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https://issues.apache.org/jira/browse/PIG-1411?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12866003#action_12866003
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Gaurav Jain commented on PIG-1411:
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We ran few performance tests and found that:
-- Zebra Table with 700 file and 70G of data in them
-- Ceated a HAR file for the above table with 36 files of ~2GB
Observed:
10-15 seconds overhead in creating split per HAR file
50% increase in SLOT_MILLI_MAPS b/w HAR and Non-HAR reading of Zebra Table. HAR
taking more time
Similar results were observed for union of above tables ( 5 tables union )
Further performance tests are subject to fix for MAPREDUCE-1712
> [Zebra] Can Zebra use HAR to reduce file/block count for namenode
> -----------------------------------------------------------------
>
> Key: PIG-1411
> URL: https://issues.apache.org/jira/browse/PIG-1411
> Project: Pig
> Issue Type: New Feature
> Components: impl
> Affects Versions: 0.8.0
> Reporter: Gaurav Jain
> Assignee: Gaurav Jain
> Priority: Minor
> Fix For: 0.8.0
>
>
> Due to column group structure, Zebra can create extra files for namenode to
> remember. That means namenode taking more memory for Zebra related files.
> The goal is to reduce the no of files/blocks
> The idea among various options is to use HAR ( Hadoop Archive ). Hadoop
> Archive reduces the block and file count by copying data from small files (
> 1M, 2M ...) into a hdfs-block of larger size. Thus, reducing the total no. of
> blocks and files.
>
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