On Thu, Nov 14, 2013 at 3:53 PM, Michael Paquier <michael.paqu...@gmail.com> wrote: > On Thu, Nov 14, 2013 at 3:02 PM, Sawada Masahiko <sawada.m...@gmail.com> > wrote: >> I attached patch adds new wal_level 'all'. >> If wal_level is set 'all', the server logs WAL not only when wal_level >> is set 'hot_standby' ,but also when updating hint bit. >> That is, we will be able to know all of the changed block number by >> reading the WALs. > Is 'all' a name really suited? It looks too general. I don't have a > name on top of my mind but what about something like full_pages or > something similar...
Yes, I'm worried about name of value. But 'full_pages' sounds good for me. > >> This wal_level is infrastructure for fast failback. (i.g., without fresh >> backup) >> It need to cooperate with pg_rewind. > I am not sure that using as reason the possible interactions of a > contrib module not in core is a reason sufficient to justify the > presence of a new wal_level, and pg_rewind is still a young solution > that needs to be improved. So such a patch looks premature IMO, but > the idea is interesting and might cover many needs for external > projects. > >> Not only that, I think it will be profitable infrastructure for >> differential backup. > Yep, agreed. This might help some projects in this area. > >> And it leads to improve performance at standby server side. Because >> the standby server doesn't update hintbit by itself, but FPW is >> replicated to standby server and applied. > It would be interesting to see some numbers here. I think this patch provide several benefit for feature. The fast failback with pg_rewind is one of them. If I want to provide only the fast failback with pg_rewind, this patch logs too much information. Just logging changed block number is enough for that. As you said pg_rewind is still a young solution. But It very cool and flexible solution. I'm going to improve pg_rewind actively. > > This is clearly a WIP patch so it does not matter now, but if you > submit it later on, be sure to add some comments in bufmgr.c as well > as documentation for the new option. Yes, will do. -- Regards, ------- Sawada Masahiko -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers