Unable to Add Multiple Columns in Single ALTER TABLE Statement on Iceberg Table via Unity REST Catal

Ashok_Vengala
New Contributor

‎10-23-2025 05:22 AM


Hello Databricks Team,

I have implemented code to integrate the Iceberg Unity REST Catalog with the Teradata OTF engine and successfully performed read and write operations, following the documentation at https://docs.databricks.com/aws/en/external-access/iceberg#gsc.tab=0. However, I am encountering the following problem:

When attempting to add multiple columns in a single ALTER TABLE statement on an Iceberg table managed via Databricks Unity Catalog and cloud storage (AWS/GCP/AZURE), the operation fails with the error:

Commit failed: Failed to commit to the table, requirement failed: There may be at most 1 SetCurrentSchema metadata update.

Steps to reproduce:
1) Create a table with two columns.
2) Add a single column using ALTER TABLE ... ADD ... (works as expected).
3) Attempt to add two columns in one statement: ALTER TABLE ... ADD col1 type, ADD col2 type; (fails with the above error).



I do not have access to the Databricks Unity Catalog code base to debug this issue, as it is owned by the Databricks team. Could you clarify if this is a known limitation or a bug in the REST Catalog implementation?
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