Comments on foreign tables

Beta

This feature is in Beta. Workspace admins can control access to this feature from the Previews page. See Manage Databricks previews.

Lakehouse Federation can sync table and column comments from supported external data sources to foreign tables in Unity Catalog. Synced comments appear in table metadata, including Catalog Explorer, DESCRIBE, and DESCRIBE EXTENDED output.

Requirements

• Compute: Use Databricks Runtime 18.2 or above, or a SQL warehouse on a channel that runs Databricks SQL version 2026.15 or above. See SQL warehouse channels.

Supported data sources

Foreign table comments are synced for the following data sources:

• AWS Glue metastore

• Google BigQuery
• Hive metastore federation
• MySQL
• Oracle on Databricks Runtime 18.3 or above
• PostgreSQL
• Amazon Redshift
• Snowflake query federation and Snowflake catalog federation
• Teradata

Foreign table comments are not synced for the following data sources:

• Azure Synapse (SQL Data Warehouse)
• Databricks-to-Databricks query federation
• Microsoft SQL Server
• Salesforce Data 360 and Salesforce Data 360 file sharing

Sync comments from the external source

For supported data sources, Databricks fetches foreign table comments when it resolves foreign table metadata at query time. When comments change in the external source, the updated comments are synced the next time a query resolves the foreign table.

To sync comments without running a query against the table data, run DESCRIBE EXTENDED on the foreign table:

SQL

DESCRIBE EXTENDED <catalog-name>.<schema-name>.<table-name>;