RE: NDC.remove / memory issues

[John Volkar]

Hmm,   We are preparing to do some preliminary load testing on our application here, and had actually figured on relying on the lazy NDC.remove() behaviour.  (We figured that at least initially it should be good enough.)   Does it seem to not work 1)at all, or 2)poorly, or what?    I've looked at the source code for the NDC class and it seemed perfectly adequate and correct.  (That is of course by no means a GOOD test of it, but hey it LOOKS like it should work!)   So, do you have more details on what you observe to be it's issues?   John Volkar     -----Original Message----- From: Wes [mailto:[EMAIL PROTECTED]] Sent: Tuesday, June 12, 2001 1:37 PM To: [EMAIL PROTECTED] Subject: NDC.remove / memory issues We just began stress testing our application, and found memory leaks.  Eventually, I isolated the leak to the NDC push/pop that we were doing in each thread that was created.  Then, after looking more carefully at the NDC class documentation, I saw the following regarding the remove method:   "Remove the diagnostic context for this thread. Each thread that created a diagnostic context by calling pop() should call this method before exiting. Otherwise, the memory used by the diagnostic context for the thread cannot be reclaimed by the VM. As this is such an important problem in heavy duty systems and because it is difficult to always guarantee that the remove method is called before exiting a thread, this method has been augmented to lazily remove references to dead threads. In practice, this means that you can be a little sloppy and occasionally forget to call remove() before exiting a thread"   I had not known about the remove method, probably because I initially looked only at a few examples, such as Trivial.java, and the remove was not used there.  I also noticed that the documentation for the push and pop methods does not mention the remove() method at all.   Furthermore, according to the remove() documentation, we should be OK anyway because of the lazy cleanup mechanism, but according to our tests, it did not clean up enough, as we eventually ran out of memory.   So, if anyone else is currently doing push/pop in threads that come and go frequently, be sure to call remove as the thread exits... and perhaps the remove method could be mentioned in the documentation for push and pop.   Wes