Upstream least_conn behavior irregularity

[John Watson]

Going to pushing out the change to 1 worker later today.

It's just become more of an exercise in understanding why it was behaving
that way.

Even under "high" load (in this case ~50 active_connections), the 3 socks
don't seem to be getting equal number of requests.


On Thu, Mar 21, 2013 at 12:29 PM, Ruslan Ermilov <ru at nginx.com> wrote:

> On Thu, Mar 21, 2013 at 12:03:59PM -0700, John Watson wrote:
> >    Well doesn't make sense when theres >4 concurrent requests
> >    At any given time there's around 12 active_connections, but sock-3 is
> >    still never being used
>
> Can you see a difference with only one worker process?
>
> Currently, different workers have distinct counters of active connections.
> It should be unnoticed under a high load.
>
> >    On Thu, Mar 21, 2013 at 9:34 AM, John Watson <[1]john at disqus.com>
> wrote:
> >
> >      Ohhhh... that makes complete sense now.
> >      Had 4 workers.
> >      Thanks!
> >
> >      On Thu, Mar 21, 2013 at 4:47 AM, Ruslan Ermilov <[2]ru at nginx.com>
> wrote:
> >
> >        On Thu, Mar 21, 2013 at 01:45:14AM -0700, John Watson wrote:
> >        >    Was investigating some issues today when we noticed that
> >        least_conn wasn't
> >        >    behaving as expected.
> >        >    upstream backend {
> >        >      least_conn;
> >        >      server unix:/tmp/sock-1.sock;
> >        >      server unix:/tmp/sock-2.sock;
> >        >      server unix:/tmp/sock-3.sock;
> >        >    }
> >        >    The expected behavior for 4 simultaneous requests it should
> >        distribute
> >        >    them:
> >        >    sock-1: 2
> >        >    sock-2: 1
> >        >    sock-3: 1
> >        >    However, what we're seeing is:
> >        >    sock-1: 3
> >        >    sock-2: 1
> >        >    sock-3: 0
> >        >    Which coincidentally lines up with the number of requests a
> >        socket can
> >        >    service simultaneously.
> >        >    This is using 1.2.7
> >
> >        And the number of configured worker processes is?
>
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