"Page Map Locked By Thread" Error?

Classic Servoy
1

Anyone seen this one? I’m not sure what it means…

org.mozilla.javascript.WrappedException: Wrapped org.apache.wicket.WicketRuntimeException: After 1 minute the Pagemap null is still locked by: Thread[http-80-3,5,main], giving up trying to get the page for path: 4 (onShow#1174) 
    	at com.servoy.j2db.scripting.ScriptVariableScope.put(Unknown Source) 
    	at org.mozilla.javascript.ScriptableObject.putProperty(ScriptableObject.java:1768) 
    	at org.mozilla.javascript.ScriptRuntime.setObjectProp(ScriptRuntime.java:1531) 
    	at org.mozilla.javascript.ScriptRuntime.setObjectProp(ScriptRuntime.java:1519) 
    	at org.mozilla.javascript.Interpreter.interpretLoop(Interpreter.java:3355) 
    	at script.onShow(onShow:1174) 
    	at org.mozilla.javascript.Interpreter.interpret(Interpreter.java:2680) 
    	at org.mozilla.javascript.InterpretedFunction.call(InterpretedFunction.java:166) 
    	at org.mozilla.javascript.ContextFactory.doTopCall(ContextFactory.java:387) 
    	at org.mozilla.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3134) 
    	at org.mozilla.javascript.InterpretedFunction.call(InterpretedFunction.java:165) 
    	at com.servoy.j2db.scripting.ScriptEngine.executeFunction(Unknown Source) 
    	at com.servoy.j2db.FormController.executeFunction(Unknown Source) 
    	at com.servoy.j2db.FormController.executeFormMethod(Unknown Source) 
    	at com.servoy.j2db.FormController.executeOnShowMethod(Unknown Source) 
    	at com.servoy.j2db.FormController.access$1500(Unknown Source) 
    	at com.servoy.j2db.FormController$3.run(Unknown Source) 
    	at com.servoy.j2db.server.headlessclient.WebClient.executeEvents(Unknown Source) 
    	at com.servoy.j2db.server.headlessclient.WebClient.executeEvents(Unknown Source) 
    	at com.servoy.j2db.server.headlessclient.WebClient.onBeginRequest(Unknown Source) 
    	at com.servoy.j2db.server.headlessclient.WebClientsApplication$7.onBeginRequest(Unknown Source) 
    	at org.apache.wicket.RequestCycle.prepare(RequestCycle.java:1242) 
    	at org.apache.wicket.RequestCycle.step(RequestCycle.java:1306) 
    	at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1438) 
    	at org.apache.wicket.RequestCycle.request(RequestCycle.java:546) 
    	at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:486) 
    	at com.servoy.j2db.server.servlets.Zm.doGet(Unknown Source) 
    	at org.apache.wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:138) 
    	at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) 
    	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
    	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) 
    	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
    	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) 
    	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) 
    	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) 
    	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) 
    	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:554) 
    	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) 
    	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) 
    	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859) 
    	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) 
    	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) 
    	at java.lang.Thread.run(Thread.java:636) 
    Caused by: org.apache.wicket.WicketRuntimeException: After 1 minute the Pagemap null is still locked by: Thread[http-80-3,5,main], giving up trying to get the page for path: 4 
    	at org.apache.wicket.session.pagemap.LeastRecentlyAccessedEvictionStrategy.evict(LeastRecentlyAccessedEvictionStrategy.java:61) 
    	at org.apache.wicket.AccessStackPageMap.put(AccessStackPageMap.java:310) 
    	at org.apache.wicket.Session.requestDetached(Session.java:1462) 
    	at org.apache.wicket.RequestCycle.detach(RequestCycle.java:1178) 
    	at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1464)
2

somehow something is very busy doing stuff (loading a form or something) but the other is waiting for that to happen, and it will wait 1 minute until it times out with that exception.
Please to try figure out why the first request takes so long.

What version are you seeing this?

3

I’m getting this too. On a server Servoy version 5.2.13 -build 1025.
I also see there was a support case here, but never any resolution: https://support.servoy.com/browse/SVY-2162

Any suggestions?

4

what are you doing that makes one request so slow that it takes more the 1 minute to complete?

5

I don’t know, and there isn’t any information in the error or log to tell me exactly why it happens.

6

but the stacktrace says a lot
if you get this:

After 1 minute the Pagemap null is still locked by: Thread[http-80-3,5,main],

then the stacktrace you see next is of the thread that is busy so Thread[http-80-3,5,main] so we can see what that thread is really doing.

7

Yes, but what am I supposed to do with that? I would like to know what code is running in that thread that is blocking it. Is that detail in a log somewhere? How can I see exactly what that thread is doing?

8

yes that is what you see, you see which thread is really doing stuff (for more then a minute), blocking all other incoming request

9

Getting a thread ID doesn’t help me much. Lets look at Bob’s example in the first post.

After 1 minute the Pagemap null is still locked by: Thread[http-80-3,5,main], giving up trying to get the page for path: 4 (onShow#1174)

So that’s saying that its attempting to run the onShow method, but its blocked because another thread, Thread[http-80-3,5,main], is blocking it (because its taking more than 1 minute). So my question is, what is Thread[http-80-3,5,main] doing?

10

thats what i explain to say
The stack trace you get after the exception that says that as a title is the stack dump of the “http-80-3,5,main”

so

org.mozilla.javascript.WrappedException: Wrapped org.apache.wicket.WicketRuntimeException: After 1 minute the Pagemap null is still locked by: Thread[http-80-3,5,main], giving up trying to get the page for path: 4 (onShow#1174)
at com.servoy.j2db.scripting.ScriptVariableScope.put(Unknown Source)
at org.mozilla.javascript.ScriptableObject.putProperty(ScriptableObject.java:1768)
at org.mozilla.javascript.ScriptRuntime.setObjectProp(ScriptRuntime.java:1531)
at org.mozilla.javascript.ScriptRuntime.setObjectProp(ScriptRuntime.java:1519)
at org.mozilla.javascript.Interpreter.interpretLoop(Interpreter.java:3355)
at script.onShow(onShow:1174)

that means that thread http-80-3,5,main that is blocking the thread that wants to get the lock is doing the onshow…
It is currently setting a scope variable…

11

This looks suspiciously similar to an issue we reported (https://support.servoy.com/browse/SVY-4922) where we sometimes see form variable updates taking a very long time resulting in page lock timeout errors with very similar stack traces…