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

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Jena 2.10.0
• Fix Version/s: Jena 2.10.1, Jena 2.11.1
• Component/s: ARQ, Optimizer
• Assignee: Andy Seaborne
• Reporter: Simon Helsen
• Created: 10/Apr/13 17:12
• Updated: 24/Dec/13 17:42
• Resolved: 24/Dec/13 17:41

Description

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)))))

Issue Links

• relates to: JENA-294 TransformFilterEquality does not handle starting OPTIONAL well