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https://issues.apache.org/jira/browse/HIVE-6430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sergey Shelukhin updated HIVE-6430:
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Attachment: HIVE-6430.10.patch
Make bypass work... still has a hack to remove ReduceSinkOp tag on hashtable
side. Join-to-mapjoin conversion code is very convoluted, need to get hold of
ReduceSink that feeds hashtable values and remove tag output from there
reliably. Will read code later. And perf test with this
> MapJoin hash table has large memory overhead
> --------------------------------------------
>
> Key: HIVE-6430
> URL: https://issues.apache.org/jira/browse/HIVE-6430
> Project: Hive
> Issue Type: Improvement
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Attachments: HIVE-6430.01.patch, HIVE-6430.02.patch,
> HIVE-6430.03.patch, HIVE-6430.04.patch, HIVE-6430.05.patch,
> HIVE-6430.06.patch, HIVE-6430.07.patch, HIVE-6430.08.patch,
> HIVE-6430.09.patch, HIVE-6430.10.patch, HIVE-6430.patch
>
>
> Right now, in some queries, I see that storing e.g. 4 ints (2 for key and 2
> for row) can take several hundred bytes, which is ridiculous. I am reducing
> the size of MJKey and MJRowContainer in other jiras, but in general we don't
> need to have java hash table there. We can either use primitive-friendly
> hashtable like the one from HPPC (Apache-licenced), or some variation, to map
> primitive keys to single row storage structure without an object per row
> (similar to vectorization).
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