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 NameDescription
CHARACTER_SETSprovides information about available character sets.
CHECK_CONSTRAINTSNot implemented. Returns zero rows.
COLLATIONSProvides a list of collations that the server supports.
COLLATION_CHARACTER_SET_APPLICABILITYExplains which collations apply to which character sets.
COLUMNSProvides a list of columns for all tables.
COLUMN_PRIVILEGESNot implemented. Returns zero rows.
COLUMN_STATISTICSNot supported.
ENGINESProvides a list of supported storage engines.
EVENTSNot implemented. Returns zero rows.
FILESNot implemented. Returns zero rows.
GLOBAL_STATUSNot implemented. Returns zero rows.
GLOBAL_VARIABLESNot supported.
KEY_COLUMN_USAGEDescribes the key constraints of the columns, such as the primary key, and time index constraint.
OPTIMIZER_TRACENot implemented. Returns zero rows.
PARAMETERSNot implemented. Returns zero rows.
PARTITIONSProvides a list of table partitions.
PLUGINSNot supported.
PROCESSLISTNot supported.
PROFILINGNot implemented. Returns zero rows.
REFERENTIAL_CONSTRAINTSNot implemented. Returns zero rows.
ROUTINESNot implemented. Returns zero rows.
SCHEMATAProvides similar information to SHOW DATABASES.
SCHEMA_PRIVILEGESNot implemented. Returns zero rows.
SESSION_STATUSNot implemented. Returns zero rows.
SESSION_VARIABLESNot supported.
STATISTICSNot supported.
TABLESProvides a list of tables that the current user has visibility of. Similar to SHOW TABLES.
TABLESPACESNot supported.
TABLE_PRIVILEGESNot implemented. Returns zero rows.
TRIGGERSNot implemented. Returns zero rows.
USER_ATTRIBUTESNot supported.
USER_PRIVILEGESNot supported.
VARIABLES_INFONot supported.
VIEWSNot supported.

Tables that GreptimeDB provides

Table NameDescription
BUILD_INFOProvides the system build info.
GREPTIME_REGION_PEERSProvides details about where regions are stored.
RUNTIME_METRICSProvides the system runtime metrics.