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From "Vikram Dixit K (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-4105) Hive MapJoinOperator unnecessarily deserializes values for all join-keys
Date Tue, 05 Mar 2013 02:31:13 GMT

    [ https://issues.apache.org/jira/browse/HIVE-4105?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13592974#comment-13592974
] 

Vikram Dixit K commented on HIVE-4105:
--------------------------------------

Hey Vinod,

You are missing the piece of code required for outer joins. Near the if (!noOuterJoin), I
recommend that you keep the previous code and set the jionNeeded flag to true when noOuterJoin
= false.

Basically:
{noformat}
            if (!noOuterJoin) {
              joinNeeded = true;
              storage[pos] = dummyObjVectors[pos];
            } else {
              storage[pos] = emptyList;
            }

{noformat}
                
> Hive MapJoinOperator unnecessarily deserializes values for all join-keys
> ------------------------------------------------------------------------
>
>                 Key: HIVE-4105
>                 URL: https://issues.apache.org/jira/browse/HIVE-4105
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Vinod Kumar Vavilapalli
>         Attachments: HIVE-4105-20130301.1.txt, HIVE-4105-20130301.txt
>
>
> We can avoid this for inner-joins. Hive does an explicit value de-serialization up front
so even for those rows which won't emit output. In these cases, we can do just with key de-serialization.

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