From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
        Andres Freund <andres@anarazel.de>,
        Thomas Munro <thomas.munro@enterprisedb.com>,
        Dilip Kumar <dilipbalaut@gmail.com>,
        Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: shared memory based stat collector (was: Sharing record typmods
 between backends)
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 14 Aug 2017 12:21:30 -0400"
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Date: Mon, 14 Aug 2017 12:28:39 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Aug 14, 2017 at 12:16 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Just FYI, the only values being reported by buildfarm animals are
>> "posix", "sysv", and "windows".  So while mmap may be a thing,
>> it's an untested thing.

> I'm pretty sure I dev-tested it before committing anything, but,
> certainly, having ongoing BF coverage woudn't be a bad thing.

Looking closer, the reason those are the only reported values is
that those are the only possible results from initdb's
choose_dsm_implementation().  So the real question here is whether
"mmap" should be considered to dominate "sysv" if it's available.
If so, why isn't choose_dsm_implementation() trying it; and if not,
why are we carrying it?

			regards, tom lane


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