On Wed, Feb 10, 2016 at 2:46 PM, Andres Freund <and...@anarazel.de> wrote:
> Hi, > > On 2016-02-10 13:46:05 +0100, Magnus Hagander wrote: > > Per discussionat the developer meeting in Brussels, here's a patch that > > makes some updates to the backup APIs, to support non-exclusive backups > > without using pg_basebackup. > > Thanks for following through with this! > > > * If the client disconnects with a non-exclusive backup running, the > backup > > is automatically aborted. This is the same thing that pg_basebackup does. > > To use these non-exclusive backups the backup software will have to > > maintain a persistent connection to the database -- something that should > > not be a problem for any of the modern ones out there (but would've been > > slightly trickier back in the days when we suggested shellscripts) > > I think we might want to make this one optional, but I'm not going to > fight super hard for it. > Not sure what you're referring to here. Do you mean being able to make a non-exclusive backup while not maintaining a connection? That's going to make things a *lot* more complicated, as we'd have to invent something like "backup slots" similar to what we're doing with replication slots. I doubt it's worth all that work and complexity. > > > * A new version of pg_stop_backup is created, taking an argument > specifying > > if it's exclusive or not. The current version of pg_stop_backup() > continues > > to work for exclusive backups, with no changes to behavior. The new > > pg_stop_backup will return a record of three columns instead of just the > > value -- the LSN (pglsn), the backup label file (text) and the tablespace > > map file (text). > > I wonder if we shouldn't change the API a bit more aggressively. Right > now we return the label and the map - but what if there's more files at > some later point? One way would be to make it a SETOF function returning > 'filename', 'content' or such. Makes it less clear what to do with the > lsn admittedly. > *Adding* more columns to the API shouldn't be a problem in the future. If there's another file, we can return a fourth column. A backup program is going to have to know about those things anyway and shouldn't just blindly write those files to the backup, IMO. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/
