Re: backup manifests

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: David Steele <david(at)pgmasters(dot)net>, Noah Misch <noah(at)leadboat(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Suraj Kharage <suraj(dot)kharage(at)enterprisedb(dot)com>, tushar <tushar(dot)ahuja(at)enterprisedb(dot)com>, Rajkumar Raghuwanshi <rajkumar(dot)raghuwanshi(at)enterprisedb(dot)com>, Rushabh Lathia <rushabh(dot)lathia(at)gmail(dot)com>, Tels <nospam-pg-abuse(at)bloodgate(dot)com>, Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Jeevan Chalke <jeevan(dot)chalke(at)enterprisedb(dot)com>, vignesh C <vignesh21(at)gmail(dot)com>
Subject: Re: backup manifests
Date: 2020-03-30 18:35:40
Message-ID: CA+TgmoZj9tuVRDw=wj1p2-TTSJ+qUEWvh6updZJsw-5gxWUW1w@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Sun, Mar 29, 2020 at 10:08 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> See the attached minimal prototype for what I am thinking of.
>
> This would not correctly handle the case where the timeline changes
> while taking a base backup. But I'm not sure that'd be all that serious
> a limitation for now?
>
> I'd personally not want to use a base backup that included a timeline
> switch...

Interesting concept. I've never (or almost never) used the -s and -e
options to pg_waldump, so I didn't think about using those. I think
having a --just-parse option to pg_waldump is a good idea, though
maybe not with that name e.g. we could call it --quiet.

It is less obvious to me what to do about all that as it pertains to
the current patch. If we want pg_validatebackup to run pg_waldump in
that mode or print out a hint about how to run pg_waldump in that
mode, it would need to obtain the relevant LSNs. I guess that would
require reading the backup_label file. It's not clear to me what we
would do if the backup crosses a timeline switch, assuming that's even
a case pg_basebackup allows. If we don't want to do anything in
pg_validatebackup automatically but just want to document this as a a
possible technique, we could finesse that problem with some
weasel-wording.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Andres Freund 2020-03-30 18:59:44 Re: backup manifests
Previous Message Justin Pryzby 2020-03-30 18:34:39 Re: Allow CLUSTER, VACUUM FULL and REINDEX to change tablespace on the fly