This topic describes the system variables of OceanBase Database.
- Global level
Security-related
| Variable | Description |
|---|---|
| validate_password_check_user_name | Specifies whether to allow the password to 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 for the tenant. Supports the use of the percent sign (%), underscore (_), and multiple IP addresses separated by commas. Supports IP list matching, mask matching, and fuzzy matching. |
| default_password_lifetime | Specifies the password expiration time. |
| block_encryption_mode | Specifies the encryption algorithm used in the aes_encrypt and aes_decrypt functions. |
| sql_safe_updates | Specifies whether to enable the SQL safe mode of MySQL. The default value is OFF. |
| lower_case_table_names | Specifies whether to be case-sensitive. |
| super_read_only | Controls the read and write permissions of the database. 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, but the setting will not take effect and no error will be reported. |
| check_proxy_users | Specifies whether to enable or disable checks for proxy user mappings. 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, but the setting will not take effect and no error will be reported. |
| keyring_aws_cmk_id | Specifies the customer master key (CMK) ID of the Amazon Web Services (AWS) Key Management Service (KMS).
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| keyring_aws_region | Specifies the AWS region for the Key Management Service. The default value is us-east-1.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| keyring_encrypted_file_data | Specifies the path of the file used to store the encrypted key.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| keyring_encrypted_file_password | Specifies the password used to encrypt the key file.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| keyring_file_data | Specifies the file path used to store the key.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| keyring_okv_conf_dir | Specifies the path of the Oracle Key Vault configuration directory.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| keyring_operations | Specifies the key operation mode, such as read and write. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect and no error will be reported. |
| max_connect_errors | Specifies the maximum number of connection errors. After this number is exceeded, the user is prohibited from connecting. The default value is 100.
NoteThis 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. |
| mysql_firewall_mode | Specifies the working mode of the MySQL firewall. The default value is ON.
NoteThis 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. |
| mysql_firewall_trace | Specifies whether to enable or disable firewall tracing. The default value is OFF.
NoteThis 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. |
| mysql_native_password_proxy_users | Specifies whether to support proxy users for native password authentication. The default value is OFF.
NoteThis 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. |
| net_retry_count | Specifies the number of network retries. The default value is 10.
NoteThis 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. |
| old_passwords | Specifies the password hashing method used by functions. The default value is 0.
NoteThis 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. |
| secure_auth | Specifies whether to use new passwords for secure authentication. The default value is ON.
NoteThis 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. |
| sha256_password_proxy_users | Specifies whether to support proxy users for SHA-256 password authentication. The default value is OFF.
NoteThis 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. |
| show_compatibility_56 | Specifies whether to be compatible with MySQL 5.6. The default value is OFF.
NoteThis 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. |
| validate_password_dictionary_file | Specifies the path of the dictionary file for password validation.
NoteThis 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. |
| auto_generate_certs | Specifies whether to automatically generate SSL key and certificate files in the data directory. The default value is ON.
NoteThis 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. |
| disconnect_on_expired_password | Specifies whether to disconnect the connection when the password expires. The default value is ON.
NoteThis 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. |
| have_dynamic_loading | Specifies whether to support dynamic loading of plugins. The default value is YES.
NoteThis 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. |
| keyring_aws_conf_file | Specifies the path of the AWS keyring configuration file.
NoteThis 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. |
| keyring_aws_data_file | Specifies the path of the AWS keyring data file.
NoteThis 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. |
| lower_case_file_system | Specifies whether to run MySQL on a case-insensitive file system. The default value is OFF.
NoteThis 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. |
| max_digest_length | Specifies the maximum memory in bytes that each session can occupy. The default value is 1024.
NoteThis 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. |
| ndbinfo_database | Specifies the database for NDB information. The default value is ndbinfo.
NoteThis 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. |
| sha256_password_private_key_path | The path where the private key for SHA-256 password authentication is stored. The default value is private_key.pem.
NoteThis variable is available only for compatibility with MySQL 5.7. You can query the value but cannot set it. |
| sha256_password_public_key_path | The path where the public key for SHA-256 password authentication is stored. The default value is public_key.pem.
NoteThis variable is available only for compatibility with MySQL 5.7. You can query the value but cannot set it. |
| skip_show_database | Whether to allow only users with the SHOW DATABASES privilege to execute the SHOW DATABASES statement and display all database names. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. You can query the value but cannot set it. |
Version information related attributes
| Variable name | Description |
|---|---|
| version_comment | Displays the version information of the OBServer node. |
| version | 1. The value of this variable indicates the version of the server. |
| ob_proxy_global_variables_version | Sets the latest version of global variables that the OBServer node returns to the OBproxy node. |
| ob_enable_transmission_checksum | Sets whether to enable the data packet checksum between the ODP and OBServer nodes. This option takes effect immediately after being set. |
| ob_compatibility_control | Controls the behavior mode when there are compatibility conflicts between MySQL 5.7 and MySQL 8.0. Specify the compatibility mode when you create a tenant. You cannot modify the mode after the tenant is created. |
| ob_compatibility_version | The compatible OceanBase Database version for the features that change the product behavior. Specify the compatible version when you create a tenant. You cannot change the compatible version after the tenant is created. |
| ob_security_version | The OceanBase Database version that is compatible with the security feature. Specify the compatible version when you create a tenant, and this parameter cannot be modified after the tenant is created. |
| new | Sets whether to enable some behaviors introduced in MySQL 4.1 in MySQL 4.0 and ensure backward compatibility. The default value is OFF.
NoteThis variable is available only for MySQL 5.7 backward compatibility. You can query and set the variable, but the variable setting does not take effect. |
| version_tokens_session | The variable to set the version tokens for a session. Its default value is NULL, which means all server versions are matched.
NoteThis variable is only for compatibility with MySQL 5.7. The related functions are not supported, but you can query and modify it. The modifications do not take effect. |
Debugging
| Variable | Description |
|---|---|
| debug | For debugging. The default value is d:t:i:o,/tmp/mysqld.trace.
NoteThis variable is for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. The setting does not trigger an error, but has no effect. |
| ob_global_debug_sync | Specifies a debug synchronization point. When you set this variable, all sessions are affected. |
Read/write and query-related variables
| Variable | Description |
|---|---|
| query_cache_size | Specifies the amount of memory allocated for storing query results that are not yet used. |
| query_cache_type | Specifies the query cache type. |
| ob_query_timeout | Specifies the query timeout. |
| 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 | 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 to the connection 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 is not allowed to be executed. |
| parallel_servers_target | Specifies the conditions for queuing 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. |
| big_tables | Specifies whether to enable large table queries. If enabled, you can use the features of large MyISAM tables. 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, but the settings will not take effect. |
| optimizer_prune_level | Controls the behavior of the query optimizer. The optimizer skips unnecessary query plans based on the estimated number of rows accessed from each table, thereby reducing query compilation time. The default value is 1.
NoteThis 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. |
| optimizer_search_depth | Specifies the depth of query execution plan search performed by the optimizer. The default value is 62.
NoteThis 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. |
| optimizer_switch | Specifies the behavior options of the optimizer to enable or disable specific features.
NoteThis 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. |
| optimizer_trace | Enables the query optimizer trace feature for debugging and analyzing query execution plans.
NoteThis 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. |
| optimizer_trace_features | Specifies the features to include in the optimizer trace.
NoteThis 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. |
| optimizer_trace_limit | This variable specifies the maximum number of optimizer trace entries. The default value is 1.
NoteThis variable is available 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 return an error. |
| optimizer_trace_max_mem_size | This variable specifies the maximum memory usage of the optimizer trace. The default value is 16384.
NoteThis variable is available 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 return an error. |
| optimizer_trace_offset | This variable specifies the offset of the optimizer trace. The default value is -1.
NoteThis variable is available 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 return an error. |
| range_optimizer_max_mem_size | This variable specifies the maximum memory usage of the range optimizer. The default value is 8388608.
NoteThis variable is available 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 return an error. |
| rewriter_enabled | This variable specifies whether to enable the query rewrite feature. The default value is OFF.
NoteThis variable is available 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 return an error. |
| rewriter_verbose | This variable specifies whether to enable verbose mode for debugging the query rewrite process. The default value is 0.
NoteThis variable is available 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 return an error. |
| show_create_table_verbosity | This variable specifies whether to display the row format when a table is created. The default value is OFF.
NoteThis variable is available 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 return an error. |
| sql_big_selects | This variable specifies whether to enable large queries. The default value is ON.
NoteThis variable is available 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 return an error. |
Scheduler-related
| Variable | Description |
|---|---|
| event_scheduler | Indicates whether the event scheduler is enabled and running on the server. |
Variables related to replicas
| 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.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 | Specifies whether to enable shared locks to improve the performance of semi-synchronous replication. The default value is OFF.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 | Specifies whether to enable limited callbacks to improve the performance of semi-synchronous replication. The default value is OFF.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 | Specifies whether to enable semi-synchronous replication on a replica. The default value is OFF.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 for semi-synchronous replication on a replica. The default value is 32, which indicates the network waiting level.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 the STOP SLAVE statement times out, in seconds. The default value is 31536000.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 the multi-threaded replication threads before a checkpoint operation is called to update the progress status. The default value is 512.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 the multi-threaded replication threads, in milliseconds. The default value is 300.
NoteThis variable is only used for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the settings will not take effect. |
| slave_compressed_protocol | Specifies whether to use the compression of the source or replica protocol when both the source and replica support compression. The default value is OFF.
NoteThis variable is only used for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable. |
| slave_exec_mode | Specifies how the replication threads resolve conflicts and errors during replication. Setting this variable to IDEMPOTENT suppresses errors for duplicate and missing keys; setting it to STRICT does not suppress these errors. The default value is STRICT.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 an SQL or I/O thread data packet, in bytes. The default value is 1073741824.
NoteThis variable is only used for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the settings will not take effect. |
| slave_net_timeout | Specifies the time to wait for more data or a heartbeat signal from the source before the replica considers the connection to be disconnected, aborts reading, and attempts to reconnect, in seconds. The default value is 60.
NoteThis variable is only used for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable. |
| slave_parallel_type | Specifies the type of parallel execution for replication transactions when multi-threaded replication is enabled. The default value is DATABASE.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 to execute replication transactions in parallel. The default value is 0, which indicates that parallel execution of replication transactions is disabled.
NoteThis variable is only used for MySQL 5.7 compatibility. 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 for storing unapplied events, in bytes. The default value is 16777216.
NoteThis variable is available 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 but does not return an error. |
| slave_preserve_commit_order | For multi-threaded replication, specifies whether to commit transactions in the order they are replayed from the logs. The default value is OFF.
NoteThis variable is available 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 but does not return an error. |
| slave_rows_search_algorithms | Specifies the algorithm used by the replica to search for related rows. The default value is TABLE_SCAN,INDEX_SCAN.
NoteThis variable is available 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 but does not return an error. |
| slave_sql_verify_checksum | Specifies whether to verify data using the checksum read from the replayed logs. The default value is OFF.
NoteThis variable is available 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 but does not return an error. |
| slave_transaction_retries | Specifies the number of times the system automatically retries a transaction that fails due to a deadlock or because the transaction execution time exceeds the value specified by the innodb_lock_wait_timeout variable. The default value is 10.
NoteThis variable is available 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 but does not return an error. |
| slave_type_conversions | Specifies the type conversion mode for replicas when using row-based replication. The default value is empty, indicating that type conversion between the source and replica is disabled.
NoteThis variable is available 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 but does not return an error. |
| sql_slave_skip_counter | Specifies the number of events from the source that the replica should skip. The default value is 0.
NoteThis variable is available 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 but does not return an error. |
| skip_slave_start | Specifies whether to skip starting the replication thread when the replica server starts. The default value is OFF.
NoteThis 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 creating temporary files on the replica. The default value is empty.
NoteThis 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.
NoteThis 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. |
| max_relay_log_size | Specifies the threshold for automatically rotating relay log files. The default value is 0.
NoteThis variable is available 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 but does not return an error. |
| relay_log_info_repository | Specifies whether to store the application metadata repository of the replica server as an InnoDB table in the mysql system database or as a file in the data directory. The default value is FILE.
NoteThis variable is available 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 but does not return an error. |
| relay_log_purge | Specifies whether to enable or disable automatic purging of unnecessary relay log files. The default value is 1.
NoteThis variable is available 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 but does not return an error. |
| sync_relay_log | Specifies how to synchronize relay logs to relay log files. When the value of this variable is greater than 0, the MySQL server synchronizes relay logs to disk after every sync_relay_log events are written to the relay log. The default value is 10000.
NoteThis variable is available 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 but does not return an error. |
| sync_relay_log_info | Specifies how to synchronize the position information of the application relay log to a file or table. Setting this variable immediately takes effect for all replication channels, including those that are running. The default value is 10000.
