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Posted to dev@hive.apache.org by "Carl Steinbach (JIRA)" <ji...@apache.org> on 2011/08/23 04:27:29 UTC
[jira] [Resolved] (HIVE-2350) Improve RCFile Read Speed
[ https://issues.apache.org/jira/browse/HIVE-2350?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Carl Steinbach resolved HIVE-2350.
----------------------------------
Resolution: Fixed
Committed to trunk (for real this time!). Thanks Tim!
> Improve RCFile Read Speed
> -------------------------
>
> Key: HIVE-2350
> URL: https://issues.apache.org/jira/browse/HIVE-2350
> Project: Hive
> Issue Type: Improvement
> Components: Serializers/Deserializers
> Reporter: Tim Armstrong
> Assignee: Tim Armstrong
> Priority: Minor
> Labels: rcfile
> Fix For: 0.8.0
>
> Attachments: rcfile-2011-08-04.diff, rcfile_opt_2011-08-05.diff, rcfile_opt_2011-08-05b.diff, rcfile_opt_2011-08-11.patch, rcfile_opt_2011-08-11.patch
>
> Original Estimate: 0h
> Remaining Estimate: 0h
>
> By tweaking the RCFile$Reader implementation to allow more efficient memory access I was able to reduce CPU usage. I measured the speed required to scan a gzipped RCFile, decompress and assemble into records. CPU time was reduced by about 7% for a full table scan, An improvement of about 2% was realised when a smaller subset of columns (3-5 out of tens) were selected.
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