> From: Pieter Temmerman [mailto:ptemmerman....@sadiel.es] > Subject: Thread dump analysis > > Memory usage looks healthy, but CPU usage goes sky high (mainly caused > by the Java Tomcat process).
If you're truly out of memory, the GC thread(s) may be running almost continuously. However, with modern JVMs (you didn't bother to tell us what JVM you're using, nor what platform you're on), that's a pretty rare occurrence; it's more likely an application thread that's looping. As Leon suggested, look for threads in the runnable state and check the state of the heap. > org.apache.commons.dbcp.PoolingDataSource.getConnection(Poolin > gDataSource.java:96) This shows that indeed the thread is waiting for a DB connection. Note that the connection pool here is managed by the webapp, not Tomcat; the class names are different for Tomcat. > My first question is, what is a TP-Processor exactly? Is each client > connection to Tomcat being assigned a TP-Processor or am I wrong? You're not wrong; each request (not client) is handled by a TP-Processor thread. When processing for that request completes, the thread goes back to the thread pool to wait for another request from any client. > So my guess is that the freeze is being caused by a database > connection pool that is out of open connections You seem to have two symptoms: high CPU usage, and running out of DB connections. It is quite likely the two are related, perhaps the webapp gets in an infinite loop and therefore never releases DB connections back to the pool. > Note the line "locked <0x00002aabadaabff8>" and "waiting on > <0x00002aabadaabff8>" later on. So first it's locking that > "thing" and then it's waiting on that "thing". That "thing" is just a plain java.lang.Object, which is here serving the purpose of being a synchronization point. Java synchronization semantics require that an object be locked before it can be waited on; the wait() releases the lock until someone other thread calls notify() on that object. > Is that normal behavior? Yes. > Is there any way to know what the 0x00002aabadaabff8 means? It's the virtual address of the object being waited on. Not terribly useful other than as an identifier for the object at a given point in time. The object can move during a garbage collection. You really should move up to something a bit newer than 5.5.7; it's over four years old and lots of bug fixes have gone into the 5.5 line since then. 5.5.27 is the current level for that leg. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