NoteThis variable is available 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 but does not return an error. |
| sync_master_info | The impact of this variable on a replica depends on whether the master_info_repository parameter is set to FILE or TABLE. The default value is 10000.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is 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 SQL thread of the replica is started. The default value is null.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_slow_slave_statements | If the slow query log is enabled on the replica, specifies whether to record slow SQL statements executed by the replication threads to the slow query log. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable. However, the setting does not take effect. |
| report_host | The hostname or IP address of the source to be reported during the registration of the replica. The default value is null.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| report_password | The password of the replication user account to be reported during the registration of the replica. The default value is null.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| report_port | The TCP/IP port number used to connect to the replica, to be reported during the registration of the replica. The default value is null.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| report_user | The username of the account to be reported during the registration of the replica. The default value is null.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| relay_log_recovery | If this variable is enabled, the relay log is automatically recovered when the replica is started. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
Source-related
| 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 provided only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| rpl_semi_sync_master_timeout | Specifies the time in milliseconds that the source waits for a replica to acknowledge a commit. The default value is 10000.
NoteThis 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 has no effect. |
| rpl_semi_sync_master_trace_level | Specifies the debug trace level of semi-synchronous replication on the source. The default value is 32, which indicates the network waiting level.
NoteThis 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 has no effect. |
| rpl_semi_sync_master_wait_for_slave_count | Specifies the number of replicas that must acknowledge a transaction before the source continues. The default value is 1.
NoteThis 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 has no effect. |
| rpl_semi_sync_master_wait_no_slave | Specifies whether the source waits for a timeout (set by the rpl_semi_sync_master_timeout variable) even if the number of replicas is less than the value set by the rpl_semi_sync_master_wait_for_slave_count variable. The default value is OFF.
NoteThis 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 has no effect. |
| rpl_semi_sync_master_wait_point | Specifies the point at which the semi-synchronous source waits for a replica to acknowledge a transaction before returning the status to the client that submitted the transaction. The default value is AFTER_SYNC.
NoteThis 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 has no effect. |
GTID-related
| Variable name | Description |
|---|---|
| enforce_gtid_consistency | Specifies whether to use GTID-safe statements to enforce GTID consistency. The default value is OFF.
NoteThis 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 has no effect. |
| gtid_executed_compression_period | Specifies the frequency at which the server compresses the gtid_executed value. The default value is 1000.
NoteThis 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 has no effect. |
| gtid_mode | Specifies whether to enable GTID-based logging and the type of log transactions. The default value is OFF.
NoteThis 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 has no effect. |
| gtid_purged | Specifies the GTID set of all transactions that have been committed on the server but are not present in any binary log file on the server. The default value is NULL.
NoteThis 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 has no effect. |
Recycle bin-related
| Variable name | Description |
|---|---|
| recyclebin | Specifies whether to enable the recycle bin. |
| ob_enable_truncate_flashback | Specifies whether to enable truncate flashback. |
Cache-related
| Variable name | Description |
|---|---|
| ob_enable_pl_cache | Controls whether to enable the PL cache module. |
| ob_enable_plan_cache | Specifies whether to enable the plan cache. |
| ob_plan_cache_percentage | Specifies the percentage of memory that can be used by 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 cached in a single Batch Nested Loop Join (BNLJ) operation. |
| stored_program_cache | Specifies the number of stored procedures and functions cached. The default value is 256.
NoteThis 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 does not take effect. |
| table_open_cache_instances | Specifies the number of table cache instances opened. The default value is 16.
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. |
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 noninteractive connection. |
| group_concat_max_len | Specifies the maximum length of the result of the GROUP_CONCAT() function. |
Session-related
| Variable name | Description |
|---|---|
| session_track_gtids | Controls whether the server returns GTID to the client. 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, but the setting does not take effect. |
| session_track_transaction_info | Controls whether the server tracks the transaction status of the current session. 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, but the setting does not take effect. |
InnoDB storage engine
| Variable | Description |
|---|---|
| innodb_change_buffering_debug | The debug level for changing the InnoDB buffer. The default value is 0.
NoteThis variable is 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. |
| innodb_compress_debug | The debug level for adjusting and controlling the compression behavior. The default value is 0.
NoteThis variable is 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. |
| innodb_disable_resize_buffer_pool_debug | Whether to enable the size adjustment of the InnoDB buffer pool. The default value is 1.
NoteThis variable is 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. |
| innodb_fil_make_page_dirty_debug | The debug level for dirtying the specified number of pages in InnoDB. The default value is 0.
NoteThis variable is 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. |
| innodb_limit_optimistic_insert_debug | The number of records on each B-tree page. The default value is 0.
NoteThis variable is 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. |
| innodb_merge_threshold_set_all_debug | The percentage of full pages for an index. The default value is 50.
NoteThis variable is 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. |
| innodb_saved_page_number_debug | The number of pages saved in InnoDB for debugging. The default value is 0.
NoteThis variable is 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. |
| innodb_strict_mode | The SQL check mode for specific syntax. |
| innodb_stats_persistent | Whether to persist InnoDB index statistics to disk. |
| innodb_trx_purge_view_update_only_debug | The debug level for updating only the purge view during transaction cleanup. The default value is 0.
NoteThis variable is 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. |
| innodb_trx_rseg_n_slots_debug | The number of slots in the transaction rollback segment. Each slot stores transaction rollback information. The default value is 0.
NoteThis variable is 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. |
| innodb_replication_delay | The delay time of the replication thread on the replica server when the value of the innodb_replication_delay variable is reached. The unit is milliseconds. The default value is 0.
NoteThis variable is 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. |
| innodb_force_recovery | The crash recovery mode for repairing data of the InnoDB storage engine. The default value is 0.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| innodb_flush_log_at_timeout | The interval for flushing logs. The unit is seconds. The default value is 1.
NoteThis variable is 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. |
| innodb_flush_log_at_trx_commit | The balance between the strict compliance with ACID characteristics and higher performance. The default value is 1.
NoteThis variable is 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. |
| innodb_log_checkpoint_now | The debug option for forcing InnoDB to write a checkpoint. The default value is 0.
NoteThis variable is 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. |
| innodb_log_checksums | Whether to enable checksums for Redo log pages. The default value is 1.
NoteThis variable is 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. |
| innodb_log_compressed_pages | Whether to save compressed pages in Redo logs. The default value is 1.
NoteThis variable is 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. |
| innodb_log_write_ahead_size | The size of the redo log write-ahead block, in bytes. The default value is 8192.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_max_undo_log_size | The threshold size of the undo tablespace. The default value is 1073741824.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_online_alter_log_max_size | The maximum size of the temporary log file used during online DDL operations on a table, in bytes. The default value is 134217728.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_undo_log_truncate | When this variable is enabled, the undo tablespace exceeding the threshold defined by the innodb_max_undo_log_size variable is marked for truncation. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_undo_logs | The number of rollback segments used by InnoDB. The default value is 128.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_rollback_on_timeout | Specifies whether to abort and roll back the entire transaction when a transaction times out. The default value is OFF.
NoteThis 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. |
| innodb_api_disable_rowlock | Specifies whether to disable row locks when InnoDB Memcached executes DML operations. The default value is OFF.
NoteThis 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. |
| innodb_autoinc_lock_mode | The locking mode for generating auto-increment values. The default value is 1.
NoteThis 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. |
| innodb_read_only | Specifies whether to start InnoDB in read-only mode. The default value is OFF.
NoteThis 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. |
| innodb_api_bk_commit_interval | The frequency at which InnoDB Memcached automatically commits connections. The default value is 5.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_api_trx_level | The transaction isolation level for queries processed by the Memcached interface. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_support_xa | Specifies whether to enable XA transactions for InnoDB. The default value is 1.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_sync_debug | Specifies whether to enable synchronization debugging checks for the storage engine. The default value is OFF.
NoteThis 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. |
| innodb_adaptive_flushing | Specifies whether to dynamically adjust the rate at which dirty pages are flushed from the buffer pool based on the workload. The default value is ON.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_adaptive_flushing_lwm | The minimum percentage of redo log capacity for adaptive flushing. The default value is 10.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_adaptive_hash_index | Specifies whether to enable the InnoDB adaptive hash index mechanism. The default value is ON.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_adaptive_max_sleep_delay | The delay time that InnoDB automatically adjusts based on the current workload. The default value is 150000.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_autoextend_increment | The increment size for extending InnoDB data files, in MB. The default value is 64.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting has no effect. |
| innodb_background_drop_list_empty | This variable specifies whether to perform operations such as dropping tables or indexes when the background task list is empty. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_buffer_pool_dump_at_shutdown | This variable specifies whether to dump the contents of the InnoDB buffer pool to disk when the database is shut down, so that the contents can be quickly restored during the next startup. The default value is ON.
NoteThis variable is provided 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. |
| innodb_buffer_pool_dump_now | This variable specifies whether to immediately dump the contents of the InnoDB buffer pool. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_buffer_pool_dump_pct | This variable specifies the percentage of the buffer pool content to be dumped. The default value is 25.
NoteThis variable is provided 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. |
| innodb_buffer_pool_filename | This variable specifies the format of the file that stores the tablespace IDs and page IDs generated in the buffer pool. The default value is ib_buffer_pool.
NoteThis variable is provided 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. |
| innodb_buffer_pool_load_abort | This variable specifies whether to terminate the ongoing buffer pool loading operation. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_buffer_pool_load_now | This variable specifies whether to immediately load the previously dumped buffer pool content. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_buffer_pool_size | This variable specifies the size of the InnoDB buffer pool. The default value is 134217728.
NoteThis variable is provided 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. |
| innodb_change_buffer_max_size | This variable specifies the maximum percentage of the InnoDB buffer pool that can be occupied by the change buffer. The default value is 25.
NoteThis variable is provided 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. |
| innodb_change_buffering | This variable specifies the change buffering strategy for InnoDB, such as insert and delete operations. The default value is all.
NoteThis variable is provided 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. |
| innodb_checksum_algorithm | This variable specifies the checksum algorithm used to generate and verify the checksums of disk blocks stored in the InnoDB tablespace. The default value is crc32.
NoteThis variable is provided 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. |
| innodb_cmp_per_index_enabled | This variable specifies whether to collect compression statistics for each index. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_commit_concurrency | This variable specifies the maximum number of threads that can perform commit operations simultaneously. The default value is 0.
NoteThis variable is provided 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. |
| innodb_compression_failure_threshold_pct | This variable specifies the threshold percentage for table compression failure rate. The default value is 5.
NoteThis variable is provided 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. |
| innodb_compression_level | This variable specifies the zlib compression level for compressing tables and indexes in InnoDB. The default value is 6.
NoteThis variable is provided 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. |
| innodb_compression_pad_pct_max | This variable specifies the maximum percentage of each compressed page that can be reserved as available space. The default value is 50.
NoteThis variable is provided 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. |
| innodb_concurrency_tickets | This variable specifies the number of concurrent threads for InnoDB. The default value is 5000.
NoteThis variable is provided 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. |
| innodb_default_row_format | This variable specifies the default row format for InnoDB tables and temporary tables. The default value is DYNAMIC.
NoteThis variable is provided 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. |
| innodb_disable_sort_file_cache | Specifies whether to disable the system cache for merge sort temporary files. The default value is OFF.
NoteThis variable is provided 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_file_format | Specifies the InnoDB file format for tablespace files. The default value is Barracuda.
NoteThis variable is provided 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_file_format_max | Specifies the file format tag for the system tablespace. The default value is Barracuda.
NoteThis variable is provided 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_file_per_table | Specifies whether to create tables in the system tablespace. The default value is ON.
NoteThis variable is provided 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_fill_factor | Specifies the percentage of space to fill on each B-tree page during the construction of a sorted index. The default value is 100.
NoteThis variable is provided 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_flush_neighbors | Specifies whether to flush other dirty pages in the same range when you flush pages from the InnoDB buffer pool. The default value is 1.
NoteThis variable is provided 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_flush_sync | Specifies whether to immediately write data to disk when you write data to the InnoDB buffer pool. The default value is ON.
NoteThis variable is provided 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_flushing_avg_loops | Specifies the average number of loops for InnoDB when you write data to the buffer pool. The default value is 30.
NoteThis variable is provided 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_lru_scan_depth | Specifies the depth of the page cleaner thread in each buffer pool instance for scanning the LRU page list in the buffer pool to find dirty pages to be flushed. The default value is 1024.
NoteThis variable is provided 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_max_dirty_pages_pct | Specifies the maximum percentage of dirty pages in the InnoDB buffer pool. The default value is 75.
NoteThis variable is provided 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_max_dirty_pages_pct_lwm | Specifies the minimum percentage of dirty pages to be pre-flushed. The default value is 0.
NoteThis variable is provided 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_max_purge_lag | Specifies the maximum delay time between the transaction commit and the complete purge of the transaction. The default value is 0.
NoteThis variable is provided 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_max_purge_lag_delay | Specifies the maximum delay time (in microseconds) for delaying the execution of INSERT, UPDATE, and DELETE operations when the innodb_max_purge_lag threshold is exceeded. The default value is 0.
