eclipse-rdf4j / rdf4j

Eclipse RDF4J: scalable RDF for Java
https://rdf4j.org/
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GH-5151: use VALUES clause for FedX bind join with no free vars #5165

Closed aschwarte10 closed 2 weeks ago

aschwarte10 commented 1 month ago

GitHub issue resolved: #GH-5151

For evaluation of bind joins the implementation for quite some time makes use of a VALUES clause query.

Except for one code-path: for bind joins - where in the join all arguments are bound - it was still using the old UNION query approach. This approach is error prone and no longer required, i.e. the check join can be executed with the same logic as the regular VALUES clause.

Note: an additional unit test for covering bind joins with no free vars is added.

This change also marks a number of methods and classes used for the old UNION based approach as deprecated. The implementations are internal to the FedX engine and can be removed in the next major release.


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