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Message-ID: <4D5197D9.2070308@googlemail.com>
Date: Tue, 08 Feb 2011 19:22:01 +0000
From: Paolo Castagna <castagna.lists@googlemail.com>
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To: jena-users@incubator.apache.org
Subject: Re: ConcurrentModificationException with Fuseki/TDB
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Hi Benson,
thank you, you raised a good point, actually.

I need to make sure the BSBM benchmark is not sending any SPARQL Update.
It seems to me I got the exception just sending SPARQL queries.

However, I'll double check this.

Paolo

Benson Margulies wrote:
> Paolo,
> 
> I think it's a feature. Between 0.8.9 and trunk, TDB got much more
> sensitive to modifying anything at all while any iterator was live.
> 
> 
> On Tue, Feb 8, 2011 at 1:13 PM, Paolo Castagna
> <castagna.lists@googlemail.com> wrote:
>> Hi,
>> today, I have been playing with the BSBM (i.e. trying to automate as much as
>> possible).
>> I got a (reasonable?) bash script:
>> https://github.com/castagna/bsbm-automated
>>
>> If I use just one client everything is fine.
>>
>> However, when I try to run BSBM against Fuseki with more than one client
>> (i.e. BSBM uses multiple threads to run queries) I get this exception on the
>> Fuseki log:
>>
>> java.util.ConcurrentModificationException: Reader = 0, Writer = 2
>>        at
>> com.hp.hpl.jena.tdb.sys.ConcurrencyPolicyMRSW.policyError(ConcurrencyPolicyMRSW.java:127)
>>        at
>> com.hp.hpl.jena.tdb.sys.ConcurrencyPolicyMRSW.policyError(ConcurrencyPolicyMRSW.java:122)
>>        at
>> com.hp.hpl.jena.tdb.sys.ConcurrencyPolicyMRSW.checkConcurrency(ConcurrencyPolicyMRSW.java:62)
>>        at
>> com.hp.hpl.jena.tdb.sys.ConcurrencyPolicyMRSW.startUpdate(ConcurrencyPolicyMRSW.java:46)
>>        at
>> com.hp.hpl.jena.tdb.nodetable.NodeTupleTableConcrete.startWrite(NodeTupleTableConcrete.java:54)
>>        at
>> com.hp.hpl.jena.tdb.nodetable.NodeTupleTableConcrete.sync(NodeTupleTableConcrete.java:237)
>>        at com.hp.hpl.jena.tdb.store.TripleTable.sync(TripleTable.java:89)
>>        at
>> com.hp.hpl.jena.tdb.store.DatasetGraphTDB.sync(DatasetGraphTDB.java:262)
>>        at com.hp.hpl.jena.sparql.SystemARQ.sync(SystemARQ.java:47)
>>        at org.openjena.fuseki.servlets.HttpAction.sync(HttpAction.java:61)
>>        at
>> org.openjena.fuseki.servlets.HttpAction.endWrite(HttpAction.java:39)
>>        at
>> org.openjena.fuseki.servlets.SPARQL_Query.execute(SPARQL_Query.java:226)
>>        at
>> org.openjena.fuseki.servlets.SPARQL_Query.executeForm(SPARQL_Query.java:187)
>>        at
>> org.openjena.fuseki.servlets.SPARQL_Query.perform(SPARQL_Query.java:87)
>>        at
>> org.openjena.fuseki.servlets.SPARQL_ServletBase.doCommon(SPARQL_ServletBase.java:76)
>>        at
>> org.openjena.fuseki.servlets.SPARQL_Query.doGet(SPARQL_Query.java:68)
>>        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
>>        at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
>>        at
>> org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:534)
>>        at
>> org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:475)
>>        at
>> org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:224)
>>        at
>> org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:921)
>>        at
>> org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:403)
>>        at
>> org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:184)
>>        at
>> org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:856)
>>        at
>> org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
>>        at
>> org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:114)
>>        at org.eclipse.jetty.server.Server.handle(Server.java:352)
>>        at
>> org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:596)
>>        at
>> org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:1052)
>>        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:590)
>>        at
>> org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:212)
>>        at
>> org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:426)
>>        at
>> org.eclipse.jetty.server.nio.BlockingChannelConnector$BlockingChannelEndPoint.run(BlockingChannelConnector.java:292)
>>        at
>> org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:450)
>>        at java.lang.Thread.run(Thread.java:619)
>>
>> I have been using TDB (from trunk) and Fuseki (from trunk):
>>
>> Jena:       VERSION: 2.6.4
>> Jena:       BUILD_DATE: 2010-12-12T16:56:15+0000
>> ARQ:        VERSION: 2.8.8-SNAPSHOT
>> ARQ:        BUILD_DATE: 2011-02-04T18:04:22+0000
>> TDB:        VERSION: 0.8.10-SNAPSHOT
>> TDB:        BUILD_DATE: 2011-02-07T13:25:50+0000
>> Fuseki:     VERSION: 0.2.0-SNAPSHOT
>> Fuseki:     BUILD_DATE: 2011-02-08T12:43:18+0000
>>
>> I have tried to do the same with Joseki v3.4.3 (I was not able to check it
>> out using CVS as anonymous user, bah...)
>>
>> I know, I know...
>>
>> I am just asking, is it a known problem?
>>
>> Paolo
>>