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* Access to old versions of a row
@ 2023-10-08 15:25 Matthias Apitz <guru@unixarea.de>
0 siblings, 2 replies; 4+ messages in thread
From: Matthias Apitz @ 2023-10-08 15:25 UTC (permalink / raw)
To: pgsql-bugs@lists.postgresql.org
As long as the vacuum is not run, older versions of a given row should
be "somewhere". Is there a way to read them?
Thanks
matthias
--
Matthias Apitz, ✉ guru@unixarea.de, http://www.unixarea.de/ +49-176-38902045
Public GnuPG key: http://www.unixarea.de/key.pub
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Access to old versions of a row
@ 2023-10-08 19:35 Vik Fearing <vik@postgresfriends.org>
parent: Matthias Apitz <guru@unixarea.de>
1 sibling, 1 reply; 4+ messages in thread
From: Vik Fearing @ 2023-10-08 19:35 UTC (permalink / raw)
To: Matthias Apitz <guru@unixarea.de>; pgsql-bugs@lists.postgresql.org
On 10/8/23 16:25, Matthias Apitz wrote:
>
> As long as the vacuum is not run, older versions of a given row should
> be "somewhere". Is there a way to read them?
No.
But there is a pg_dirtyread extension that can do it.
https://github.com/df7cb/pg_dirtyread
--
Vik Fearing
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Access to old versions of a row
@ 2023-10-09 09:56 Alvaro Herrera <alvherre@alvh.no-ip.org>
parent: Matthias Apitz <guru@unixarea.de>
1 sibling, 0 replies; 4+ messages in thread
From: Alvaro Herrera @ 2023-10-09 09:56 UTC (permalink / raw)
To: Matthias Apitz <guru@unixarea.de>; +Cc: pgsql-bugs@lists.postgresql.org
On 2023-Oct-08, Matthias Apitz wrote:
>
> As long as the vacuum is not run, older versions of a given row should
> be "somewhere". Is there a way to read them?
Maybe with
https://github.com/df7cb/pg_dirtyread
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Access to old versions of a row
@ 2023-10-09 23:55 Andres Freund <andres@anarazel.de>
parent: Vik Fearing <vik@postgresfriends.org>
0 siblings, 0 replies; 4+ messages in thread
From: Andres Freund @ 2023-10-09 23:55 UTC (permalink / raw)
To: Vik Fearing <vik@postgresfriends.org>; +Cc: Matthias Apitz <guru@unixarea.de>; pgsql-bugs@lists.postgresql.org
Hi,
On 2023-10-08 21:35:15 +0200, Vik Fearing wrote:
> On 10/8/23 16:25, Matthias Apitz wrote:
> >
> > As long as the vacuum is not run, older versions of a given row should
> > be "somewhere". Is there a way to read them?
(auto-)vacuum not having processed a table doesn't guarantee that row versions
have not been removed. Most importantly, on-access pruning can lead to row
versions being removed. There's also the issue that the toast table could
have been autovacuumed independently from the "main" table.
> No.
>
> But there is a pg_dirtyread extension that can do it.
> https://github.com/df7cb/pg_dirtyread
Note that there's a lot of potential for bogus data and even crashes when
using something like this. Which is fine when used for data recovery purposes,
but not for many other potential usecases.
Greetings,
Andres Freund
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2023-10-09 23:55 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2023-10-08 15:25 Access to old versions of a row Matthias Apitz <guru@unixarea.de>
2023-10-08 19:35 ` Vik Fearing <vik@postgresfriends.org>
2023-10-09 23:55 ` Andres Freund <andres@anarazel.de>
2023-10-09 09:56 ` Alvaro Herrera <alvherre@alvh.no-ip.org>
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