Brien, Depending on the HTTP connector you use (may be basic HTTP, APR or NIO) and whether you use the comet API or not, the limit to number of maximum concurrent long-lived connections in tomcat may be very different. In my experience, the most scalable is with: 1) NIO + comet or APR + comet 2) APR or NIO without comet 3) standard HTTP connector
The OS you are running onto has also an impact. For example, with standart HTTP connector (default one) on a Linux Red Hat 4 , dual cpu box with 2Gb of RAM (under VMWare), we managed to run a successful 3000 concurrent HTTP requests (long running HTTP requests) at a customer site. The same box under Windows was behind, but it may due to our inability to tune it? We had to tune the linux system and the JVM to reach those numbers, but your load may differ from that of our application and you may get very different numbers: plan some testing ahead ... The system limits you usually bump into: 1) max number of threads per process 2) max memory per process (use java option -Xss to reduce thread stack size and -Xmx to up the java heap size, tune the corresponding system limit) 3) max file descriptors per process There are many others that I don't have at the top of my mind right now... Type "man ulimit" at your linux prompt to get some more hints. Using comet + NIO or APR, you may break these barriers by not using one thread per long-lived request. I hope this helps and points you to some area of research. Best regards, Christophe Pierret -----Message d'origine----- De : brien colwell [mailto:[EMAIL PROTECTED] Envoyé : samedi 1 décembre 2007 23:23 À : dev@tomcat.apache.org Objet : max number of concurrent requests hi all, I'm building a framework that needs to block on HTTP requests. That is, at some point when executing my servlet, the thread will wait for some event to happen. Of course this wait may be very long. Is there a limit to threads in Tomcat? Is there a mechanism to yield processing a request, and then pick it up later? Sorry if this is unclear ... Thanks, Brien --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
