OOM on gatling

Gatling (Open-Source)
1

I am getting this when running gatling:

Dumping heap to java_pid8409.hprof …
Heap dump file created [585273257 bytes in 5.761 secs]
Uncaught error from thread [GatlingSystem-akka.actor.default-dispatcher-7] shutting down JVM since ‘akka.jvm-exit-on-fatal-error’ is enabled for ActorSystem[GatlingSystem]
java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOfRange(Arrays.java:2694)
at java.lang.String.(String.java:203)
at java.nio.HeapCharBuffer.toString(HeapCharBuffer.java:561)
at java.nio.CharBuffer.toString(CharBuffer.java:1201)
at org.jboss.netty.buffer.ChannelBuffers.decodeString(ChannelBuffers.java:1207)
at org.jboss.netty.buffer.AbstractChannelBuffer.toString(AbstractChannelBuffer.java:550)
at org.jboss.netty.buffer.AbstractChannelBuffer.toString(AbstractChannelBuffer.java:542)
at com.ning.http.client.providers.netty.NettyResponse.getResponseBody(NettyResponse.java:92)
at io.gatling.http.response.GatlingResponse.getResponseBody(Response.scala:61)
at io.gatling.http.check.HttpCheckBuilders$$anonfun$2.apply(HttpCheckBuilders.scala:36)
at io.gatling.http.check.HttpCheckBuilders$$anonfun$2.apply(HttpCheckBuilders.scala:36)
at io.gatling.core.check.CheckBase$$anonfun$memoizedPrepared$1$1.apply(Check.scala:53)
at io.gatling.core.check.CheckBase$$anonfun$memoizedPrepared$1$1.apply(Check.scala:53)
at scala.collection.mutable.MapLike$class.getOrElseUpdate(MapLike.scala:189)
at scala.collection.mutable.AbstractMap.getOrElseUpdate(Map.scala:91)
at io.gatling.core.check.CheckBase.memoizedPrepared$1(Check.scala:53)
at io.gatling.core.check.CheckBase.check(Check.scala:63)
at io.gatling.http.check.HttpCheck.check(HttpCheck.scala:30)
at io.gatling.http.check.HttpCheck.check(HttpCheck.scala:29)
at io.gatling.core.check.Checks$$anonfun$check$1$$anonfun$apply$1.apply(Check.scala:30)
at io.gatling.core.check.Checks$$anonfun$check$1$$anonfun$apply$1.apply(Check.scala:30)
at io.gatling.core.validation.Success.flatMap(Validation.scala:27)
at io.gatling.core.check.Checks$$anonfun$check$1.apply(Check.scala:30)
at io.gatling.core.check.Checks$$anonfun$check$1.apply(Check.scala:29)
at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:111)
at scala.collection.immutable.List.foldLeft(List.scala:84)
at io.gatling.core.check.Checks$.check(Check.scala:29)
at io.gatling.http.ahc.GatlingAsyncHandlerActor.checkAndProceed$1(GatlingAsyncHandlerActor.scala:224)
at io.gatling.http.ahc.GatlingAsyncHandlerActor.io$gatling$http$ahc$GatlingAsyncHandlerActor$$processResponse(GatlingAsyncHandlerActor.scala:237)
at io.gatling.http.ahc.GatlingAsyncHandlerActor$$anonfun$receive$1.applyOrElse(GatlingAsyncHandlerActor.scala:103)
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:425)
at akka.actor.ActorCell.invoke(ActorCell.scala:386)

2

I am getting it quite often now even i am up the xmx to 3072M (used to be 512M).

My scenario is a little bit tricky, since as requested, our testing scenarios are long sessions from the start of the run to the end of the run. So I guess probably that is why the memory can not be released and cause this OOM?

Any help on this?

3

Well, I would need your heap dump.
Would you happen to do your own stuff with the response bodies, like saving them into the Session (willingly, or unwillingly, like doing a substring or a regex and saving the result)?

4

Add this option to Java for the heap dump: -XX:+HeapDumpOnOutOfMemoryError

5

Yeah, I do need to save some bodyString to parse since the regex does not fit me. Should I use the tranform function instead of saving the body string in sessions and do the parse there? Will that make differences?

6

Yes, you should be using transform so that you only save the bits you’re interested in and the body strings can be garbage collected ASAP.
If you don’t/can’t do that, at least remove the attributes storing body strings as soon as you’re done parsing them.

7

Ok I will remove those attributes from the sessions after done.

So I am using 2.0.0M.
https://github.com/excilys/gatling/wiki/Gatling-2

Does session still have the removeAttribute functions? Seems like it goes away for 2.0.0. What's the best way to do that?

session.set(attributeName, null)?

8

BTW, Do you have some good examples on how to use transform function? I looked at wiki one, it is pretty simple. Want to get more help on how to write those

9

Never mind, it is more about scala, I can figure it out by myself

Thx for the help!