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  1. Blazegraph (by SYSTAP)
  2. BLZG-894

RDR query does too much work

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      Description

      The following query is doing a full scan on

      select * {<<?s ?p ?o>> ?p1 ?o1 } LIMIT 10
      

      If you look at the EXPLAIN of this query, you can see that it visited ALL statements on SPOPredicate[1](?src, ?p2, ?tgt, ?-anon-2 then did the (pipeline) join with SPOPredicate[4](?-sid-1, ?p, ?o, ?-anon-5).

      The right way to run this query is to do a scan of the SID region of the SPO index and then unpack the <<?s ?p ?o>> from the subject position of the visited triples. There is no other join.

      The RDR syntax <<x y z>> p o implies that <<x y z>> must exist (in a query) and asserts that statement (when parsing data). An interpretation that does not respect this might be the root of the problem.

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            Assignee:
            mikepersonick mikepersonick
            Reporter:
            bryan b. thompson bryan b. thompson
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