error during simulation

When I run my simulation with 20-50 users everything is ok. Whenever I put it 100+ users I get the following error:
[ERROR] [09/10/2014 17:03:59.350]
[GatlingSystem-akka.actor.default-dispatcher-5]
[ActorSystem(GatlingSystem)] exception while executing timer task
java.lang.IllegalStateException: cannot enqueue after timer shutdown
What can be the reason?

Version?
Do you use something like a max duration?

I am using Gatling.2.0.0-RC4, my simulation setup is:
scenarioName.inject(rampUsers(100) over 300).protocols(protocolName)

What’s the full stacktrace, please?

[ERROR] [09/10/2014 16:55:05.387] [GatlingSystem-akka.actor.default-dispatcher-9] [ActorSystem(GatlingSystem)] exception while executing timer task
java.lang.IllegalStateException: cannot enqueue after timer shutdown
at akka.actor.LightArrayRevolverScheduler.scheduleOnce(Scheduler.scala:277)
at akka.actor.Scheduler$class.scheduleOnce(Scheduler.scala:117)
at akka.actor.LightArrayRevolverScheduler.scheduleOnce(Scheduler.scala:182)
at io.gatling.core.scenario.Scenario.io$gatling$core$scenario$Scenario$$batchSchedule$1(Scenario.scala:70)
at io.gatling.core.scenario.Scenario$$anonfun$io$gatling$core$scenario$Scenario$$batchSchedule$1$2.apply$mcV$sp(Scenario.scala:78)
at akka.actor.Scheduler$$anon$7.run(Scheduler.scala:117)
at akka.actor.LightArrayRevolverScheduler$TaskHolder.run(Scheduler.scala:476)
at akka.actor.LightArrayRevolverScheduler$$anonfun$close$1.apply(Scheduler.scala:282)
at akka.actor.LightArrayRevolverScheduler$$anonfun$close$1.apply(Scheduler.scala:281)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
at akka.actor.LightArrayRevolverScheduler.close(Scheduler.scala:280)
at akka.actor.ActorSystemImpl.stopScheduler(ActorSystem.scala:687)
Exception in thread “main” java.lang.IllegalStateException: Feeder is now empty, stopping engine
at io.gatling.core.action.SingletonFeed.feed(SingletonFeed.scala:60)
at io.gatling.core.action.SingletonFeed$$anonfun$receive$1.applyOrElse(SingletonFeed.scala:28)
at akka.actor.Actor$class.aroundReceive(Actor.scala:465)
at io.gatling.core.akka.BaseActor.aroundReceive(BaseActor.scala:23)
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
at akka.actor.ActorCell.invoke(ActorCell.scala:487)
at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
at akka.dispatch.Mailbox.run(Mailbox.scala:220)
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
at akka.actor.ActorSystemImpl$$anonfun$liftedTree2$1$1.apply$mcV$sp(ActorSystem.scala:616)
at akka.actor.ActorSystemImpl$$anonfun$liftedTree2$1$1.apply(ActorSystem.scala:616)
at akka.actor.ActorSystemImpl$$anonfun$liftedTree2$1$1.apply(ActorSystem.scala:616)
at akka.actor.ActorSystemImpl$$anon$3.run(ActorSystem.scala:640)
at akka.actor.ActorSystemImpl$TerminationCallbacks$$anonfun$run$1.runNext$1(ActorSystem.scala:807)
at akka.actor.ActorSystemImpl$TerminationCallbacks$$anonfun$run$1.apply$mcV$sp(ActorSystem.scala:810)
at akka.actor.ActorSystemImpl$TerminationCallbacks$$anonfun$run$1.apply(ActorSystem.scala:803)
at akka.actor.ActorSyl$TerminationCallbacks$$anonfun$run$1.apply(ActorSystem.scala:803)
at akka.util.ReentrantGuard.withGuard(LockUtil.scala:15)
at akka.actor.ActorSystemImpl$TerminationCallbacks.run(ActorSystem.scala:803)
at akka.actor.ActorSystemImpl$$anonfun$terminationCallbacks$1.apply(ActorSystem.scala:637)
at akka.actor.ActorSystemImpl$$anonfun$terminationCallbacks$1.apply(ActorSystem.scala:637)
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
at akka.dispatch.BatchingExecutor$Batch$$anonfun$run$1.processBatch$1(BatchingExecutor.scala:67)
at akka.dispatch.BatchingExecutor$Batch$$anonfun$run$1.apply$mcV$sp(BatchingExecutor.scala:82)
at akka.dispatch.BatchingExecutor$Batch$$anonfun$run$1.apply(BatchingExecutor.scala:59)
at akka.dispatch.BatchingExecutor$Batch$$anonfun$run$1.apply(BatchingExecutor.scala:59)
at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:72)
at akka.dispatch.BatchingExecutor$Batch.run(BatchingExecutor.scala:58)
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41)
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

OK, so your real problem is the second stacktrace:
Exception in thread “main” java.lang.IllegalStateException: Feeder is now empty, stopping engine

Your feeder is empty => Gatling stops the Akka ActorSystem => Some other part of Gatling might still be in the process of injecting users.

You’re probably using a CSV file with less lines than you’re injecting virtual users. And as the default strategy is queue…

Please have a look at the Feeder documentation.

I do understand this part:

"Every time a virtual user reaches this step, it will pop a record out of the Feeder, which will be injected into the user’s Session, resulting in a new Session instance.

If the Feeder can’t produce enough records, Gatling will complain about it and your simulation will stop."

But what do I do if the csv file is a password file and I do not want records to be deleted because there are only 15 passwords that I need to use for users(user can require different password - its random)?

use another strategy than the default one: random, circular

Thanks a lot! Circular works for me. Now I know a little more about Gatlling.