This topic describes the system variables of OceanBase Database based on the functions of the system variables.
Global level
Security-related variables
| Variable | Description |
|---|---|
| validate_password_check_user_name | Specifies whether a user password can be the same as the username. |
| validate_password_length | Specifies the minimum length of a user password. |
| validate_password_mixed_case_count | Specifies the minimum number of uppercase and lowercase letters in a user password. |
| validate_password_number_count | Specifies the minimum number of digits in a user password. |
| validate_password_policy | Specifies the password check strategy. |
| validate_password_special_char_count | Specifies the minimum number of special characters in a user password. |
| ob_tcp_invited_nodes | Specifies the IP address list of a tenant, which serves as the IP address whitelist. The IP address list supports the percent sign (%), hyphen (-), and IP address. Multiple IP addresses are separated with commas (,). The IP address list supports IP address list matching, mask matching, and fuzzy matching. |
| default_password_lifetime | Specifies the password expiration period. |
| block_encryption_mode | Specifies the encryption algorithm used in the AES encryption and decryption functions. |
| sql_safe_updates | Specifies whether to enable the MySQL SQL security mode. The default value is OFF. |
| super_read_only | Specifies the read/write permissions of the database. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
Variables related to version information
| Variable name | Description |
|---|---|
| version_comment | Displays the version information of the OBServer node. |
| version | Displays the server version number. |
| ob_last_schema_version | Specifies the latest schema version used in the session. |
| ob_proxy_global_variables_version | Specifies the latest version of global variables that the OBServer node returns to the OBproxy. |
| ob_enable_transmission_checksum | Specifies whether to perform packet checksum verification between the obproxy and the OBServer node. This setting takes effect immediately. |
| ob_compatibility_control | Controls the behavior mode when compatibility conflicts occur between MySQL 5.7 and MySQL 8.0. |
| ob_compatibility_version | Specifies the OceanBase Database version that the product is compatible with when its behavior changes. |
| ob_security_version | Specifies the OceanBase Database version that the security feature is compatible with. The compatible version is specified when the tenant is created and cannot be modified after the tenant is created. |
| old_alter_table | Specifies whether to use the ALTER TABLE syntax and operation mode of the earlier version. The default value is OFF.
NoteThis 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 does not take effect and no error is reported. |
Debug-related variables
| Variable name | Description |
|---|---|
| debug | Specifies the debug options. The default value is d:t:i:o,/tmp/mysqld.trace.
NoteThis variable is supported only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| debug_sync | Specifies the synchronization points when Debug is enabled. The default value is an empty string.
NoteThis variable is supported only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| ob_global_debug_sync | Specifies the synchronization points when Debug is enabled. This variable differs from debug_sync in that setting this variable affects all sessions. |
Case sensitivity
| Variable name | Description |
|---|---|
| lower_case_table_names | Specifies whether to use case-sensitive table names. |
Read and write/Query-related
| Variable name | Description |
|---|---|
| query_cache_size | Specifies the memory size allocated for storing the results of historical queries, which is the unused memory. |
| query_cache_type | Specifies the query cache type. |
| ob_query_timeout | Specifies the query timeout period. |
| is_result_accurate | When a query contains the topk hint, is_result_accurate indicates whether the result is accurate. |
| net_buffer_length | Specifies the maximum size of an SQL query that an OBServer node can accept. |
| 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 latency threshold (in microseconds) for weak-consistency reads. |
| net_read_timeout | Specifies the number of seconds that a connection waits for other data to be read before it is interrupted. |
| net_write_timeout | Specifies the number of seconds that a connection waits for block writes before it is interrupted. |
| ob_enable_index_direct_select | Specifies whether to allow users to directly query index tables. |
| ob_enable_aggregation_pushdown | Specifies whether to allow aggregation operations to be pushed down. |
| ob_enable_jit | Specifies the JIT execution engine mode. |
| sql_throttle_network | Specifies the request queuing time. If the queuing time exceeds or equals this value, queries are not executed. |
| parallel_servers_target | Specifies the large query queuing conditions on each server. |
| cte_max_recursion_depth | Specifies the maximum recursion depth of common table expressions (CTEs). The server terminates any operation that exceeds this CTE value. |
| regexp_stack_limit | Specifies the maximum available memory size 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. |
Event Scheduler
| Variable | Description |
|---|---|
| event_scheduler | Specifies whether the event scheduler is enabled and running on the server. |
Replica-related variables
| 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 store replica metadata in an InnoDB table of the MySQL system database or as a file in the data directory. The default value is FILE.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| replication_optimize_for_static_plugin_config | Specifies whether to enable shared locks to improve the performance of semi-synchronous replication. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| replication_sender_observe_commit_only | Specifies whether to enable restricted callbacks to improve the performance of semi-synchronous replication. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| rpl_semi_sync_slave_enabled | Specifies whether to enable semi-synchronous replication on the replica. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| rpl_semi_sync_slave_trace_level | Specifies the debugging trace level for semi-synchronous replication on the replica. The default value is 32, which indicates the network wait level.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| rpl_stop_slave_timeout | Specifies the time to wait for more data or a heartbeat signal from the source before the STOP SLAVE operation times out, in seconds. The default value is 31536000.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_checkpoint_period | Specifies the maximum time allowed, in milliseconds, between the start of a checkpoint operation and the start of the next one to update the progress status of multi-threaded replication. The default value is 300.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_compressed_protocol | When both the source and the replica support compression, specifies whether to use the compression of the source or the replica. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_exec_mode | Specifies how the replication threads resolve conflicts and errors during replication. Setting this variable to IDEMPOTENT suppresses errors for duplicate and not-found keys. Setting this variable to STRICT does not suppress errors for duplicate and not-found keys. The default value is STRICT.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_max_allowed_packet | Specifies the maximum size of data packets for the replication SQL and I/O threads, in bytes. The default value is 1073741824.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_net_timeout | Specifies 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_parallel_type | Specifies the type of parallelism to use for executing replication transactions when multi-threaded replication is enabled. The default value is DATABASE.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_parallel_workers | Specifies the number of threads to use for parallel execution of replication transactions. The default value is 0, which disables parallel execution of replication transactions.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_pending_jobs_size_max | For multi-threaded replication, specifies the maximum length of the work queue for events that have not been applied, in bytes. The default value is 16777216.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_preserve_commit_order | For multi-threaded replication, specifies whether to commit transactions in the order of the relay logs. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_rows_search_algorithms | Specifies the algorithm that the replica uses to search for related rows. The default value is TABLE_SCAN,INDEX_SCAN.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_sql_verify_checksum | Specifies whether to use the checksums read from the relay logs to verify data during replication. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_transaction_retries | Specifies the number of times the system automatically re-executes a transaction when the replication SQL thread fails 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| slave_type_conversions | Specifies the type conversion mode on the replica when using row-based replication. The default value is empty, which specifies to prohibit type conversion between the source and the replica.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| sql_slave_skip_counter | Specifies the number of events to skip from the source for the replica. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect and does not generate an error. |
| skip_slave_start | Specifies whether to skip the startup of the replication thread when the replica server starts. The default value is OFF.
NoteThis 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. |
| slave_load_tmpdir | Specifies the directory name for temporary files created by the replica. The default value is empty.
NoteThis 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. |
| slave_skip_errors | Specifies which errors to skip during replication. The default value is OFF.
NoteThis 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. |
Variables related to the source
| Variable name | Description |
|---|---|
| rpl_semi_sync_master_enabled | Specifies whether to enable semi-synchronous replication on the source. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| rpl_semi_sync_master_timeout | Specifies the time in milliseconds that the source waits for a replica to confirm the transaction after the transaction is committed. The default value is 10000.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| rpl_semi_sync_master_wait_for_slave_count | Specifies the number of replica acknowledgments that each transaction must receive before the source continues. The default value is 1.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| rpl_semi_sync_master_wait_no_slave | Specifies whether to wait for the timeout period specified by the rpl_semi_sync_master_timeout variable when the number of replicas falls below the value set by the rpl_semi_sync_master_wait_for_slave_count variable. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| rpl_semi_sync_master_wait_point | Specifies the point in time at which the semi-synchronous source waits for replica acknowledgment of transaction reception before returning the status to the client that committed the transaction. The default value is AFTER_SYNC.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
Variables related to the recycle bin
| Variable name | Description |
|---|---|
| recyclebin | Specifies whether to enable the recycle bin feature. |
| ob_enable_truncate_flashback | Specifies whether to enable flashback for table truncation. |
Cache-related
| Variable name | Description |
|---|---|
| ob_enable_plan_cache | Specifies whether to enable the plan cache. |
| ob_plan_cache_percentage | Specifies the percentage of memory available to the plan cache out of the total memory of the tenant. |
| ob_plan_cache_evict_high_percentage | Specifies the percentage of memory at which plan cache eviction is triggered, relative to the absolute maximum memory. |
| ob_plan_cache_evict_low_percentage | Specifies the percentage of memory at which plan cache eviction is stopped, relative to the absolute maximum memory. |
| ob_bnl_join_cache_size | Specifies the number of data records to cache for each batch in a Batch Nest Loop Join operation. |
| stored_program_cache | Specifies the number of cached stored procedures and functions. The default value is 256.
