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https://issues.apache.org/jira/browse/HIVE-5834?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gopal V updated HIVE-5834:
--------------------------
Attachment: HIVE-5834.00-tez.patch
Tested with a count(1) with a filter
For a table of 1500 x 70mb ORC files.
Before = 26 seconds
After = 18 seconds
For a table of 23699 x ~2mb ORC files
Before = 32.9 seconds
After = 23.0 seconds
> Avoid reading ORC footers for files which will not be split in
> OrcInputFormat::getSplits()
> ------------------------------------------------------------------------------------------
>
> Key: HIVE-5834
> URL: https://issues.apache.org/jira/browse/HIVE-5834
> Project: Hive
> Issue Type: Improvement
> Components: Tez
> Affects Versions: 0.13.0
> Reporter: Gopal V
> Assignee: Gopal V
> Attachments: HIVE-5834.00-tez.patch
>
>
> OrcInputFormat::getSplits() fires off a SplitGenerator task for every file in
> the task.
> The footer & data are on the same node for all files with only 1 hdfs block.
> On top of that, it will never need a further split as long as its total size
> is < context.maxSize.
> Reading that footer locally is faster than reading it in the split gen and
> sending it from the AM.
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