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https://issues.apache.org/jira/browse/JENA-875?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andy Seaborne closed JENA-875.
------------------------------
Resolution: Done
> Additional optimization for BIND :
> -----------------------------------
>
> Key: JENA-875
> URL: https://issues.apache.org/jira/browse/JENA-875
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 2.12.1
> Reporter: Andy Seaborne
> Assignee: Andy Seaborne
> Priority: Minor
> Fix For: Jena 2.12.2
>
>
> This is split out from investigation of JENA-874. It is not the cause but was
> noticed writing the simplified test case.
> With {{extend}}, the filter-placement optimization can apply filter
> expressions directly when the {{extend}} introduces variables.
> Currently, the filter-placement optimization only covers expressions pushed
> inside the {{extend}}.
> Example:
> Input:
> {noformat}
> (filter (= ?x 123)
> (distinct
> (extend ((?x 123))
> (bgp (triple ?s ?p ?o)))))
> {noformat}
> The {{distinct}} is just some operation that is between the {{extend}} and
> the outer most level.
> Otherwise, the difference does not show up.
> Current optimization:
> {noformat}
> (filter (= ?x 123)
> (distinct
> (extend ((?x 123))
> (bgp (triple ?s ?p ?o)))))
> {noformat}
> The filter is not placed around the {{extend}} but bubbles further up.
> With the improved optimization:
> {noformat}
> (distinct
> (filter (= ?x 123)
> (extend ((?x 123))
> (bgp (triple ?s ?p ?o)))))
> {noformat}
> The filter is placed around the {{extend}} at the lowest point possible point.
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