[teiid-issues] [JBoss JIRA] (TEIID-4459) Convert project semi-joins to (dependent) join queries
Steven Hawkins (JIRA)
issues at jboss.org
Mon Sep 26 16:30:00 EDT 2016
[ https://issues.jboss.org/browse/TEIID-4459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13298665#comment-13298665 ]
Steven Hawkins edited comment on TEIID-4459 at 9/26/16 4:29 PM:
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Added the initial work that is hint driven or requires the use of the system property subqueryUnnestDefault=true. The odata logic was updated to automatically add the hint.
The hint is a leading mj (merge join):
{code}
select x, /*+ mj */ (select ...) as sub from ...
{code}
was (Author: shawkins):
Added the initial work that is hint driven or requires the use of the system property subqueryUnnestDefault=true. The odata logic was updated to automatically add the hint.
> Convert project semi-joins to (dependent) join queries
> ------------------------------------------------------
>
> Key: TEIID-4459
> URL: https://issues.jboss.org/browse/TEIID-4459
> Project: Teiid
> Issue Type: Quality Risk
> Components: Query Engine
> Reporter: Steven Hawkins
> Assignee: Steven Hawkins
> Fix For: 9.1
>
>
> In many situations subqueries in the where clause can be planned as semi-joins. The same logic should be updated to handle the select clause.
> This will also help ensure better performance with odata generated array_agg queries.
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