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https://issues.apache.org/jira/browse/IMPALA-9789?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wenzhe Zhou resolved IMPALA-9789.
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Resolution: Fixed
> Disable ineffective bloom filters for Kudu scan
> -----------------------------------------------
>
> Key: IMPALA-9789
> URL: https://issues.apache.org/jira/browse/IMPALA-9789
> Project: IMPALA
> Issue Type: Improvement
> Components: Backend, Frontend
> Affects Versions: Impala 3.4.0
> Reporter: Wenzhe Zhou
> Assignee: Wenzhe Zhou
> Priority: Major
> Fix For: Impala 4.0
>
>
> In bloom-filter benchmark for Kudu, there is performance regression for query
> TPCH-Q9. In Profile shows that 5 bloom filters are generated by hash join.
> Some of those filters are not useful for filtering rows. When pushing all
> bloom filters to Kudu, the bloom filter evaluations add extra cost for Kudu
> scan, which cause performance regression.
>
> The regression on Q9 looks a lot like
> https://issues.apache.org/jira/browse/IMPALA-9302, where Q9 regressed a lot
> with multithreading initially because ineffective filters weren't being
> disabled. This query is a bit special in that there are many filters pushed
> to scan 2, and most of them are not useful. Based on our experience there, we
> need to add a method to disable ineffective filters for Kudu scan.
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