NoteThis variable is supported only for MySQL 5.7 compatibility. The related feature is not supported. You can query and set this variable, but the setting does not take effect and no error is reported. |
| table_definition_cache | Specifies the number of memory spaces for caching table definitions. The default value is -1.
NoteThis variable is supported only for MySQL 5.7 compatibility. The related feature is not supported. You can query and set this variable, but the setting does not take effect and no error is reported. |
Function-related
| 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 non-interactive connection. |
| group_concat_max_len | Specifies the maximum length of the result of the GROUP_CONCAT() function. |
InnoDB storage engine-related variables
| Variable name | Description |
|---|---|
| innodb_change_buffering_debug | Specifies the debugging level for changing the InnoDB buffer. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_compress_debug | Specifies the debugging level for adjusting and controlling the compression behavior. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_disable_resize_buffer_pool_debug | Specifies whether to enable the adjustment of the InnoDB buffer pool size. The default value is 1.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_fil_make_page_dirty_debug | Specifies the number of pages to dirty in the InnoDB buffer for debugging. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_limit_optimistic_insert_debug | Specifies the number of records on each B-tree page. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_merge_threshold_set_all_debug | Specifies the page full percentage of index pages. The default value is 50.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_saved_page_number_debug | Specifies the number of page numbers to save in the InnoDB buffer for debugging. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_trx_purge_view_update_only_debug | Specifies the debugging level for updating only the purge view during transaction cleanup. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_trx_rseg_n_slots_debug | Specifies the number of slots in the transaction rollback segment (transaction rollback segment). Each slot stores the rollback information of a transaction. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_stats_persistent | Specifies whether to persist the InnoDB index statistics to the disk. |
| innodb_force_recovery | Specifies the crash recovery mode for repairing the data of the damaged InnoDB storage engine. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| innodb_replication_delay | Specifies the delay of the replication threads on the replication server when the value of the innodb_thread_concurrency variable is reached, in milliseconds. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_large_prefix | Specifies whether to allow index key prefixes longer than 767 bytes (up to 3072 bytes) for InnoDB tables that use the DYNAMIC or COMPRESSED row format. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_sort_buffer_size | Specifies the size of the buffer for sorting operations. The default value is 1048576.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| default_tmp_storage_engine | Specifies the default temporary table storage engine. The default value is InnoDB.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_tmpdir | Specifies the directory for storing temporary files of InnoDB.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| mecab_rc_file | Specifies the path of the MeCab configuration file.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| innodb_temp_data_file_path | Specifies the storage path for temporary data files of InnoDB. The default value is ibtmp1:12M:autoextend, which indicates that InnoDB will use a temporary data file named ibtmp1, with an initial size of 12 MB, and the file will automatically expand as needed to store additional temporary data.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| innodb_data_file_path | Specifies the storage path and filename for InnoDB data files, with the default value of ibdata1:12M:autoextend. This indicates that InnoDB will use a temporary data file named ibdata1, with an initial size of 12 MB, and the file will automatically expand as needed to store additional temporary data.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| innodb_data_home_dir | Specifies the root directory for InnoDB data files.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
Cluster-related variables
| Variable | Description |
|---|---|
| ob_capability_flag | The capabilities of an OBServer node. This variable is used to negotiate capabilities with the proxy. It informs the proxy of the features supported by the current OBServer node. |
| ob_compatibility_mode | The compatibility mode of the tenant. |
| ob_route_policy | The routing strategy for selecting a data replica on an OBServer node. |
| performance_schema | Specifies whether to support queries for performance information. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 8.0. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| resource_manager_plan | The resource management plan. If you specify different plans, different CPU quotas are used to limit user activities in a resource group. |
| license | The type of the license. |
| ob_proxy_partition_hit | Specifies whether to send SQL statements to the OBServer node that hosts the primary partition where the data is located. |
| ob_org_cluster_id | The CLUSTER_ID of the OceanBase cluster. |
| server_uuid | The UUID of the OBServer node. |
| default_storage_engine | 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
