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Posted to dev@hive.apache.org by "Gopal V (JIRA)" <ji...@apache.org> on 2013/03/01 23:03:14 UTC

[jira] [Assigned] (HIVE-4103) Remove System.gc() call from the map-join local-task loop

     [ https://issues.apache.org/jira/browse/HIVE-4103?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Gopal V reassigned HIVE-4103:
-----------------------------

    Assignee: Gopal V
    
> Remove System.gc() call from the map-join local-task loop
> ---------------------------------------------------------
>
>                 Key: HIVE-4103
>                 URL: https://issues.apache.org/jira/browse/HIVE-4103
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Gopal V
>            Assignee: Gopal V
>            Priority: Minor
>         Attachments: HIVE-4103.patch
>
>
> Hive's HashMapWrapper calls System.gc() twice within the HashMapWrapper::isAbort() which produces a significant slow-down during the loop.
> {code}
> 2013-03-01 04:54:28 The gc calls took 677 ms
> 2013-03-01 04:54:28     Processing rows:        200000  Hashtable size: 199999  Memory usage:   62955432        rate:   0.033
> 2013-03-01 04:54:31 The gc calls took 956 ms
> 2013-03-01 04:54:31     Processing rows:        300000  Hashtable size: 299999  Memory usage:   90826656        rate:   0.048
> 2013-03-01 04:54:33 The gc calls took 967 ms
> 2013-03-01 04:54:33     Processing rows:        384160  Hashtable size: 384160  Memory usage:   114412712       rate:   0.06
> {code}

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