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Posted to oak-issues@jackrabbit.apache.org by "Thomas Mueller (JIRA)" <ji...@apache.org> on 2017/07/28 13:17:01 UTC
[jira] [Commented] (OAK-937) Query engine index selection tweaks:
shortcut and hint
[ https://issues.apache.org/jira/browse/OAK-937?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16104930#comment-16104930 ]
Thomas Mueller commented on OAK-937:
------------------------------------
http://svn.apache.org/r1803272 (trunk) support for "option(index abc)"
(missing: tests, documentation, and further options)
> Query engine index selection tweaks: shortcut and hint
> ------------------------------------------------------
>
> Key: OAK-937
> URL: https://issues.apache.org/jira/browse/OAK-937
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: query
> Reporter: Alex Deparvu
> Assignee: Thomas Mueller
> Priority: Critical
> Labels: performance
> Fix For: 1.8
>
>
> This issue covers 2 different changes related to the way the QueryEngine selects a query index:
> Firstly there could be a way to end the index selection process early via a known constant value: if an index returns a known value token (like -1000) then the query engine would effectively stop iterating through the existing index impls and use that index directly.
> Secondly it would be nice to be able to specify a desired index (if one is known to perform better) thus skipping the existing selection mechanism (cost calculation and comparison). This could be done via certain query hints [0].
> [0] http://en.wikipedia.org/wiki/Hint_(SQL)
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