On Thu, Jul 26, 2012 at 9:59 AM, Peter Eisentraut <pete...@gmx.net> wrote: >> I think I could create a list and pass that into a loop so only >> the command has to be modified, but again, how do we do that on Windows? >> Can we create a shell function in Windows and pass the file name as an >> argument? > > I don't know, but I assume that somewhere in the known universe there is > a way on Windows to say, here is a list of files, copy them to that > host. > >> Another problem is that the standby cluster might create _new_ files >> that don't exist on the master, e.g. WAL files, and those have to be >> removed. I am not clear how to do that either, except by removing all >> files with a hard link count of 1, and again, this is difficult on >> Windows. > > Well, then that would call for another list of files.
I cannot escape the feeling that if we go down this route in any form we're going to spend years tracking down data-loss-inducing bugs. The ones we have on the master are bad enough, but doing it on the standby is almost worse because (1) few enough people will use this functionality that we won't get many bug reports even if it's badly broken and (2) people who are affected may not discover it until something bad has already happened on the master. I don't hear anyone thinking very hard about ways that the master could be different from the standby, and without a lot of careful thought on that topic I think this is all kinds of bad news. Just to take one example, how are you going to ensure that the standby has replayed all the WAL that the master generated prior to the upgrade? If the answer is "shut everything down cleanly and hope for the best", color me unimpressed. IMV, pg_upgrade is not yet sufficiently reliable that we should be looking for new projects that seem certain to make it less reliable. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers