On Sun, 2018-11-25 at 22:01 +0100, Magnus Hagander wrote: [about managing backups from pre- and post-file-system-backup scrips] > I agree with your point that it's not an uncommon thing to need. If a good solution > for it can be proposed that requires the exclusive backup interface, then I wouldn't > be against un-deprecating that. But that's going to require a lot more than just a > documentation change, IMHO. What could perhaps be handled with a documentation change, > however, is to document a good way for this type of setup to use the new interfaces.
Good point, and it puts the ball in my court :^)
Enjoy :)
> > I'm arguing on behalf of users that run a few databases, want a simple backup > > solution and are ready to deal with the shortcomings. > > Those that want a simple backup solution have one -- pg_basebackup. > > The exclusive backup API is *not* simple. It is convenient, but it is not simple. > > Actually having a simple API that worked with the pre/post backup scripts, that > would be an improvement that we should definitely want!
Right; unfortunately it is not simple to come up with one that doesn't exhibit the problems of the existing exclusive backup.
Right, it turns out to actually be a hard problem. The old API pretended it wasn't, which wasn't really very helpful in the long run...
Perhaps it's theoretically impossible. The goal is to disambiguate what a file system backup sees in backup mode and what the startup process sees after a crash in backup mode, and I can't see how that could be done.
Not if it's in the same physical location, no, I think that's really hard.