[teiid-issues] [JBoss JIRA] Updated: (TEIID-1474) Add query hint to limit parallel execution of union members

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-1474?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins updated TEIID-1474:
----------------------------------

    Fix Version/s: 7.4
      Component/s: Query Engine
          Affects: [Documentation (Ref Guide, User Guide, etc.), Release Notes]


The config now has userRequestSourceConcurrency, which is also covered in the admin guide, to limit parallel source execution on a per user query basis.  Having a hint override this value is now straight-forward to implement, but it would take effect for the entire user query, rather than a specific union or join.  Would that cover your usecase, or would you need control down to a specific operation?

> Add query hint to limit parallel execution of union members
> -----------------------------------------------------------
>
>                 Key: TEIID-1474
>                 URL: https://issues.jboss.org/browse/TEIID-1474
>             Project: Teiid
>          Issue Type: Feature Request
>          Components: Query Engine
>            Reporter: Howard Abrams
>            Assignee: Steven Hawkins
>             Fix For: 7.4
>
>
> We would like a new query hint to limit the number of parallel executions of union members. This is useful in two situations:
> 1. When the queries are expensive, but the overall union contains a limit that is most likely to be fulfilled by the first member of the union
> 2. When the queries are backed by a common resource which may be overloaded by multiple queries
> The addition of a hint would make this manageable by the client; perhaps something like "/*+ parallel=2*/"? 

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