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https://issues.jboss.org/browse/TEIID-1543?page=com.atlassian.jira.plugin...
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Steven Hawkins updated TEIID-1543:
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Fix Version/s: (was: 8.3)
Priority: Minor (was: Major)
Added logic in 8.3 to make an explicit hint less of an issue. The most common case this
hint applies to is a limited union, so now the processing logic will detect this case and
automatically reduce the parallelism based upon how tight the limit is.
In specific cases a hint may still be desirable, but the current implementation of the
concurrency restriction is implemented at the request level and not at the plan level
making it difficult to restrict concurrency effectively based upon the particulars of the
plan.
Add a query hint to limit the number of concurrent source queries
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Key: TEIID-1543
URL:
https://issues.jboss.org/browse/TEIID-1543
Project: Teiid
Issue Type: Sub-task
Components: Query Engine
Affects Versions: 7.4
Reporter: Steven Hawkins
Assignee: Steven Hawkins
Priority: Minor
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*/"?
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