NoteThis variable is provided 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. |
| ignore_builtin_innodb | Specifies whether to ignore the built-in InnoDB storage engine. The default value is NO.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
| innodb_buffer_pool_chunk_size | Specifies the size of an InnoDB buffer pool chunk. The default value is 134217728.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
| innodb_buffer_pool_instances | Specifies the number of InnoDB buffer pool instances. The default value is 1.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
| innodb_buffer_pool_load_at_startup | Specifies whether to automatically load the buffer pool at startup. The default value is 1.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
| innodb_checksums | Specifies whether to use checksums for all tables read from disk. The default value is ON.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
| innodb_doublewrite | Specifies whether to store all data twice in InnoDB. First, the data is stored in the doublewrite buffer, and then it is stored in the actual data file. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it. |
| innodb_file_format_check | Specifies whether to enable InnoDB to check the file format flags in the system tables. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it. |
| innodb_flush_method | Specifies the method for flushing data to the InnoDB data and log files. The default value is NULL.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it. |
| innodb_force_load_corrupted | Specifies whether to load tables marked as corrupted during InnoDB startup. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it. |
| innodb_page_size | Specifies the page size of the InnoDB tablespace. The default value is 16384.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it. |
| innodb_version | Specifies the InnoDB version. The default value is 5.7.38.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query it, but you cannot set it. |
| information_schema_stats_expiry | Specifies the number of seconds for the server to obtain data from the storage engine and replace the cached data. The default value is 86400.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| low_priority_updates | Specifies whether to control the priority of INSERT, UPDATE, DELETE, and REPLACE statements. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| max_error_count | Specifies the maximum number of errors, warnings, and notifications that the server can store in the diagnostic context. The default value is 64.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| max_insert_delayed_threads | Specifies the maximum number of threads for executing INSERT DELAYED statements. The default value is 20.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_monitor_disable | This variable acts as a switch to disable specific metrics counters.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_monitor_enable | This variable acts as a switch to enable specific metrics counters.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_monitor_reset | This variable acts as a switch to reset specific metrics counters to 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_monitor_reset_all | This variable acts as a switch to reset all values (maximum, minimum, etc.) of specific metrics counters to 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_old_blocks_pct | Specifies the approximate percentage of the old data blocks in the InnoDB buffer pool. The default value is 37.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_old_blocks_time | Specifies the time in milliseconds that a block must remain in the old sublist after its first access before it can be moved to the new sublist. The default value is 1000.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_purge_batch_size | Specifies the number of undo log pages to parse and process at a time from the history list. The default value is 300.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_purge_rseg_truncate_frequency | Specifies the frequency at which to truncate rollback segments. The default value is 128.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it. Setting this variable does not generate an error, but the setting does not take effect. |
| innodb_random_read_ahead | Specifies whether to enable random read-ahead to optimize I/O for the InnoDB storage engine. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_read_ahead_threshold | Specifies the number of pages that must be read sequentially from a segment before asynchronous reads from the next segment are initiated. The default value is 56.
NoteThis variable is provided 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. |
| innodb_rollback_segments | Specifies the number of rollback segments for transactions that generate undo logs. The default value is 128.
NoteThis variable is provided 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. |
| innodb_spin_wait_delay | Specifies the interval between spin lock waits. The default value is 6.
NoteThis variable is provided 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. |
| innodb_status_output | Specifies whether to enable regular output from the standard InnoDB monitor. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_status_output_locks | Specifies whether to enable InnoDB lock monitoring. The default value is OFF.
NoteThis variable is provided 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. |
| innodb_sync_spin_loops | Specifies the number of times a thread waits for an InnoDB mutex to be released before it is suspended. The default value is 30.
NoteThis variable is provided 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. |
| innodb_fast_shutdown | Specifies the shutdown mode for the InnoDB storage engine. The default value is 1.
NoteThis variable is provided 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. |
| innodb_io_capacity | Specifies the approximate number of IOPS that can be performed per second by background tasks for the InnoDB storage engine. The default value is 200.
NoteThis variable is provided 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. |
| innodb_io_capacity_max | Specifies the maximum number of IOPS that can be performed per second by background tasks in an emergency. The default value is 2000.
NoteThis variable is provided 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. |
| innodb_thread_concurrency | Specifies the maximum number of threads allowed internally for the InnoDB storage engine. The default value is 0, which indicates that no limit is set.
NoteThis variable is provided 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. |
| innodb_thread_sleep_delay | Specifies the time in microseconds that an InnoDB thread sleeps before being added to the InnoDB wait queue. The default value is 10000.
NoteThis variable is provided 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. |
| innodb_adaptive_hash_index_parts | Specifies the number of partitions in the adaptive hash index search system. The default value is 8.
NoteThis variable is provided only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it. |
| innodb_numa_interleave | Specifies whether to enable the NUMA interleaving memory allocation strategy for the buffer pool. The default value is OFF.
NoteThis variable is provided only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it. |
| innodb_open_files | Specifies the maximum number of files that can be opened at a time. The default value is 2000.
NoteThis variable is provided only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it. |
| innodb_page_cleaners | Specifies the number of threads for flushing dirty pages from the buffer pool. The default value is 1.
NoteThis variable is provided only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it. |
| innodb_purge_threads | Specifies the number of background threads for purge operations. The default value is 4.
NoteThis variable is provided only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but cannot set it. |
| innodb_read_io_threads | The number of I/O threads for read operations. The default value is 4.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_sync_array_size | The size of the mutex/lock wait array. The default value is 1.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_use_native_aio | Whether to use the Linux asynchronous I/O subsystem. The default value is 1.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_write_io_threads | The number of I/O threads for write operations. The default value is 4.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_locks_unsafe_for_binlog | This variable affects how InnoDB uses gap locks for searches and index scans. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_log_buffer_size | The size of the InnoDB transaction log buffer, in bytes. The default value is 16777216.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_log_files_in_group | The number of log files in a log group. The default value is 2.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_log_file_size | The size of each log file in a log group, in bytes. The default value is 50331648.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_log_group_home_dir | The directory path for InnoDB redo logs. The default value is ./.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_undo_directory | The directory for the undo tablespaces created by InnoDB. The default value is ./.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_undo_tablespaces | The number of undo tablespaces available to InnoDB. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| default_tmp_storage_engine | The default temporary table storage engine. The default value is InnoDB.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, the setting does not take effect. |
| innodb_tmpdir | The directory for storing temporary files for InnoDB.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set the variable. However, the setting does not take effect. |
| mecab_rc_file | The path to the MeCab configuration file.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_temp_data_file_path | The storage path for temporary data files for 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 that automatically extends as needed to store additional temporary data.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_data_file_path | The storage path and filename for InnoDB data files. The default value is ibdata1:12M:autoextend, which indicates that InnoDB will use a temporary data file named ibtmp1 with an initial size of 12 MB that automatically extends as needed to store additional temporary data.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query the variable but cannot set it. |
| innodb_data_home_dir | The root directory for InnoDB data files.
NoteThis 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. |
| delayed_insert_limit | The maximum number of insert operations that can be performed using the INSERT DELAYED option. The default value is 100.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. The setting does not take effect but does not return an error. |
| delayed_insert_timeout | The maximum time that a delayed insert operation can be delayed. The default value is 300.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. The setting does not take effect but does not return an error. |
| delayed_queue_size | The size of the delayed insert queue. The default value is 1000.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. The setting does not take effect but does not return an error. |
| eq_range_index_dive_limit | The maximum number of rows that the optimizer can scan when it performs an index dive for an equality range query. The default value is 200.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. The setting does not take effect but does not return an error. |
| innodb_stats_auto_recalc | The option to enable or disable automatic recalculation. The default value is ON.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. The setting does not take effect but does not return an error. |
Temporary files
| Variable | Description |
|---|---|
| max_tmp_tables | Specifies the maximum number of temporary tables that a user session can hold simultaneously. The default value is 32.
NoteThis 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. |
Cluster
| Variable | Description |
|---|---|
| ob_compatibility_mode | Specifies the compatibility mode of a tenant. |
| ob_route_policy | Specifies the routing strategy for selecting data replicas within an OBServer node. |
| performance_schema | Specifies whether to support queries for Performance information. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 8.0. The related feature is not supported. You can query and set this variable, but the setting has no effect. |
| resource_manager_plan | Activates the resource management plan. Different plans use different CPU quotas to limit user activities in resource groups. |
| license | Displays the type of license. |
| server_uuid | Displays the UUID of an OBServer node. |
| default_storage_engine | Displays the default storage engine of an OBServer node. |
Directory path
| Variable | Description |
|---|---|
| datadir | Displays the local disk path for storing data. |
| plugin_dir | Displays the path for storing plugin DLLs. |
| secure_file_priv | Specifies the path that can be accessed when importing or exporting files. |
| ob_enable_hash_group_by | Specifies whether to enable the Hash Group by feature. |
MyISAM storage engine
| Variable | Description |
|---|---|
| skip_external_locking | Specifies whether to disable the external locking mechanism for MyISAM tables. The default value is ON.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| myisam_mmap_size | Specifies the maximum memory size for memory-mapping compressed MyISAM files. The default value is 18446744073709551615.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
Memory
| Variable | Description |
|---|---|
| ob_sql_work_area_percentage | Specifies the percentage of tenant memory for SQL execution. |
| ob_sql_audit_percentage | Specifies the percentage of tenant memory for SQL audit. |
| ob_reserved_meta_memory_percentage | Specifies the percentage of reserved memory for a tenant, mainly for storing Meta-related structure information. |
| ob_temp_tablespace_size_percentage | Specifies the percentage of temporary table space size in the tenant disk. |
| range_alloc_block_size | Specifies the size of the block allocated for range optimization. The default value is 4096 bytes.
NoteThis 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. |
NDB storage engine
| Variable name | Description |
|---|---|
| ndb_allow_copying_alter_table | Specifies whether to allow the ALTER TABLE statement and other DDL statements to use the copy operation for a table. The default value is OFF.
NoteThis 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 will not take effect and no error will be returned. |
| 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.
NoteThis 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 will not take effect and no error will be returned. |
| 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.
NoteThis 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 will not take effect and no error will be returned. |
| 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.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_cache_check_time | Specifies the interval in milliseconds at which to check whether the cache needs to be refreshed on each NDB node. The default value is 0.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_clear_apply_status | Specifies whether to clear the application status. The default value is OFF.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_data_node_neighbour | Defines the neighbor relationships of data nodes. The default value is 0.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_default_column_format | Defines the default column format for a table, which can be fixed-length or variable-length. The default value is FIXED, indicating fixed-length storage.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_deferred_constraints | Specifies whether to defer constraint checks for a table. The default value is 0.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_distribution | Specifies the default distribution method for an NDB table, which can be partitioned by hash key or linear hash. The default value is KEYHASH, indicating hash key partitioning.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_eventbuffer_free_percent | Specifies the percentage of free space in the event buffer of an NDB cluster. The default value is 20.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_eventbuffer_max_alloc | Specifies the maximum size of memory that can be allocated for the event buffer, in bytes. The default value is 0, indicating no limit.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_extra_logging | Specifies whether to record information about the NDB storage engine in the MySQL error log. The default value is 1.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_force_send | Specifies whether to immediately send the cache to NDB without waiting for other threads. The default value is OFF.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_fully_replicated | Specifies whether to fully replicate a new table. The default value is OFF.
NoteThis 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 will not take effect and no error will be returned. |
| ndb_index_stat_enable | Specifies whether to enable the NDB index statistics collection feature. The default value is OFF.
NoteThis variable is 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. |
| 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.
NoteThis variable is 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. |
| ndb_join_pushdown | Specifies whether to enable the join pushdown optimization feature in the storage engine. The default value is OFF.
NoteThis variable is 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. |
| ndb_log_binlog_index | Specifies whether to insert the mapping of epochs to binlog positions into the ndb_binlog_index table. The default value is OFF.
NoteThis variable is 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. |
| ndb_log_empty_epochs | Specifies whether to write unchanged epoch transactions to the binlog. The default value is OFF.
NoteThis variable is 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. |
| ndb_log_empty_update | Specifies whether to write unchanged update transactions to the binlog. The default value is OFF.
NoteThis variable is 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. |
| ndb_log_exclusive_reads | Specifies whether to use an exclusive lock to record primary key reads. The default value is OFF.
NoteThis variable is 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. |
| ndb_log_update_as_write | Specifies whether to write updates to the binlog as updates (OFF) or writes (ON). The default value is OFF.
NoteThis variable is 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. |
| ndb_log_update_minimal | Specifies the logging behavior of NDB Cluster. If the value is ON, NDB Cluster records only the minimal information of update operations. If the value is OFF, NDB Cluster records the changes of the entire row. The default value is OFF.
NoteThis variable is 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. |
| ndb_log_updated_only | Specifies whether to write only the updated rows or the entire rows to the binlog when Mysqld writes updates to the binlog. The default value is OFF.
NoteThis variable is 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. |
| ndb_optimization_delay | Specifies the wait time between groups of rows when you execute the OPTIMIZE TABLE statement on an NDB table. The unit is microseconds. The default value is 10.
NoteThis variable is 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. |
| ndb_read_backup | Specifies whether to allow reading data from any fragment of any NDB table created later. The default value is OFF.
NoteThis variable is 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. |
| ndb_recv_thread_activation_threshold | Specifies the activation threshold for receive threads. The default value is 8.
