MySQL System Tables

Replication System Tables

The server uses these system tables to support replication:

• gtid_executed: Table for storing GTID values. See mysql.gtid_executed Table.

• ndb_binlog_index: Binary log information for NDB Cluster replication. This table is created only if the server is built with NDBCLUSTER support. See Section 23.7.4, “NDB Cluster Replication Schema and Tables”.

• slave_master_info, slave_relay_log_info, slave_worker_info: Used to store replication information on replica servers. See Section 17.2.4, “Relay Log and Replication Metadata Repositories”.

All of the tables just listed use the InnoDB storage engine.

Optimizer System Tables

These system tables are for use by the optimizer:

• innodb_index_stats, innodb_table_stats: Used for InnoDB persistent optimizer statistics. See Section 15.8.10.1, “Configuring Persistent Optimizer Statistics Parameters”.

• server_cost, engine_cost: The optimizer cost model uses tables that contain cost estimate information about operations that occur during query execution. server_cost contains optimizer cost estimates for general server operations. engine_cost contains estimates for operations specific to particular storage engines. See Section 8.9.5, “The Optimizer Cost Model”.

Miscellaneous System Tables

Other system tables do not fit the preceding categories:

• audit_log_filter, audit_log_user: If MySQL Enterprise Audit is installed, these tables provide persistent storage of audit log filter definitions and user accounts. See Audit Log Tables.

• firewall_group_allowlist, firewall_groups, firewall_memebership, firewall_users, firewall_whitelist: If MySQL Enterprise Firewall is installed, these tables provide persistent storage for information used by the firewall. See Section 6.4.7, “MySQL Enterprise Firewall”.

• servers: Used by the FEDERATED storage engine. See Section 16.8.2.2, “Creating a FEDERATED Table Using CREATE SERVER”.

• innodb_dynamic_metadata: Used by the InnoDB storage engine to store fast-changing table metadata such as auto-increment counter values and index tree corruption flags. Replaces the data dictionary buffer table that resided in the InnoDB system tablespace.