Can't setup copyjob to read partitioned delta table

Hi nicolasbejar 

You're not doing anything wrong — the issue is simply that the Copy Job UI doesn’t currently expose a “Delta” option at all. Even if your folder clearly contains _delta_log and the partition folders, the Copy Job still only treats ADLS Gen2 sources as “files” (Parquet, CSV, JSON, etc.). Because of that, it will always try to read the Parquet files directly and skip the Delta transaction log, which is why the load fails.

So to answer your questions:

1. Pointing to the root is correct, and the presence of _delta_log means the table is valid — the Copy Job just doesn’t understand it natively.

2. You don’t need another connection type. ADLS Gen2 is correct. The limitation is in the Copy Job reader, not the connection.

3. It’s expected that you don’t see “Delta” in the format list — the UI hasn’t added Delta support yet for ADLS sources. That’s why the “Delta” option doesn’t appear.

At the moment, the only reliable way to copy from a Delta Lake table stored in ADLS is to use Dataflows Gen2 or a notebook (PySpark or pandas) instead of the Copy Job wizard. Those fully understand the Delta transaction log, partitions, and schema.

In short:
Your setup is right — the Copy Job just doesn’t support Delta formats from ADLS yet. Once Microsoft updates the Copy Job to recognize Delta automatically, the same path you’re using should work without any changes.

Hope this helps.

– Gopi Krishna