Re: Remove Deprecated Exclusive Backup Mode

On 11/26/18 11:04 PM, Robert Haas wrote:
> On Mon, Nov 26, 2018 at 10:13 PM David Steele <david@pgmasters.net> wrote:
>> I propose we remove the deprecated exclusive backup mode of
>> pg_start_backup()/pg_stop_backup() for Postgres 12.
> 
> -1. I don't have a problem with deprecating exclusive backup mode
> eventually, but I don't see any good reason to do it this soon.
> 
> It's not like the problems with exclusive backup are so serious that
> you can't work around them.  If you know which machine is your master,
> you can arrange to remove backup_label on reboot (only) on the master
> (only). 

I do not recommend that users write automated scripts to delete files
out of $PGDATA.  Accidents happen that way.

If this is our recommendation on how the mitigate the problem with
exclusive backup then I think it proves the point that it is broken and
should be removed.

> Sure, a lot of people probably do this wrong, but it's
> infeasible to disallow all the things that people might use
> incorrectly without making the system useless.

But we have already fixed this problem -- it only remains to remove the
old method.

> There must be hundreds or thousands of backup scripts written by
> individual users that still use exclusive mode floating around out
> there.  Forcing all of those to be updated or scrapped will annoy
> users to no benefit.

But we are OK with forcing them to scrap their recovery scripts?

And there is a benefit -- Postgres will be able to restart if it crashes
during a backup.

Regards,
-- 
-David
david@pgmasters.net