Overview
- Tables for MySQL compatibility
- Tables that GreptimeDB provides

Overview

INFORMATION_SCHEMA provides access to system metadata, such as the name of a database or table, the data type of a column, etc. GreptimeDB also provides some custom INFORMATION_SCHEMA tables to query metadata about the GreptimeDB system itself, cluster information, and runtime telemetry for example.

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

There is still lots of work to do for INFORMATION_SCHEMA. The tracking issue for INFORMATION_SCHEMA.

Tables for MySQL compatibility

Table Name	Description
CHARACTER_SETS	provides information about available character sets.
`CHECK_CONSTRAINTS`	Not implemented. Returns zero rows.
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. Returns zero rows.
`COLUMN_STATISTICS`	Not supported.
ENGINES	Provides a list of supported storage engines.
`EVENTS`	Not implemented. Returns zero rows.
`FILES`	Not implemented. Returns zero rows.
`GLOBAL_STATUS`	Not implemented. Returns zero rows.
`GLOBAL_VARIABLES`	Not supported.
KEY_COLUMN_USAGE	Describes the key constraints of the columns, such as the primary key, and time index constraint.
`OPTIMIZER_TRACE`	Not implemented. Returns zero rows.
`PARAMETERS`	Not implemented. Returns zero rows.
PARTITIONS	Provides a list of table partitions.
`PLUGINS`	Not supported.
`PROCESSLIST`	Not supported.
`PROFILING`	Not implemented. Returns zero rows.
`REFERENTIAL_CONSTRAINTS`	Not implemented. Returns zero rows.
`ROUTINES`	Not implemented. Returns zero rows.
SCHEMATA	Provides similar information to `SHOW DATABASES`.
`SCHEMA_PRIVILEGES`	Not implemented. Returns zero rows.
`SESSION_STATUS`	Not implemented. Returns zero rows.
`SESSION_VARIABLES`	Not supported.
`STATISTICS`	Not supported.
TABLES	Provides a list of tables that the current user has visibility of. Similar to `SHOW TABLES`.
`TABLESPACES`	Not supported.
`TABLE_PRIVILEGES`	Not implemented. Returns zero rows.
`TRIGGERS`	Not implemented. Returns zero rows.
`USER_ATTRIBUTES`	Not supported.
`USER_PRIVILEGES`	Not supported.
`VARIABLES_INFO`	Not supported.
`VIEWS`	Not supported.

Tables that GreptimeDB provides

Table Name	Description
BUILD_INFO	Provides the system build info.
GREPTIME_REGION_PEERS	Provides details about where regions are stored.
RUNTIME_METRICS	Provides the system runtime metrics.