Hi Sebastian,
Can you please provide the explain output detailing the execution plan for both
queries for comparison, as detailed at:
http://docs.openlinksw.com/virtuoso/perfdiag.html#perfdiagqueryplans
http://docs.openlinksw.com/virtuoso/fn_explain.html
Note you must include the "sparql" keyword before the start of each query.
Please also provide the output of running the status(); command to provide
access statistics on the server.
Best Regards
Hugh Williams
Professional Services
OpenLink Software
Web: http://www.openlinksw.com
Support: http://support.openlinksw.com
Forums: http://boards.openlinksw.com/support
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On 29 Apr 2010, at 16:40, Sebastian Trüg wrote:
> Hello,
>
> using a V6 server with default indexes I would like to know why the
> following queries are different in performance. The store contains
> thousands of different graphs but adding a "graph ?g {}" around all
> patterns does not change the execution time.
>
> select * where { ?r a nfo:FileDataObject .
> ?r nfo:fileName ?f .
> ?f bif:contains 'breaking' . }
>
> takes a long time to finish - almost a minute.
>
>
> select * where { ?r nfo:fileName ?f .
> ?f bif:contains 'breaking' . }
>
> is finished in no time.
>
> I just would like to understand the reasons behind the difference. If
> possible also a solution. :)
>
> Cheers,
> Sebastian
>
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