[teiid-issues] [JBoss JIRA] Resolved: (TEIID-1497) misc subquery enhancements

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-1497?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins resolved TEIID-1497.
-----------------------------------

    Resolution: Done


added the MJ and NO_UNNEST hints and the org.teiid.subqueryUnnestDefault system property to control the optimization of subqueries to traditional joins or to a merge join implemenation of a semijoin or antijoin

the default for org.teiid.subqueryUnnestDefault was left as false so that we are not too aggressive in optimizing in the rewriter without costing.  for 8.0 we should change this property to only refer to the rewrite optimization to a traditional join as the conversion to a semi or anti semi join is done with costing.

> misc subquery enhancements
> --------------------------
>
>                 Key: TEIID-1497
>                 URL: https://issues.jboss.org/browse/TEIID-1497
>             Project: Teiid
>          Issue Type: Feature Request
>          Components: Query Engine
>    Affects Versions: 7.4
>            Reporter: Steven Hawkins
>            Assignee: Steven Hawkins
>             Fix For: 7.4
>
>
> Federated exists and scalar subqueries should be implicitly limited to not pull back extra results.
> The subquery aware evaluator should have a small cache to reuse correlated results.
> uncorrelated subqueryin and some forms of quantified comparison should be processed as dependent set criteria or use an indexed structure for teiid evaluation.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira