[Spark] Ignore internal metadata when detecting schema changes in Delta source #3849
+102
−14
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Description
When reading from a Delta streaming source with schema tracking enabled - by specifying
schemaTrackingLocation- internal metadata in the table schema causes a schema change to be detected.This is especially problematic for identity columns that track the current high-water mark for ids as metadata in the table schema and update it on every write, causing streams to repeatedly fail and requiring a restart.
This change addresses the issue by ignoring internal metadata fields when detecting schema changes.
A flag is added to revert to the old behavior if needed.
How was this patch tested?
Added test case covering problematic use case with both fix enabled and disabled.