What causes DELTA_TRANSACTION_CONFLICT?

A long-running MERGE or UPDATE read an old snapshot and another transaction committed changes to the same rows before the first could commit. Streaming and batch jobs sharing the same table and writing at high frequency create overlapping read snapshots. Row-level conflict detection exceeded the configured resolution time limit

How do I fix DELTA_TRANSACTION_CONFLICT?

Retry the transaction — with a shorter-lived concurrent transaction gone, the retry will commit cleanly.. Reduce MERGE statement complexity so it commits faster and reduces the window for conflict.. Use partition-level isolation: partition the table such that each concurrent job writes to a distinct partition.. Switch to Serializable isolation only where required — SnapshotIsolation is the default and handles most cases with fewer conflicts.

High severitysql

Power BI Refresh Error:
DELTA_TRANSACTION_CONFLICT

What does this error mean?

A Delta transaction was aborted because its read snapshot is no longer valid — another committed transaction changed the state the current transaction depended on. This is raised when Delta's conflict detection identifies that proceeding would violate serializability.

Common causes

1A long-running MERGE or UPDATE read an old snapshot and another transaction committed changes to the same rows before the first could commit
2Streaming and batch jobs sharing the same table and writing at high frequency create overlapping read snapshots
3Row-level conflict detection exceeded the configured resolution time limit

How to fix it

1Retry the transaction — with a shorter-lived concurrent transaction gone, the retry will commit cleanly.
2Reduce MERGE statement complexity so it commits faster and reduces the window for conflict.
3Use partition-level isolation: partition the table such that each concurrent job writes to a distinct partition.
4Switch to Serializable isolation only where required — SnapshotIsolation is the default and handles most cases with fewer conflicts.

Frequently asked questions

Does increasing Delta table isolation level help?

No — stricter isolation (Serializable vs. SnapshotIsolation) causes more conflicts, not fewer. Use SnapshotIsolation (the default) and rely on partition design to reduce contention.