tracking 502s

Given a log line like this:www haproxy[15344]: xx.x.xx.xx:33521 [22/Feb/2009:20:27:13.580] webservers mongrels/webapp02-133 0/0/0/-1/5301 502 204 - - SH-- 250/246/9/0/0 0/0 "GET /info/heartbeat?1235334327821716000 HTTP/1.1" Where I don't see the matching string in the mongrel logs, how might I go about finding the cause? Received on 2009/02/22 22:44