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https://issues.apache.org/jira/browse/JENA-595?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13826970#comment-13826970
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Andy Seaborne commented on JENA-595:
------------------------------------
The JENA-383 query:
{noformat}
PREFIX ex: <http://example/>
SELECT * WHERE {
?var ex:p1 ?x.
OPTIONAL { ?x ex:p2 ?y. }
FILTER (?var != ex:i)
}
{noformat}
Up to Jena 2.11.0:
{noformat}
(prefix ((ex: <http://example/>))
(filter (= ?var ex:i)
(conditional
(bgp (triple ?var ex:p1 ?x))
(conditional
(bgp (triple ?x ex:p2 ?y))
(bgp (triple ?y ex:p3 ?z))))))
{noformat}
and with patch:
{noformat}
(prefix ((ex: <http://example/>))
(conditional
(filter (= ?var ex:i)
(bgp (triple ?var ex:p1 ?x)))
(conditional
(bgp (triple ?x ex:p2 ?y))
(bgp (triple ?y ex:p3 ?z)))))
{noformat}
The filter is done on the LHS of the outer OPTIONAL.
> Improve filter placement optimization
> -------------------------------------
>
> Key: JENA-595
> URL: https://issues.apache.org/jira/browse/JENA-595
> Project: Apache Jena
> Issue Type: Improvement
> Components: ARQ
> Reporter: Andy Seaborne
> Assignee: Andy Seaborne
> Attachments: JENA-595-FilterPlacement.patch
>
>
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