On Sat, Jun 15, 2013 at 10:34 PM, Amit kapila <amit.kap...@huawei.com> wrote: > > On Saturday, June 15, 2013 1:19 PM Sawada Masahiko wrote: > On Fri, Jun 14, 2013 at 10:15 PM, Amit Kapila <amit.kap...@huawei.com> wrote: >> On Friday, June 14, 2013 2:42 PM Samrat Revagade wrote: >>> Hello, >> >>>> We have already started a discussion on pgsql-hackers for the problem of >>>> taking fresh backup during the failback operation here is the link for >>>> that: >>>> >>>> >>>> http://www.postgresql.org/message-id/CAF8Q-Gxg3PQTf71NVECe-6OzRaew5pWhk7yQtb >>>> jgwrfu513...@mail.gmail.com >>>> >>>> Let me again summarize the problem we are trying to address. >>> >>> >>> How will you take care of extra WAL on old master during recovery. If it >>> plays the WAL which has not reached new-master, it can be a problem. > >> you means that there is possible that old master's data ahead of new >> master's data. > > I mean to say is that WAL of old master can be ahead of new master. I > understood that > data files of old master can't be ahead, but I think WAL can be ahead. > >> so there is inconsistent data between those server when fail back. right? >> if so , there is not possible inconsistent. because if you use GUC option >> as his propose (i.g., failback_safe_standby_mode = remote_flush), >> when old master is working fine, all file system level changes aren't >> done before WAL replicated. > > Would the propose patch will take care that old master's WAL is also not > ahead in some way? > If yes, I think i am missing some point.
yes it will happen that old master's WAL ahead of new master's WAL as you said. but I think that we can solve them by delete all WAL file when old master starts as new standby. thought? 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
