On 29 July 2015 at 11:43, Andres Freund <and...@anarazel.de> wrote: > On 2015-07-29 09:17:04 +0100, Simon Riggs wrote: > > On 29 July 2015 at 09:09, Andres Freund <and...@anarazel.de> wrote: > > > The point of using a temporary slot is to not have a > > > leftover slot afterwards, reserving resources. Especially important if > > > the basebackup actually failed... > > > > > > > Creating a slot and then deleting it if the session disconnects does not > > successfully provide the functionality desired above. > > Uh? If you create the slot, start streaming, and then start the > basebackup, it does. It does *not* guarantee that the base backup can be > converted into a replica, but it's sufficient to guarantee it can > brought out of recovery. >
Perhaps we are misunderstanding the word "it" here. "it can be brought out of recovery"? You appear to be saying that a backup that disconnects before completion is useful in some way. How so? If the slot is cleaned up on disconnect, as suggested, then you end up with half a backup and WAL is cleaned up. The only possible use for slots is to reserve resources (as you say); the resources will clearly not be reserved if we drop the slot on disconnect. What use is that? -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
