Re: Unsafe GUCs and ALTER SYSTEM WAS: Re: ALTER SYSTEM SET

* Josh Berkus (josh@agliodbs.com) wrote:
> Nope.  ALTER SYSTEM, from my POV, is mainly for folks who *don't* use
> Puppet/Chef/whatever.  

Ok, that's fine, but let's try to avoid making life difficult for those
who *do* use puppet/chef/whatever.  This capability runs a very high
risk of that by allowing a DBA who *isn't* a sysadmin to go modifying
things that depend on external-to-PG factors.

> Here's where I see ALTER SYSTEM being useful:
> 
> * invididually managed servers with out centralized management (i.e. one
> DBA, one server).
> * developer machines (i.e. laptops and vms)

The above strikes me as being already dealt with through pgAdmin and the
'admin pack', if the user wants a GUI to use for modifying these
parameters (which seems like what they'd primairly get out of ALTER
SYSTEM SET- pgAdmin, or whatever $gui wouldn't have to depend on the
admin pack).

> * automated testing of tweaking performance parameters

This sounds like you'd need tooling around it to make it work anyway,
which could probably handle modifying a text file, but even if not,
these paremeters may be on the 'safe' list.

> * setting logging parameters temporarily on systems under centralized
> management

This is the kind of argument that I could get behind- in an environment
where logs are shipped to a server where DBAs can view and analyze them,
being able to modify the logging parameters on the fly could be useful
(eg: log_min_duration_statement or similar).  As I tried to get at
up-thread, my concern is primairly around those parameters which can't
be set sensibly through ALTER SYSTEM because they depend on other
activities happening.

	Thanks,

		Stephen