NoteThis variable is 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. |
| ndb_recv_thread_cpu_mask | Specifies the CPU mask for receive threads. The default value is an empty string.
NoteThis variable is 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. |
| 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.
NoteThis variable is 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. |
| ndb_report_thresh_binlog_mem_usage | Specifies the percentage threshold of the remaining available memory for binlog before sending a report. When the remaining available memory for binlog is less than this value, the system will send a report. 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, the setting will not take effect. |
| ndb_row_checksum | Specifies the checksum value for table rows. When the value is 1, the checksum values for each row of data are calculated and saved. When the value is 0, no checksum check is performed on the data of table rows. The default value is 1.
NoteThis 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 will not take effect. |
| ndb_show_foreign_key_mock_tables | Specifies whether to display the mock tables for foreign key dependencies. 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, the setting will not take 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.
NoteThis 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 will not take effect. |
| ndb_use_exact_count | Specifies whether to force NDB to use record counts to accelerate SELECT count(*) queries. 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, the setting will not take effect. |
| ndb_use_transactions | Controls whether to enable NDB transaction support. 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, the setting will not take effect. |
| ndbinfo_max_bytes | For testing and debugging only. 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, the setting will not take effect. |
| ndbinfo_max_rows | For testing and debugging only. 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, the setting will not take effect. |
| ndbinfo_offline | Specifies whether to set the ndbinfo database to offline mode. 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, the setting will not take 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.
NoteThis 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 will not take effect. |
| server_id_bits | Specifies the number of least significant bits in the 32-bit server_id that actually identify the server. The default value is 32.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndbinfo_database | Specifies the database for NDB information. The default value is ndbinfo.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndbinfo_table_prefix | Specifies the prefix for NDB information tables. The default value is ndb$.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndbinfo_version | Specifies the version of NDB information tables.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndb_batch_size | Specifies the batch size for NDB. The default value is 32768.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndb_cluster_connection_pool | Specifies the connection pool size for the NDB cluster. The default value is 1.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndb_cluster_connection_pool_nodeids | Specifies the IDs of the NDB nodes to connect to.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| ndb_log_apply_status | Specifies the status of NDB log application. 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 cannot set it. |
| ndb_log_bin | Specifies whether to enable binary logging for NDB. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_log_fail_terminate | Specifies whether to terminate operations when a log failure occurs. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_log_orig | Specifies whether to retain original log data. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_log_transaction_id | Specifies whether to record transaction IDs in NDB logs. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_optimized_node_selection | Specifies whether to enable optimized transaction node selection. The default value is 3.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| Ndb_system_name | Specifies the name of the NDB system.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_use_copying_alter_table | Specifies whether to use copy-based ALTER TABLE operations in NDB. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_version | Specifies the version of the NDB storage engine.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_version_string | Specifies the version string of the NDB storage engine.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_wait_connected | Specifies whether to block and wait for a connection. The default value is 30.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_wait_setup | Specifies whether to block and wait for NDB setup. The default value is 30.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
| ndb_batch_size | Specifies the batch size for NDB. The default value is 32768.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query this variable but cannot set it. |
Privilege-related
| Variable name | Description |
|---|---|
| activate_all_roles_on_login | Specifies whether to automatically enable all roles upon login. |
| automatic_sp_privileges | Specifies whether to automatically grant ALTER and EXECUTE privileges to stored procedures. |
Full-text index-related
| Variable name | Description |
|---|---|
| innodb_ft_enable_diag_print | Enables or disables diagnostic output for InnoDB full-text indexes. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect. |
| innodb_ft_num_word_optimize | Specifies the minimum number of words to optimize during an OPTIMIZE TABLE operation. The default value is 2000.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect. |
| innodb_ft_result_cache_limit | Specifies the size of the InnoDB full-text index result cache. The default value is 2000000000 bytes.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect. |
| innodb_ft_server_stopword_table | Specifies the server stopword table for InnoDB full-text indexes. The default value is NULL.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect. |
| innodb_optimize_fulltext_only | Controls the behavior of the OPTIMIZE TABLE statement on InnoDB tables with FULLTEXT indexes. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set this variable, but the settings will not take effect. |
| innodb_ft_cache_size | Specifies the size of the InnoDB full-text index cache. The default value is 8000000 bytes.
NoteThis 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_ft_sort_pll_degree | Specifies the number of parallel threads for full-text index sorting. The default value is 2.
NoteThis 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_ft_total_cache_size | Specifies the total cache size for InnoDB full-text indexes. The default value is 640000000 bytes.
NoteThis 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. |
| ft_stopword_file | Specifies the file path for stopword processing. The default value is built-in.
NoteThis 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. |
Runtime Filter-related
| Variable name | Description |
|---|---|
| runtime_filter_type | Specifies the type of Runtime Filter at the tenant level. |
| runtime_filter_wait_time_ms | Specifies the maximum wait time for a Runtime Filter. |
| runtime_filter_max_in_num | Specifies the number of distinct values (NDV) for a Runtime In Filter. |
| runtime_bloom_filter_max_size | Specifies the maximum memory usage for a Runtime Bloom Filter, in bytes. |
Time zone and date-related
| Variable name | Description |
|---|---|
| lc_time_names | Controls the language for displaying date and month names and abbreviations. |
| time_zone | Sets the time zone for the current tenant session. It supports the Offset format '+08:00' and the region format Asia/Shanghai. |
| system_time_zone | Sets the system time zone of the server machine. |
| error_on_overlap_time | Specifies whether to return an error when ambiguous time zones occur in the daylight saving time overlap period. |
| nls_territory | Specifies the current region in database internationalization support. It is used with nls_language. |
| nls_date_language | Specifies the default date language in database internationalization support. |
| nls_calendar | Controls the calendar system used by the database. |
| ob_timestamp_service | Specifies the timestamp service to use. |
| default_week_format | Sets the default mode value of the WEEK() function for calculating the day of the week. The default value is 0.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| show_old_temporals | Controls whether to display the old timestamp columns. The default value is OFF.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| date_format | Sets the default date format. The default value is %Y-%m-%d.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query this variable but cannot set it. |
| datetime_format | Sets the default date and time format. The default value is %Y-%m-%d %H:%i:%s.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query this variable but cannot set it. |
| language | Sets the language used by MySQL.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query this variable but cannot set it. |
| lc_messages_dir | Sets the language used for error messages.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query this variable but cannot set it. |
View-related
| Variable name | Description |
|---|---|
| updatable_views_with_limit | Controls whether to allow UPDATE or DELETE operations on views with the LIMIT clause. The default value is 1.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable, but the setting has no effect. |
Transaction and transaction log
| Variable name | Description |
|---|---|
| autocommit | Specifies whether to automatically commit transactions. |
| tx_isolation | Specifies the transaction isolation level. |
| ob_proxy_set_trx_executed | Specifies whether to send the START TRANSACTION Syntax statement to an OBServer through an ODP. |
| ob_early_lock_release | Specifies whether to enable early lock release (ELR) for a transaction.
NoteThis variable is deprecated starting from V2.2.30. ELR behavior is now controlled by the tenant-level parameter |
| ob_trx_idle_timeout | Specifies the transaction idle timeout. A transaction is considered idle if the execution interval between two statements exceeds the specified value. |
| transaction_isolation | Specifies the transaction isolation level. |
| transaction_read_only | Specifies whether to allow only read-only transactions. |
| ob_trx_lock_timeout | Specifies the transaction lock timeout. |
| tx_read_only | Specifies whether to allow only read-only transactions. |
| ob_trx_timeout | Specifies the transaction timeout. |
| gtid_executed | Stores all committed transactions and GTIDs set by statements. The default value is NULL.
NoteThis variable is for MySQL 5.7 compatibility. You can query this variable, but cannot set it. |
| gtid_owned | Stores the list of all GTIDs in use and the thread IDs of the threads that own them. The default value is NULL.
NoteThis variable is for MySQL 5.7 compatibility. You can query this variable, but cannot set it. |
| completion_type | Specifies the transaction type to be selected when a statement is completed. The default value is NO_CHAIN.
NoteThis variable is for MySQL 5.7 compatibility. You can query and set this variable. However, the settings do not take effect. |
| transaction_alloc_block_size | Specifies the initial memory block size allocated to each transaction. The default value is 8192.
NoteThis variable is for MySQL 5.7 compatibility. You can query and set this variable. However, the settings do not take effect. |
| transaction_prealloc_size | Specifies the preallocated memory block size for each transaction. The default value is 4069.
NoteThis variable is for MySQL 5.7 compatibility. You can query and set this variable. However, the settings do not take effect. |
| transaction_write_set_extraction | Specifies the algorithm type for generating identifiers for write operations related to transactions. The default value is OFF.
NoteThis variable is for MySQL 5.7 compatibility. You can query and set this variable. However, the settings do not take effect. |
Audit
| Variable name | Description |
|---|---|
| ob_enable_sql_audit | Specifies whether to enable SQL Audit for the current tenant. |
Upgrade
| Variable name | Description |
|---|---|
| avoid_temporal_upgrade | Manages the upgrade behavior of temporal data (such as dates and times). The default value is OFF.
NoteThis variable is for MySQL 5.7 compatibility. You can query and set this variable. However, the settings do not take effect. |
Data types
| 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 decimal separator and thousand separator for strings during conversion between numbers and strings. |
| nls_currency | Specifies the local currency symbol for the L element in the number format. |
| nls_iso_currency | Specifies the local currency symbol for the C element in the number format. |
| nls_dual_currency | Specifies the local currency symbol for the U element in the number format. |
| nls_date_format | Specifies the format for converting a date to a string and for implicitly converting a string to a date. |
| nls_timestamp_format | Specifies the format for converting a TIMESTAMP or TIMESTAMP_LTZ value to a string and for implicitly converting a string to a TIMESTAMP or TIMESTAMP_LTZ value. |
| nls_timestamp_tz_format | Specifies the format for converting a TIMESTAMP_TZ value to a string and for implicitly converting a string to a TIMESTAMP_TZ value. |
| explicit_defaults_for_timestamp | Specifies whether to enable nonstandard behavior for the TIMESTAMP data type when handling default values and NULL values. |
| log_row_value_options | Specifies whether to enable partial updates for LOBs. |
| ob_default_lob_inrow_threshold | Specifies the default in-row storage threshold for LOB fields when creating a table. |
SQL/PL-related
| Variable | Description |
|---|---|
| connect_timeout | Specifies the connection timeout. |
| ob_pl_block_timeout | Specifies the maximum timeout for PL. |
| cursor_sharing | Specifies whether to parameterize SQL statements. |
| profiling | Enables or disables statement analysis. The default value is 0.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect. |
| profiling_history_size | Specifies the number of query performance records to be saved. The default value is 15.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect. |
| have_profiling | Specifies whether query performance analysis is supported. The default value is NO.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query this variable, but cannot set it. |
| innodb_strict_mode | Specifies the SQL check mode for specific syntax. |
| 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 behaviors such as insertions. |
| sql_quote_show_create | Specifies whether to enable identifier quoting 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. Requests on 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. A value of 0 indicates no limit. |
| max_sp_recursion_depth | Specifies the maximum number of recursive calls allowed for 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 allow block nested loop joins. |
| parallel_max_servers | Specifies the maximum number of threads in the parallel execution (PX) thread pool on each server. |
| innodb_stats_persistent | Specifies whether to persist InnoDB index statistics to disk. |
| ob_enable_parameter_anonymous_block | Specifies whether to enable the anonymous block parameterization feature globally. |
| parser_max_mem_size | Specifies the maximum amount of memory available for the parser. The default value is 18446744073709551615.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set this variable. However, setting this variable does not take effect. |
Lock-related variables
| Variable | Description |
|---|---|
| innodb_deadlock_detect | Specifies whether to disable deadlock detection. The default value is ON.
NoteThis 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_lock_wait_timeout | Specifies the maximum time (in seconds) that an InnoDB transaction waits for a lock. The default value is 50.
NoteThis 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_print_all_deadlocks | Specifies whether to record all InnoDB deadlock information of user transactions in the error log. 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, but the setting will not take effect. |
| innodb_table_locks | Specifies the behavior of InnoDB table-level locking. The default value is ON.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect. |
| max_write_lock_count | Limits the number of write locks that can be obtained to prevent excessive lock resource consumption in high-concurrency write scenarios. The default value is 18446744073709551615.
NoteThis 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. |
| metadata_locks_cache_size | Specifies the size of the metadata lock cache. The default value is 1024 (in bytes).
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. |
| metadata_locks_hash_instances | Specifies the number of instances of the metadata lock hash table. The default value is 8.
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. |
Statistics-related variables
| Variable | Description |
|---|---|
| innodb_stats_include_delete_marked | Specifies whether to include rows marked for deletion in statistics calculations. 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, but the setting will not take effect. |
| innodb_stats_method | Specifies the method for calculating InnoDB statistics. The default value is nulls_equal.
NoteThis 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_stats_on_metadata | Controls the method for retrieving table and column statistics from INFORMATION_SCHEMA. 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, but the setting will not take effect. |
| innodb_stats_persistent | Specifies whether to persist statistics. The default value is ON.
