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From "Namit Jain (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-1110) add counters to show that skew join triggered
Date Thu, 28 Jan 2010 17:43:34 GMT

    [ https://issues.apache.org/jira/browse/HIVE-1110?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12805999#action_12805999
] 

Namit Jain commented on HIVE-1110:
----------------------------------

I am not sure about the semantics of counters - why do you need a bitvector for keeping track
of which one got updated.
Isnt a non-zero value good enough ?

Is the assumption that only 1 reducer will update a particular tag. Even then you will only
be able to know the number
of skew joins - in that case, why do you need to tag array - just increment the counter every
time you see a new key.
Even if you update it multiple times, it is OK.


> add counters to show that skew join triggered
> ---------------------------------------------
>
>                 Key: HIVE-1110
>                 URL: https://issues.apache.org/jira/browse/HIVE-1110
>             Project: Hadoop Hive
>          Issue Type: Improvement
>          Components: Query Processor
>            Reporter: Namit Jain
>            Assignee: He Yongqiang
>             Fix For: 0.6.0
>
>         Attachments: hive-1110.patch
>
>
> It would be very useful to debug, and quickly find out if the skew join was triggered.

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