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From "Chao (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-9503) Update 'hive.auto.convert.join.noconditionaltask.*' descriptions
Date Thu, 29 Jan 2015 00:53:37 GMT

    [ https://issues.apache.org/jira/browse/HIVE-9503?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14296175#comment-14296175
] 

Chao commented on HIVE-9503:
----------------------------

In MR, both conditional task AND backup task are used, but for us, only backup task is needed,
since no decision needs to be made (only one mapjoin task). If we always use backup task for
auto converted join, it will add overhead to plan compilation, because to generate a backup
task we need to clone the whole operator tree.

> Update 'hive.auto.convert.join.noconditionaltask.*' descriptions
> ----------------------------------------------------------------
>
>                 Key: HIVE-9503
>                 URL: https://issues.apache.org/jira/browse/HIVE-9503
>             Project: Hive
>          Issue Type: Bug
>          Components: Configuration
>            Reporter: Szehon Ho
>            Priority: Minor
>
> 'hive.auto.convert.join.noconditionaltask' flag does not apply to Spark or Tez, and only
to MR (which has the legacy conditional mapjoin)
> However, 'hive.auto.convert.join.noconditionaltask.size' flag does apply to Spark, Tez,
and MR, even though the description indicates it only applies if the above flag is on, which
is true only for MR.
> These configs should be updated to reflect this case.



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