On Fri, Feb 15, 2013 at 3:49 PM, Heikki Linnakangas <hlinnakan...@vmware.com> wrote: >> While this solution would help solve my issue, it assumes that the >> correct amount of WAL files are actually there. Currently the docs for >> setting up a standby refer to "24.3.4. Recovering Using a Continuous >> Archive Backup", and that step recommends emptying the contents of >> pg_xlog. If this is chosen as the solution the docs should be adjusted >> to recommend using pg_basebackup -x for setting up the standby. > > When the backup is taken using pg_start_backup or pg_basebackup, > minRecoveryPoint is set correctly anyway, and it's OK to clear out pg_xlog.
How is minRecoveryPoint supposed to get set? I just tried taking a pg_basebackup on master running pgbench. The resulting data dir controlfile had this: Min recovery ending location: 0/0 The end location was not in the backup_label either. Looking at basebackup.c the process seems to be: 1. pg_start_backup 2. copy out backup_label 3. copy out rest of the datadir 4. copy out control file 5. pg_stop_backup 6. copy out WAL 7. send backup stop location And pg_basebackup.c only uses the stop location to decide how much WAL to fetch. I don't see anything here that could correctly communicate min recovery point. Maybe I'm missing something. > Yeah, it probably could use some editing, as the underlying code has evolved > a lot since it was written. The suggestion to clear out pg_xlog seems like > an unnecessary complication. It's safe to do so, if you restore with an > archive, but unnecessary. > > The "File System Level Backup" chapter > (http://www.postgresql.org/docs/devel/static/backup-file.html) probably > should mention "pg_basebackup -x", too. > > Docs patches are welcome.. I will give it a shot. Ants Aasma -- Cybertec Schönig & Schönig GmbH Gröhrmühlgasse 26 A-2700 Wiener Neustadt Web: http://www.postgresql-support.de -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