NoteThis 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_stats_persistent_sample_pages | Specifies the number of sample pages for persistent statistics. The default value is 20.
NoteThis 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_stats_sample_pages | Specifies the number of sample pages for InnoDB statistics. The default value is 8.
NoteThis 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_stats_transient_sample_pages | Specifies the number of sample pages for transient statistics. The default value is 8.
NoteThis 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. |
System logs
| Variable name | Description |
|---|---|
| binlog_row_image | Specifies whether to record full-column logs. |
| ob_log_level | Specifies the log level for 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 tracking 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 features are not supported. You can query and set this variable, but the setting will not take effect. |
| binlog_cache_size | Specifies the size of the transaction cache. The unit is bytes. The default value is 32768.
NoteThis 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. |
| binlog_direct_non_transactional_updates | If this variable is enabled, updates to non-transactional tables are directly written to the binlog instead of the transaction cache. 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, but the setting will not take effect. |
| binlog_error_action | Specifies the server behavior when an error occurs. The default value is ABORT_SERVER.
NoteThis 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. |
| binlog_group_commit_sync_delay | Specifies the time to wait after binlog submission before synchronizing the binlog file to disk. The unit is microseconds. 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, but the setting will not take effect. |
| binlog_group_commit_sync_no_delay_count | Specifies the maximum number of delayed transactions to wait for. 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, but the setting will not take effect. |
| binlog_max_flush_queue_time | This variable has no effect on the system. 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, but the setting will not take effect. |
| binlog_order_commits | If this variable is enabled on the source server, transaction commit instructions are serialized on a single thread. The default value is 1.
NoteThis 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. |
| binlog_stmt_cache_size | Specifies the binlog cache size for non-transactional statements issued during a transaction. The default value is 32768.
NoteThis 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. |
| binlog_transaction_dependency_history_size | Specifies the maximum number of row hashes stored in memory for finding the last transaction that modified a specified row. The default value is 25000.
NoteThis 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. |
| binlog_transaction_dependency_tracking | Specifies the source of dependency information. The source uses this information to determine which transactions can be executed in parallel by the multithreaded applications of the replica. The default value is COMMIT_ORDER.
NoteThis 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. |
| expire_logs_days | Specifies the retention period of binlog files. The unit is days. 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, but the setting will not take effect. |
| log_bin_trust_function_creators | Specifies whether to trust that the creators of stored functions will not create stored functions that cause unsafe events to be written to the binlog. 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, but the setting will not take effect. |
| log_bin_use_v1_row_events | Specifies whether to use binlog version 2. 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, but the setting will not take effect. |
| log_builtin_as_identified_by_password | This variable affects the binlog of user management statements. 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, the setting does not take effect and no error is returned. |
| max_binlog_cache_size | This variable specifies the maximum cache size that can be used for binlogs, in bytes. If the number of bytes required for a transaction exceeds the value specified by this variable, an error is returned indicating that the transaction requires more than max_binlog_cache_size bytes of storage. The default value is 18446744073709500416.
NoteThis 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. |
| max_binlog_size | This variable specifies the maximum size of a binlog file, in bytes. If the size of the current binlog file exceeds the value specified by this variable, the server automatically closes the current binlog file and creates a new binlog file to continue recording subsequent database operations. 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, the setting does not take effect and no error is returned. |
| max_binlog_stmt_cache_size | This variable specifies the cache size required for non-transactional statements executed within a transaction, in bytes. The default value is 18446744073709547520.
NoteThis 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. |
| sync_binlog | This variable specifies how frequently the server synchronizes binlogs to the disk. The default value is 1.
NoteThis 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. |
| binlog_direct_non_transactional_updates | When this variable is enabled, updates to non-transactional tables are directly written to the binlog instead of being cached in the transaction cache. 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, the setting does not take effect and no error is returned. |
| log_statements_unsafe_for_binlog | Specifies whether to record error code 1592 information to the error log. The default value is 1.
NoteThis 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. |
| binlog_gtid_simple_recovery | This variable specifies how the server iterates through binlog files when searching for GTIDs during startup or restart. The default value is 1, which means that the values of gtid_executed and gtid_purged are calculated based on the values of previous_gtids_log_event in the latest and oldest binlog files at startup.
NoteThis 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_bin_basename | The full path name of the binlog file. The default value is null.
NoteThis 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_bin_index | The name and path of the binlog index file. The default value is null.
NoteThis 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_slave_updates | Specifies whether the replica server records updates received from the primary server's binlog to its own binlog. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query this variable but cannot set it. |
System server variables
| Variable name | Description |
|---|---|
| join_buffer_size | The minimum size of the buffer used for pure index scans, range index scans, and full table scans without using an index. The unit is bytes, and the default value is 262144.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| max_join_size | The maximum number of rows allowed in a JOIN operation. The default value is 18446744073709547520.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| max_length_for_sort_data | The truncation value for index values, used to determine which file sort algorithm to use. The default value is 1024.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| max_prepared_stmt_count | The maximum number of prepared statements allowed on the server. The default value is 16382.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| max_sort_length | The number of bytes used for sorting numeric values. The default value is 1024.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| min_examined_row_limit | The minimum number of rows that must be examined to be recorded in the slow query log. Queries that examine fewer rows than this variable specifies will not be recorded in the slow query log. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| multi_range_count | The maximum number of Range ranges allowed in a query statement. The default value is 256.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| query_alloc_block_size | The size of memory blocks allocated for objects created during statement parsing and execution. The unit is bytes, and the default value is 8192.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| query_prealloc_size | The size of the fixed buffer used for statement parsing and execution. The unit is bytes, and the default value is 8192.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| slow_query_log | Controls whether to enable the slow query log. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| slow_query_log_file | Specifies the filename for the slow query log. The default value is /usr/local/mysql/data/obrd-slow.log.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| sort_buffer_size | The size of the buffer used for sorting. The unit is bytes, and the default value is 262144.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| sql_buffer_result | Controls whether to store the results of SELECT statements in a temporary table. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| flush | Controls whether to persist SQL statement modifications to disk. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| flush_time | Controls the automatic refresh of all tables to disk at specified intervals in seconds. The default value is 0.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| myisam_data_pointer_size | The default pointer size for MyISAM tables created without the MAX_ROWS option specified. The unit is bytes, and the default value is 6.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not produce an error but has no effect. |
| myisam_max_sort_file_size | The maximum size of a temporary file that can be used when rebuilding a MyISAM index during REPAIR TABLE, ALTER TABLE, or LOAD DATA operations. The unit is bytes. The default value is 9223372036853720064.
NoteThis 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. |
| myisam_repair_threads | The number of concurrent threads for repairing a MyISAM table. The default value is 1.
NoteThis 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. |
| myisam_sort_buffer_size | The size of the buffer allocated for sorting MyISAM indexes during REPAIR TABLE operations or for creating indexes using CREATE INDEX (or ALTER TABLE). The unit is bytes. The default value is 8388608.
NoteThis 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. |
| myisam_stats_method | The method used by the server to calculate NULL values when collecting statistics about the distribution of index values in MyISAM tables. The default value is nulls_unequal, which treats NULL values as regular values.
NoteThis 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. |
| myisam_use_mmap | Whether to use memory mapping for reading and writing MyISAM tables. 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, but the settings will not take effect. |
| preload_buffer_size | The size of the buffer used for preloading indexes. The unit is bytes. The default value is 32768.
NoteThis 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. |
| read_buffer_size | The size of the buffer available for reading data. The unit is bytes. The default value is 131072.
NoteThis 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. |
| read_rnd_buffer_size | The size of the buffer used for reading data from MyISAM tables and for optimizing multi-range reads for any storage engine. The unit is bytes. The default value is 262144.
NoteThis 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. |
| sync_frm | Whether to synchronize the metadata of InnoDB tables to the .frm files on the disk. The default value is 1.
NoteThis 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. |
| table_open_cache | The maximum number of tables that can be opened simultaneously by all threads. The default value is 2000.
NoteThis 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. |
| internal_tmp_disk_storage_engine | The storage engine for internal temporary tables on disk. The default value is INNODB.
NoteThis 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. |
| keep_files_on_create | When the DATA DIRECTORY or INDEX DIRECTORY option is not used to specify the location of data files or index files, this variable controls whether the server retains existing files in the corresponding directory when creating a MyISAM table. The default value is OFF, which means existing files will be overwritten.
NoteThis 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. |
| max_heap_table_size | The maximum size to which a user-created memory table can grow. The unit is 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, but the settings will not take effect. |
| bulk_insert_buffer_size | The size of the buffer used for bulk inserts. The unit is bytes per thread. The default value is 8388608.
NoteThis 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. |
| general_log_file | The name of the general query log file. The default format is host_name.log.
NoteThis 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. |
| host_cache_size | The size of the host cache. The default value is 279.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_error_verbosity | The level of detail for writing error, warning, and comment information to the error log. The default value is 3.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_output | The output destination for general query logs and slow query logs. The default value is FILE.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_queries_not_using_indexes | Whether to record queries that do not use indexes to the slow query log. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_syslog | Whether to record error logs to the system log. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_syslog_facility | The tool for writing error logs to the system log. The default value is daemon.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_syslog_include_pid | Whether to write the service process ID in the error log output to the system log. The default value is 1.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_syslog_tag | The tag to be added to the server identifier in the error log output written to the system log. The default value is null.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_throttle_queries_not_using_indexes | The maximum number of statements to be written to the slow query log per minute. The default value is 0, indicating no limit.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_timestamps | The timezone for the timestamps of error logs, general logs, and slow query logs written to files. The default value is UTC.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| log_warnings | The level of additional warning information to be recorded to the error log. The default value is 2.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| max_delayed_threads | The maximum number of threads that can be created to process INSERT DELAYED statements. The default value is 20.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| require_secure_transport | Whether to use a secure transport for the connection between the client and the server. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| slow_launch_time | The threshold for the time taken to create a thread. If the time exceeds this threshold, the value of the Slow_launch_threads status variable increases. The unit is seconds. The default value is 2.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query and set this variable. However, the setting does not take effect. |
| sql_log_off | Specifies whether to enable (OFF) or disable (ON) the general query log for the current session. The default value is OFF.
NoteThis variable is 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. |
| thread_cache_size | The maximum number of threads that can be cached in the thread cache. The default value is 9.
NoteThis variable is 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. |
| thread_pool_high_priority_connection | Specifies whether to reserve idle threads for high-priority connections in the thread pool. The default value is 0.
NoteThis variable is 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. |
| thread_pool_max_unused_threads | The maximum number of unused threads in the thread pool. The default value is 0.
NoteThis variable is 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. |
| 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.
NoteThis variable is 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. |
| thread_pool_stall_limit | The maximum time in 10 milliseconds that a statement must complete after it starts executing. The default value is 6.
NoteThis variable is 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. |
| have_statement_timeout | Specifies whether to enable the statement timeout feature. The default value is ON.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| old | A compatibility variable used to resolve compatibility issues. The default value is OFF.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| version_tokens_session_number | An internal variable. The default value is 0.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| back_log | The maximum number of connection requests that can be saved in the waiting connection request queue while the server is processing connection requests. The default value is 80.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| basedir | The path name of the installation root directory. The default value is /usr/local/mysql/.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| bind_address | The IP address to which the server binds when listening for TCP/IP client connections. The default value is *.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| core_file | Specifies whether to generate a core file before the server exits when a fatal error occurs. The default value is OFF.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| have_compress | Specifies 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.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is 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.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is 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.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| large_files_support | Specifies whether the server supports processing large files. The default value is 1, indicating that the server supports processing large files.
NoteThis variable is for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable but cannot set it. |
| large_pages | Specifies whether to enable the large page feature. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| large_page_size | If the large page feature is enabled, this variable specifies the size of the memory page, in bytes. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| locked_in_memory | Indicates whether the server is locked in memory. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| named_pipe | Indicates whether the server allows clients to connect by using named pipes. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| named_pipe_full_access_group | If the server allows clients to connect by using named pipes, this variable specifies the Windows user group that has permission to use named pipes. The default value is empty string.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| shared_memory | Indicates whether the server allows clients to connect by using shared memory. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| shared_memory_base_name | The name of the shared memory used for shared memory connections. The default value is MYSQL.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| skip_name_resolve | Specifies whether to resolve hostnames when checking client connections. The default value is OFF, which indicates that hostnames must be resolved.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| thread_handling | The thread model used by the server to handle client connections. The default value is one-thread-per-connection.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| thread_pool_algorithm | The algorithm used by the thread pool plugin. The default value is 0, which indicates the conservative low-concurrency algorithm.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| thread_pool_size | The number of thread groups in the thread pool. The default value is 16.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| thread_stack | The stack size of each thread. The default value is 262144.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
| tls_version | The protocols that the server allows for encrypted connections.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported, so you can query this variable but cannot set it. |
X Plugin related variables
| Variable name | Description |
|---|---|
| mysqlx_connect_timeout | The time that the X plugin waits for the first data packet from a new client connection, in seconds. Default value: 30.
NoteThis 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 will not take effect. |
| mysqlx_idle_worker_thread_timeout | The time that an idle worker thread can remain idle before being terminated, in seconds. Default value: 60.
