On Fri, Nov 4, 2016 at 1:18 PM, Venkata B Nagothi <nag1...@gmail.com> wrote: > I see the following contents in the file > "000000010000000000000044.00000060.backup" which was generated in the pg_wal > location during the online backup. When pg_stop_backup() is executed, the > following content is written which includes the content copied from the > backup_label file. > > [...] > > Can someone please help me know the importance of the above file?
It is not actually critical, and useful for debugging (you could say the same about backup_label.old). > How about having the same contents in the backup_label file as well? > As of now, the backup_label file does not have any information related to > when and at what position the backup actually completed. Yes, and it is not actually possible to write the stop information because when a backup finishes the backup_label is simply removed and it has been included in the backup before it finishes. The role of this file is to provide the LSN start location from which the backup is able to replay things cleanly. The stop position, aka when everything on disk is consistent, is determined at replay by the XLOG_BACKUP_END record. This stop position is not something you can know when the backup_label file is generated. And I am of course talking about exclusive backups here. For non-exclusive backups, it could be possible to add some information related to the backup stop locations directly in the backup_label file generated and returned to the caller, though the information it would contain does not seem much pertinent as what really matters is the LSN end location, and that's already a piece of information available. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
