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Posted to issues@hive.apache.org by "Panagiotis Garefalakis (Jira)" <ji...@apache.org> on 2020/04/09 15:35:00 UTC
[jira] [Work started] (HIVE-23166) Guard VGB from flushing too
often
[ https://issues.apache.org/jira/browse/HIVE-23166?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Work on HIVE-23166 started by Panagiotis Garefalakis.
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> Guard VGB from flushing too often
> ---------------------------------
>
> Key: HIVE-23166
> URL: https://issues.apache.org/jira/browse/HIVE-23166
> Project: Hive
> Issue Type: Improvement
> Components: llap
> Affects Versions: 4.0.0
> Reporter: Panagiotis Garefalakis
> Assignee: Panagiotis Garefalakis
> Priority: Major
> Attachments: HIVE-23166.01.patch
>
>
> The existing flush logic in our VectorGroupByOperator is completely static.
> It depends on the: number of HtEntries (*hive.vectorized.groupby.maxentries*) and the MAX memory threshold (by default 90% of available memory)
>
> Assuming that we are not memory constrained the periodicity of flushing is currently dictated by the static number of entries (1M by default) which can be also misconfigured to a very low value.
> I am proposing along with maxHtEntries, to also take into account current memory usage, to avoid flushing too ofter as it can hurt op throughput for particular workloads.
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