Re: Possible mistake in backup documentation

On Fri, 2020-09-25 at 14:50 +0200, Magnus Hagander wrote:
> On Fri, Sep 25, 2020 at 2:32 PM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> wrote:
> > On Tue, 2020-09-22 at 14:17 +0000, PG Doc comments form wrote:
> > > In "25.3.3.2. Making An Exclusive Low-Level Backup", you said that "The
> > > exclusive backup method is deprecated and should be avoided. Prior to
> > > PostgreSQL 9.6, this was the only low-level method available, but it is now
> > > recommended that all users upgrade their scripts to use non-exclusive
> > > backups". But in the example in "25.3.6.1. Standalone Hot Backups" you use
> > > the exclusive version of backup command. Is it a mistake or not?
> >
> > Yes, that's true.
>
> Well, technically it is *correct*. It's just rather silly that we are using the deprecated API in the example.
>
> > How about the attached patch?
> > Perhaps that is too complicated, but I have no idea how to make it simpler.
>
> For this example, can't we just show two sessions. That is, "in a psql, run pg_start_backup().
> Then in a different session, copy all the files, and then back in psql run pg_stop_backup()" or such?
>
> This is still just an example of a low level operation, where the recommendation is (and is there iirc)
> to use a different tool for it already.

I thought the point of the example is to show a workable script that could
perform a backup and could be used as a starting point to develop your own
backup solution. (I know that there are people who think writing your own
backup solution is evil, but I am not one of them.)

If we replace that with a verbal description of how to do it, the example just
duplicates what is already documented.

In that case I would opt for simply removing the example.

Yours,
Laurenz Albe