What causes DELTA_CONCURRENT_DELETE_READ?

A DELETE or MERGE (delete phase) ran concurrently with a SELECT or streaming read on overlapping partitions. A VACUUM operation removed files that a long-running query still referenced. A Z-ORDER OPTIMIZE compacted and replaced data files while a streaming job was reading them. Partition pruning was not in effect and the reader scanned the full table while a delete ran

How do I fix DELTA_CONCURRENT_DELETE_READ?

Retry the read transaction — Delta will now see the post-delete state and complete cleanly.. Add partition filters to your read queries to reduce the surface area of overlap with delete operations.. Schedule deletes and VACUUM operations outside peak read windows.. Increase `delta.deletedFileRetentionDuration` to give long-running reads a larger time window before files are cleaned up.. For streaming reads, use `ignoreDeletes=true` if the stream does not need to process deletions.

High severitysql

Power BI Refresh Error:
DELTA_CONCURRENT_DELETE_READ

What does this error mean?

A transaction read data files that were concurrently deleted by another transaction. Delta Lake detects this conflict at commit time and aborts the reader's transaction to preserve consistency.

Common causes

1A DELETE or MERGE (delete phase) ran concurrently with a SELECT or streaming read on overlapping partitions
2A VACUUM operation removed files that a long-running query still referenced
3A Z-ORDER OPTIMIZE compacted and replaced data files while a streaming job was reading them
4Partition pruning was not in effect and the reader scanned the full table while a delete ran

How to fix it

1Retry the read transaction — Delta will now see the post-delete state and complete cleanly.
2Add partition filters to your read queries to reduce the surface area of overlap with delete operations.
3Schedule deletes and VACUUM operations outside peak read windows.
4Increase `delta.deletedFileRetentionDuration` to give long-running reads a larger time window before files are cleaned up.
5For streaming reads, use `ignoreDeletes=true` if the stream does not need to process deletions.

Frequently asked questions

Does enabling `ignoreDeletes` on a stream compromise data correctness?

Only if your stream logic needs to react to deletions. For append-only pipelines where deletes are maintenance operations, ignoreDeletes is safe.