db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Dag H. Wanvik (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4742) Make outer join reordering work for right outer joins
Date Mon, 12 Jul 2010 18:47:50 GMT

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

Dag H. Wanvik updated DERBY-4742:

    Affects Version/s:

> 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
> 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.

This message is automatically generated by JIRA.
You can reply to this email to add a comment to the issue online.

View raw message