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https://issues.apache.org/jira/browse/JENA-587?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13820038#comment-13820038
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Andy Seaborne commented on JENA-587:
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Slight stronger condition - if all the {{DISTINCT}} variables appear in {{ORDER
BY}} and also only those variables. {{DISTINCT ?v ORDER BY ?v}} and {{DISTINCT
?v ?w ORDER BY ?v ?w}}
The order in {{ORDER BY}} matters. {{DISTINCT ?v ORDER BY ?v ?w}} is OK but
reversing v and ?w {{DISTINCT ?v ORDER BY ?w ?v}} is not because the sorting on
?w first scrambles the ?v adjacency needed by {{REDUCED}}
Shall we disable the optimization in trunk for now to give space to think about
it? Better slow/correct than fast/incorrect.
> SELECT DISTINCT returns duplicate results
> -----------------------------------------
>
> Key: JENA-587
> URL: https://issues.apache.org/jira/browse/JENA-587
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 2.11.0
> Reporter: Veyriere
> Attachments: D.ttl, Q.rq, bug Jena2.11.0.zip, jena-587.zip
>
>
> SELECT DISTINCT returns duplicate results. Attaching a small quads dump and
> the query to reproduce with TDB
> Reproduced with Jena 2.11.0 and Jena 2.10.1 (was working with 2.7.4)
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