External to Managed

[adeosthali]

We are looking to migrate to managed tables using ALTER TABLE fq_table_name SET MANAGED

During migration process we need to have ability to switch between external & managed tables & vice versa.

UNSET MANAGED works for 14 days.

But I'm unable to just delete the converted managed table & rebuild as external exact same external location.
Once table is deleted spark.catalog.tableExists(fq_table_name) returns false as expected.

While trying to recreate it using below code returns error that table does not exist instead of creating table.

                df_final.write.format("delta")

                .mode("append")

                .option("path","Original_External_Storage_Path")

                .saveAsTable(runtime_contract.entity_full_name)

same process works if the table starts its life as managed.

i.e. I can have managed table x deleted & created as external.

[anshu_roy · Accepted solution]

Hello,

Thanks for sharing your investigation.

You’re correct: you can’t immediately recreate the converted table as an external table on the same original path after dropping it. The Unity Catalog table object remains in a soft‑deleted state for 7 days and is only fully removed after that period, so the underlying path remains reserved for the SET MANAGED / UNSET MANAGED lifecycle (with a rollback window of up to 14 days).

During that window you must either:

• Use ALTER TABLE ... UNSET MANAGED to roll back to the original external table, or

• Create a new external table on a different path, or recreate it as a managed table instead.

You can find the official documentation here:
https://learn.microsoft.com/azure/databricks/tables/convert-external-managed