is used only for MySQL clients.
auto_increment_offset	Specifies the starting value of the `AUTO_INCREMENT` column.
last_insert_id	Returns the value of the last auto-increment column inserted in the current session.
identity	`identity` and the `last_insert_id` variable are synonyms. You can query them by using the `select @@identity` statement.
sql_auto_is_null	Specifies whether to obtain the value of the auto-increment column of the last inserted row.
auto_increment_cache_size	Sets the number of cached auto-increment values.
div_precision_increment	Sets 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.

Variable	Description
character_set_client	Specifies the character set for statements sent by the client.
character_set_connection	Specifies the character set to which received statements should be converted.
character_set_database	Specifies the character set for the default database.
character_set_results	Specifies the character set to which the server should convert result sets or error messages before sending them back to the client.
character_set_server	Specifies the server character set.
character_set_system	Specifies the character set used by the server.
collation_connection	Specifies the character set and collation for the connection.
collation_database	Specifies the default character set and collation for the database.
collation_server	Specifies the default character set and collation for the server.
character_set_filesystem	Specifies the character set type for the file system.
sql_warnings	Controls whether an information string is generated for each line of an INSERT statement when an alert occurs.
init_connect	Specifies the string to be executed by the server for each client connection. The string consists of one or more SQL statements separated by semicolons.
nls_sort	Specifies the collation for string values.
nls_comp	Specifies the comparison rule for string values.
nls_characterset	Specifies the default character set for data types such as CHAR, VARCHAR2, and CLOB in the database.
nls_nchar_characterset	Specifies the default character set for data types such as NCHAR, NVARCHAR2, and NCLOB.

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 setting will not take effect and no error will be reported.
group_replication_allow_local_lower_version_join	Specifies whether to allow a server to join a group if it is running a lower version of MySQL Server than the other members. 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 setting will not take effect and no error will be reported.
group_replication_auto_increment_increment	Specifies the step value for the auto-increment column in each member of the replication group. This ensures that the auto-increment column values are ordered and non-overlapping 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 setting will not take effect and no error will be reported.
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 is only applicable during the initial bootstrap or when 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 setting will not take effect and no error will be reported.
group_replication_components_stop_timeout	Specifies the timeout in seconds for waiting for each component to stop during group replication shutdown. The default value is `2` seconds. 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 setting will not take effect and no error will be reported.
group_replication_compression_threshold	Specifies the threshold for message compression between group members. If the message size exceeds this threshold, it will be compressed. 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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
group_replication_force_members	Specifies the list of member addresses in the format `host1:port1,host2:port2`. This variable is used to force the creation of 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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
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 setting will not take effect and no error will be reported.
group_replication_gtid_assignment_block_size	The number of consecutive GTIDs to reserve 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 and no error is returned.
group_replication_ip_whitelist	The list of hosts (IP addresses or host names) that are allowed to connect to the group. These hosts are referred to as the white list. 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 and no error is returned.
group_replication_local_address	The network address of a group replication member that is provided to other members of the group for connection. 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 and no error is returned.
group_replication_member_weight	The percentage weight of a group member. This weight affects the chance of the member being selected as the primary node during a failover. This variable is meaningful only for a group in single-primary mode. When the primary node of a group in single-primary mode leaves the group, the member with the higher weight is prioritized for selection as the 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 and no error is returned.
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 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 and no error is returned.
group_replication_recovery_complete_at	The strategy for applying cached transactions after the status transfer 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 and no error is returned.
group_replication_recovery_reconnect_interval	The interval between reconnection attempts when a new server cannot find an available donor for distributed recovery. The unit is seconds. 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 and no error is returned.
group_replication_recovery_retry_count	The number of reconnection attempts when a new server cannot find an available donor for 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 and no error is returned.
group_replication_recovery_ssl_ca	The path of the file that contains 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 and no error is returned.
group_replication_recovery_ssl_capath	The path of the directory that contains the certificates issued by 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 and no error is returned.
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 and no error is returned.
group_replication_recovery_ssl_cipher	The list of allowed encryption algorithms for SSL encryption. The supported encryption algorithms vary depending on the version of the SSL library used to compile MySQL Server. 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 and no error is returned.
group_replication_recovery_ssl_crl	The name of the file that contains 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 and no error is returned.
group_replication_recovery_ssl_crlpath	The path of the directory that contains 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 and no error is returned.
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 and no error is returned.
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 feature is not supported. You can query and set this variable, but the setting has no effect.
group_replication_recovery_use_ssl	Specifies whether to use SSL for the connection channel during distributed recovery. 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 has no effect.
group_replication_single_primary_mode	Specifies whether to enable single-primary mode for group replication and automatically select a server to handle read/write workloads. If set to `ON`, only one primary node is readable and writable, and all other group members are secondary nodes. If set to `OFF`, single-primary mode is disabled, and multi-primary mode is enabled. In multi-primary mode, all group members are readable and writable. 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 has no effect.
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 feature is not supported. You can query and set this variable, but the setting has no effect.
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 feature is not supported. You can query and set this variable, but the setting has no effect.
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 feature is not supported. You can query and set this variable, but the setting has no effect.
group_replication_unreachable_majority_timeout	Specifies the waiting time before a group member leaves the group when it is disconnected from the majority of other 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 feature is not supported. You can query and set this variable, but the setting has no effect.

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 provided 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.

Variable name	Description
debug	Specifies the debug options. The default value is `d:t:i:o,/tmp/mysqld.trace`. Note This variable is provided 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.

