Andy Seaborne created JENA-875:
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Summary: 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 betwen the {{(extend)}} nad 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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