System variables related to directory paths
| Variable | Description |
|---|---|
| datadir | The local disk path for storing data. |
| plugin_dir | The path for storing plugin DLLs. |
| secure_file_priv | The path that can be accessed when importing or exporting to a file. |
| ob_enable_hash_group_by | Specifies whether to enable Hash Group by. |
System variables related to the MyISAM storage engine
| Variable | Description |
|---|---|
| delay_key_write | Specifies whether to delay the writing of index keys for MyISAM tables. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and no error is reported. |
| key_buffer_size | Specifies the size of the key buffer for the MyISAM storage engine. The default value is 8388608.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and no error is reported. |
| key_cache_age_threshold | Specifies the threshold for degrading the hot sublists of the key cache to the warm sublists. A lower value means faster degradation. The default value is 300.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and no error is reported. |
| key_cache_block_size | Specifies the size of each block in the MyISAM key cache. The default value is 1024.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and no error is reported. |
| key_cache_division_limit | Specifies the division limit for the MyISAM key cache. The default value is 100.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and no error is reported. |
| max_seeks_for_key | Specifies the maximum number of address operations performed in a MyISAM query. The default value is 18446744073709551615.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and no error is reported. |
Temporary files
| Variable | Description |
|---|---|
| max_tmp_tables | The maximum number of temporary tables that a user session can hold simultaneously. The default value is 32.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not trigger an error but also does not take effect. |
Memory
| Variable | Description |
|---|---|
| ob_sql_work_area_percentage | The percentage of tenant memory that is allocated for SQL execution. |
| ob_sql_audit_percentage | The maximum percentage of tenant memory that is allocated for SQL audit. |
| ob_reserved_meta_memory_percentage | The percentage of tenant memory that is reserved for storing meta-related structural information. |
| ob_temp_tablespace_size_percentage | The percentage of tenant memory that is allocated for temporary tablespaces. |
System logs
| Variable | Description |
|---|---|
| binlog_row_image | Specifies whether to record full-column logs. |
| ob_enable_show_trace | Specifies whether to use trace logs. |
| ob_log_level | The log level of the session. If not specified, the system log level is used. |
| tracefile_identifier | Specifies the content to be added to the log for filtering row iteration trace logs. |
| master_verify_checksum | Specifies whether to enable checksum verification. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not trigger an error but also does not take effect. |
Full-text indexing-related
| Variable name | Description |
|---|---|
| innodb_ft_enable_diag_print | Specifies whether to enable or disable diagnostic output for InnoDB full-text indexing. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and does not generate an error. |
| innodb_ft_num_word_optimize | Specifies the minimum number of words to be processed during an OPTIMIZE TABLE operation. The default value is 2000.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and does not generate an error. |
| innodb_ft_result_cache_limit | Specifies the size of the result cache for InnoDB full-text indexing. The default value is 2000000000, which is in bytes.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and does not generate an error. |
| innodb_ft_server_stopword_table | Specifies the server stopword table for InnoDB full-text indexing. The default value is NULL.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and does not generate an error. |
| innodb_optimize_fulltext_only | Specifies whether to perform an OPTIMIZE TABLE operation only on InnoDB tables that contain FULLTEXT indexes. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting it does not take effect and does not generate an error. |
| innodb_ft_cache_size | Specifies the size of the InnoDB full-text index cache. The default value is 8000000, which is in bytes.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| innodb_ft_sort_pll_degree | Specifies the number of parallel threads for sorting full-text indexes. The default value is 2.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| innodb_ft_total_cache_size | Specifies the total size of the InnoDB full-text index cache. The default value is 640000000, which is in bytes.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| ft_stopword_file | Specifies the path of the file that contains stop words to be excluded. The default value is built-in.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
Runtime Filter related
| Variable name | Description |
|---|---|
| runtime_filter_type | Specifies the type of runtime filter for a tenant. |
| runtime_filter_wait_time_ms | Specifies the maximum wait time for a runtime filter. |
| runtime_filter_max_in_num | Specifies the number of NDV (number of distinct values) for a runtime in filter. |
| runtime_bloom_filter_max_size | Specifies the maximum memory size of a runtime Bloom filter, in bytes. |
Upgrade related
| Variable name | Description |
|---|---|
| avoid_temporal_upgrade | Specifies the behavior of upgrading time-sensitive data (such as dates and times). The default value is OFF.
