user：用户帐户、全局权限和其他非权限列。

db：数据库级权限。

tables_priv：表级权限。

columns_priv: 列级权限。

procs_priv: 存储过程和函数权限。

proxies_priv: Proxy-user privileges.

event: The registry for Event Scheduler events installed using CREATE EVENT. If the server is started with the --skip-grant-tables option, the event scheduler is disabled and events registered in the table do not run. See Section 23.4.2, “Event Scheduler Configuration”.

func: The registry for loadable functions installed using CREATE FUNCTION. During the normal startup sequence, the server loads functions registered in this table. If the server is started with the --skip-grant-tables option, functions registered in the table are not loaded and are unavailable. See Section 5.6.1, “Installing and Uninstalling Loadable Functions”.

plugin: The registry for server-side plugins installed using INSTALL PLUGIN. During the normal startup sequence, the server loads plugins registered in this table. If the server is started with the --skip-grant-tables option, plugins registered in the table are not loaded and are unavailable. See Section 5.5.1, “Installing and Uninstalling Plugins”.

The plugin table uses the InnoDB storage engine as of MySQL 5.7.6, MyISAM before that.

proc: Information about stored procedures and functions. See Section 23.2, “Using Stored Routines”.

general_log: The general query log table.

slow_log: The slow query log table.

help_category: Information about help categories.

help_keyword: Keywords associated with help topics.

help_relation: Mappings between help keywords and topics.

help_topic: Help topic contents.

time_zone: Time zone IDs and whether they use leap seconds.

time_zone_leap_second: When leap seconds occur.

time_zone_name: Mappings between time zone IDs and names.

time_zone_transition, time_zone_transition_type: Time zone descriptions.

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

The gtid_executed table uses the InnoDB storage engine.

ndb_binlog_index: Binary log information for NDB Cluster replication. See Section 21.7.4, “NDB Cluster Replication Schema and Tables”.

Prior to NDB 7.5.2, this table employed the MyISAM storage engine. In NDB 7.5.2 and later, it uses InnoDB. If you are planning an upgrade from a NDB Cluster previous release to NDB 7.5.2 or later, see Section 21.3.7, “Upgrading and Downgrading NDB Cluster”, for important information relating to this change.

slave_master_info, slave_relay_log_info, slave_worker_info: Used to store replication information on replica servers. See Section 16.2.4, “Relay Log and Replication Metadata Repositories”.

All three of these tables use the InnoDB storage engine.

innodb_index_stats, innodb_table_stats: Used for InnoDB persistent optimizer statistics. See Section 14.8.11.1, “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”.

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_users, firewall_whitelist: If MySQL Enterprise Firewall is installed, these tables provide persistent storage for information used by the firewall. See Section 6.4.6, “MySQL Enterprise Firewall”.

servers: Used by the FEDERATED storage engine. See Section 15.8.2.2, “Creating a FEDERATED Table Using CREATE SERVER”.

该servers表在此之前使用 InnoDBMySQL 5.7.6 的存储引擎 MyISAM。