Re: Database logins taking longer and longer, showing up as "authentication" in ps(1)

On Tue, Aug 18, 2020, 8:04 PM Stephen Frost <sfrost(at)snowman(dot)net> wrote:

> Greetings,
>
> * Adam Sjøgren (asjo(at)koldfront(dot)dk) wrote:
> > We have a PostgreSQL 11.3¹ running on an Ubuntu 16.04 server, which
> > sometimes exhibits a behaviour I can't quite understand: simply logging
> > into the database starts to take minutes to complete.
> >
> > We have 60 processes (workers) running on different machines accessing
> > the database, that all grab jobs from a queue and update rows in a table
> > after doing some calculations (which vary in time from <1s to perhaps a
> > minute, many of them fast).
> >
> > Sometimes new database logins slow down, from usually taking <0.05s to
> > taking minutes. This is for psql as a normal user using Kerberos, for
> > psql as the postgres superuser, for the web-application logging into the
> > database, for everything.
>
> When in doubt, blame DNS.
>
> Alternatively, in your case, the issue might be the KDC taking forever
> to issue a ticket for the service.
>
> Note that, in both cases, this is a client-side issue.

If it is a client side issue, how do you explain the behaviour that OP is
not facing problem when there are only few clients?

Regards,
Seenu.

> Once the ticket
> has been acquired for the PG service, the actual authentication on the
> server side should be very fast and not depend on things external
> (though you might check if you have log_hostnames on..).
>
> Thanks,
>
> Stephen
>