Dear Tobias,

thanks for your report and all the helpful details. My assumption is that the concurrency problem you came across may be related to an existing GitHub issue, which is why I've just added your info to this entry:

https://github.com/BaseXdb/basex/issues/458

Expect this bug to be fixed soon, Christian ___________________________

On Sat, Mar 31, 2012 at 1:25 AM, Tobias Hofer tobias.hofer@basis06.ch wrote:

Hi,

I'm using the REST API of BaseX 7.2 and run into concurrency problems. If I add new documents in parallel then the server will stop working after adding a few documents.

My command template looks like:

<?xml version="1.0" encoding="UTF-8"?>

<command xmlns="http://basex.org/rest"><text><![CDATA[ ADD TO $KEY$

<node id="$KEY$" /> ]]></text></command>

I call the REST API using curl: for ((i=0; i<10; i++)); do   (cp tx-template tx$i; replace '$KEY$' $i -- tx$i;    curl -i -X POST -H "Content-Type: application/xml" -T tx$i    "admin:admin@localhost:8984/rest/QDEV") & done

After four or less insert the following error occurs: HTTP/1.1 400 Bad Request Content-Type: text/plain; charset=utf-8 Content-Length: 2247 Server: Jetty(6.1.26)

java.lang.NullPointerExceptionjava.lang.NullPointerExceptionjava.lang.NullPointerExceptionorg.xml.sax.SAXParseException: cvc-type.3.1.2: Element 'command' is a simple type, so it must have no element information item [children].org.xml.sax.SAXParseException: cvc-type.3.1.2: Element 'command' is a simple type, so it must have no element information item [children].Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk@mailman.uni-konstanz.de Version: BaseX 7.2 Java: Sun Microsystems Inc., 1.6.0_26 OS: Linux, amd64 Stack Trace: java.lang.NullPointerException  org.basex.core.cmd.Add.run(Add.java:92)  org.basex.core.Command.run(Command.java:345)  org.basex.core.Command.exec(Command.java:324)  org.basex.core.Command.execute(Command.java:76)  org.basex.server.LocalSession.execute(LocalSession.java:134)  org.basex.server.LocalSession.execute(LocalSession.java:126)  org.basex.server.Session.execute(Session.java:51)  org.basex.http.rest.RESTCommand.run(RESTCommand.java:40)  org.basex.http.rest.RESTPost.run(RESTPost.java:129)  org.basex.http.rest.RESTServlet.run(RESTServlet.java:14)  org.basex.http.BaseXServlet.service(BaseXServlet.java:38)  javax.servlet.http.HttpServlet.service(HttpServlet.java:820)  org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)  org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:401)  org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)  org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)  org.mortbay.jetty.handler.HandlerList.handle(HandlerList.java:49)  org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)  org.mortbay.jetty.Server.handle(Server.java:326)  org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)  org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:945)  org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)  org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)  org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)  org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)

Now, the server cannot be accessed any more. Any further call will return "Database 'MYDB' is currently opened by another client. A restart helps.

The error does not happen if the commands are executed in sequence.

Please help.

Regards, Tobias Hofer _______________________________________________ BaseX-Talk mailing list BaseX-Talk@mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk