From: Michael Paquier <michael@paquier.xyz>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: exclusion@gmail.com
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #16577: Segfault on altering a table located in a dropped tablespace
Date: Fri, 30 Oct 2020 13:13:06 +0900
Message-ID: <20201030041306.GF1693@paquier.xyz> (raw)
In-Reply-To: <1251838.1603893564@sss.pgh.pa.us>
References: <20201028134045.GA6709@alvherre.pgsql>
<1251838.1603893564@sss.pgh.pa.us>
On Wed, Oct 28, 2020 at 09:59:24AM -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
>> I haven't started on this one yet, but I intend to do so shortly.
Cool. Glad to hear that.
>> Strictly speaking, we can still introduce a new category of pg_shdepend
>> entries in back branches; it won't break anything that works today.
>
> Yeah, as long as the patched version won't actively fail when those
> pg_shdepend entries are missing, I don't think a backpatch is too
> hazardous. It might be worth checking that the extra entries don't
> create huge problems if one does downgrade after some of them exist
> --- but my feeling for how that mechanism works is that it'd Just
> Work, and indeed provide the missing DROP protection even without
> explicit action by the backend.
Good point. Even with that, we have never considered the case of a
downgrade as something actually supported, right? We had in the past
for example bug fixes that involve slight tweaks in the WAL records
that are upward-compatible, changing the way these get interpreted
when replayed, but it could be possible to finish with logical
corruptions or replay failures if a downgraded version replays a
slightly-modified record generated by a newer version, no?
--
Michael
Attachments:
signature.asc (application/pgp-signature, 832B) download
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-bugs@postgresql.org
Cc: michael@paquier.xyz, tgl@sss.pgh.pa.us, alvherre@alvh.no-ip.org, tomas.vondra@2ndquadrant.com, exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #16577: Segfault on altering a table located in a dropped tablespace
In-Reply-To: <20201030041306.GF1693@paquier.xyz>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox