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https://issues.apache.org/jira/browse/JENA-1952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17232987#comment-17232987
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Andy Seaborne commented on JENA-1952:
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One goal of the implementation is no persistent storage changes.
On-disk changes are a big deal for all users and changing, then changing again,
would be a disruption for every user, not just RDF* users.
So the decision is whether {{<<?s ?p ?o>>}} is done by using an available
triple index, which implies it is PG-like and hence follows the paper, or a
scan, getting all the subject terms,seeing which are RDF* triple terms and also
match the pattern doing something like {{<<?s ?p ?o>> FILTER(?s = :john && ?p =
:name)}} with no index support.
The setup at the moment is to avoid the scan and so SPARQL* isn't SA.
RDF* is defined as PG so that's the setting currently for SPARQL*.
Easy to change code-wise but disk changes need to await the community direction.
> Jena support for SPARQL*
> ------------------------
>
> Key: JENA-1952
> URL: https://issues.apache.org/jira/browse/JENA-1952
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 3.16.0
> Reporter: Adrika Mukherjee
> Assignee: Andy Seaborne
> Priority: Major
> Fix For: Jena 3.17.0
>
> Time Spent: 40m
> Remaining Estimate: 0h
>
> SPARQL * does not able to return variables on embedded triples. For example :
> "SELECT ?o ?o1 WHERE \{<<?s ?p ?o>> dct:rank ?o1}"; this query does not work.
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