On Tue, 2018-10-09 at 11:45 +0900, Michael Paquier wrote: > (Please do not forget to add the community mailing list in CC.) > > On Tue, Oct 09, 2018 at 10:33:56AM +0800, magodo wrote: > > Since the backup history aims to aid administrator to identify the > > point from which wal archive should be kept and before which the > > archive could be cleaned. It is very helpful in kinds of use cases. > > > > Why not also create it when do basebackup on standby? > > The backup_label file is equally helpful, and backup history files > are > not mandatory for backups. One of the reasons behind why we cannot > have > those on standbys is that there is no actual way to ensure the > uniqueness of this file, as two backups could be started in parallel > with the same start location and the *same* file name. If an archive > command is not able to handle correctly the duplicates, you could > bloat > pg_wal. And that's a real problem. > -- > Michael Oh, I almost forget backup_label.. Thank you for point it out! Yet, I am still not so clear how does the bloat of pg_wal happen? Do you mean pg_wal will be filled up by many .backup(s)? Magodo
