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Posted to oak-issues@jackrabbit.apache.org by "Thomas Mueller (JIRA)" <ji...@apache.org> on 2014/12/04 16:37:12 UTC

[jira] [Created] (OAK-2320) Wrong optimization for joins with ISDESCENDANTNODE conditions

Thomas Mueller created OAK-2320:
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             Summary: Wrong optimization for joins with ISDESCENDANTNODE conditions
                 Key: OAK-2320
                 URL: https://issues.apache.org/jira/browse/OAK-2320
             Project: Jackrabbit Oak
          Issue Type: Bug
          Components: core, query
    Affects Versions: 1.1.2, 1.0.8
            Reporter: Thomas Mueller
            Assignee: Thomas Mueller


Joins with ISDESCENDANTNODE condition are incorrectly optimized when the join is executed in the reverse order: instead of a path condition of the form "all parents", a path condition of the form "parent" is used. That means, the first selector only traverse the parent node, when the TraversingIndex is used, instead of all possible parent nodes. As of now, there is no path condition of the form "all parents".

This affects both SQL-2 and XPath queries.

It is a problem if the join is reversed due to lower potential cost, which is so far seldom, and it looks like only in combination with the TraversingIndex. There are some existing tests that only fail when the new cost estimation is used (OAK-1907). Still, it is theoretically possible that existing code is affected (even without OAK-1907).



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