[teiid-issues] [JBoss JIRA] (TEIID-4865) DISTINCT not pushed down to multisource sources

[Harold Campbell (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-4865?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13394154#comment-13394154 ] 

Harold Campbell commented on TEIID-4865:
----------------------------------------

The latter, yes. I'm dealing with millions of rows, so not doing an initial distinct at the lowest level is a pretty drastic performance hit.

> DISTINCT not pushed down to multisource sources
> -----------------------------------------------
>
>                 Key: TEIID-4865
>                 URL: https://issues.jboss.org/browse/TEIID-4865
>             Project: Teiid
>          Issue Type: Bug
>          Components: Query Engine
>    Affects Versions: 9.2.2
>            Reporter: Harold Campbell
>            Assignee: Steven Hawkins
>         Attachments: DEBUG_LOG
>
>
> Simple DISTINCT queries do not push down DISTINCT to the underlying sources (SQL Server, in this case) of a multisource schema. Instead, all values are selected, and the sorting out is done in teiid.
> {noformat}
> select distinct bic_status
> from account;
> {noformat}
> Debug plan attached.



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