Stardog concurrency issue (Windows OS)

[kyber...@gmail.com]

Hi forum, 

While performing multiple concurrent queries to the Stardog server (4.1.3) I just noticed that the server from time to time triggers the following exception:

13:14:12.396 [StardogServer.WorkerGroup-0] ERROR com.complexible.stardog.protocols.http.server.HttpMessageEncoder - There was an error while encoding the response
java.io.IOException: java.nio.channels.ClosedChannelException

        at com.complexible.stardog.protocols.http.server.HttpMessageEncoder$SendResponseChannelOutputStream.assertNoError(HttpMessageEncoder.java:472) ~[stardog-protocols-http-server-4.1.3.jar:?]

        at com.complexible.stardog.protocols.http.server.HttpMessageEncoder$SendResponseChannelOutputStream.flush(HttpMessageEncoder.java:367) ~[stardog-protocols-http-server-4.1.3.jar:?]

        at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:297) ~[?:1.8.0_77]

        at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:141) ~[?:1.8.0_77]

        at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:229) ~[?:1.8.0_77]

        at com.fasterxml.jackson.core.json.WriterBasedJsonGenerator.flush(WriterBasedJsonGenerator.java:836) ~[jackson-core-2.4.4.jar:2.4.4]

        at org.openrdf.query.resultio.sparqljson.AbstractSPARQLJSONWriter.endDocument(AbstractSPARQLJSONWriter.java:423) ~[sesame-queryresultio-sparqljson-4.0.0.jar:?]

        at org.openrdf.query.resultio.sparqljson.AbstractSPARQLJSONWriter.endQueryResult(AbstractSPARQLJSONWriter.java:223) ~[sesame-queryresultio-sparqljson-4.0.0.jar:?]

        at org.openrdf.query.resultio.sparqljson.SPARQLResultsJSONWriter.endQueryResult(SPARQLResultsJSONWriter.java:29) ~[sesame-queryresultio-sparqljson-4.0.0.jar:?]

        at org.openrdf.query.QueryResults.report(QueryResults.java:166) ~[sesame-query-4.0.0.jar:?]

        at org.openrdf.query.resultio.QueryResultIO.writeTuple(QueryResultIO.java:449) ~[sesame-queryresultio-api-4.0.0.jar:?]

        at com.complexible.stardog.protocols.http.server.io.ResponseBodyEncoders$13.encode(ResponseBodyEncoders.java:468) ~[stardog-protocols-http-server-4.1.3.jar:?]

        at com.complexible.stardog.protocols.http.server.io.ResponseBodyEncoders$2.encode(ResponseBodyEncoders.java:99) ~[stardog-protocols-http-server-4.1.3.jar:?]

        at com.complexible.stardog.protocols.http.server.HttpMessageEncoder$SingletonMessageResponseBodyEncoder.encode(HttpMessageEncoder.java:510) ~[stardog-protocols-http-server-4.1.3.jar:?]

        at com.complexible.stardog.protocols.http.server.HttpMessageEncoder.write(HttpMessageEncoder.java:158) [stardog-protocols-http-server-4.1.3.jar:?]

        at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:633) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at io.netty.channel.AbstractChannelHandlerContext.access$1900(AbstractChannelHandlerContext.java:32) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at io.netty.channel.AbstractChannelHandlerContext$AbstractWriteTask.write(AbstractChannelHandlerContext.java:908) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at io.netty.channel.AbstractChannelHandlerContext$AbstractWriteTask.run(AbstractChannelHandlerContext.java:893) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:358) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:112) [netty-all-4.0.32.Final.jar:4.0.32.Final]

        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_77]

Caused by: java.nio.channels.ClosedChannelException

It can also get to "not responding" state in the worst cases. 

Any idea?

Best Regards, Rolando.