[redland-dev] [Rasqal RDF Query Library 0000422]: Performance hit with "SELECT DISTINCT"

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://bugs.librdf.org/mantis/view.php?id=422 
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Reported By:                dbrnz
Assigned To:                
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Project:                    Rasqal RDF Query Library
Issue ID:                   422
Category:                   query engine
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Query Language:              
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Date Submitted:             2011-02-04 20:52
Last Modified:              2011-02-04 20:52
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Summary:                    Performance hit with "SELECT DISTINCT"
Description: 
The query "SELECT * WHERE { ?s ?p ?o } LIMIT 10" completes after getting the
first 10 triples. In contrast, the query "SELECT DISTINCT * WHERE { ?s ?p ?o }
LIMIT 10" is gets *all* triples from the store before returning the first 10
distinct ones. Could the code not check for distinctness when results are stored
and then stop the query once LIMIT had been reached??

Thanks.


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Issue History 
Date Modified    Username       Field                    Change               
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2011-02-04 20:52 dbrnz          New Issue                                    
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