Re: recovering from "found xmin ... from before relfrozenxid ..."

From: Andres Freund <andres(at)anarazel(dot)de>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>, Mark Dilger <mark(dot)dilger(at)enterprisedb(dot)com>, Masahiko Sawada <masahiko(dot)sawada(at)2ndquadrant(dot)com>, "Andrey M(dot) Borodin" <x4mmm(at)yandex-team(dot)ru>, MBeena Emerson <mbeena(dot)emerson(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>
Subject: Re: recovering from "found xmin ... from before relfrozenxid ..."
Date: 2020-10-15 08:37:35
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On 2020-09-21 14:20:03 -0700, Andres Freund wrote:
> I can give it a try. I can see several paths of varying invasiveness,
> not sure yet what the best approach is. Let me think about if for a bit.

Ugh, sorry for taking so long to get around to this.

Attached is a *prototype* implemention of this concept, which clearly is
lacking some comment work (and is intentionally lacking some

I described my thoughts about how to limit the horizons for temp tables in

Besides comments this probably mainly needs a bit more tests around temp
table vacuuming. Should have at least an isolation test that verifies
that temp table rows can be a) vacuumed b) pruned away in the presence
of other sessions with xids.


Andres Freund

Attachment Content-Type Size
WIP-horizon-stuff.diff text/x-diff 7.7 KB

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