information-schema.md

title	summary	aliases
Information Schema	TiDB implements the ANSI-standard information_schema for viewing system metadata.	/docs/dev/system-tables/system-table-information-schema/ /docs/dev/reference/system-databases/information-schema/ /tidb/dev/system-table-information-schema/

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_PRIVILEGES	Summarizes the privileges associated with the current user.
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_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.
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.
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_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.