Hi Aldo,
Have yout tried passing the log_enable(2) option in your query string which is
recommended when performing multiple concurrent SPARUL operations to avoid
deadlocks as detailed at:
http://docs.openlinksw.com/virtuoso/rdfperformancetuning.html#rdfperfsparul
Assuming you are querying a Virtuoso SPARQL endpoint log_enable can be passed
as a pragma in the query as detailed at:
http://docs.openlinksw.com/virtuoso/rdfsparql.html#rdfsparqlimplementatioptragmas
I hope this solves the problem for you ...
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 21 Feb 2011, at 06:30, Aldo Bucchi wrote:
> Hi,
>
> I was running a test suite for an app that talks profusely to Virtuoso
> via SPARQL HTTP and I kept running into a deadlock.
> I was able to isolate the problem by HTTP POSTing the following two
> queries consecutively and w/o waiting for the previous one to complete
> ( with a non blocking client such as a Browser or Node.js ).
>
> FIRST:
> modify <urn:test:graph> delete { <urn:test:s1> <urn:test:p1> ?x }
> insert { <urn:test:s1> <urn:test:p1> 1 } where { optional{
> <urn:test:s1> <urn:test:p1> ?x } }
>
> SECOND:
> delete from <urn:test:graph> { <urn:test:s1> <urn:test:p1> ?x } where
> { <urn:test:s1> <urn:test:p1> ?x }
>
> I am posting this quickly to see it rings some bells just by looking
> at the queries and the explanation. If it doesn't, I can try to
> provide you with the setup to reproduce.
>
> The machine runs the following version of Virtuoso:
> Virtuoso Open Source Edition (multi threaded)
> Version 6.1.0.3126-pthreads as of Feb 16 2010
>
> --
> Aldo Bucchi
> @aldonline
> skype:aldo.bucchi
> http://facebook.com/aldo.bucchi
> http://aldobucchi.com/
>
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