[SPARK-56995][SQL][DML] Allow dataframe caching in the DSv2 Transaction API#56121
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andreaschat-db wants to merge 6 commits into
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[SPARK-56995][SQL][DML] Allow dataframe caching in the DSv2 Transaction API#56121andreaschat-db wants to merge 6 commits into
andreaschat-db wants to merge 6 commits into
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Is this PR aiming for 4.2? |
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Yes. It is an important fix for the DSv2 Transaction API. |
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Currently, the DSv2 Transaction API skips dataframe caching. This can cause significant performance regression to existing workloads. Dataframes cached prior to the transaction should be allowed to be reused within the transaction. Cache substitution during a transaction now delegates to the connector via
Transaction.registerScans. Spark hands every materialized scan in a candidate cached subtree to the active transaction, and the connector decides whether reusing the cached snapshots is compatible with its isolation contract.What changes were proposed in this pull request?
This transaction introduces
Transaction.registerScansin the transaction API. Check above for more details.Why are the changes needed?
Without this fix cached dataframes cannot be used in transactions. As a result, the DSv2 transaction API will introduce significant performance regression for relevant workloads.
Does this PR introduce any user-facing change?
No.
How was this patch tested?
Existing and new tests.
Was this patch authored or co-authored using generative AI tooling?
Opus 4.7