The typical way to solve this today is to know the keepalive timeout of the backend and set ttl for this worker to a value a few seconds below.
Regards Rüdiger > -----Ursprüngliche Nachricht----- > Von: Jim Jagielski > Gesendet: Freitag, 2. August 2013 14:29 > An: dev@httpd.apache.org > Betreff: Re: mod_proxy, oooled backend connections and the keep-alive > race condition > > +1 for the theory, but I'm not sure if it's feasible or not. > > On Aug 2, 2013, at 5:28 AM, Thomas Eckert <thomas.r.w.eck...@gmail.com> > wrote: > > > So I've been seeing lots of "proxy: error reading status line from > remote server" by mod_proxy lately. Usually this is caused by the race > condition between checking the connection state and the backend closing > the connection due to the keep-alive timeout. As Covener pointed out to > me in IRC, using mod_proxy_http's env variable "proxy-initial-not- > pooled" does offer a solution to the problem albeit at the cost of > performance. > > > > The call to ap_proxy_http_process_response() in mod_proxy_http.c > eventually boils down to ap_rgetline_core() which calls ap_get_brigade() > on r->input_filters. This looks to me like a simple input filter might > do the trick if it only checked for a possibility to read on the socket > and reopens the connection upon failure type "reset by peer". I took a > short look at core_create_proxy_req() in server/core.c to see how > connections are set up and I wonder if it's possible to recreate/reuse > that logic in an input filter. If so, this input filter would offer a > nice alternative if hard coding this behavior into mod_proxy/core is > frowned upon. Simply make the filter dependant on an env variable, just > like proxy-initial-not-pooled. > >