NoteThis 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 will not take effect. |
| mysqlx_max_allowed_packet | The maximum size of a network data packet that the X plugin can receive, in bytes. Default value: 67108864.
NoteThis 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 will not take effect. |
| mysqlx_max_connections | The maximum number of concurrent client connections that the X plugin can accept. Default value: 100.
NoteThis 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 will not take effect. |
| mysqlx_min_worker_threads | The minimum number of worker threads that the X plugin uses to process client requests. Default value: 2.
NoteThis 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 will not take effect. |
| mysqlx_bind_address | The network address where the X plugin listens for TCP/IP connections. The default value is *, which indicates that the X plugin accepts TCP/IP connections from all server hosts.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_port | The network port where the X plugin listens for TCP/IP connections. The default value is 33060.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_port_open_timeout | The time that the X plugin waits for a TCP/IP port to be idle, in seconds. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_socket | The path of the Unix socket file used by the X plugin for connections. The default value is /tmp/mysqlx.sock.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_ca | The path name of the SSL certificate authority (CA) file used by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_capath | The directory path of the SSL certificate authority (CA) certificate files used by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_cert | The path name of the SSL certificate file used by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_cipher | The list of encryption algorithms used for SSL encryption by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_crl | The file name of the certificate revocation list (CRL) file used by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_crlpath | The directory path of the certificate revocation list (CRL) file used by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
| mysqlx_ssl_key | The path name of the SSL certificate key file used by the X plugin.
NoteThis variable is available only for compatibility with MySQL 5.7. The related feature is not supported. You can query this variable, but you cannot set it. |
Performance schema
| Variable name | Description |
|---|---|
| performance_schema_show_processlist | This variable specifies the implementation of SHOW PROCESSLIST. The default value is 0.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| performance_schema_accounts_size | This variable specifies the number of rows in the accounts table. The default value is -1, indicating automatic scaling.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_digests_size | This variable specifies the maximum number of rows in the events_statements_summary_by_digest table. The default value is 10000.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_stages_history_long_size | This variable specifies the number of rows in the events_stages_history_long table. The default value is 10000.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_stages_history_size | This variable specifies the number of rows per thread in the events_stages_history table. The default value is 10.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_statements_history_long_size | This variable specifies the number of rows in the events_statements_history_long table. The default value is 10000.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_statements_history_size | This variable specifies the number of rows per thread in the events_statements_history table. The default value is 10.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_transactions_history_long_size | This variable specifies the number of rows in the events_transactions_history_long table. The default value is 10000.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_transactions_history_size | This variable specifies the number of rows per thread in the events_transactions_history table. The default value is 10.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_waits_history_long_size | This variable specifies the number of rows in the events_waits_history_long table. The default value is 10000.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_events_waits_history_size | This variable specifies the number of rows per thread in the events_waits_history table. The default value is 10.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_hosts_size | This variable specifies the number of rows in the hosts table. The default value is -1, indicating automatic scaling.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_max_cond_classes | This variable specifies the maximum number of condition collectors. The default value is 80.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_max_cond_instances | This variable specifies the maximum number of condition objects to be collected. The default value is -1, indicating automatic scaling.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_max_digest_length | This variable specifies the maximum length of a normalized SQL statement in bytes when it is stored in the performance schema. The default value is 1024.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but cannot set it. |
| performance_schema_max_file_classes | Specifies the maximum number of file instruments. The default value is 80.
NoteThis 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_handles | Specifies the maximum number of file handles. The default value is 32768.
NoteThis 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 instances. The default value is -1, which indicates automatic scaling.
NoteThis 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 | Specifies the maximum number of indexes in the statistics maintained by the Performance Schema. The default value is -1, which indicates automatic scaling.
NoteThis 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 instruments. The default value is 320.
NoteThis 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 instruments. The default value is -1, which indicates automatic scaling.
NoteThis 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 instruments. The default value is 200.
NoteThis 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 instances. The default value is -1, which indicates automatic scaling.
NoteThis 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.
NoteThis 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 | Specifies the maximum number of stored programs in the statistics maintained by the Performance Schema. The default value is -1, which indicates automatic scaling.
NoteThis 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 instruments. The default value is 50.
NoteThis 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 instances. The default value is -1, which indicates automatic scaling.
NoteThis 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 instruments. The default value is 10.
NoteThis 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 instances. The default value is -1, which indicates automatic scaling.
NoteThis 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.
NoteThis 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 instruments. The default value is 150.
NoteThis 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 instruments. The default value is 193.
NoteThis 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 procedure calls in the statistics maintained by the Performance Schema. The default value is 10.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so you can query this variable but cannot set it. |
| performance_schema_max_table_lock_stat | The maximum number of tables in the lock statistics maintained by the Performance Schema. The default value is -1, indicating automatic scaling.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so you can query this variable but cannot set it. |
| performance_schema_session_connect_attrs_size | The preallocated memory size in bytes for storing key-value pairs of connection attributes for each thread. The default value is 512.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported, so you can query this variable but cannot set it. |
Foreign key
| Variable name | Description |
|---|---|
| foreign_key_checks | Specifies whether to check foreign key constraints in DML/DDL operations. |
Optimizer
| Variable name | Description |
|---|---|
| optimizer_capture_sql_plan_baselines | Specifies whether to automatically capture new plans to the plan baseline. |
| optimizer_use_sql_plan_baselines | Specifies whether the optimizer uses the plan baseline. |
| parallel_degree_policy | Specifies the parallelism selection strategy. |
| parallel_degree_limit | Specifies the upper limit of the parallelism selected by the optimizer when the Auto DOP strategy is used. |
| parallel_min_scan_time_threshold | Specifies the minimum execution time for evaluating 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. |
| range_index_dive_limit | Specifies the maximum number of ranges to use when the optimizer estimates rows based on the storage layer. |
| partition_index_dive_limit | Specifies the maximum number of partitions to use when the optimizer estimates rows based on the storage layer. |
Auto-increment column
| Variable name | Description |
|---|---|
| auto_increment_increment | Specifies the auto-increment step size. This variable is available only for MySQL clients. |
| auto_increment_offset | Specifies the starting value of the AUTO_INCREMENT column. |
| identity | identity and the last_insert_id variable are synonyms. You can execute the select @@identity statement to query the value. |
| sql_auto_is_null | Specifies whether to obtain the value of the auto-increment column of the last inserted row. |
| auto_increment_cache_size | Specifies the number of cached auto-increment values. |
| 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 name | Description |
|---|---|
| character_set_client | The character set for statements sent by the client. |
| character_set_connection | The character set to which received statements should be converted. |
| character_set_database | The character set for the default database. |
| character_set_results | The character set to which result sets or error messages should be converted before being sent back to the client. |
| character_set_server | The character set for the server. |
| character_set_system | The character set used by the server. |
| collation_connection | The character set and collation for the connection. |
| collation_database | The default character set and collation for the database. |
| collation_server | The default character set and collation for the server. |
| character_set_filesystem | The character set type for the filesystem. |
| sql_warnings | Controls whether a single-line INSERT statement generates an information string when an alert occurs. |
| init_connect | 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 | The collation for string values. |
| nls_comp | The comparison rule for string values. |
| nls_characterset | The default character set for data types such as CHAR, VARCHAR2, and CLOB in the database. |
| nls_nchar_characterset | The default character set for data types such as NCHAR, NVARCHAR2, and NCLOB. |
| default_collation_for_utf8mb4 | The default collation for the utf8mb4 character set, which defaults to utf8mb4_general_ci.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. Setting it does not cause an error, but the setting has no effect. |
| have_symlink | Whether to support symbolic links, default value is YES.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. |
| character_sets_dir | The directory for character set files.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query it. |
Group Replication
| Variable name | Description |
|---|---|
| group_replication_allow_local_disjoint_gtids_join | Specifies whether to allow a server with local transactions not in the group to join the group. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_allow_local_lower_version_join | Specifies whether to allow a server with a lower MySQL Server version than other members to join the group. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_auto_increment_increment | Specifies the increment value for the auto-increment column of each member in the replication group. This ensures that the auto-increment column values are ordered and non-overlapping in a multi-primary group. The default value is 7.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_bootstrap_group | Specifies whether to use the current server to bootstrap the group. This variable can only be set on one server and only during the initial bootstrap or re-bootstrap. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_components_stop_timeout | Specifies the timeout for stopping each component when group replication is disabled, in seconds. The default value is 2.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_compression_threshold | Specifies the threshold for compressing messages between group members. When the threshold is exceeded, messages between group members are compressed. The default value is 1000000.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_enforce_update_everywhere_checks | Specifies whether to enable or disable strict consistency checks for multi-primary updates at any time. The default value is OFF, indicating that checks are disabled.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_exit_state_action | Specifies the behavior of group replication when a server instance leaves the group due to an exception. The default value is READ_ONLY.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_flow_control_applier_threshold | Specifies the number of transactions waiting in the application queue that triggers flow control. The default value is 25000.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_flow_control_certifier_threshold | Specifies the number of transactions waiting in the certifier queue that triggers flow control. The default value is 25000.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| 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 features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| 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 it, 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 empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_group_name | Specifies the name of the group replication group to which the current server belongs. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_group_seeds | Specifies the list of seed member addresses in the format host1:port1,host2:port2. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported, but you can query and set it. The setting will not take effect and will not return an error. |
| group_replication_gtid_assignment_block_size | The number of consecutive GTIDs to be reserved for each member. The default value is 1000000.
NoteThis variable is available 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. |
| 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 whitelist hosts. The default value is AUTOMATIC.
NoteThis variable is available 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. |
| group_replication_local_address | The network address for other members to connect to the group replication member. The default value is empty.
NoteThis variable is available 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. |
| group_replication_member_weight | The percentage weight of a member. This weight affects the chance of the member being selected as the primary node during a failover. This parameter 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 highest weight is selected as the new primary node. The default value is 50.
NoteThis variable is available 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. |
| group_replication_poll_spin_loops | The number of times the communication thread of group replication waits for the communication engine mutex to be released before waiting for more incoming network messages. The default value is 0.
NoteThis variable is available 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. |
| group_replication_recovery_complete_at | The strategy for applying cached transactions after the status transmission is completed in a distributed recovery. The default value is TRANSACTIONS_APPLIED.
NoteThis variable is available 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. |
| group_replication_recovery_reconnect_interval | The interval for reconnection attempts to find an available donor when a new server cannot find a donor for distributed recovery. The unit is seconds. The default value is 60.
NoteThis variable is available 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. |
| group_replication_recovery_retry_count | The number of reconnection attempts to find an available donor when a new server cannot find a donor for distributed recovery. The default value is 10.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_ca | The path to the file that contains the list of trusted SSL certificate authorities for distributed recovery connections. The default value is empty.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_capath | The path to the directory that contains the certificates issued by trusted SSL certificate authorities for distributed recovery connections. The default value is empty.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_cert | The name of the SSL certificate file for establishing a secure connection for distributed recovery. The default value is empty.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_cipher | The list of allowed encryption algorithms for SSL encryption. The available encryption algorithms depend on the version of the SSL library used when MySQL Server is compiled. Different SSL libraries support different encryption algorithms. The default value is empty.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_crl | The name of the file that contains the certificate revocation list. The default value is empty.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_crlpath | The path to the directory that contains the certificate revocation list. The default value is empty.
NoteThis variable is available 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. |
| group_replication_recovery_ssl_key | The name of the SSL key file for establishing a secure connection for distributed recovery. The default value is empty.
NoteThis variable is available 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. |
| 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 available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| group_replication_recovery_use_ssl | Specifies whether to use SSL for the connection channel used in distributed recovery by group replication members. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| group_replication_single_primary_mode | Specifies whether to run group replication in single-primary mode and automatically select a server to handle read/write workloads. If this variable is set to ON, only one readable/writable primary node exists, and all other group members are secondary nodes. If this variable is set to OFF, the single-primary mode is disabled, and the multi-primary mode is enabled. In the multi-primary mode, all group members are readable/writable primary nodes. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| group_replication_ssl_mode | Specifies the security state of the SSL connection between group replication members. The default value is DISABLED.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| group_replication_start_on_boot | Specifies whether to start group replication when the server starts. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| 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.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
| group_replication_unreachable_majority_timeout | Specifies the wait time before a group member leaves the group when it loses contact with the majority of other group members due to a network partition. The unit is seconds. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting has no effect. |
Session level
Security
| Variable | Description |
|---|---|
| block_encryption_mode | Specifies the encryption algorithm used in the aes_encrypt and aes_decrypt functions. |
| net_retry_count | Specifies the number of network retries. The default value is 10.
NoteThis 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. |
| old_passwords | Specifies the password hashing method used by functions. The default value is 0.
NoteThis 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. |
| disconnect_on_expired_password | Specifies whether to disconnect a session when the password expires. The default value is ON.
NoteThis 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. |
| external_user | Specifies the external user that connects to MySQL.
NoteThis 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. |
| have_crypt | Specifies whether MySQL supports the crypt() function. The default value is YES.
NoteThis 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. |
| proxy_user | Specifies the proxy user for authentication.