NoteThis 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 does not take effect and no error is reported. |
Time zones and dates
| Variable name | Description |
|---|---|
| time_zone | Specifies the time zone for the current tenant session. Valid values are in the offset format, such as '+08:00', and the region format, such as Asia/Shanghai. |
| timestamp | TIMESTAMP is a timestamp in seconds. This variable 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 time zone overlaps occur. |
| nls_language | Specifies the default language for database internationalization support. This variable is used to specify the default values for prompts, dates, month names, NLS_SORT, and NLS_DATE_LANGUAGE. |
| nls_territory | Specifies the current region for database internationalization support. This variable is used in combination with nls_language. |
| nls_date_language | Specifies the default language for dates in database internationalization support. |
| nls_calendar | Specifies the calendar system used by the database. |
| ob_timestamp_service | Specifies the timestamp service to be used. |
Transaction and transaction log related
| Variable name | Description |
|---|---|
| autocommit | Specifies whether to automatically commit a transaction. |
| tx_isolation | Specifies the transaction isolation level. |
| ob_proxy_set_trx_executed | Specifies whether to send the START TRANSACTION Syntax statement to the OBServer node through obproxy. |
| ob_early_lock_release | Specifies whether to enable the early lock release (ELR) feature for a transaction.
NoteThis variable is deprecated in V2.2.30. The ELR feature is now controlled by the tenant-level configuration item |
| ob_trx_idle_timeout | Specifies the transaction idle timeout period, which is the time interval between the execution of two statements in a transaction that exceeds the timeout period. |
| transaction_isolation | Specifies the transaction isolation level. |
| transaction_read_only | Specifies whether to allow only read-only transactions. |
| ob_trx_lock_timeout | Specifies the timeout period for a transaction to wait for a lock. |
| tx_read_only | Specifies whether to set a transaction to read-only. |
| ob_trx_timeout | Specifies the transaction timeout period. |
| ob_trace_info | Specifies whether to pass trace information, which can be persisted to the redo log. |
Audit related
| Variable name | Description |
|---|---|
| ob_enable_sql_audit | Specifies whether to enable the SQL audit feature for the current tenant. |
Data types
| Variable name | Description |
|---|---|
| nls_length_semantics | Specifies the length semantics for the CHAR and VARCHAR2 data types. |
| nls_nchar_conv_excp | Specifies whether to return an error when data is lost during conversion between the NCHAR and NVARCHAR2 data types and the CHAR and VARCHAR2 data types. |
| nls_numeric_characters | Specifies the characters used for decimal and thousand separators in string representations of numbers. |
| nls_currency | Specifies the local currency symbol for the L format element in the number format. |
| nls_iso_currency | Specifies the local currency symbol for the C format element in the number format. |
| nls_dual_currency | Specifies the local currency symbol for the U format element in the number format. |
| nls_date_format | Specifies the format for converting the date data type to a string and for implicitly converting a string to a date. |
| nls_timestamp_format | Specifies the format for converting the TIMESTAMP or TIMESTAMP_LTZ data types to a string and for implicitly converting a string to a TIMESTAMP or TIMESTAMP_LTZ data type. |
| nls_timestamp_tz_format | Specifies the format for converting the TIMESTAMP_TZ data type to a string and for implicitly converting a string to a TIMESTAMP_TZ data type. |
| 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 LOBs. |
| ob_default_lob_inrow_threshold | Specifies the default in-row storage threshold for LOB fields when a table is created. |
SQL/PL related
| 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 performance analysis is supported. The default value is NO.
NoteThis variable is supported only for MySQL 5.7 compatibility. The related feature is not supported. You can query this variable, but cannot set it. |
| profiling | Specifies whether to enable the statement analysis feature. The default value is 0.
NoteThis variable is supported only for MySQL 5.7 compatibility. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| profiling_history_size | Specifies the number of records to be saved for query performance information. The default value is 15.
