From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: [patch] demote
Date: Thu, 18 Jun 2020 13:24:38 -0400
Message-ID: <1554844.1592501078@sss.pgh.pa.us> (raw)
In-Reply-To: <CA+TgmoaPsDysv4S1FYdgyJ3vubjByjBm7fSqiB=xNyj5ZtORTA@mail.gmail.com>
References: <20200617174451.222078b4@firost>
<CA+TgmoaZ28PXLC1j3SBm=NCNOnS0ieThZJ7vKVp4yfdSvBKnZA@mail.gmail.com>
<2eb2fd8f-c9a0-ac31-66dc-2c56dd048540@oss.nttdata.com>
<CA+TgmoagXhAERpYG=Kc1keEtg_2xj8ySN+A4Yv1EMYTm3w5Bdw@mail.gmail.com>
<e0c986b5-921f-4dff-97c0-eb298aa9196c@oss.nttdata.com>
<CA+TgmoaPsDysv4S1FYdgyJ3vubjByjBm7fSqiB=xNyj5ZtORTA@mail.gmail.com>
Robert Haas <robertmhaas@gmail.com> writes:
> ... To go back to recovery rather than just to a read-only
> state, I think you'd need to grapple with some additional issues that
> patch doesn't touch, like some of the snapshot-taking stuff, but I
> think you still need to solve all of the problems that it does deal
> with, unless you're OK with killing every session.
It seems like this is the core decision that needs to be taken. If
we're willing to have these state transitions include a server restart,
then many things get simpler. If we're not, it's gonna cost us in
code complexity and hence bugs. Maybe the usability gain is worth it,
or maybe not.
I think it would probably be worth the trouble to pursue both designs in
parallel for awhile, so we can get a better handle on exactly how much
complexity we're buying into with the more ambitious definition.
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, robertmhaas@gmail.com, masao.fujii@oss.nttdata.com, jgdr@dalibo.com
Subject: Re: [patch] demote
In-Reply-To: <1554844.1592501078@sss.pgh.pa.us>
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