Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY

From: Andres Freund <andres(at)anarazel(dot)de>
To: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
Cc: Peter Geoghegan <pg(at)bowt(dot)ie>, Michael Paquier <michael(at)paquier(dot)xyz>, Andrey Borodin <x4mmm(at)yandex-team(dot)ru>, Петър Славов <pet(dot)slavov(at)gmail(dot)com>, PostgreSQL mailing lists <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY
Date: 2022-05-24 18:37:05
Message-ID: 20220524183705.cmgbqq32z63qynhe@alap3.anarazel.de
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-bugs

Hi,

On 2022-05-24 11:15:42 -0700, Andres Freund wrote:
> I suspect the problem might be related to pruning done during the validation
> scan. Once PROC_IN_SAFE_IC is set, the backend itself will not preserve tids
> its own snapshot might need. Which will wreak havoc during the validation
> scan.

Looking at it more, I don't see when PROC_IN_SAFE_IC is safe as defined,
tbh. Afaict it basically completely breaks snapshots - which we rely on to
work for both the initial build scan and then for the validation scan.

It seems safe to make CIC to ignore other CICs when deciding whether to wait
for those transactions. But it seems utterly unsafe to ignore CICs when when
determining horizons.

Greetings,

Andres Freund

In response to

Browse pgsql-bugs by date

  From Date Subject
Next Message Andrey Borodin 2022-05-24 18:38:07 Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY
Previous Message Andres Freund 2022-05-24 18:15:42 Re: BUG #17485: Records missing from Primary Key index when doing REINDEX INDEX CONCURRENTLY