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From "Zheng Shao (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-502) Optimize RCFile's performance by removeing all synchronized modifiers
Date Fri, 22 May 2009 04:55:45 GMT

    [ https://issues.apache.org/jira/browse/HIVE-502?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12711948#action_12711948

Zheng Shao commented on HIVE-502:

In the future if needed, we can add synchronized keyword to RCFile's read/write methods.
These methods will be called once per row, so the cost is much smaller than what we had -
once per row per column.

> Optimize RCFile's performance by removeing all synchronized modifiers
> ---------------------------------------------------------------------
>                 Key: HIVE-502
>                 URL: https://issues.apache.org/jira/browse/HIVE-502
>             Project: Hadoop Hive
>          Issue Type: Improvement
>          Components: Query Processor
>            Reporter: He Yongqiang
>         Attachments: hive-502-2009-05-21.patch
> Tests by Zheng and me both show that removing all synchronized modifiers can improve
RCFile's performance by  about 15+%.
> This will make RCFile's reader and writer not thread safe any longer. This will be ok,since
hive always does its work in single thread.

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