From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@enterprisedb.com>
cc: Robert Haas <robertmhaas@gmail.com>, Jakub Glapa <jakub.glapa@gmail.com>,
        Justin Pryzby <pryzby@telsasoft.com>,
        Fabio Isabettini <fisabettini@voipfuture.com>,
        Arne Roland <A.Roland@index.de>, Sand Stone <sand.m.stone@gmail.com>,
        Rick Otten <rottenwindfish@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: dsa_allocate() faliure
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Comments: In-reply-to Thomas Munro <thomas.munro@enterprisedb.com>
	message dated "Mon, 11 Feb 2019 09:45:07 +1100"
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Date: Sun, 10 Feb 2019 18:33:53 -0500
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Thomas Munro <thomas.munro@enterprisedb.com> writes:
> This brings us to a difficult choice: we're about to cut a new
> release, and this could in theory be included.  Even though the fix is
> quite convincing, it doesn't seem wise to change such complicated code
> at the last minute, and I know from an off-list chat that that is also
> Robert's view.

Yeah ... at this point we're just too close to the release deadline,
I'm afraid, even though the fix *looks* pretty safe.  Not worth the risk
given that this seems to be a low-probability bug.

I observe from

https://coverage.postgresql.org/src/backend/utils/mmgr/freepage.c.gcov.html

that the edge cases in this function aren't too well exercised by
our regression tests, meaning that the buildfarm might not prove
much either way about the correctness of this patch.  That is one
factor pushing me to think we shouldn't risk it.  But, taking a
longer view, is that something that's practical to improve?

> So I'll wait until after the release, and we'll have
> to live with the bug for another 3 months.

Check.  Please hold off committing until you see the release tags
appear, probably late Tuesday my time / Wednesday noonish yours.

			regards, tom lane