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  1. Blazegraph (by SYSTAP)
  2. BLZG-1751

Optimize FILTER NOT EXISTS when there is a single triple pattern

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Medium
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: Query Plan Generator
    • Labels:
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      Description

      FILTER NOT EXISTS could probably be optimized for the case where (a) a single triple pattern is specified in the FILTER; and (b) the triple pattern is fully bound. If it were fully bound statically (when the query is submitted), then it could be turned into a range count and resolved during query optimization.

      We could still use a range count to optimize FILTER NOT EXIST even when the triple pattern is not fully bound when it is evaluated.

      If the FILTER NOT EXISTS includes more than one triple pattern then we need to evaluate the conjunctive query, which means turning it into a sub-query. This is how FILTER NOT EXISTS is getting handled by default.

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              Assignee:
              michaelschmidt michaelschmidt
              Reporter:
              bryanthompson bryanthompson
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                Created:
                Updated: