From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: David Fetter <david@fetter.org>,
 Ian Barwick <ian.barwick@2ndquadrant.com>,
        Tomas Vondra <tomas.vondra@2ndquadrant.com>,
        Andres Freund <andres@anarazel.de>,
 Stephen Frost <sfrost@snowman.net>,
        Amit Kapila <amit.kapila16@gmail.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: [PATCH] Stop ALTER SYSTEM from making bad assumptions
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 05 Aug 2019 12:31:00 -0400"
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Date: Mon, 05 Aug 2019 12:43:24 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Aug 5, 2019 at 12:25 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Perhaps as a future improvement, but it's not happening for v12,
>> at least not unless you accept "use ALTER SYSTEM in a standalone
>> backend" as a usable answer.

> I'm not sure that would even work for the cases at issue ... because
> we're talking about setting up recovery parameters, and wouldn't the
> server run recovery before it got around to do anything with ALTER
> SYSTEM?

Yeah, good point.  There are a lot of other cases where you really
don't want system startup to happen, too.  On the other hand,
people have also opined that they want full error checking on
the inserted values, and that seems out of reach with less than
a full running system (mumble extensions mumble).

In the end, I think I don't buy Stephen's argument that there should
be a one-size-fits-all answer.  It seems entirely reasonable that
we'll have more than one way to do it, because the constraints are
different depending on what use-case you think about.

			regards, tom lane