NoteThis variable is supported only for MySQL 5.7 compatibility. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is returned. |
| innodb_strict_mode | Specifies the SQL check mode for specific syntaxes. |
| max_connections | Specifies the maximum number of connections for the tenant. |
| sql_mode | Specifies the SQL mode, which has a significant impact on operations such as data insertion. |
| sql_quote_show_create | Specifies whether to enable identifier quoting for 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 SQL execution error occurs. |
| sql_throttle_current_priority | Specifies the throttling priority. Only requests from sessions where sql_throttle_current_priority is less than sql_throttle_priority will be throttled. |
| sql_throttle_priority | Specifies the throttling priority. |
| sql_throttle_rt | Specifies the response time (RT) value. |
| max_allowed_packet | Specifies the maximum size of network packets. |
| max_user_connections | Specifies the maximum number of connections that a single user can establish with an OBServer node. A value of 0 indicates no limit. |
| max_sp_recursion_depth | Specifies the maximum number of recursive calls to any specified stored procedure. |
| sql_select_limit | Specifies the maximum number of rows that a single SELECT query can return. |
| max_connections | Specifies the maximum number of connections for the tenant. |
| ob_enable_blk_nestedloop_join | Specifies whether to enable block nested loop join. |
| parallel_max_servers | Specifies the maximum number of threads in the parallel execution (PX) thread pool on each server. |
Lock-related
| Variable name | Description |
|---|---|
| metadata_locks_cache_size | Specifies the cache size for metadata locks. The default value is 1024 bytes.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. It can be queried but cannot be set. |
| metadata_locks_hash_instances | Specifies the number of instances for the metadata lock hash table. The default value is 8.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. It can be queried but cannot be set. |
Foreign key-related
| Variable name | Description |
|---|---|
| foreign_key_checks | Specifies whether to check foreign key constraints during DML or DDL operations. |
Optimizer-related
| Variable name | Description |
|---|---|
| optimizer_use_sql_plan_baselines | Controls whether the optimizer uses plan baselines. |
| optimizer_capture_sql_plan_baselines | Controls whether to automatically capture new plans to plan baselines. |
| parallel_degree_policy | Specifies the parallelism selection strategy. |
| parallel_degree_limit | Specifies the maximum degree of parallelism that the optimizer selects 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 | Controls the level of dynamic sampling. |
| optimizer_features_enable | Specifies the optimizer features of different OceanBase versions. |
| ob_enable_transformation | Specifies whether to enable the rewrite feature of the SQL optimizer. |
| ob_table_access_policy | Controls the optimizer to prefer specific storage formats when generating base table plans. |
Auto-increment columns
| Variable | Description |
|---|---|
| auto_increment_increment | Specifies the auto-increment step, which is only used when a MySQL client logs in. |
| auto_increment_offset | Specifies the starting value of the AUTO_INCREMENT column. |
| last_insert_id | Returns the last auto-increment field value inserted in the current session. |
| identity | identity and last_insert_id are synonyms. You can run select @@identity to query the value. |
| sql_auto_is_null | Specifies whether to retrieve the auto-increment column value of the last inserted row. |
| auto_increment_cache_size | Specifies the number of auto-increment values cached. |
| div_precision_increment | Specifies the increment of the precision of the result of a division operation based on the precision of the dividend. This is a MySQL-compatible feature. |
Character sets and strings
| Variable | Description |
|---|---|
| character_set_client | Specifies the character set for statements sent by the client. |
| character_set_connection | Specifies the character set for statements received by the server. |
| character_set_database | Specifies the character set for the default database. |
| character_set_results | Specifies the character set for converting results or error messages sent to the client. |
| character_set_server | Specifies the character set for the server. |
| 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 creating databases. |
| collation_server | Specifies the default character set and collation for the server. |
| character_set_filesystem | Specifies the character set for the file system. |
| sql_warnings | Controls whether to generate an information string for single-line INSERT statements when an alert is triggered. |
| init_connect | Specifies the string executed by the server for each client connection, which consists of one or more SQL statements separated by semicolons. |
| nls_sort | Specifies the collation for the string value. |
| nls_comp | Specifies the comparison rule for the string value. |
| nls_characterset | Specifies the default character set for CHAR, VARCHAR2, CLOB, and other data types in the database. |
| nls_nchar_characterset | Specifies the default character set for NCHAR, NVARCHAR2, and NCLOB data types in the database. |
Group Replication-related
| Variable name | Description |
|---|---|
| group_replication_allow_local_disjoint_gtids_join | Specifies whether to allow a server to join the group if the server has local transactions that are not in the group. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_allow_local_lower_version_join | Specifies whether to allow a server to join the group if the server is running a MySQL Server version that is earlier than the version of other members in the group. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_auto_increment_increment | Specifies the auto-increment value step for each member in the group to ensure that the auto-increment values of the group members are ordered and non-overlapping in multi-primary mode. The default value is 7.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_bootstrap_group | Specifies whether to use the current server to bootstrap the group. This variable can be set on only one server and can be set on only one of the servers when the group is being bootstrapped or re-bootstrapped. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_components_stop_timeout | Specifies the timeout period for each component when the group is being shut down, in seconds. The default value is 2.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_compression_threshold | Specifies the threshold for the number of messages sent between group members. When the threshold is exceeded, the messages are compressed. The default value is 1000000.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is 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 specifies to disable the checks.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_flow_control_mode | Specifies the mode for flow control. The default value is QUOTA.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| 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 this variable is set, members not specified in this variable will not receive new view messages and will be blocked (write operations are blocked). The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_group_name | Specifies the name of the group replication group to which the current server belongs. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_group_seeds | Specifies the list of seed member addresses in the format of host1:port1,host2:port2. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_gtid_assignment_block_size | Specifies the number of consecutive GTIDs to reserve for each member. The default value is 1000000.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_ip_whitelist | Specifies the hosts (IP addresses or hostnames) that are allowed to connect to the group. The allowed addresses are called the allowlist. The default value is AUTOMATIC.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_local_address | Specifies the network address for group replication members to provide to other members in the group for connection access. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_member_weight | Specifies the percentage weight for a group member, which affects the likelihood of the member being elected as the primary node during a failover (only relevant for groups in single-primary mode). In a group in single-primary mode, if the primary node leaves the group, the member with a higher weight is more likely to be elected as the primary node. The default value is 50.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_poll_spin_loops | Specifies the number of times the group replication communication thread waits for the communication engine's mutex to be released before it proceeds to wait for more network messages. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_complete_at | Specifies the strategy for applying cached transactions after the completion of state transfer during distributed recovery. The default value is TRANSACTIONS_APPLIED.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_reconnect_interval | Specifies the interval between reconnection attempts when a new server cannot find a suitable donor for distributed recovery. The default value is 60 seconds.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_retry_count | Specifies the number of reconnection attempts when a new server cannot find a suitable donor for distributed recovery. The default value is 10.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_ca | Specifies the path of the file that contains the list of trusted SSL certificate authorities for distributed recovery. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_capath | Specifies the directory path of the file that contains the certificates issued by the trusted SSL certificate authorities for distributed recovery. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is 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 empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_cipher | Specifies the list of encryption algorithms allowed for SSL encryption. The available encryption algorithms depend on the SSL library version used when MySQL Server was compiled. Different SSL libraries support different encryption algorithms. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_crl | Specifies the file name that contains the certificate revocation list. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_crlpath | Specifies the directory path of the file that contains the certificate revocation list. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is 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 empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_use_ssl | Specifies whether to use SSL for the connection channel during distributed recovery of group replication members. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_single_primary_mode | Specifies whether the group is in single-primary mode and whether to automatically select a server to handle read and write workloads. If this variable is set to ON, only one writable primary node exists, and other group members are all secondary nodes. If this variable is set to OFF, single-primary mode is disabled, and multi-primary mode is enabled. In multi-primary mode, all group members are usually writable primary nodes. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_ssl_mode | Specifies the security state of SSL connections between group replication members. The default value is DISABLED.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_start_on_boot | Specifies whether to start group replication when the server is started. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_transaction_size_limit | Specifies the maximum transaction size that can be received in group replication, in bytes. The default value is 150000000.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_unreachable_majority_timeout | Specifies the wait time before a group member leaves the group when the member is disconnected from the majority of members in the group due to a network partition. The default value is 0 seconds.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
Session-level
Session variables related to version information
| Variable name | Description |
|---|---|
| ob_last_schema_version | Specifies the latest schema version used in the session. |
| old_alter_table | Specifies whether to enable the ALTER TABLE syntax and operation mode of the earlier version. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting this variable does not trigger an error, but the setting does not take effect. |
Debug-related variables
| Variable name | Description |
|---|---|
| debug | Specifies the debugging options. The default value is d:t:i:o,/tmp/mysqld.trace.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting this variable does not trigger an error, but the setting does not take effect. |
| debug_sync | Specifies the synchronization points when debugging. The default value is an empty string.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting this variable does not trigger an error, but the setting does not take effect. |
Read/write and query-related variables
| Variable name | Description |
|---|---|
| is_result_accurate | When a query contains the topk hint, is_result_accurate indicates whether the result is correct. |
| long_query_time | Specifies the threshold for slow queries. |
Replica-related variables
| Variable name | Description |
|---|---|
| master_info_repository | Specifies whether to record the metadata in the InnoDB table mysql of the system database or as a file in the data directory. The default value is FILE.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting this variable does not trigger an error, but the setting does not take effect. |
Cache-related variables
| Variable name | Description |
|---|---|
| table_definition_cache | Specifies the number of memory spaces for caching table definitions. The default value is -1.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, setting this variable does not trigger an error, but the setting does not take effect. |
Cluster-related
| Variable | Description |
|---|---|
| ob_capability_flag | The capabilities of the OBServer node, which are used for capability negotiation with the Proxy. This variable informs the Proxy of the features supported and not supported by the current OBServer node. |
| ob_proxy_partition_hit | Specifies whether to send SQL statements to the OBServer nodes hosting the primary partitions of the data. |
| ob_org_cluster_id | The CLUSTER_ID of the OceanBase cluster. |
SQL/PL-related
| Variable | Description |
|---|---|
| have_profiling | Indicates whether performance analysis is supported. The default value is NO.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. It can be queried but cannot be set. |
| profiling | Specifies whether to enable statement analysis. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. It can be queried and set, but setting it does not result in an error or take effect. |
| profiling_history_size | The number of historical records for query performance information. The default value is 15.