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

Variable name	Description
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 provided 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.

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 provided 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.
table_open_cache_instances	Specifies the number of open table cache instances. The default value is `16`. Note This variable is provided only for compatibility with MySQL 5.7. The related features are not supported. You can query, but cannot set this variable.

Variable name	Description
ob_capability_flag	Specifies the capabilities provided by the OBServer node. This variable is used to negotiate capabilities with the Proxy, to inform the Proxy of the capabilities supported by the current OBServer node.
ob_proxy_partition_hit	Specifies whether to send SQL statements to the OBServer node where the primary partitions of the requested data are 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 `ALTER TABLE` statements and other DDL statements to use copy operations on tables. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
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 only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_blob_read_batch_bytes	Specifies the size of BLOB data to be read in batches in an NDB Cluster, in bytes. The default value is `65536`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_blob_write_batch_bytes	Specifies the size of BLOB data to be written in batches in an NDB Cluster, in bytes. The default value is `65536`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_deferred_constraints	Specifies whether to delay constraint checks on tables. The default value is `0`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_fully_replicated	Specifies whether to fully replicate new tables. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_index_stat_enable	Specifies whether to enable index statistics collection in NDB. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
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 available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_join_pushdown	Specifies whether to enable join pushdown optimization in the storage engine. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_log_binlog_index	Specifies whether to insert the mapping between epochs and binlog positions into the ndb_binlog_index table. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
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 available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_row_checksum	Specifies the checksum value of a table row. When the value is `1`, the checksum value of each row is calculated and saved. When the value is `0`, no checksum check is performed on the table rows. The default value is `1`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_use_exact_count	Specifies whether to force NDB to use record counts to accelerate `SELECT count(*)` queries during query plan generation. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndb_use_transactions	Specifies whether to enable transaction support in NDB. The default value is `OFF`. Note This variable is available only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. Setting this variable does not generate an error, but the setting does not take effect.
ndbinfo_max_bytes	This variable is available starting with yyy. It is used only for testing and 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. However, the setting does not take effect and no error is returned.
ndbinfo_max_rows	This variable is available starting with yyy. It is used only for testing and debugging. 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 and no error is returned.
ndbinfo_show_hidden	This variable is available starting with yyy. It 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 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.
myisam_repair_threads	This variable is available starting with yyy. It specifies the number of threads to use for repairing MyISAM tables. 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. However, the setting does not take effect and no error is returned.
myisam_sort_buffer_size	This variable is available starting with yyy. It specifies the size of the buffer allocated for sorting MyISAM indexes during the REPAIR TABLE operation or for creating indexes using 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. However, the setting does not take effect and no error is returned.
myisam_stats_method	This variable is available starting with yyy. It 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 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.
myisam_use_mmap	This variable is available starting with yyy. It specifies 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. However, the setting does not take effect and no error is returned.

Variable name	Description
have_profiling	Indicates whether the query performance analysis feature is supported. The default value is `NO`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it.
profiling	Indicates whether to enable or disable the statement analysis feature. The default value is `0`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable 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 feature is not supported. You can query and set the variable. However, setting the variable does not take effect.
enable_sql_plan_monitor	Specifies whether to record SQL statements to the SQL plan monitor for the current session.

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

Variable name	Description
pseudo_slave_mode	Specifies whether to convert the server to a pseudo slave mode. 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 the variable. However, setting the variable does not take effect.
pseudo_thread_id	Specifies the ID of the session thread. The default value is `2147483647`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable does not take effect.
rbr_exec_mode	Specifies whether to set the session thread mode to IDEMPOTENT or STRICT. The default value is `STRICT`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable 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 only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable 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 only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable does not take effect.
read_rnd_buffer_size	Specifies the cache size for reading data from a MyISAM table, and also for multi-range read optimization for any storage engine, in bytes. The default value is `262144`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable does not take effect.
keep_files_on_create	When you do not specify the `DATA DIRECTORY` or `INDEX DIRECTORY` option to specify the location of data or index files, this variable specifies whether to retain existing files in the corresponding directory when a MyISAM table is created. The default value is `OFF`, which indicates to overwrite existing files. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable does not take effect.
max_heap_table_size	Specifies the maximum size to which a memory table can grow, in bytes. The default value is `16777216`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable does not take effect.
bulk_insert_buffer_size	Specifies the cache size for bulk data insertion, in bytes per thread. The default value is `8388608`. Note This variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, setting the variable does not take effect.

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

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

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: the higher the value, the higher the recall rate, but the longer the search time.

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

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

Variable name	Description
group_replication_force_members	Specifies the list of member addresses in the format of `host1:port1,host2:port2`. This variable is used to forcibly establish a new group. After it is set, 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 error will be reported.
group_replication_group_name	Specifies the name of the group replication 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 error will be reported.
group_replication_gtid_assignment_block_size	Specifies the number of consecutive GTIDs to retain 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 error will be reported.
group_replication_ip_whitelist	Specifies the list of hosts (IP addresses or hostnames) that are allowed to connect to the group. These hosts are referred to as whitelist hosts. 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 error 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 error will be reported.
group_replication_recovery_ssl_ca	Specifies the path of 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 error will be reported.
group_replication_recovery_ssl_capath	Specifies the directory path containing the certificates issued by the 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 error 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 error 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 error will be reported.
group_replication_recovery_ssl_crl	Specifies the name of the file 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 error 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 error 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 error will be reported.

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