2018-06-01 18:36 GMT+02:00 Euler Taveira <eu...@timbira.com.br>: > 2018-06-01 9:00 GMT-03:00 Michael Paquier <mich...@paquier.xyz>: > > On Thu, May 31, 2018 at 10:59:04PM -0400, Robert Haas wrote: > >> On Wed, May 30, 2018 at 2:00 PM, Michael Paquier <mich...@paquier.xyz> > wrote: > >>> Hm. There could be an argument for improving the user experience here > >>> so as some cleanup is at least attempted except if --no-clean is > defined > >>> by the caller when --create-slot is used. Do we want an open item for > >>> this issue? > >> > >> Sounds like new development to me. This isn't a bug. > > > > Still, it seems to me that the user experience is a bit horrible with > > this new interface of pg_basebackup. If --create-slot is used, then a > > slot is created before starting a backup. If the slot already exists, > > then pg_basebackup complains and exits. In order to drop the slot with > > a only user who has replication access rights (because nobody is really > > going to have a user who has SQL access so as the slot is dropped), then > > the only simple way is to use pg_receivewal --drop-slot, making the > > whole flow inconsistent. pg_basebackup is usually in server-side > > packages, and pg_receivewal is on the client side. The server packages > > requiring the client packages, then we are sure that pg_basebackup will > > drag in pg_receivewal. > > > Debian and derivatives put pg_basebackup in the client package > (indeed, it a client program). A possible fix is to drop the slot if > there is an error. However, if the problem is connectivity, we can't > drop it. In this case, we can print a user-friendly error saying that > the user should drop that slot before try again). If we follow this > idea, then I consider it to be a bug fix. > > > Still, shouldn't there be a --drop-slot option in pg_basebackup? In > > this case, if --drop-slot is used, then the slot is dropped and > > pg_basebackup exits immediately. > > > I don't like it. You should send an extra command to recover from an > error. It also does not follow the idempotent behavior. I know that > you are trying to mimic pg_receivewal options but I prefer another > option that removes the slot if it exists (say, > --drop-slot-if-exists). In this case, I consider this option as new > development. > > +1
Pavel > -- > Euler Taveira Timbira - > http://www.timbira.com.br/ > PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento >
