Re: WAL Archiving and base backup

On Tue, Jan 18, 2022 at 10:53 AM Stephen Frost <sfrost(at)snowman(dot)net> wrote:

> We already have pg_receivewal, which is part of pg_basebackup, and is
> able to use a slot and such. I'm not sure that making pg_basebackup
> somehow also work as an archive command makes much sense

I suppose my proposal should have been:

Create and document a new "PostgreSQL Server Application" [1] and name it:
pg_archive_wal
Advise people to set their archive_command to "pg_archive_wal
--path=/location/of/archive %p/%f

1. https://www.postgresql.org/docs/current/reference-server.html

Having pg_basebackup still prompt for permission to add that command to the
system via ALTER SYSTEM (probably will some other logic) seems doable.

Having created a base backup one still must decide on a wal archiving
strategy. There appear to be two options, though as far as I can tell if
one simply reads the documentation regarding backups they will not discover
the pg_receivewal option. I, not knowing of that option myself, have been
operating under the assumption that if one uses pg_basebackup that one
would be required to setup an archive_command as well.

The superior option is having a persistently running pg_receivewal command
on a server. As noted above, the documentation does not do this option
justice.
The alternative option is to set archive_command; which at present is also
poorly documented. My proposal above simply tries to improve on this. And
while that is a good and easy starting point if there is agreement on
pg_receivewal being a superior archiving option (leaving archive_command
unset) reworking the documentation to guide the inexperience PostgreSQL DBA
toward a "minimal but effective" backup procedure is needed.

David J.