Information Schema

The StarRocks information_schema is a database within each StarRocks instance. information_schema contains several read-only, system-defined tables which store extensive metadata information of all objects that the StarRocks instance maintains.

View metadata via Information Schema

You can view the metadata information within a StarRocks instance by querying the content of tables in information_schema.

The following example views metadata information about a table named sr_member in StarRocks by querying the table tables.

mysql> SELECT * FROM information_schema.tables WHERE TABLE_NAME like 'sr_member'\G
*************************** 1. row ***************************
  TABLE_CATALOG: def
   TABLE_SCHEMA: sr_hub
     TABLE_NAME: sr_member
     TABLE_TYPE: BASE TABLE
         ENGINE: StarRocks
        VERSION: NULL
     ROW_FORMAT: NULL
     TABLE_ROWS: 6
 AVG_ROW_LENGTH: 542
    DATA_LENGTH: 3255
MAX_DATA_LENGTH: NULL
   INDEX_LENGTH: NULL
      DATA_FREE: NULL
 AUTO_INCREMENT: NULL
    CREATE_TIME: 2022-11-17 14:32:30
    UPDATE_TIME: 2022-11-17 14:32:55
     CHECK_TIME: NULL
TABLE_COLLATION: utf8_general_ci
       CHECKSUM: NULL
 CREATE_OPTIONS: NULL
  TABLE_COMMENT: OLAP
1 row in set (1.04 sec)

Information Schema tables

StarRocks have optimized the metadata information provided by the following tables in information_schema:

Information Schema table name	Description
tables	Provides general metadata information of tables.
tables_config	Provides additional table metadata information that is unique to StarRocks.

tables

The following fields are provided in tables:

Field	Description
TABLE_CATALOG	Name of the catalog that stores the table.
TABLE_SCHEMA	Name of the database that stores the table.
TABLE_NAME	Name of the table.
TABLE_TYPE	Type of the table. Valid values: "BASE TABLE" or "VIEW".
ENGINE	Engine type of the table. Valid values: "StarRocks", "MySQL", "MEMORY" or an empty string.
VERSION	Applies to a feature not available in StarRocks.
ROW_FORMAT	Applies to a feature not available in StarRocks.
TABLE_ROWS	Row count of the table.
AVG_ROW_LENGTH	Average row length (size) of the table. It is equivalent to `DATA_LENGTH` / `TABLE_ROWS`. Unit: Byte.
DATA_LENGTH	Data length (size) of the table. Unit: Byte.
MAX_DATA_LENGTH	Applies to a feature not available in StarRocks.
INDEX_LENGTH	Applies to a feature not available in StarRocks.
DATA_FREE	Applies to a feature not available in StarRocks.
AUTO_INCREMENT	Applies to a feature not available in StarRocks.
CREATE_TIME	The time when the table is created.
UPDATE_TIME	The last time when the table is updated.
CHECK_TIME	The last time when a consistency check is performed on the table.
TABLE_COLLATION	The default collation of the table.
CHECKSUM	Applies to a feature not available in StarRocks.
CREATE_OPTIONS	Applies to a feature not available in StarRocks.
TABLE_COMMENT	Comment on the table.

tables_config

The following fields are provided in tables_config:

Field	Description
TABLE_SCHEMA	Name of the database that stores the table.
TABLE_NAME	Name of the table.
TABLE_ENGINE	Engine type of the table.
TABLE_MODEL	Table type. Valid values: "DUP_KEYS", "AGG_KEYS", "UNQ_KEYS" or "PRI_KEYS".
PRIMARY_KEY	The primary key of a Primary Key table or a Unique Key table. An empty string is returned if the table is not a Primary Key table or a Unique Key table.
PARTITION_KEY	The partitioning columns of the table.
DISTRIBUTE_KEY	The bucketing columns of the table.
DISTRIBUTE_TYPE	The data distribution method of the table.
DISTRIBUTE_BUCKET	Number of buckets in the table.
SORT_KEY	Sort keys of the table.
PROPERTIES	Properties of the table.