Re: Disabling ALTER SYSTEM SET WAS: Re: ALTER SYSTEM SET command to change postgresql.conf parameters

On Mon, Aug 5, 2013 at 11:16:24AM -0700, Josh Berkus wrote:
> I don't see this as a solution at all. "Mr. Sysadmin, we've given the
> DBAs a new tool which allows them to override your version-controlled
> database parameter settings. You can turn it off, though, by using this
> incredibly complicated, brand-new Event Trigger tool which requires
> writing lots of SQL code to make work."
>
> Per Stephen Frost's arguments, some system owners are going to be
> opposed to allowing ALTER SYSTEM SET at all because it can mess systems
> up and cause downtime. Yes, that's already true of ALTER ROLE and ALTER
> DATABASE, but ALTER SYSTEM SET expands this the ability of the DBA to
> change setting substantially. That's obviously its benefit, but it's
> also clearly a misfeature for some system owners. Also, to be blunt,
> most DBAs/DEVs don't *know* about ALTER ROLE/DATABASE.
>
> I don't think this is a small thing. I really think we'll get a LOT of
> blowback from sysadmins -- and maybe even refusals to upgrade -- if we
----------------------------------

Really? Is that a reasonable statement?

> add ALTER SYSTEM SET in 9.4.0 with no easy way to disable it. Having an
> easy way to disable ALTER SYSTEM SET is *also* a good way to get out of
> the whole situation of "I set shared_buffers to 100GB using ALTER SYSTEM
> SET and now PostgreSQL won't start" problem.
>
> As I've said before, I think the disable switch can be a follow-up patch
> to the main ALTER SYSTEM SET patch.

You are mixing the behaviors of disabling the ALTER SYSTEM SET command
with recognizing ALTER SYSTEM SET settings already made --- the later
would be to fix a problem with the server not starting. However,
frankly, these are flat files, so I don't see a problem with having the
administrator modify the flat file.

Would disabling the ALTER SYSTEM SET command also disable recognizing
any ALTER SYSTEM SET commands already performed? Maybe that was already
understood, but I missed that point.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +