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