AW: [Extern] Re: postgres restore & needed history files

> -----Ursprüngliche Nachricht-----
> Von: Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
> Gesendet: Freitag, 6. Januar 2023 06:28
> An: Zwettler Markus (OIZ) <Markus(dot)Zwettler(at)zuerich(dot)ch>; pgsql-
> general(at)lists(dot)postgresql(dot)org
> Betreff: [Extern] Re: postgres restore & needed history files
>
> On Tue, 2023-01-03 at 16:03 +0000, Zwettler Markus (OIZ) wrote:
> > We are using a DIY Postgres backup:
> > ---
> > psql -c "select pg_start_backup ('Full');"
> > save -s "${NSR_SERVER}" -g "${NSR_POOL}" "${PGDATA}"
> > psql -c "select pg_stop_backup();"
> > ---
> > The pg_wal directory is not saved with it because it is a linked directory.
> >
> >
> > After some time, we had to perform a point-in-time recovery of 1 of the 5
> databases to a point in time 7 days in the past.
> > We tried to perform a point-in-time restore on another host, which did not work
> until we copied the contents of the current pg_wal directory.
> > The current pg_wal directory included 8 history files: 00000002.history to
> 00000009.history.
> > The point-in-time restore worked smoodly after it had all these history files.
> >
> >
> > Afaik, all necessary history files should also be restored by the
> restore_command.
> > I had a look at our archived wal backups and found that 00000002.history to
> 00000008.history files already had been deleted due to our NSR backup retention
> of 30 days.
> >
> > Question: Is it necessary to retain all history files?
>
> Yes, the history files are an integral part of the database.
> You must not delete them from your WAL archive.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>

What would you do in case of a disaster when all history files in pg_wal are gone and also deleted in the backup due to the backup retention?

Thanks, Markus