On Fri, Dec 21, 2012 at 9:54 PM, Heikki Linnakangas <hlinnakan...@vmware.com> wrote: > Yes, this should be backpatched to 9.2. I came up with the attached.
In this patch, if '-X stream' is specified in pg_basebackup, the timeline history files are not backed up. We should change pg_backup background process and walsender so that they stream also timeline history files, for example, by using 'TIMELINE_HISTORY' replication command? Or basebackup.c should send all timeline history files at the end of backup even if '-X stream' is specified? > However, thinking about this some more, there's a another bug in the way WAL > files are included in the backup, when a timeline switch happens. > basebackup.c includes all the WAL files on ThisTimeLineID, but when the > backup is taken from a standby, the standby might've followed a timeline > switch. So it's possible that some of the WAL files should come from > timeline 1, while others should come from timeline 2. This leads to an error > like "requested WAL segment 00000001000000000000000C has already been > removed" in pg_basebackup. > > Attached is a script to reproduce that bug, if someone wants to play with > it. It's a bit sensitive to timing, and needs tweaking the paths at the top. > > One solution to that would be to pay more attention to the timelines to > include WAL from. basebackup.c could read the timeline history file, to see > exactly where the timeline switches happened, and then construct the > filename of each WAL segment using the correct timeline id. Another approach > would be to do readdir() on pg_xlog, and include all WAL files, regardless > of timeline IDs, that fall in the right XLogRecPtr range. The latter seems > easier to backpatch. The latter sounds good to me. But how all WAL files with different timelines are shipped in pg_basebackup -X stream mode? Regards, -- Fujii Masao -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
