Hi all, ----- Original Message ----
> From: Yves Raimond <[email protected]> > To: [email protected] > Sent: Thursday, 18 June, 2009 9:57:51 PM > Subject: [Virtuoso-devel] Deadlocking and slow queries > Another major issue we're running into is the deadlocking mechanism. > We have a constant flow of updates going in through SPARQL/Update. Our > dataset is a collection of fairly small graphs (around 30 triples > each). When we do a query like the above, going through all these > graphs, we're almost sure to reach a deadlock at some point. At almost > any point in time, there is an update going on in one of the graphs. I have been having this issue too as I am fairly constantly running SPARQL INSERT's on a single graph and intermittently asking the graph for results. It would be nice to have a consistent solution if possible even if the read-only query is postponed for a second to allow the concurrent insert to run its course. None of the inserts are very large (30 or so triples each), so it is a little strange that the two queries needed to interfere with each other. I have five indexes on the RDF_QUAD table btw if that interferes with things. (RDF_QUAD_GPOS RDF_QUAD_OGPS RDF_QUAD_OPGS RDF_QUAD_POGS RDF_QUAD_SPOG) The whole database actually silently locked up at one point and stopped INSERT's working at all when I was experimenting with CLEAR'ing the graph while INSERT's were happening, but I restarted it and haven't tried the same thing again so I can't say whether it was a consistent bug. You might be able to test some concurrent CLEAR GRAPH queries along with consistent INSERT's (every second or so)and see if the lockup happens in a test scenario. The inserts are some experimental statistics gathering based on Bio2RDF queries that I thought would be cool and I want to periodically check the progress without stopping the statistics gathering process. Cheers, Peter Access Yahoo!7 Mail on your mobile. Anytime. Anywhere. Show me how: http://au.mobile.yahoo.com/mail
