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  1. Apache Jena
  2. JENA-1023

Algebra execution join library

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: Jena 3.0.1
    • Component/s: ARQ
    • Labels:
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      Description

      This JIRA is for refactoring and adding more join algorithms into a join library.

      This is for joins between results from intermediate patterns, not joins that solve basic graph patterns.

      Normal use is a index join algorithm but it has some requirements about variable scope. ARQ falls back to a general join mechanism if the scoping requirements aren't met (this unusual).

      The general join code is not good. It should be, for example, a hash join if possible.

      Relation to JENA-266: There is hash-based anti-join code in org.apache.jena.sparql.engine.index in support of MINUS. This is not a proposal to combine that code into the join library. It is not immediately clear that code to cover all cases (inner join, left join and anti-join) at once is really a good idea if it leads to excessively complicated code.

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              • Assignee:
                andy Andy Seaborne
                Reporter:
                andy Andy Seaborne
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                • Created:
                  Updated:
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