NoteThis 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. |
Version information
| Variable | Description |
|---|---|
| ob_enable_transmission_checksum | Specifies whether to enable packet checksum verification between OBProxy and OBServer nodes. The setting takes effect immediately. |
| ob_last_schema_version | Specifies the latest schema version used in the current session. |
| ob_proxy_global_variables_version | Specifies the latest version of global variables to be returned by OBServer nodes to OBProxy. |
| new | Specifies whether to enable certain behaviors of MySQL 4.1 in MySQL 4.0 and retain them for backward compatibility. The default value is OFF.
NoteThis 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. |
| version_tokens_session | Specifies the session-level version tag. The default value is NULL, which indicates that any server version list matches.
NoteThis 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. |
Plugin management
| Variable | Description |
|---|---|
| plugin_load | Specifies the list of plugins to be loaded at startup.
NoteThis 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. |
| plugin_load_add | Specifies the plugins to be added at runtime.
NoteThis 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. |
Debug
| Variable | Description |
|---|---|
| debug | Specifies the debug options. The default value is d:t:i:o,/tmp/mysqld.trace.
NoteThis 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. |
| ob_global_debug_sync | Specifies a synchronization point for debugging. Setting this variable affects all sessions. |
Read and write related
| Variable name | Description |
|---|---|
| cte_max_recursion_depth | The maximum recursion depth of a common table expression (CTE). The server terminates the execution of any CTE that exceeds this value. |
| is_result_accurate | Indicates whether the query result is accurate when the topk hint is specified. |
| net_read_timeout | The number of seconds to wait for additional data before interrupting a read operation. |
| net_write_timeout | The number of seconds to wait for a block to be written to the connection before interrupting a write operation. |
| ob_enable_aggregation_pushdown | Specifies whether to allow aggregation pushdown. |
| ob_enable_index_direct_select | Specifies whether to allow direct queries on index tables. |
| ob_enable_jit | Specifies the JIT execution engine mode. |
| ob_query_timeout | The query timeout period. |
| ob_read_consistency | The read consistency level. |
| big_tables | Specifies whether to enable large table queries. If this variable is enabled, you can use the features of large MyISAM tables. The default value is OFF.
NoteThis variable is 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 no error is returned. |
| optimizer_prune_level | Controls the behavior of the query optimizer. The optimizer skips unnecessary query plans based on the estimated number of rows accessed from each table, thereby reducing query compilation time. The default value is 1.
NoteThis variable is 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 no error is returned. |
| optimizer_search_depth | The maximum depth of query execution plans to be searched by the optimizer. The default value is 62.
NoteThis variable is 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 no error is returned. |
| optimizer_switch | Specifies the behavior options of the optimizer to enable or disable specific features.
NoteThis variable is 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 no error is returned. |
| optimizer_trace | Enables the query optimizer trace feature for debugging and analyzing query execution plans.
NoteThis variable is 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 no error is returned. |
| optimizer_trace_features | Specifies the features to be included in the optimizer trace.
NoteThis variable is 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 no error is returned. |
| optimizer_trace_limit | The maximum number of trace entries for the optimizer. The default value is 1.
NoteThis variable is 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 no error is returned. |
| optimizer_trace_max_mem_size | The maximum memory usage for the optimizer trace. The default value is 16384.
NoteThis variable is 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 no error is returned. |
| range_optimizer_max_mem_size | The maximum memory usage for the range optimizer. The default value is 8388608.
NoteThis variable is 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 no error is returned. |
| show_create_table_verbosity | Specifies whether to display the row format when a table is created. The default value is OFF.
NoteThis variable is 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 no error is returned. |
| sql_big_selects | Specifies whether to enable large queries. The default value is ON.
NoteThis variable is available 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. |
Replica-related
| 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 tables in each cluster. |
| recyclebin | Specifies whether to enable the recycle bin. |
| master_info_repository | Specifies whether to record metadata in the mysql table of the InnoDB 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, the setting does not take effect. |
GTID-related
| Variable | Description |
|---|---|
| gtid_next | Specifies the GTID value of the next transaction. The default value is AUTOMATIC.
NoteThis 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. |
Recycle bin-related
| Variable | Description |
|---|---|
| ob_enable_truncate_flashback | Specifies whether to enable truncate flashback. |
Cache-related
| Variable | Description |
|---|---|
| ob_enable_plan_cache | Controls whether to enable the PL cache module. |
| ob_enable_plan_cache | Specifies whether to enable the Plan Cache. |
| ob_bnl_join_cache_size | Specifies the amount of data cached in each Batch Nested Loop Join (BNLJ) operation. |
Function-related
| Variable | Description |
|---|---|
| group_concat_max_len | Specifies the maximum length of the result of the GROUP_CONCAT() function. |
| interactive_timeout | Specifies the number of seconds for which the server waits for activity before closing an interactive connection. |
| wait_timeout | Specifies the number of seconds for which the server waits for activity before closing a noninteractive connection. |
Session-related
| Variable | Description |
|---|---|
| session_track_gtids | Specifies whether to return GTID information to the client. 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, the setting does not take effect. |
| session_track_transaction_info | Specifies whether to track the transaction status of the current session. 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, the setting does not take effect. |
InnoDB storage engine
| Variable | Description |
|---|---|
| innodb_strict_mode | Specifies the SQL syntax check mode. |
| information_schema_stats_expiry | Specifies the number of seconds for the server to retrieve data from the storage engine and replace cached data. The default value is 86400.
NoteThis 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. |
| low_priority_updates | Specifies whether to control the priority of INSERT, UPDATE, DELETE, and REPLACE statements. 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, but the setting will not take 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the setting will not take effect. |
| max_insert_delayed_threads | Specifies the maximum number of threads for executing INSERT DELAYED statements. The default value is 20.
NoteThis 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. |
| eq_range_index_dive_limit | Specifies whether the optimizer performs index dives during equal-range queries. The default value is 200.
NoteThis 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. |
Cluster
| Variable | Description |
|---|---|
| default_storage_engine | Displays the default storage engine of an OBServer node. |
| ob_capability_flag | Specifies the capabilities of an OBServer node. This variable is used for capability negotiation with a proxy to inform the proxy of the supported and unsupported features of the OBServer node. |
| ob_compatibility_mode | Specifies the compatibility mode of a tenant. |
| ob_proxy_partition_hit | Specifies whether obproxy sends SQL requests for data to the OBServer nodes where the data resides. |
| ob_org_cluster_id | Specifies the CLUSTER_ID of an OceanBase cluster. |
| ob_route_policy | Specifies the routing policy for selecting data replicas in an OBServer node. |
| slave_allow_batching | Specifies whether to enable batch updates for replication threads. 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, but the setting will not take effect. |
Directory path
| Variable | Description |
|---|---|
| ob_enable_hash_group_by | Specifies whether to enable the Hash Group by path. |
Memory
| Variable | Description |
|---|---|
| ob_temp_tablespace_size_percentage | Specifies the percentage limit for the size of the temporary tablespace in the tenant's disk. |
| range_alloc_block_size | Specifies the size of the block allocated during range optimization. The default value is 4096 bytes.
NoteThis 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. |
NDB storage engine
| Variable name | Description |
|---|---|
| ndb_allow_copying_alter_table | Specifies whether to allow ALTER TABLE and other DDL statements to use the copy operation on a table. The default value is OFF.
NoteThis variable is available starting 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 return an error. |
| ndb_autoincrement_prefetch_sz | Specifies the number of auto-increment values to be prefetched. This value can affect the performance and concurrency of auto-increment columns. The default value is 1.
NoteThis variable is available starting 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 return an error. |
| ndb_blob_read_batch_bytes | Specifies the size of BLOB data to be read in batches in an NDB cluster. The unit is bytes. The default value is 65536.
NoteThis variable is available starting 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 return an error. |
| ndb_blob_write_batch_bytes | Specifies the size of BLOB data to be written in batches in an NDB cluster. The unit is bytes. The default value is 65536.
NoteThis variable is available starting 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 return an error. |
| ndb_deferred_constraints | Specifies whether to delay constraint checks on a table. The default value is 0.
NoteThis variable is available starting 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 return an error. |
| ndb_force_send | Specifies whether to immediately send the cache to NDB without waiting for other threads. The default value is OFF.
NoteThis variable is available starting 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 return an error. |
| ndb_fully_replicated | Specifies whether to fully replicate a new table. The default value is OFF.
NoteThis variable is available starting 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 return an error. |
| ndb_index_stat_enable | Specifies whether to use NDB index statistics in query optimization. The default value is OFF.
NoteThis variable is available starting 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 return an error. |
| 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.
NoteThis variable is available starting 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 return an error. |
| ndb_join_pushdown | Specifies whether to enable the join pushdown optimization feature in the storage engine. The default value is OFF.
NoteThis variable is available starting 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 return an error. |
| 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.
NoteThis variable is available starting 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 return an error. |
| ndb_log_exclusive_reads | Specifies whether to use an exclusive lock to record primary key reads. The default value is OFF.
NoteThis variable is available starting 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 return an error. |
| ndb_row_checksum | Specifies the checksum value of a table row. If the value is 1, the checksum value of each row is calculated and saved. If the value is 0, the checksum of table rows is not checked. The default value is 1.
NoteThis variable is available starting 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 return an error. |
| ndb_table_no_logging | Controls the logging behavior of NDB tables. When the value is ON, all tables created or modified using the NDB storage engine are in a non-logging state. 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, but the settings will not take effect and will not generate errors. |
| 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.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors. |
| ndb_use_exact_count | Specifies whether to force NDB to use record counts to accelerate SELECT count(*) queries. The default value is OFF.
NoteThis variable is only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings will not take effect and will not generate errors. |
| ndb_use_transactions | Controls whether to enable transaction support for NDB. 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, but the settings will not take effect and will not generate errors. |
| ndbinfo_max_bytes | Only for testing and debugging. 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, but the settings will not take effect and will not generate errors. |
| ndbinfo_max_rows | Only for testing and debugging. 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, but the settings will not take effect and will not generate errors. |
| ndbinfo_show_hidden | Specifies whether to display the underlying internal tables of the ndbinfo database in the MySQL client. 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, but the settings will not take effect and will not generate errors. |
Runtime Filter related
| Variable | Description |
|---|---|
| runtime_bloom_filter_max_size | The maximum memory size used by a runtime Bloom filter, in bytes. |
| runtime_filter_max_in_num | The number of distinct values in a column for a runtime IN filter. |
| runtime_filter_type | The type of a runtime filter at the tenant level. |
| runtime_filter_wait_time_ms | The maximum wait time for a runtime filter. |
Time zone and date related
| Variable | Description |
|---|---|
| lc_time_names | The language for displaying date and month names and abbreviations. |
| timestamp | TIMESTAMP is the timestamp, in seconds. This variable affects the result of select now(6). |
| nls_calendar | The calendar system used by the database. |
| nls_language | The default language for database internationalization. It is used for prompts, dates, month names, and the default values of NLS_SORT and NLS_DATE_LANGUAGE. |
| error_on_overlap_time | Whether to return an error when there is ambiguity in the time zone overlap area. |
| nls_territory | The current region for database internationalization. It is used in combination with nls_language. |
| time_zone | The time zone for the current tenant session. It supports the offset format '+08:00' and the region format Asia/Shanghai. |
| show_old_temporals | Whether to display the old timestamp columns. The default value is OFF.
NoteThis variable is only used 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. |
| date_format | The default date format. The default value is %Y-%m-%d.
NoteThis variable is only used for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
| datetime_format | The default date and time format. The default value is %Y-%m-%d %H:%i:%s.
NoteThis variable is only used for compatibility with MySQL 5.7. The related features are not supported. You can query this variable, but you cannot set it. |
View related
| Variable | Description |
|---|---|
| updatable_views_with_limit | Whether to allow UPDATE or DELETE operations on a view with the LIMIT clause. The default value is 1.
NoteThis variable is only used 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. |
Transaction and transaction log-related variables
| Variable name | Description |
|---|---|
| autocommit | Specifies whether to automatically commit transactions. |
| ob_proxy_set_trx_executed | Specifies whether to send the START TRANSACTION Syntax statement to the OBServer node through the OBProxy node. |
| ob_trace_info | Used to pass through trace information, which can be persisted to the REDO log. |
| nls_date_language | Specifies the default language for date in database internationalization. |
| ob_trx_idle_timeout | Specifies the transaction idle timeout, which is the time interval between two statements in a transaction. |
| ob_trx_lock_timeout | Specifies the lock wait timeout for a transaction. |
| ob_trx_timeout | Specifies the transaction timeout. |
| transaction_isolation | Specifies the transaction isolation level. |
| transaction_read_only | Controls whether to allow only read-only transactions. |
| tx_isolation | Specifies the transaction isolation level. |
| tx_read_only | Specifies whether to set a transaction to read-only. |
| gtid_owned | Stores the GTID used and owned by the current session. The default value is NULL.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query the variable, but cannot set it. |
| transaction_alloc_block_size | Specifies the initial memory block size allocated to each transaction. The default value is 8192.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set the variable, but the setting does not take effect. |
| transaction_allow_batching | Specifies whether to enable statement batching within the same transaction. The default value is OFF.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set the variable, but the setting does not take effect. |
| transaction_prealloc_size | Specifies the size of the memory block preallocated for each transaction. The default value is 4069.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set the variable, but the setting does not take effect. |
| transaction_write_set_extraction | Specifies the algorithm type for generating identifiers for transaction-related writes. The default value is OFF.
NoteThis variable is for MySQL 5.7 compatibility. The related features are not supported. You can query and set the variable, but the setting does not take effect. |
Data types
| Variable name | Description |
|---|---|
| explicit_defaults_for_timestamp | Specifies whether to enable non-standard behavior for the timestamp data type when handling default values and null values. |
| nls_currency | Specifies the local currency symbol for the L element of the number format. |
| nls_date_format | Controls the format for converting date types to strings and for implicitly converting strings to date types. |
| nls_dual_currency | Specifies the local currency symbol for the U element of the number format. |
| nls_iso_currency | Specifies the local currency symbol for the C element of the number format. |
| nls_length_semantics | Specifies the length semantics for the CHAR and VARCHAR2 data types. |
| nls_nchar_conv_excp | Controls whether to report an error when data is lost during conversion between NCHAR/NVARCHAR2 and CHAR/VARCHAR2. |
| nls_numeric_characters | Controls the characters used for decimal separators and thousand separators in number-to-string and string-to-number conversions. |
| nls_timestamp_format | Controls the format for converting TIMESTAMP or TIMESTAMP_LTZ types to strings and for implicitly converting strings to TIMESTAMP or TIMESTAMP_LTZ types. |
| nls_timestamp_tz_format | Controls the format for converting TIMESTAMP_TZ types to strings and for implicitly converting strings to TIMESTAMP_TZ types. |
| ob_default_lob_inrow_threshold | Specifies the default in-row storage threshold for LOB fields when creating a table. |
SQL/PL related
| Variable | Description |
|---|---|
| cursor_sharing | Specifies whether to parameterize SQL statements. |
| have_profiling | Specifies whether to enable query performance analysis. The default value is NO.
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. |
| max_sp_recursion_depth | Specifies the maximum number of recursive calls allowed for a stored procedure. |
| ob_enable_blk_nestedloop_join | Specifies whether to enable block nested loop join. |
| 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. |
| ob_pl_block_timeout | Specifies the maximum timeout period for PL. |
| profiling | Specifies whether to enable or disable statement analysis. 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, but the setting does not take effect. |
| profiling_history_size | Specifies the number of query performance records to be saved. The default value is 15.
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. |
| sql_mode | Specifies the SQL mode. Different SQL modes have significant impacts on operations such as insertions. |
| sql_quote_show_create | Specifies whether to enable reference identifiers for the SHOW CREATE TABLE and SHOW CREATE DATABASE statements. |
| sql_safe_updates | Specifies whether to enable MySQL's SQL safe mode. The default value is OFF. |
| sql_select_limit | Specifies the maximum number of rows that a Select query can return. |
| sql_throttle_current_priority | Specifies the throttling priority. Requests on sessions where sql_throttle_current_priority is less than sql_throttle_priority will be throttled. |
| ob_enable_parameter_anonymous_block | Specifies whether to enable anonymous block parameterization for the current session. |
| parser_max_mem_size | Specifies the maximum memory size available to the parser. 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, but the setting does not take effect. |
Lock related
| Variable | Description |
|---|---|
| innodb_lock_wait_timeout | Specifies the maximum time (in seconds) that an InnoDB transaction waits for a lock. 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, but the setting does not take effect. |
| innodb_table_locks | Specifies the behavior of InnoDB table-level locking. 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, but the setting does not take effect. |
Random number related
| Variable | Description |
|---|---|
| rand_seed1 | Specifies the seed value for the random number generator. 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, but the setting does not take effect. |
| rand_seed2 | Specifies the additional seed value for the random number generator. The default value is ``.
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. |
System logs
| Variable name | Description |
|---|---|
| binlog_row_image | Specifies whether to record full-column logs. |
| ob_enable_show_trace | Specifies whether to use Show Trace logs. |
| tracefile_identifier | Adds specified content to logs to facilitate filtering of row iteration trace logs. |
| ob_log_level | Specifies the log level for the session. If not specified, the system log level is used. |
System server-related
| Name | Description |
|---|---|
| pseudo_slave_mode | Specifies whether to enable the pseudo-slave mode on the server. The default value is OFF.
NoteThis variable is compatible with MySQL 5.7. The related functionality is unavailable. You can query and set this variable. The setting will not be applied but no error will be returned. |
| pseudo_thread_id | Specifies the ID of the session thread. The default value is 2147483647.
NoteThis variable is provided for compatibility with MySQL 5.7. The related features are not supported, but you can query and set this variable. The behavior of setting this variable does not result in an error but does not take effect. |
| rbr_exec_mode | Set the mode to IDEMPOTENT or STRICT for the session thread. Default value is |
STRICT.
NoteThis variable is for compatibility with MySQL 5.7. You can query or set it without encountering an error. However, its value does not take effect. |
|
| insert_id | This variable specifies the insert ID that is used by subsequent INSERT or ALTER TABLE statements to automatically generate and insert an auto-incrementing value. The default value is 0.
NoteThis variable is only provided for compatibility with MySQL 5.7. The related functionality is not supported, so querying and setting this variable is allowed. Although the setting behavior does not trigger an error, it does not take effect. |
| join_buffer_size | The minimum buffer size for join operations of pure index scan, range index scan, or full table scan. The unit is bytes. The default value is 262144.
NoteThis variable is for MySQL compatibility. You can query and set the variable without causing an error. However, the settings do not take effect. |
| max_join_size | This variable specifies the maximum number of rows allowed in Join operations. The default value is 18446744073709547520.
NoteThis variable is retained for MySQL 5.7 compatibility. It is not supported and will not take effect. You can execute the |
| max_length_for_sort_data | Specifies the truncation value of index value size for determining which file sorting algorithm to use. The default value is 1024.
NoteThis variable is only for MySQL 5.7 compatibility. The related feature is not supported, but the value can be queried and set. Setting the value will not produce an error, but the change will not take effect. |
| max_sort_length | The number of bytes used for sorting numeric values. The default value is 1024.
NoteThis variable is for compatibility with MySQL 5.7. You can query and set the variable. However, changes do not take effect. |
| min_examined_row_limit | Specifies the minimum number of rows to be examined in a query before the query is recorded to the slow query log. Queries that examine fewer than the specified minimum number of rows are not recorded. The default value is 0.
NoteThis variable is for MySQL 5.7 compatibility. It is not supported in TiDB. You can execute the |
| multi_range_count | Specifies the maximum number of Range types allowed in a query statement. The default value is 256.
NoteThis variable is introduced only for compatibility with MySQL 5.7. The related feature is unavailable, and this variable can be queried and set. Setting this variable does not result in an error, but the setting does not take effect. |
| query_alloc_block_size | The size, in bytes, of memory blocks allocated to objects during statement parsing and execution. The default value is 8192.
NoteThis variable is compatible with MySQL 5.7. The corresponding feature is not supported. You can query and set the value, but modifications are not effective. |
| query_prealloc_size | The size of the fixed buffer used for statement parsing and execution. Unit: bytes. Default value: 8192.
NoteThis 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. |
| sort_buffer_size | Specifies the size of the sort buffer in bytes. The default value is 262144.
NoteThis variable is for compatibility with MySQL 5.7. It cannot be modified. However, the system does not report an error when you set it. |
| sql_buffer_result | Specifies whether to store the result of the SELECT statement in a temporary table. The default value is 0.
NoteThis variable is only supported for MySQL 5.7 compatibility. The specified value is accepted but has no effect. You can query the variable and set it to any value, but the setting takes no effect. |
| myisam_repair_threads | The number of concurrent threads to be used for repairing the MyISAM table. The default value is 1.
NoteThis variable is provided only for MySQL 5.7 compatibility. The related features are not supported. You can query and modify this variable, but the modifications do not take effect. |
| myisam_sort_buffer_size | The size of the buffer used for sorting MyISAM indexes during REPAIR TABLE operations or when creating indexes with CREATE INDEX or ALTER TABLE. The unit is bytes. The default value is 8388608.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| 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 treats them the same as other values.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| preload_buffer_size | The size of the buffer used for preloading indexes. The unit is bytes. The default value is 32768.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| read_buffer_size | The size of the buffer used for reading data. The unit is bytes. The default value is 131072.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| read_rnd_buffer_size | The size of the buffer used for reading data from MyISAM tables. It is also used for multi-range read optimization for any storage engine. The unit is bytes. The default value is 262144.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| keep_files_on_create | When the DATA DIRECTORY or INDEX DIRECTORY option is not used to specify the location of data files or index files, this variable controls whether the server retains existing files in the corresponding directory when creating a MyISAM table. The default value is OFF, which means that existing files are overwritten.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| max_heap_table_size | The maximum size to which a memory table created by a user can grow. The unit is bytes. The default value is 16777216.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| bulk_insert_buffer_size | The size of the buffer used for bulk insert operations. The unit is bytes per thread. The default value is 8388608.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| max_delayed_threads | The maximum number of threads that can be created to handle INSERT DELAYED statements. The default value is 20.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| sql_log_off | Specifies whether to enable (OFF) or disable (ON) the logging of regular queries for the current session. The default value is OFF.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| thread_pool_high_priority_connection | Specifies whether to reserve idle threads for high-priority connections in the thread pool. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
| version_tokens_session_number | An internal variable. The default value is 0.
NoteThis variable is available only for compatibility with MySQL 5.7. The related features are not supported. You can query and set this variable, but the settings do not take effect and no errors are reported. |
Foreign key
| Variable name | Description |
|---|---|
| foreign_key_checks | Specifies whether to check foreign key constraints in DML/DDL statements. |
Optimizer
| Variable name | Description |
|---|---|
| ob_enable_transformation | Specifies whether to enable the rewrite feature of the SQL optimizer. |
| optimizer_capture_sql_plan_baselines | Specifies whether to automatically capture new plans to the Plan Baseline. |
| optimizer_features_enable | Specifies whether to enable the optimizer features of different OceanBase Database versions. |
| optimizer_use_sql_plan_baselines | Specifies whether to use the Plan Baseline plan. |
Auto-increment column
| Variable name | Description |
|---|---|
| auto_increment_increment | Specifies 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. |
| identity | identity and the last_insert_id variable are synonyms. You can execute the select @@identity statement to query the value. |
| last_insert_id | Returns the value of the auto-increment column of the last inserted row in the current session. |
| 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. |
| sql_auto_is_null | Specifies whether to obtain the value of the auto-increment column of the last inserted row. |
Character set and string-related variables
| Variable name | Description |
|---|---|
| character_set_client | The character set for statements sent by the client. |
| character_set_database | The character set for the default database. |
| character_set_filesystem | The character set for the filesystem. |
| character_set_results | The character set to which the server converts result sets and error messages before sending them back to the client. |
| character_set_server | The character set for the server. |
| character_set_system | The character set used by the server. |
| collation_connection | The character set and collation for the connection. |
| collation_database | The default character set and collation for the database. |
| collation_server | The default character set and collation for the server. |
| nls_comp | The collation rules for string values. |
| nls_sort | The sorting rules for string values. |
| sql_warnings | Controls whether an information string is generated for a single-row INSERT statement when an alert occurs. |
| default_collation_for_utf8mb4 | The default collation for the utf8mb4 character set, which is utf8mb4_general_ci by default.
NoteThis variable is 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. |
Group Replication
| Variable name | Description |
|---|---|
| group_replication_force_members | Specifies the list of member addresses in the format host1:port1,host2:port2. This variable is used to forcibly create a new group. After 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 empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_group_name | Specifies the name of the group to which the current server belongs. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_gtid_assignment_block_size | Specifies the number of consecutive GTIDs to retain for each member. The default value is 1000000.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_ip_whitelist | Specifies the list of hosts (IP addresses or hostnames) that are allowed to connect to the group. These hosts are referred to as whitelist hosts. The default value is AUTOMATIC.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_local_address | The network address that group replication members use to provide access to other members in the group. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_ca | Specifies the path to the file containing the list of trusted SSL certificate authorities for distributed recovery connections. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_capath | Specifies the directory path to the certificates issued by the trusted SSL certificate authorities for distributed recovery connections. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_cert | Specifies the name of the SSL certificate file required to establish a secure connection for distributed recovery. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_cipher | Specifies the list of encryption algorithms allowed for SSL encryption. The available encryption algorithms depend on the version of the SSL library used to compile MySQL Server. Different SSL libraries support different encryption algorithms. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_crl | Specifies the file name containing the certificate revocation list. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_crlpath | Specifies the directory path containing the certificate revocation list files. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |
| group_replication_recovery_ssl_key | Specifies the name of the SSL key file required to establish a secure connection for distributed recovery. The default value is empty.
NoteThis variable is only for compatibility with MySQL 5.7. The related functionality is not supported. You can query and set it, but the settings will not take effect and no errors will be reported. |