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https://issues.apache.org/jira/browse/BEAM-12153?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Etienne Chauchot reassigned BEAM-12153:
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Assignee: Etienne Chauchot
> OOM on GBK in SparkRunner and SpartStructuredStreamingRunner
> ------------------------------------------------------------
>
> Key: BEAM-12153
> URL: https://issues.apache.org/jira/browse/BEAM-12153
> Project: Beam
> Issue Type: Bug
> Components: runner-spark
> Reporter: Etienne Chauchot
> Assignee: Etienne Chauchot
> Priority: P3
> Time Spent: 20m
> Remaining Estimate: 0h
>
> We have being experiencing OOM errors on GroupByKey in batch mode in both
> Spark runners even if behind the woods spark spills data to disk in such
> cases: taking a look at the translation in the two runners, it might be due
> to using ReduceFnRunner for merging windows in GBK translation.
> ReduceFnRunner.processElements expects to have all elements to merge the
> windows between each other.:
> RDD spark runner:
> https://github.com/apache/beam/blob/752798e3b0e6911fa84f8d138dacccdb6fcc85ef/runners/spark/src/main/java/org/apache/beam/runners/spark/translation/SparkGroupAlsoByWindowViaOutputBufferFn.java#L99
> structured streaming spark: runner:
> [https://github.com/apache/beam/blob/752798e3b0e6911fa84f8d138dacccdb6fcc85ef/runners/spark/2/src/main/java/org/apache/beam/runners/spark/structuredstreaming/translation/batch/functions/GroupAlsoByWindowViaOutputBufferFn.java#L74|https://github.com/apache/beam/blob/752798e3b0e6911fa84f8d138dacccdb6fcc85ef/runners/spark/2/src/main/java/org/apache/beam/runners/spark/structuredstreaming/translation/batch/functions/GroupAlsoByWindowViaOutputBufferFn.java#L106]
> Even replacing the Iterable with an Iterator in ReduceFnRunner to avoid
> materialization does not work because deep in
> ReduceFnRunner.processElements(), the collection is iterated twice.
> It could be better to do what flink runner does and translate GBK as
> CombinePerKey with a Concatenate combine fn and thus avoid elements
> materialization.
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