Query internal data in StarRocks using the default_catalog - E-MapReduce

Each StarRocks cluster (version 2.3 and later) has exactly one built-in internal catalog named default_catalog. Use it to query data stored directly in the StarRocks cluster, as opposed to data in external sources such as Hive or Iceberg.

How it works

StarRocks uses a three-tier naming hierarchy: catalog.database.table. The default_catalog is the top-level root for all internal databases and tables. For example, default_catalog.sales_db.orders refers to the orders table in the sales_db database of the internal catalog.

The default_catalog name is fixed — you cannot rename it or create additional internal catalogs.

Query internal data

Note

Replace <db_name> and <table_name> with actual values.

Connect to the StarRocks cluster. For more information, see Getting started.
- MySQL client: After connecting, default_catalog is active by default.
- Java Database Connectivity (JDBC): Specify the database in the connection string using the default_catalog.<db_name> format.

(Optional) List all databases in the cluster.

SHOW DATABASES;
-- Or specify the catalog explicitly
SHOW DATABASES FROM default_catalog;

(Optional) Switch to a database.

USE <db_name>;
-- Or specify the catalog explicitly
USE default_catalog.<db_name>;

Query internal data.

SELECT * FROM <table_name>;

If you skipped step 3, include the database name in the query:

-- Without specifying the catalog
SELECT * FROM <db_name>.<table_name>;
-- With the catalog specified
SELECT * FROM default_catalog.<db_name>.<table_name>;