Re: [COMMITTERS] pgsql: Fix freezing of a dead HOT-updated tuple

From: Stephen Frost <sfrost(at)snowman(dot)net>
To: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
Cc: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, "Wood, Dan" <hexpert(at)amazon(dot)com>, "Wong, Yi Wen" <yiwong(at)amazon(dot)com>, Peter Geoghegan <pg(at)bowt(dot)ie>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com>
Subject: Re: [COMMITTERS] pgsql: Fix freezing of a dead HOT-updated tuple
Date: 2017-10-06 14:11:40
Message-ID: 20171006141140.GB4628@tamriel.snowman.net
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Robert,

* Alvaro Herrera (alvherre(at)alvh(dot)no-ip(dot)org) wrote:
> Michael Paquier wrote:
> > On Fri, Oct 6, 2017 at 10:18 PM, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> > > Wood, Dan wrote:
> > >> Yes, I’ve been testing 9.6. I’ll try Alvaro’s patch today.
> > >>
> > >> I would prefer to focus on either latest 9X or 11dev.
> > >
> > > I tested my patch on 9.4 and 9.5 today and it seems to close the problem
> > > (with the patch, I waited 10x as many iterations as it took for the
> > > problem to occur ~10 times without the patch), but I can reproduce a
> > > problem in 9.6 with my patch installed. There must be something new in
> > > 9.6 that is causing the problem to reappear.
> >
> > The freeze visibility map has been introduced in 9.6... There could be
> > interactions on this side.
>
> Ah, thanks for the tip. I hope the authors of that can do the gruntwork
> of researching this problem there, then. I'll go commit what I have
> now.

I don't doubt you're watching this thread too, but just to be 110% sure
that we don't end up with the November releases still having this issue,
I'm adding you to the CC on this thread as the one who did the freeze
visibility map work. Depending on hope here is a bit too squishy for me
when we're talking about corruption issues.

Thanks!

Stephen

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