Re: Re: Proposal for Allow postgresql.conf values to be changed via SQL [review]

On 2013-01-24 11:22:52 -0500, Tom Lane wrote:
> Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> > On 2013-01-24 16:45:42 +0530, Amit Kapila wrote:
> >>> * Writing the temporary file to .$pid seems like a bad idea, better use
> >>> one file for that, SET PERSISTENT is protected by an exclusive lock
> >>> anyway.
>
> >> I think we can use one temporary file, infact that was one of the ways I
> >> have asked in one of the previous mails.
> >> However Tom and Zoltan felt this is better way to do it.
>
> > The have? I didn't read it like that. The file can only ever written by
> > a running postmaster and we already have code that ensures that. There's
> > absolutely no need for the tempfile to have a nondeterministic
> > name. That makes cleanup way easier as well.
>
> Say again? Surely the temp file is being written by whichever backend
> is executing SET PERSISTENT, and there could be more than one.

Sure, but the patch acquires SetPersistentLock exlusively beforehand
which seems fine to me.

Any opinion whether its acceptable to allow SET PERSISTENT in functions?
It seems absurd to me to allow it, but Amit seems to be of another
opinion.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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