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From "Namit Jain (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-1938) Cost Based Query optimization for Joins in Hive
Date Wed, 02 Feb 2011 01:21:28 GMT

    [ https://issues.apache.org/jira/browse/HIVE-1938?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12989488#comment-12989488
] 

Namit Jain commented on HIVE-1938:
----------------------------------

Yes, but do need column stats for this

> Cost Based Query optimization for Joins in Hive
> -----------------------------------------------
>
>                 Key: HIVE-1938
>                 URL: https://issues.apache.org/jira/browse/HIVE-1938
>             Project: Hive
>          Issue Type: Improvement
>          Components: Query Processor
>         Environment: *nix,java
>            Reporter: bharath v
>            Assignee: bharath v
>
> Current optimization in Hive is just rule-based and involves applying a set of rules
on the Plan tree. This depends on hints given by the user (which may or may-not be correct)
and might result in execution of costlier plans.So this jira aims at building a cost-model
which can give a good estimate various plans before hand (using some meta-data already collected)
and we can choose the best plan which incurs the least cost.

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