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Date: Sat, 21 Feb 2015 07:29:11 +0000 (UTC)
From: "Gopal V (JIRA)" <jira@apache.org>
To: hive-dev@hadoop.apache.org
Message-ID: <JIRA.12774002.1423608332000.101820.1424503751501@Atlassian.JIRA>
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 <JIRA.12774002.1423608332271@arcas>
Subject: [jira] [Updated] (HIVE-9644) CASE comparison operator rotation
 optimization
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     [ https://issues.apache.org/jira/browse/HIVE-9644?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Gopal V updated HIVE-9644:
--------------------------
    Summary: CASE comparison operator rotation optimization  (was: Constant folding case for CASE/WHEN)

> CASE comparison operator rotation optimization
> ----------------------------------------------
>
>                 Key: HIVE-9644
>                 URL: https://issues.apache.org/jira/browse/HIVE-9644
>             Project: Hive
>          Issue Type: Bug
>          Components: Logical Optimizer
>    Affects Versions: 1.2.0
>            Reporter: Gopal V
>
> Constant folding for queries don't kick in for some automatically generated query patterns which look like this.
> {code}
> hive> explain select count(1) from store_sales where (case ss_sold_date when '1998-01-01' then 1 else null end)=1;
> {code}
> This should get rewritten by pushing the equality into the case branches.
> {code}
> select count(1) from store_sales where (case ss_sold_date when '1998-01-01' then 1=1 else null=1 end);
> {code}
> Ending up with a simplified filter condition, resolving itself as 
> {code}
> select count(1) from store_sales where ss_sold_date= '1998-01-01' ;
> {code}


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