[teiid-issues] [JBoss JIRA] Updated: (TEIID-1474) Add a limit to the number of concurrent source queries issued.

[Steven Hawkins (JIRA)]

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

Steven Hawkins updated TEIID-1474:
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        Summary: Add a limit to the number of concurrent source queries issued.  (was: Add query hint to limit parallel execution of union members)
    Description: The default of allowing an unlimited number of concurrent source queries is not desirable in extreme situations.  A limit should be added to prevent contention or other problems with issuing a large number of source queries.  (was: 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*/"? )


updated to split into separate issues.

> Add a limit to the number of concurrent source queries issued.
> --------------------------------------------------------------
>
>                 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
>
>
> The default of allowing an unlimited number of concurrent source queries is not desirable in extreme situations.  A limit should be added to prevent contention or other problems with issuing a large number of source queries.

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