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https://issues.apache.org/jira/browse/HIVE-2988?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13265073#comment-13265073
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Rohini Palaniswamy commented on HIVE-2988:
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I ran with 128M to investigate the OOM. We have resorted to running with 1G as
XmX because we keep hitting OOM with bigger tables in hive. There were other
things that contributed to the memory usage - mostly Path objects because of
the higher number of partitions. But they are absolutely needed. XMLEncoder is
something that created too much garbage in a very short span and caused GC.
That would be something easy to change/fix without having to touch the core
logic.
We should be looking at fixing the root cause of the problem instead of
keeping on increasing the memory requirements. Ours is a highly multi-tenant
system and there are lot of other programs(pig,etc) running too in the gateway.
So running with a lower memory(256-512MB) will help.
Found two other reports of this issue:
http://mail-archives.apache.org/mod_mbox/hive-user/201106.mbox/%[email protected]%3E
https://issues.apache.org/jira/browse/HIVE-1316
- This fix increased the max heap size of CLI client and disabled GC
overhead limit.
> Use of XMLEncoder to serialize MapredWork causes OOM in hive cli
> ----------------------------------------------------------------
>
> Key: HIVE-2988
> URL: https://issues.apache.org/jira/browse/HIVE-2988
> Project: Hive
> Issue Type: Improvement
> Components: CLI
> Reporter: Rohini Palaniswamy
> Labels: Performance
>
> When running queries on tables with 6000 partitions, hive cli if configured
> with 128M runs into OOM. Heapdump showed 37MB occupied by one XMLEncoder
> object while the MapredWork was 500K which is highly inefficient. We should
> switch to using something more efficient like XStream.
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