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==Query Issues (SPARQL, SQL, etc.)==

===SPARQL Queries Fail After Virtuoso Server Upgrade===

Use the {{{explain}}} function to diagnose problems that arise with queries after a Virtuoso Server upgrade. 

Virtuoso Functions Guide - {{{explain}}}
http://docs.openlinksw.com/virtuoso/fn_explain.html


If you require assistance from <nop>OpenLink Product Support, be sure to provide {{{explain}}} output along with the original query. For best results, run the {{{explain}}} function against the problem query using the prior version of Virtuoso and submit the output. This will provide Product Support with something from which a comparison can be drawn.