On Wed, May 23, 2018 at 5:33 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Magnus Hagander <magnus@hagander.net> writes: > On Wed, May 23, 2018 at 5:05 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> I've been getting a lot of Varnish "Error 503 Backend fetch failed" >> from https://git.postgresql.org/gitweb/ sub-pages yesterday and >> today. Is anybody looking into that?
> Have you seen any pattern to when it's happening?
Not particularly. When the problem occurs, it seems to persist for awhile (several minutes at least), but beyond that I can't think of anything.
I think this may simply be the result of overload. We currently limit the system to two concurrent cache misses to gitweb, and while they are still running everything else gets put in a backlog. We time them out fairly aggressively, but given the performance of gitweb.
I'm going to give that VM some extra resources and restart it -- let's see if that helps a bit.