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Posted to issues@kylin.apache.org by "Shaofeng SHI (JIRA)" <ji...@apache.org> on 2017/02/04 08:56:51 UTC

[jira] [Resolved] (KYLIN-2404) Add "hive.merge.mapfiles" and "hive.merge.mapredfiles" to kylin_hive_conf.xml

     [ https://issues.apache.org/jira/browse/KYLIN-2404?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Shaofeng SHI resolved KYLIN-2404.
---------------------------------
    Resolution: Fixed

> Add "hive.merge.mapfiles" and "hive.merge.mapredfiles" to kylin_hive_conf.xml
> -----------------------------------------------------------------------------
>
>                 Key: KYLIN-2404
>                 URL: https://issues.apache.org/jira/browse/KYLIN-2404
>             Project: Kylin
>          Issue Type: Improvement
>          Components: Job Engine
>            Reporter: Shaofeng SHI
>            Assignee: Shaofeng SHI
>            Priority: Minor
>             Fix For: v2.0.0
>
>
> Since 1.5.3, Kylin uses a "redistribute" step to merge the small files to proper size after creating the intermediate hive table. While in some users' environment, hive merge small files is enabled by default, that will cause additional CPU and will impact on the cube building performance (in extreme case the files will be merged to 256MB, then only very small number of mappers be started in building).
> So Kylin should explicitly tell Hive to disable the merge small files feature when  creating and redistributing the intermediate flat table. Adding "hive.merge.mapfiles" and "hive.merge.mapredfiles" to conf/kylin_hive_conf.xml with value "false" will solve this. The meaning of these two parameters can be found in https://cwiki.apache.org/confluence/display/Hive/AdminManual+Configuration



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