Help Center/ CloudTable Service/ User Guide/ Using Doris/ Doris Enterprise-class Enhancement/ Interconnecting Doris with Data Sources/ About Doris Multi-Source Data
Updated on 2025-12-18 GMT+08:00
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About Doris Multi-Source Data

Hive foreign tables of Doris support CREATE CATALOG. By connecting to Hive Metastore, or a metadata service compatible with Hive Metastore, Doris can automatically obtain Hive database table information and perform data queries. This avoids complex manual mapping and data migration when there is a large number of conventional external data directories.

Multi-Catalog is designed to make it easier to connect to external data catalogs to enhance Doris' data lake analysis and federated data query capabilities. It is a function launched in Doris 1.2.0.

In older versions of Doris, user data is in a two-tiered structure: database and table. Therefore, connections to external catalogs could only be done at the database or table level. For example, you could create a mapping to a table in an external catalog via create external table, or to a database via create external database. If there were large amounts of databases or tables in the external catalog, you would need to create mappings to them one by one, which could be a heavy workload.

With the advent of Multi-Catalog, Doris now has a new three-tiered metadata hierarchy (including catalog, database, and table), A catalog may directly correspond to an external data catalog.

Basic Concepts

  1. Internal Catalog

    Existing databases and tables in Doris are all under the Internal Catalog, which is the default catalog in Doris and cannot be modified or deleted.

  2. External Catalog

    You can run the CREATE CATALOG command to create an External Catalog, and view the existing catalogs using the SHOW CATALOGS command.

  3. Switch Catalog

    After login, you will enter the Internal Catalog by default. Then, you can view or switch to your target database via SHOW DATABASES and USE DB.

    You can run the SWITCH command to switch the catalog. Example:

    SWITCH internal;
SWITCH hive_catalog;

    After switching the catalog, you can view or switch to your target database in that catalog via SHOW DATABASES and USE DB. Doris automatically passes through databases and tables in Catalog. You can view and access data in External Catalogs the same way as doing that in Internal Catalogs.

    Doris only supports read-only access to data in External Catalogs currently.

  4. Delete Catalog

    Databases and tables in external catalogs are read-only. External Catalogs are deletable via the DROP CATALOG command. (The Internal catalog cannot be deleted.) You can run the DROP CATALOG command to delete an External Catalog.

    This operation only deletes the mapping information of the Catalog in Doris, but does not modify or change the content of any external data catalog.

  5. Resource

    Resource is a set of configurations. You can run the CREATE RESOURCE command to create a Resource. Then, you can use the Resource when creating a catalog.

    A resource can be used by multiple catalogs to reuse the configuration of the resource.