NoteThis variable is only for compatibility with MySQL 5.7. The related feature is not supported. It can be queried and set, but setting it does not result in an error or take effect. |
System log-related
| Variable | Description |
|---|---|
| ob_enable_show_trace | Specifies whether to use trace logs. |
| tracefile_identifier | Specifies content to add to the log for easy filtering of row iteration trace logs. |
System server-related
| Variable name | Description |
|---|---|
| pseudo_slave_mode | Specifies whether to switch the server to a pseudo slave mode. Default value is OFF.
NoteThis variable is for backward compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable. No error is returned when you set this variable, but the variable does not take effect. |
| pseudo_thread_id | The ID of the session thread. The default value is 2147483647.
NoteThe variable is used only to support compatibility with MySQL 5.7. You can query and set the variable. However, setting the variable does not trigger an error or take effect. |
| rbr_exec_mode | Specifies whether the session thread runs in the IDEMPOTENT or STRICT mode. Default value is |
STRICT.
Note
This variable is supported only for compatibility with MySQL 5.7. You can query the value of the variable but cannot set it. If you set the variable, an error is not reported, but the setting does not take effect.
Time zones and dates
| Variable Name | Description |
|---|---|
| timestamp | TIMESTAMP specifies the timestamp in seconds. The value of 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. |
Transactions and transaction logs
| Variable Name | Description |
|---|---|
| ob_proxy_set_trx_executed | Specifies whether a START TRANSACTION Syntax statement is sent to an OBServer node through an OBProxy. |
| ob_trace_info | Specifies a trace information field to be persisted to the redo logs. |
Optimizer-related
| Variable Name | Description |
|---|---|
| ob_table_access_policy | Specifies the default preferred storage format for the optimizer to generate base table plans. |
Auto-increment columns
| Variable | Description |
|---|---|
| last_insert_id | Returns the auto-increment field value of the last insertion in the current session. |
Group Replication-related variables
| 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 this variable is set, members not specified in this variable will not receive new view messages and will be blocked (from writing). The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_group_name | Specifies the name of the group replication group to which the current server belongs. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_gtid_assignment_block_size | Specifies the number of consecutive GTIDs to be reserved for each member. The default value is 1000000.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_ip_whitelist | Specifies the host (IP address or host name) that is allowed to connect to the group. The allowed address is called a white list address. The default value is AUTOMATIC.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_local_address | Specifies the network address for a group replication member to provide to other members in the group for connection access. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_ca | Specifies the path of the file that contains the list of trusted SSL certificate authorities for distributed recovery connections. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_capath | Specifies the directory path of the certificate issued by the trusted SSL certificate authorities for distributed recovery connections. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_cert | Specifies the name of the SSL certificate file for establishing a secure connection required for distributed recovery. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_cipher | Specifies the list of encryption algorithms that can be used for SSL encryption. The available encryption algorithms depend on the version of the SSL library used when MySQL Server was compiled. Different SSL libraries support different encryption algorithms. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_crl | Specifies the name of the file that contains the certificate revocation list. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_crlpath | Specifies the directory path of the certificate revocation list file. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |
| group_replication_recovery_ssl_key | Specifies the name of the SSL key file for establishing a secure connection required for distributed recovery. The default value is empty.
NoteThis variable is only supported for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect and no error is reported. |