From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Andres Freund <andres@anarazel.de>,
        Thomas Munro <thomas.munro@enterprisedb.com>,
        Alvaro Herrera <alvherre@2ndquadrant.com>,
        Amit Kapila <amit.kapila16@gmail.com>,
        Stephen Frost <sfrost@snowman.net>,
        Michael Paquier <michael.paquier@gmail.com>,
        Masahiko Sawada <sawada.mshk@gmail.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: Reviewing freeze map code
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Tue, 21 Jun 2016 10:38:10 -0400"
Date: Tue, 21 Jun 2016 10:47:30 -0400
Message-ID: <10075.1466520450@sss.pgh.pa.us>
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Sender: pgsql-hackers-owner@postgresql.org

Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Jun 20, 2016 at 5:59 PM, Andres Freund <andres@anarazel.de> wrote:
>> Consider what happens if we, after restarting at l2, notice that we
>> can't actually insert, but return in the !HeapTupleMayBeUpdated
>> branch.

> OK, I see what you mean.  Still, that doesn't seem like such a
> terrible cost.  If you try to update a tuple and if it looks like you
> can update it but then after TOASTing you find that the status of the
> tuple has changed such that you can't update it after all, then you
> might need to go set xmax = MyTxid() on all of the TOAST tuples you
> created (whose CTIDs we could save someplace, so that it's just a
> matter of finding them by CTID to kill them).

... and if you get an error or crash partway through that, what happens?

			regards, tom lane


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