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https://issues.apache.org/jira/browse/SPARK-32794?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tathagata Das resolved SPARK-32794.
-----------------------------------
Fix Version/s: (was: 2.4.8)
2.4.7
Resolution: Fixed
Issue resolved by pull request 29700
[https://github.com/apache/spark/pull/29700]
> Rare corner case error in micro-batch engine with some stateful queries +
> no-data-batches + V1 streaming sources
> -----------------------------------------------------------------------------------------------------------------
>
> Key: SPARK-32794
> URL: https://issues.apache.org/jira/browse/SPARK-32794
> Project: Spark
> Issue Type: Bug
> Components: Structured Streaming
> Affects Versions: 2.3.4, 2.4.6, 3.0.0, 3.0.1
> Reporter: Tathagata Das
> Assignee: Tathagata Das
> Priority: Major
> Fix For: 2.4.7, 3.1.0, 3.0.2
>
>
> Structured Streaming micro-batch engine has the contract with V1 data sources
> that, after a restart, it will call `source.getBatch()` on the last batch
> attempted before the restart. However, a very rare combination of sequences
> violates this contract. It occurs only when
> - The streaming query has specific types of stateful operations with
> watermarks (e.g., aggregation in append, mapGroupsWithState with timeouts).
> - These queries can execute a batch even without new data when the
> previous updates the watermark and the stateful ops are such that the new
> watermark can cause new output/cleanup. Such batches are called
> no-data-batches.
> - The last batch before termination was an incomplete no-data-batch. Upon
> restart, the micro-batch engine fails to call `source.getBatch` when
> attempting to re-execute the incomplete no-data-batch.
> This occurs because no-data-batches has the same and end offsets, and when a
> batch is executed, if the start and end offset is same then calling
> `source.getBatch` is skipped as it is assumed the generated plan will be
> empty. This only affects V1 data sources which rely on this invariant to
> initialize differently when the query is being started from scratch or
> restarted. How will a source misbehave is very source-specific.
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