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https://issues.apache.org/jira/browse/JCR-2852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13005037#comment-13005037
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Jukka Zitting commented on JCR-2852:
------------------------------------
Looks good, thanks! I committed the patch in revision 1080186.
Some comments:
* The many "if (multiple)" conditions in ConstraintSplitInfo and related code
suggest that we might want to use the strategy pattern instead of treating
ConstraintSplitInfo as just a data class. Something like that could also
simplify the current ConstraintSplitter class.
* I find the "if (...) { ...; return; } ...;" pattern you use somewhat
confusing. I'd rather just use "if (...) { ...; } else { ...; }". If that leads
to too much indentation, it's time to break the method to smaller subtasks.
* It would be good to have an outer join test case as well. I'm not sure how
the OR conditions interact with outer join semantics.
* I removed some trailing whitespace from here and there in the patch. Not a
big issue.
> Support multi-selector OR constraints in join queries
> -----------------------------------------------------
>
> Key: JCR-2852
> URL: https://issues.apache.org/jira/browse/JCR-2852
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core, query
> Reporter: Jukka Zitting
> Attachments: JCR-2852.patch
>
>
> Our current join implementation doesn't support OR constraints that refer to
> more than one selector. For example the following query is not possible:
> SELECT a.* FROM [my:type] AS a INNER JOIN [my:type] as b ON a.foo = b.bar
> WHERE a.baz = 'x' OR b.baz = 'y'
> This limitation is a result of the way the join execution splits the query
> into per-selector components and merges the result based on the given join
> condition.
> A simple but often inefficient solution would be to process such OR
> constraints as post-processing filters like we already do for some other more
> complex constraint types.
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