Re: OOME crushing tomcat
The nature of OOMEs is, that they can happen in every part of the code, that needs a new peace of memory. No one is able to write code in a way, that can handle memory allocation failures in all places new memory is needed. If you run into an OOME, it is very unwise to let the JVM run along, even if it looks OK (only this request got aborted etc.). If the JVM needs memory, it tries to free memory. If you get an OOME, it's not unlikely, that not only object couldn't get allocated and also it's likely, that the OOME will happen again. The failed allocations could be in your webapp, in your 3rd party libraries, in the container, in the 3rd party libs of the container etc. After an OOME, the behaviour of the whole stack is UNDEFINED. You can't even be sure, that the data you deliver is correct! That's why an OOME usually means you have to restart the JVM. There's no stable way to detect, how big the damage is. If you let the JVM run, you are taking a huge risk. All those are true for general Java processes, including Tomcat. There are no application controlled allocation pools in Java, such that a container can shield itself from the deployed app eating all the memory. One special case is OOME in Tomcat thread pool. If your load increases and Tomcat needs more threads, it could happen that during initialization of this thread memory allocation fails and the new thread - supposed to take over the network listen fails to get into live and you loose your listen on the socket. In this case Tomcat indeed looks dead, because the request accepting mechanism got hit by the OOME. In this case Tomcat is the victim, not the culprit. I think there's no sense in making this thread allocation more robust (at least as long as we are talking about OOME coming from heap), because then the OOME will simply hit some other place with a more subtle impact. By my above statements, the immediate impact is not relevant, because you can't really control which components are affected and need to restart anyways. Regards, Rainer Leon Rosenberg wrote: Hi, one of my customers recently increased amount of memory they use, so OOME are happening more often. Most of them however do no harm, since just the request is aborted, but the container remains functional and next request wents well (they have a throughput of 100MB per second in young generation so chances are good next request will get some memory again). However, this exception killed tomcat completely (no replies anymore): Sep 30, 2007 6:56:51 PM org.apache.tomcat.util.threads.ThreadPool$ControlRunnable run SEVERE: Caught exception (java.lang.OutOfMemoryError: Java heap space) executing [EMAIL PROTECTED], terminating thread Any opinions, is that a bug in tomcat or is it inescapable after an OOME? regards Leon - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: OOME crushing tomcat
I had face the same problem, OOME sometimes kill tomcat connector. I setup two connectors (HTTP and AJP), while one connector was dead, the other still alive, and I could access manager/status from the live one to watch the dead one's status. I think it is tomcat's bug Leon Rosenberg-3 wrote: Hi, one of my customers recently increased amount of memory they use, so OOME are happening more often. Most of them however do no harm, since just the request is aborted, but the container remains functional and next request wents well (they have a throughput of 100MB per second in young generation so chances are good next request will get some memory again). However, this exception killed tomcat completely (no replies anymore): Sep 30, 2007 6:56:51 PM org.apache.tomcat.util.threads.ThreadPool$ControlRunnable run SEVERE: Caught exception (java.lang.OutOfMemoryError: Java heap space) executing [EMAIL PROTECTED], terminating thread Any opinions, is that a bug in tomcat or is it inescapable after an OOME? regards Leon - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- View this message in context: http://www.nabble.com/OOME-crushing-tomcat-tf4545506.html#a13120810 Sent from the Tomcat - User mailing list archive at Nabble.com. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: OOME crushing tomcat
Leon Rosenberg wrote: Any opinions, is that a bug in tomcat or is it inescapable after an OOME? OOME will kill Tomcat. I have seen it struggle on after an OOME but it always dies shortly afterwards. You need to get a profiler (I use YourKit) and find out what is using all the memory. Then: fix the leak if there is one; report a bug in Tomcat it it has a memory leak (fairly unlikely these days); add ram to the machine; or reduce the load on the machine. Mark - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: OOME crushing tomcat
William Leung wrote: I had face the same problem, OOME sometimes kill tomcat connector. I setup two connectors (HTTP and AJP), while one connector was dead, the other still alive, and I could access manager/status from the live one to watch the dead one's status. I think it is tomcat's bug Almost certainly not. Chances are it is an application bug. A profiler will tell you for sure. Mark - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
OOME crushing tomcat
Hi, one of my customers recently increased amount of memory they use, so OOME are happening more often. Most of them however do no harm, since just the request is aborted, but the container remains functional and next request wents well (they have a throughput of 100MB per second in young generation so chances are good next request will get some memory again). However, this exception killed tomcat completely (no replies anymore): Sep 30, 2007 6:56:51 PM org.apache.tomcat.util.threads.ThreadPool$ControlRunnable run SEVERE: Caught exception (java.lang.OutOfMemoryError: Java heap space) executing [EMAIL PROTECTED], terminating thread Any opinions, is that a bug in tomcat or is it inescapable after an OOME? regards Leon - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
