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From "Mamta A. Satoor (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DERBY-4742) Make outer join reordering work for right outer joins
Date Fri, 28 Sep 2012 18:33:07 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4742?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Mamta A. Satoor updated DERBY-4742:

    Urgency: Normal
     Labels: derby_triage10_10  (was: )
> Make outer join reordering work for right outer joins
> -----------------------------------------------------
>                 Key: DERBY-4742
>                 URL: https://issues.apache.org/jira/browse/DERBY-4742
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions:,,,,,,,,,,,,,,,
>            Reporter: Dag H. Wanvik
>              Labels: derby_triage10_10
> Currently, Derby only attempts to reorder (into left deep) left outer join queries. Right
outer join queries are commented out, apparently due to implementation difficulties, cf. this
comment in HalfOuterJoinNode.LOJ_reorderable.
> // It is much easier to do LOJ reordering if there is no ROJ.
> // However, we ran into some problem downstream when we transform an ROJ
> // into LOJ -- transformOuterJoin() didn't expect ROJ to be transformed
> // into LOJ alread.  So, we skip optimizing ROJ at the moment.

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