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Posted to dev@jena.apache.org by "Simon Helsen (JIRA)" <ji...@apache.org> on 2013/04/10 19:14:15 UTC

[jira] [Created] (JENA-432) Filter optimization messes up when a nested select is present in the same block

Simon Helsen created JENA-432:
---------------------------------

             Summary: Filter optimization messes up when a nested select is present in the same block
                 Key: JENA-432
                 URL: https://issues.apache.org/jira/browse/JENA-432
             Project: Apache Jena
          Issue Type: Bug
          Components: ARQ
    Affects Versions: Jena 2.10.0
            Reporter: Simon Helsen


The following test query:

SELECT ?test ?s1
WHERE {
  ?test ?p1 ?o1.
  FILTER ( ?test = <http://localhost/t1> || ?test = <http://localhost/t2> )  
  OPTIONAL {
    SELECT ?s1
    { ?s1 ?p2 ?o2 }
  }
}

produces the following plan:

(project (?test ?s1)
  (disjunction
    (table empty)
    (table empty)))

Something goes wrong with the FILTER expansion. As a workaround, we observed that the following variation:

SELECT ?test ?s1
WHERE {
  { ?test ?p1 ?o1.
    FILTER ( ?test = <http://localhost/t1> || ?test = <http://localhost/t2> )  
  }
  OPTIONAL {
    SELECT ?s1
    { ?s1 ?p2 ?o2 }
  }
}

produces the correct plan:

(project (?test ?s1)
  (leftjoin
    (disjunction
      (assign ((?test <http://localhost/t1>))
        (bgp (triple <http://localhost/t1> ?p1 ?o1)))
      (assign ((?test <http://localhost/t2>))
        (bgp (triple <http://localhost/t2> ?p1 ?o1))))
    (project (?s1)
      (bgp (triple ?s1 ?/p2 ?/o2)))))


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