Re: ALTER SYSTEM SET command to change postgresql.conf parameters (RE: Proposal for Allow postgresql.conf values to be changed via SQL [review])

Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> writes:
> The main contention point I see is where conf.d lives;
> the two options are in $PGDATA or together with postgresql.conf. Tom
> and Robert, above, say it should be in $PGDATA; but this goes against
> Debian packaging and the Linux FHS (or whatever that thing is called).

Ordinarily, if postgresql.conf is not in $PGDATA, it will be somewhere
that the postmaster does not (and should not) have write permissions
for. I have no objection to inventiny a conf.d subdirectory, I just say
that it must be under $PGDATA. The argument that this is against FHS
is utter nonsense, because anything we write there is not static
configuration, it's just data.

Come to think of it, maybe part of the reason we're having such a hard
time getting to consensus is that people are conflating the "snippet"
part with the "writable" part? I mean, if you are thinking you want
system-management tools to be able to drop in configuration fragments as
separate files, there's a case to be made for a conf.d subdirectory that
lives somewhere that the postmaster can't necessarily write. We just
mustn't confuse that with support for ALTER SYSTEM SET. I strongly
believe that ALTER SYSTEM SET must not be designed to write anywhere
outside $PGDATA.

regards, tom lane