Re: Strange decreasing value of pg_last_wal_receive_lsn()

From: godjan • <g0dj4n(at)gmail(dot)com>
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: Sergei Kornilov <sk(at)zsrv(dot)org>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Strange decreasing value of pg_last_wal_receive_lsn()
Date: 2020-05-10 13:58:50
Message-ID: F60D5616-FE83-4FC1-987E-DD0554B41E04@gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

synchronous_standby_names=ANY 1(host1, host2)
synchronous_commit=on

So to understand which standby wrote last data to disk I should know receive_lsn or write_lsn.

Sent from my iPhone

> On 9 May 2020, at 13:48, Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> On Fri, May 08, 2020 at 03:02:26PM +0500, godjan • wrote:
>> Can you recommend what to use to determine which quorum standby
>> should be promoted in such case?
>> We planned to use pg_last_wal_receive_lsn() to determine which has
>> fresh data but if it returns the beginning of the segment on both
>> replicas we can’t determine which standby confirmed that write
>> transaction to disk.
>
> If you want to preserve transaction-level consistency across those
> notes, what is your configuration for synchronous_standby_names and
> synchronous_commit on the primary? Cannot you rely on that?
> --
> Michael

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Andrew Dunstan 2020-05-10 15:07:58 Re: Cast json array to postgres array and preserve order of elements
Previous Message Andrew Dunstan 2020-05-10 13:29:05 Re: valgrind error