Re: Writing WAL files

On Sun, 4 Oct 2020 at 18:01, Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 10/4/20 9:54 AM, Robert Inder wrote:
> > I am moving a database from PSQL 9 (!) on CentOS 6 to PSQL 12 on CentOS 7
>
> It would help to know what the x in 9.x is? Before version 10 of
> Postgres, the second number denoted a major version.
>

9.4.
Moving to 12.4.

>
> >
> > I have a pair of servers -- one live, one standby.
> > The live server defines an archive_command as "rsync...." to shift WAL
> > files to the standby server,
> > The standby server uses "pg_standby" to monitor and process incoming WAL
> > files.
> > I believe this is all very vanilla, and indeed changes made in the live
> > database are duly shipped to the standby.
> >
> > BUT...
> >
> > One of the things I like about the old PGSQL 9 setup is that it
> > generates and ships a WAL file every few minutes, even if nothing has
> > happened in the database.
> > I find it re-assuring to be able to see WAL files arriving and being
> > processed without problem even when the live system was idle.
> >
> > But I cannot get PGSQL 12 to do this. It only writes (and thus ships)
> > WAL files when something happens in the database.
> > If the database is idle, it simply does not write any WAL files.
> >
> > I thought I would get WAL files written from an idle database if, in
> > postgresql.conf, I set "archive_timeout" to 120.
> >
> > And I've tried setting "checkpoint_timeout" to 90s,
> >
> > But to no avail. No WAL files are written unless the database changes.
> >
> > So what am I missing? How CAN I get postgresql 12 to write
> > "unnecessary" WAL files every couple of minutes?
> >
> > Robert.
> >
> > --
> > Robert Inder, 0131 229 1052 / 07808
> > 492 213
> > Interactive Information Ltd, 3, Lauriston Gardens, Edinburgh EH3 9HH
> > Registered in Scotland, Company no. SC 150689
> > Interactions speak louder
> > than words
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>
>
>

--
Robert Inder, 0131 229 1052 / 07808 492
213
Interactive Information Ltd, 3, Lauriston Gardens, Edinburgh EH3 9HH
Registered in Scotland, Company no. SC 150689
Interactions speak louder than
words