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https://issues.apache.org/jira/browse/FLINK-2240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14661203#comment-14661203
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ASF GitHub Bot commented on FLINK-2240:
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Github user ChengXiangLi commented on the pull request:
https://github.com/apache/flink/pull/888#issuecomment-128563750
Thanks for the review, @StephanEwen , i'm very interesting in this project,
and i would like to contribute more. @vasia , I think stephan has helped to
answer the question yet, the most important reason is that i want to reuse the
memory occupied by hash table buckets. Besides, since this is a performance
sense issue, i try to make this bloom filter as much simple and efficient as i
can, for example, the hashcode of join key is already generated and stored in
hybrid hash join, i just reuse the hashcode instead of generate it by join key
value inside bloom filter again.
> Use BloomFilter to minimize probe side records which are spilled to disk in
> Hybrid-Hash-Join
> --------------------------------------------------------------------------------------------
>
> Key: FLINK-2240
> URL: https://issues.apache.org/jira/browse/FLINK-2240
> Project: Flink
> Issue Type: Improvement
> Components: Core
> Reporter: Chengxiang Li
> Assignee: Chengxiang Li
> Priority: Minor
> Fix For: 0.10
>
>
> In Hybrid-Hash-Join, while small table does not fit into memory, part of the
> small table data would be spilled to disk, and the counterpart partition of
> big table data would be spilled to disk in probe phase as well. If we build a
> BloomFilter while spill small table to disk during build phase, and use it to
> filter the big table records which tend to be spilled to disk, this may
> greatly reduce the spilled big table file size, and saved the disk IO cost
> for writing and further reading.
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