Important

You are viewing the archived documentation of TiDB, which no longer receives updates. It is recommended that you use the latest LTS version of the TiDB database.

Information Schema

Information Schema provides an ANSI-standard way of viewing system metadata. TiDB also provides a number of custom INFORMATION_SCHEMA tables, in addition to the tables included for MySQL compatibility.

Many INFORMATION_SCHEMA tables have a corresponding SHOW command. The benefit of querying INFORMATION_SCHEMA is that it is possible to join between tables.

Tables for MySQL compatibility

Table Name	Description
`CHARACTER_SETS`	Provides a list of character sets the server supports.
`COLLATIONS`	Provides a list of collations that the server supports.
`COLLATION_CHARACTER_SET_APPLICABILITY`	Explains which collations apply to which character sets.
`COLUMNS`	Provides a list of columns for all tables.
`COLUMN_PRIVILEGES`	Not implemented by TiDB. Returns zero rows.
`COLUMN_STATISTICS`	Not implemented by TiDB. Returns zero rows.
`ENGINES`	Provides a list of supported storage engines.
`EVENTS`	Not implemented by TiDB. Returns zero rows.
`FILES`	Not implemented by TiDB. Returns zero rows.
`GLOBAL_STATUS`	Not implemented by TiDB. Returns zero rows.
`GLOBAL_VARIABLES`	Not implemented by TiDB. Returns zero rows.
`KEY_COLUMN_USAGE`	Describes the key constraints of the columns, such as the primary key constraint.
`OPTIMIZER_TRACE`	Not implemented by TiDB. Returns zero rows.
`PARAMETERS`	Not implemented by TiDB. Returns zero rows.
`PARTITIONS`	Provides a list of table partitions.
`PLUGINS`	Not implemented by TiDB. Returns zero rows.
`PROCESSLIST`	Provides similar information to the command `SHOW PROCESSLIST`.
`PROFILING`	Not implemented by TiDB. Returns zero rows.
`REFERENTIAL_CONSTRAINTS`	Provides information on `FOREIGN KEY` constraints.
`ROUTINES`	Not implemented by TiDB. Returns zero rows.
`SCHEMATA`	Provides similar information to `SHOW DATABASES`.
`SCHEMA_PRIVILEGES`	Not implemented by TiDB. Returns zero rows.
`SESSION_STATUS`	Not implemented by TiDB. Returns zero rows.
`SESSION_VARIABLES`	Provides similar functionality to the command `SHOW SESSION VARIABLES`
`STATISTICS`	Provides information on table indexes.
`TABLES`	Provides a list of tables that the current user has visibility of. Similar to `SHOW TABLES`.
`TABLESPACES`	Not implemented by TiDB. Returns zero rows.
`TABLE_CONSTRAINTS`	Provides information on primary keys, unique indexes and foreign keys.
`TABLE_PRIVILEGES`	Not implemented by TiDB. Returns zero rows.
`TRIGGERS`	Not implemented by TiDB. Returns zero rows.
`USER_ATTRIBUTES`	Summarizes information about user comments and user attributes.
`USER_PRIVILEGES`	Summarizes the privileges associated with the current user.
`VARIABLES_INFO`	Provides information about TiDB system variables.
`VIEWS`	Provides a list of views that the current user has visibility of. Similar to running `SHOW FULL TABLES WHERE table_type = 'VIEW'`

Tables that are TiDB extensions

Table Name	Description
`ANALYZE_STATUS`	Provides information about tasks to collect statistics.
`CLIENT_ERRORS_SUMMARY_BY_HOST`	Provides a summary of errors and warnings generated by client requests and returned to clients.
`CLIENT_ERRORS_SUMMARY_BY_USER`	Provides a summary of errors and warnings generated by clients.
`CLIENT_ERRORS_SUMMARY_GLOBAL`	Provides a summary of errors and warnings generated by clients.
`CLUSTER_CONFIG`	Provides details about configuration settings for the entire TiDB cluster.
`CLUSTER_DEADLOCKS`	Provides a cluster-level view of the `DEADLOCKS` table.
`CLUSTER_HARDWARE`	Provides details on the underlying physical hardware discovered on each TiDB component.
`CLUSTER_INFO`	Provides details on the current cluster topology.
`CLUSTER_LOAD`	Provides current load information for TiDB servers in the cluster.
`CLUSTER_LOG`	Provides a log for the entire TiDB cluster.
`CLUSTER_MEMORY_USAGE`	Provides a cluster-level view of the `MEMORY_USAGE` table.
`CLUSTER_MEMORY_USAGE_OPS_HISTORY`	Provides a cluster-level view of the `MEMORY_USAGE_OPS_HISTORY` table.
`CLUSTER_PROCESSLIST`	Provides a cluster-level view of the `PROCESSLIST` table.
`CLUSTER_SLOW_QUERY`	Provides a cluster-level view of the `SLOW_QUERY` table.
`CLUSTER_STATEMENTS_SUMMARY`	Provides a cluster-level view of the `STATEMENTS_SUMMARY` table.
`CLUSTER_STATEMENTS_SUMMARY_HISTORY`	Provides a cluster-level view of the `STATEMENTS_SUMMARY_HISTORY` table.
`CLUSTER_TIDB_TRX`	Provides a cluster-level view of the `TIDB_TRX` table.
`CLUSTER_SYSTEMINFO`	Provides details about kernel parameter configuration for servers in the cluster.
`DATA_LOCK_WAITS`	Provides the lock-waiting information on the TiKV server.
`DDL_JOBS`	Provides similar output to `ADMIN SHOW DDL JOBS`
`DEADLOCKS`	Provides the information of several deadlock errors that have recently occurred.
`INSPECTION_RESULT`	Triggers internal diagnostics checks.
`INSPECTION_RULES`	A list of internal diagnostic checks performed.
`INSPECTION_SUMMARY`	A summarized report of important monitoring metrics.
`MEMORY_USAGE`	The memory usage of the current TiDB instance.
`MEMORY_USAGE_OPS_HISTORY`	The history of memory-related operations and the execution basis of the current TiDB instance.
`METRICS_SUMMARY`	A summary of metrics extracted from Prometheus.
`METRICS_SUMMARY_BY_LABEL`	See `METRICS_SUMMARY` table.
`METRICS_TABLES`	Provides the PromQL definitions for tables in `METRICS_SCHEMA`.
`PLACEMENT_POLICIES`	Provides information on all placement policies.
`SEQUENCES`	The TiDB implementation of sequences is based on MariaDB.
`SLOW_QUERY`	Provides information on slow queries on the current TiDB server.
`STATEMENTS_SUMMARY`	Similar to performance_schema statement summary in MySQL.
`STATEMENTS_SUMMARY_HISTORY`	Similar to performance_schema statement summary history in MySQL.
`TABLE_STORAGE_STATS`	Provides details about table sizes in storage.
`TIDB_HOT_REGIONS`	Provides statistics about which regions are hot.
`TIDB_HOT_REGIONS_HISTORY`	Provides history statistics about which Regions are hot.
`TIDB_INDEXES`	Provides index information about TiDB tables.
`TIDB_SERVERS_INFO`	Provides a list of TiDB servers (namely, tidb-server component)
`TIDB_TRX`	Provides the information of the transactions that are being executed on the TiDB node.
`TIFLASH_REPLICA`	Provides details about TiFlash replicas.
`TIKV_REGION_PEERS`	Provides details about where regions are stored.
`TIKV_REGION_STATUS`	Provides statistics about regions.
`TIKV_STORE_STATUS`	Provides basic information about TiKV servers.