Hi everyone,
I'm tryng to use Joseki with SDB (on MySQL 5.1) for serving multithread
application queries.
If all queries doesen't overlapp everything works well.
The problem comes wehn two different thread make concurrent queries that
overlaps and I got this error:
======================= log Stacktrace =====================
2012-01-11 13:05:59 - log :: REQUEST /sparql on
org.mortbay.jetty.HttpConnection@1181de1
2012-01-11 13:05:59 - log ::
sessionManager=org.mortbay.jetty.servlet.HashSessionManager@f9f91d
2012-01-11 13:05:59 - log :: session=null
2012-01-11 13:05:59 - log :: servlet=SPARQL service
processor
2012-01-11 13:05:59 - log :: chain=null
2012-01-11 13:05:59 - log :: servlet holder=SPARQL
service processor
2012-01-11 13:05:59 - Servlet :: Request:
http://localhost:2020/sparql
2012-01-11 13:05:59 - Servlet :: Service URI = <sparql>
2012-01-11 13:05:59 - SPARQL :: Query: PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX owl:
<http://www.w3.org/2002/07/owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT DISTINCT ?resourceURI ?resourceType
?resourceLabel ?resourceComment WHERE { GRAPH <http://www.imonlinfo.it/ontologie/grafi/test/bps-all> { ?resourceURI rdfs:domain
<http://www.imolinfo.it/ontologie/ea/v1.3/application-domain-model#Application> . ?resourceURI rdf:type ?resourceType OPTIONAL {
?resourceURI rdfs:label ?resourceLabel FILTER ( lang(?resourceLabel) = "en" ) } OPTIONAL { ?resourceURI
rdfs:comment ?resourceComment FILTER ( lang(?resourceComment) = "en" ) } OPTIONAL { ?resourceURI rdfs:label
?resourceLabel FILTER ( lang(?resourceLabel) = "it" ) } OPTIONAL { ?resourceURI rdfs:comment
?resourceComment FILTER ( lang(?resourceComment) = "it" ) } OPTIONAL { ?resourceURI rdfs:label
?resourceLabel } OPTIONAL { ?resourceURI rdfs:comment ?resourceComment } } }
2012-01-11 13:05:59 - SPARQL :: OK/select: PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX owl:
<http://www.w3.org/2002/07/owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT DISTINCT ?resourceURI ?resourceType
?resourceLabel ?resourceComment WHERE { GRAPH <http://www.imonlinfo.it/ontologie/grafi/test/bps-all> { ?resourceURI rdfs:domain
<http://www.imolinfo.it/ontologie/ea/v1.3/application-domain-model#Application> . ?resourceURI rdf:type ?resourceType OPTIONAL {
?resourceURI rdfs:label ?resourceLabel FILTER ( lang(?resourceLabel) = "en" ) } OPTIONAL { ?resourceURI
rdfs:comment ?resourceComment FILTER ( lang(?resourceComment) = "en" ) } OPTIONAL { ?resourceURI rdfs:label
?resourceLabel FILTER ( lang(?resourceLabel) = "it" ) } OPTIONAL { ?resourceURI rdfs:comment
?resourceComment FILTER ( lang(?resourceComment) = "it" ) } OPTIONAL { ?resourceURI rdfs:label
?resourceLabel } OPTIONAL { ?resourceURI rdfs:comment ?resourceComment } } }
2012-01-11 13:05:59 - log :: REQUEST /sparql on
org.mortbay.jetty.HttpConnection@ddc728
2012-01-11 13:05:59 - log ::
sessionManager=org.mortbay.jetty.servlet.HashSessionManager@f9f91d
2012-01-11 13:05:59 - log :: session=null
2012-01-11 13:05:59 - log :: servlet=SPARQL service
processor
2012-01-11 13:05:59 - log :: chain=null
2012-01-11 13:05:59 - log :: servlet holder=SPARQL
service processor
2012-01-11 13:05:59 - Servlet :: Request:
http://localhost:2020/sparql
2012-01-11 13:05:59 - Servlet :: Service URI = <sparql>
2012-01-11 13:05:59 - TransactionHandlerSDB :: beginTransaction: Already in
a transaction
2012-01-11 13:05:59 - Servlet :: Internal server error
com.hp.hpl.jena.sdb.SDBException: Already in transaction
at
com.hp.hpl.jena.sdb.graph.TransactionHandlerSDB.begin(TransactionHandlerSDB.java:45)
at com.hp.hpl.jena.rdf.model.impl.ModelCom.begin(ModelCom.java:1083)
at org.joseki.processors.ProcessorBase.exec(ProcessorBase.java:80)
at org.joseki.ServiceRequest.exec(ServiceRequest.java:36)
at org.joseki.Dispatcher.dispatch(Dispatcher.java:59)
at org.joseki.http.Servlet.doCommon(Servlet.java:178)
at org.joseki.http.Servlet.doGet(Servlet.java:138)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:440)
at
org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:322)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at
org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:926)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at
org.mortbay.jetty.nio.BlockingChannelConnector$Connection.run(BlockingChannelConnector.java:164)
at
org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
2012-01-11 13:05:59 - log :: RESPONSE /sparql 500
2012-01-11 13:05:59 - log :: RESPONSE /sparql 200
==========================================================================================
As you can see here I have the first REQUEST and the second one that come before RESPONSE of the first one. As a result The first ends correctly
(RESPONSE /sparql 200) whereas the second one recieve a :: RESPONSE /sparql 500 (so that I get an Http 500 error: Internal Server Error:... from
Joseki).
I already tried to configure "joseki:lockingPolicy" parameter but whatever value I specify (joseki:lockingPolicyMutex,
joseki:lockingPolicyMRSW,joseki:lockingPolicyNone ) the result doesn't change. I also have tried to increase the the "joseki:poolSize" parameter but
nothing.
What can I do to let Joseki manage correctly the concurrent queries trough SDB?
I'm working with:
- Joseki 3.4.4
- SDB-1.3.4
- Jena-2.6.4
- MySql 5.1
If it may be useful I can attach the joseki config file used.
Thanx in advance,
Matteo.
