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  1. Blazegraph (by SYSTAP)
  2. BLZG-1379

Join reordering strictly according to W3C semantics


    • Type: Improvement
    • Status: Done
    • Priority: Medium
    • Resolution: Done
    • Affects Version/s: None
    • Fix Version/s: BLAZEGRAPH_RELEASE_1_5_2
    • Component/s: None
    • Labels:


      The join reordering in Blazegraph 1.5.1 in some cases differed from the W3C standard. This has been toroughly refactored, resolving in the resolution of various issues regarding proper join ordering. In particular, this affects the time when BIND clauses are evaluated, (ii) fixes regarding the reordering of triple patterns in the context of interleaving OPTIONAL or MINUS nodes, as well as (iii) proper ordering of FILTER (NOT) EXISTS clauses. Please find below a list of tickets that were directly or undirectly associated to this refactoring:

      • BLZG-48 Query fails to project subquery variables
      • BLZG-50 Queries with multiple VALUES clauses
      • BLZG-876 BIND not executed before SERVICE call
      • BLZG-1021 optimizer = None and FILTER EXISTS
      • BLZG-1256 Service call with values clauses create a cross product
      • BLZG-1299 duplicates in VALUES get replicated
      • BLZG-1281 FILTER FILTER != not working
      • BLZG-1284 optional / filter ! bound interaction malfunction
      • BLZG-1296 named subquery and VALUES expression
      • BLZG-1315 ASTJoinOrderOptimizerByType refactoring
      • BLZG-1358 SERVICE node placement issues

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            • Assignee:
              michaelschmidt michaelschmidt
              michaelschmidt michaelschmidt
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