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help / color / mirror / Atom feedFrom: px shi <[email protected]>
To: Adrian Klaver <[email protected]>
Cc: [email protected]
Subject: Re: Questions about the continuity of WAL archiving
Date: Tue, 12 Aug 2025 16:24:44 +0800
Message-ID: <CAAccyYJ-07SzCRAEkGJ2Qa8EAPCHQM4qcpB=OvD8P0zDbCJ0KQ@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CAAccyYKpNsQMD+S-A7a8YtDevFN0uRXkzg4tYWWBOFsv_jASNg@mail.gmail.com>
<[email protected]>
<CAAccyYLYZmwQiNMoJcQgo5t+E24rDtu1ZeBUrER7ZTKNAcZesw@mail.gmail.com>
<[email protected]>
> 1) What is the current archiving setup on the primary and why is lagging?
The archive command uses pgBackRest to archive to S3. Because it is
uploaded to S3, the archiving speed is slow, which has caused lagging.
2) Have you looked at archiving off the standby node while it is in standby
> per:
Yes, archiving on the standby node is disabled. Is it recommended to share
the WAL archive between the primary and standby nodes to avoid
interruptions in archiving?
Adrian Klaver <[email protected]> 于2025年8月8日周五 23:23写道：
> On 8/7/25 22:50, px shi wrote:
> > Thank you for your reply.
> > The archived files can be used for PITR (Point-In-Time Recovery),
> > allowing recovery to any point between WAL 80 and 100 on timeline 1.
> > Additionally, if there's a backup taken during timeline 1 and a
> > switchover to a new primary has occurred without taking a new full
> > backup yet, these WAL logs can still be used to recover to any point on
> > timeline 2.
>
> Alright I see.
>
> Two things:
>
> 1) What is the current archiving setup on the primary and why is lagging?
>
> 2) Have you looked at archiving off the standby node while it is in
> standby per:
>
>
> https://www.postgresql.org/docs/current/warm-standby.html#CONTINUOUS-ARCHIVING-IN-STANDBY
>
> >
> > Regards,
> > Pixian Shi
> >
> > Adrian Klaver <[email protected]
> > <mailto:[email protected]>> 于2025年8月8日周五 12:25写道：
> >
> > On 8/7/25 20:20, px shi wrote:
> > > Hi,
> > > There is a scenario: the current timeline of the PostgreSQL
> > primary node
> > > is 1, and the latest WAL file is 100. The standby node has also
> > received
> > > up to WAL file 100. However, the latest WAL file archived is only
> > file
> > > 80. If the primary node crashes at this point and the standby is
> > > promoted to the new primary, archiving will resume from file 100
> on
> > > timeline 2. As a result, WAL files from 81 to 100 on timeline 1
> > will be
> > > missing from the archive.
> >
> > What are you planning to do with the archived files?
> >
> > Also is not the case that once the primary crashes you are in a split
> > brain case and can't really trust it's timeline anymore?
> >
> >
> > > Is there a good solution to prevent this situation?
> > >
> > > Regards,
> > > Pixian Shi
> >
> >
> > --
> > Adrian Klaver
> > [email protected] <mailto:[email protected]>
> >
>
>
> --
> Adrian Klaver
> [email protected]
>
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Subject: Re: Questions about the continuity of WAL archiving
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