I was having a problem with Tomcat creating over 600 threads on startup. I have a couple hundred hosts and a couple contexts per host. This was causing huge a huge performance problem with CPU usage in tomcat 3.2.4, but it seems to work OK with tomcat4, even though it still creates as many threads. According to the following from Craig, the huge amount of threads is normal....
The threads that Tomcat 4.x creates can be categorized as follows: * Request processing threads (configured in your <Connector> elements) that are shared across all virtual hosts and webapps * Per-host thread that manages live deployments (automatically adding new apps dropped into "webapps") if liveDeploy="true" -- should not be enabled on a production server. * Per-webapp thread to process reloading on class recompilation if reloadable="true" -- should not be enabled on a production server. * Per-webapp thread to process session invalidations. Brandon Cruz -----Original Message----- From: Milt Epstein [mailto:[EMAIL PROTECTED]] Sent: Friday, December 20, 2002 2:16 PM To: Tomcat Users List Subject: RE: "Naive question" thread On Thu, 19 Dec 2002, Denise Mangano wrote: > Hi all :) > > In response, I was running ps -ef to view what was running. I > haven't had a chance to read the man on ps, but I did quickly try > pstree -aup as you suggested. It looks like (if I am reading the > tree right) there is only one java process, with a number of threads > branching off. The same for the httpd process. > > Just out of curiousity, why would so many threads be spawned just > after starting the services before doing anything? There are several things those threads could be created for. First of all, tomcat is set up to do one request per thread, and it typically creates a pool of request processing threads to handle requests (you can control this somewhat because most/all Connector's have minProcessors and maxProcessors attributes). So, initially, some minimum number of such threads are created right away. There will be other threads for bookkeeping kinds of things, like perhaps to invalidate sessions. I'm not really sure what other things other threads would be for. I think someone (Craig McClanahan?) recently posted about what some of those threads are doing, if you're really curious, you can look that up in the archives. > -----Original Message----- > From: jon wingfield > To: Tomcat Users List > Sent: 12/19/2002 1:47 PM > Subject: RE: "Naive question" thread > > i use pstree -aup. > Very useful with multiple java apps running on one server :) > > -----Original Message----- > From: Milt Epstein [mailto:[EMAIL PROTECTED]] > Sent: 18 December 2002 20:15 > To: Tomcat Users List > Subject: "Naive question" thread > > > > Saw a post in the "naive question" thread earlier today that I wanted > to respond to, but my quick "delete" finger got to it before I got > around to it. This was a thread in which John Turner, Denise Mangano, > and some others had been participating. > > Anyway, Denise posted the output of ps that had a whole bunch of java > processes listed. I'd be concerned about the number of such > processes, because normally there shouldn't be so many -- in fact, > most typically (i.e. one tomcat instance), there should be just one. > Now, Denise said she's using linux, and it's my understanding that ps > under linux will list threads, not just processes. So it's possible > all those java listings were all the threads running in one java > process. And I think there's an option to ps to cause it list actual > processes, not threads. So you might try that and see what the output > looks like. Milt Epstein Research Programmer Integration and Software Engineering (ISE) Campus Information Technologies and Educational Services (CITES) University of Illinois at Urbana-Champaign (UIUC) [EMAIL PROTECTED] -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
