Re: BUG #4919: CREATE USER command slows down system performance

On Wed, 15 Jul 2009 16:02:09 +0200, Alvaro Herrera
<alvherre(at)commandprompt(dot)com> wrote:
> My bet is on the pg_auth flat file. I doubt we have ever tested the
> behavior of that code with 1 billion users ...
I've noticed this behaviour some time ago, on a cluster with 50k+ roles
(not sure about the number now). Restoring the backup took a lot of time,
especially when the users file grew significantly and each additional user
caused PG to rewrite the whole file.
I never bothered to report this, as it's not like the users are
(re)created every day, it was just a one-time run (== some extra time for
another coffee during restore ;-)).
I was always wondering, though, why PostgreSQL uses this approach and not
its catalogs.

Regards,
--
ru