Subject: Re: 503 Backend fetch failed errors
To: Magnus Hagander <magnus@hagander.net>
Cc: remi_zara@mac.com, buildfarm-members@lists.postgresql.org,
 sysadmins <sysadmins@lists.postgresql.org>
References: <428FDD47-5325-4904-9306-F2D6F9D8232D@mac.com>
 <c0daa190-7920-180b-71ba-7b0a6635559b@kaltenbrunner.cc>
 <CABUevExk3ytB9JPuamcpAy-d75j24JwQ657+Y-Jgt3MYuaK-Qg@mail.gmail.com>
From: Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Message-ID: <8832f403-b6ea-e581-b631-a6253731fde6@kaltenbrunner.cc>
Date: Thu, 8 Nov 2018 09:30:56 +0100
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On 11/8/18 9:19 AM, Magnus Hagander wrote:
> 
> 
> On Thu, Nov 8, 2018 at 9:01 AM Stefan Kaltenbrunner 
> <stefan@kaltenbrunner.cc> wrote:
> 
>     On 11/7/18 6:40 PM, Rémi Zara wrote:
>      > Hi,
> 
>     Hi Rémi!
> 
>      >
>      > I’m getting a lot of these errors with coypu (several per day),
>     but not systematically.
>      > Is this a problem on my end, or is this on the sever end ?
>      >
>      > Query for: stage=OK&animal=coypu&ts=1541573277
>      > Target:
>     https://buildfarm.postgresql.org/cgi-bin/pgstatus.pl/53b137e7c765b781699bbe73e3aec7751a8c4ab7
>      > Status Line: 503 Backend fetch failed
>      > Web txn failed with status: 1
>      > Query for: stage=OK&animal=coypu&ts=1541575423
>      > Target:
>     https://buildfarm.postgresql.org/cgi-bin/pgstatus.pl/5e8e0913dc9f9a580a4125264d74fff95f26c926
>      > Status Line: 503 Backend fetch failed
>      > Web txn failed with status: 1
> 
>     given the error this is something that is created by the varnish
>     instance that is in front of the buildfarm. On a quick look I could
>     immediately figure out what the problem is - but it looks like you (or
>     somebody else) tried at least to click one of the links above using
>     hist
>     desktop browser and got an error about a missing branch specification ;)
> 
> 
> 
> AFAICT:
> 
> A quick look in the logs indicates that the buildfarm is responding:
> -   RespHeader     Status: 492 bad branch parameter
> 
> However, 492 is not a valid http status code, so Varnish can't handle it 
> and thus returns 503 failure to the client.

I think that is not the actual error that Rémi is experiencing- the 492 
case (which is indeed an invalid http error code) only happens when one 
actually klicks the link in the mail above(which I guess some did and 
you found in the logs) because the actual BF client will add a parameter 
to the "Target" URL.

The actual "errors" dont seem to show up in the lighttpd logs afaiks.