Thanks Charlie, Your point about other things such as datasources creating threads is a good one, and yes our environment does generate a lot of database connections. I don't believe it's limited, and I'll find out what the timeouts etc are. We are on Coldfusion version 7.03 with JRun 4 updater 6, using JVM 1.4 (but this is all soon to be updated).
I'll see if I can monitor threads, do you have any suggestions on how best to monitor threads with either FusionReactor or JRun logging? Thanks Barry. On Apr 13, 4:02 am, "charlie arehart" <[email protected]> wrote: > Barry, for what it's worth, I'll offer some more thoughts. You're on the > right track. > > First, I'll concur with Kai and your observation that this is about the > possibility of the heap being high, thus constraining the space left for > creating stacks. As Kai noted, it's counterintuitive because we all assume > "outofmemory" means "out of heap", but it doesn't. Yours is due to running > out of stack space, not heap. > > As such, yes, lowering the stack size can help, but as you note, if your > config's default is 256k (which others should note as Kai said is dependent > on jvm, os, and architecture) so you're leery of lowering it more. You can, > but just watch out for errors due to "stackoverflow". It's a delicate > balance. > > You're right to focus first on just lowering the heap. Especially if you > have some means to have monitored and confirmed that you're not having > outofmemory errors due to running out of heap. (And you can't use as a gauge > whether you've "hit" the heap max, as shown in some monitoring tool, because > you usually will. The question is whether when the system did a GC, did it > recover a lot. If so, and consistently, then you can afford to lower the > heap. Just watch out for possible new "oom: heap space" errors.) > > But then there is also the matter, as you brought up originally, of lowering > your thread use. As much as the max threads may seem to be the issue, it may > not be. Rather, there are MANY things that create threads in a CF/JRun > environment. It could be datasource connections. Do you have them limited at > all? Timing out? Even then, there have been bugs where they've not timed out > when they should. What CF version are you running? And what hotfixes? And > are you sure you have the right ones? (It's easy to have mis-implemented 8.0 > hot fixes on an 8.0.1 server, and vice versa, for instance.) > > You can also enabled JRun metrics to track the various thread pools, which > can help identify if something is getting out of whack. You can also monitor > thread use from the jrun.exe process, from the OS perspective, which can > help. > > The good news is that this problem can be solved, generally, once you have a > clearer idea of what the problem is (and is not). > > /charlie > > From: [email protected] [mailto:[email protected]] On Behalf > Of Barry Chesterman > Sent: Monday, April 12, 2010 12:03 AM > To: [email protected] > Subject: Re: [cfaussie] RE: Coldfusion JRun Max handler threads setting > > Thanks for the replies. > > I will do some load tests with adjusting the queued threads setting, from > what I've read, the 'unable to create new native thread' errors are related > to having a large heap size (which we do) and the operating system not being > able to spawn new threads (as an OS thread is spawned to keep track of each > JVM thread). We previously had standard 'out of memory' errors which were in > fact related to a heap size that was too small. > > Kai, we use JVM 1.4 at the moment, and thread stack size is by default > 256KB, so I don't think i'll look at adjusting that as 256KB is supposed to > be pretty low, Apparently JVM 1.5 upwards use 1MB :O! > We have our max handler threads (wait queue) at 500, and our active threads > at 25, I'll have a go at decreasing the heap size and max handler threads > and do some load testing. > > Thanks for your help all. > Barry -- You received this message because you are subscribed to the Google Groups "cfaussie" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en.
