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http://issues.apache.org/bugzilla/show_bug.cgi?id=38403 ------- Additional Comments From [EMAIL PROTECTED] 2006-02-06 19:19 ------- We probably found the root of evil: a graceful restart does destroy but not reinitialize the resource list that keeps the pooled connections. this is due to a early return in ap_proxy_initialize_worker (proxy_util.c) when called again. Our patch is not nice, but worked for us. (restart instead of graceful did it also as workaround) --- proxy_util.c 2006-02-06 13:59:35.000000000 +0000 +++ proxy_util.c.orig 2006-02-06 17:48:39.000000000 +0000 @@ -1629,7 +1630,7 @@ int mpm_threads; #endif - if (worker->s->status & PROXY_WORKER_INITIALIZED && worker->cp->res) { + if (worker->s->status & PROXY_WORKER_INITIALIZED) { /* The worker is already initialized */ return APR_SUCCESS; } We noticed this when we tried to force the 99% cpu threads by stressing the webserver with ab ( -k -c 20 ). after a graceful restart the server was likely to coredump at proxy_util.c:1758 (*conn)->worker = worker; because conn was null. it seems that conn is deleted be another thread. conditional breakpoints above proxy_util.c:1745 (rv = APR_SUCCESS;) never spotted a conn = 0. before the graceful we run through this condition (no problems) but after gracefull res is null. if (worker->hmax && worker->cp->res) { rv = apr_reslist_acquire(worker->cp->res, (void **)conn); } this change in flow introduces the concurrency problems. is the else branch without the pool threadsafe or only intended for prefork ? Some facts that would speek for the graceful theory: a) 99% threads only appeared on servers in the farm that used graceful and not restart b) they only appeared after a graceful, never directly after startup c) after a graceful, there was no limit on the number of backend connections on the setup: We use Dual Xeons with Hyperthreading (so there might be higher concurrency) and we compiled with --enable-nonportable-atomics -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
