From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stephen Frost <sfrost@snowman.net>
cc: Amit Kapila <amit.kapila16@gmail.com>,
        Ian Barwick <ian.barwick@2ndquadrant.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: [PATCH] Stop ALTER SYSTEM from making bad assumptions
In-reply-to: <20190616171610.GO2480@tamriel.snowman.net>
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 <CAA4eK1JW9UfLOtMEJq5b_YcogbWdxzAGUzNi72F2Xx4r1_h6QA@mail.gmail.com>
 <20190616171610.GO2480@tamriel.snowman.net>
Comments: In-reply-to Stephen Frost <sfrost@snowman.net>
	message dated "Sun, 16 Jun 2019 13:16:11 -0400"
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Date: Sun, 16 Jun 2019 13:21:39 -0400
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Stephen Frost <sfrost@snowman.net> writes:
> Unless there's actually a use-case for duplicate entries in
> postgresql.auto.conf,

There isn't --- guc.c will just discard the earlier duplicates.

> what we should do is clean them up (and possibly
> throw a WARNING or similar at the user saying "something modified your
> postgresql.auto.conf in an unexpected way").  I'd suggest we do that on
> every ALTER SYSTEM call.

+1 for having ALTER SYSTEM clean out duplicates.  Not sure whether
a WARNING would seem too in-your-face.

			regards, tom lane