GraphDB 8.8.1 Free gets stuck - graphdb

Question

We're using GraphDB Free in our research project and I've recently come across an issue with responsiveness when inserting data into contexts.
When I use RDF4J API to insert statements into a new context, GraphDB fails to respond to subsequent requests/queries. No exceptions are reported in the logs. I assume it has something to do with the restriction to two concurrent queries.
Interestingly enough, when I create a context via a SPARQL INSERT in workbench, subsequent work with new contexts seems to be without issues. But if the new contexts are created by insertion of statements via an RDF4J connection, GraphDB often gets stuck. No such problem appears when I insert into the default context.
Here's the stacktrace I got from running jstack on the GraphDB process:
"repositories/termit" #16 daemon prio=5 os_prio=0 tid=0x00007f6481ca0000 nid=0x3c17 waiting on condition [0x00007f645ae9a000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000006c8e90748> (a java.util.concurrent.Semaphore$NonfairSync)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:997)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304)
at java.util.concurrent.Semaphore.acquire(Semaphore.java:312)
at com.ontotext.trree.GraphdbFreeConnection.<init>(GraphdbFreeConnection.java:15)
at com.ontotext.trree.OwlimSchemaRepository.getOwlimConnection(OwlimSchemaRepository.java:517)
at com.ontotext.trree.SailConnectionImpl.getStatementsInternal(SailConnectionImpl.java:316)
at com.ontotext.trree.SailConnectionImpl.getStatements(SailConnectionImpl.java:2346)
at org.eclipse.rdf4j.repository.sail.SailRepositoryConnection.getStatements(SailRepositoryConnection.java:296)
at org.eclipse.rdf4j.repository.sail.SailRepositoryConnection.exportStatements(SailRepositoryConnection.java:331)
at org.eclipse.rdf4j.http.server.repository.statements.ExportStatementsView.render(ExportStatementsView.java:108)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1325)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1069)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1008)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:870)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.ontotext.forest.core.request.RequestFilter.doFilterInternal(RequestFilter.java:41)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.github.ziplet.filter.compression.CompressingFilter.doFilter(CompressingFilter.java:263)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.ontotext.forest.security.AdminDelegatingFilterProxy.doFilter(AdminDelegatingFilterProxy.java:38)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:417)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:754)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1376)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
- locked <0x00000007b8102798> (a org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Tried it on GraphDB 8.6 and also on the latest 8.8.1.
Any help/hint would be greatly appreciated.

Answer 1

Can you give more details how did you insert the statements? I tried a simple test with GraphDB 8.8.1 and I couldn't reproduce the problem. This is what I do:
curl -X POST -d #wines.ttl -H "Content-Type: application/x-turtle" http://localhost:7200/repositories/test/rdf-graphs/service?graph=http://example.com
I did multiple inserts with different files and I cannot get to the problematic behavior