Re: Sync Rep v17

On Fri, 2011-02-18 at 21:39 -0500, Bruce Momjian wrote:
> Simon Riggs wrote:
> > Most parameters are set on the primary. Set
> > 
> >   primary: synchronous_standby_names = 'node1, node2, node3'
> > 
> > which means that whichever of those standbys connect first will
> > become the main synchronous standby. Servers arriving later will
> > be potential standbys (standby standbys doesn't sound right...).
> > synchronous_standby_names can change at reload.
> > 
> > Currently, the standby_name is the application_name parameter
> > set in the primary_conninfo.
> > 
> > When we set this for a client, or in postgresql.conf
> > 
> >   primary: synchronous_replication = on
> > 
> > then we will wait at commit until the synchronous standby has
> > reached the WAL location of our commit point.
> > 
> > If the current synchronous standby dies then one of the other standbys
> > will take over. (I think it would be a great idea to make the
> > list a priority order, but I haven't had time to code that).
> > 
> > If none of the standbys are available, then we don't wait at all
> > if allow_standalone_primary is set.
> > allow_standalone_primary can change at reload.
> 
> Are we going to allow a command to be run when these things happen, like
> archive_command does, or is that something for 9.2?

Not really sure which events you're speaking of, sorry. As I write, I
don't see a place or a reason to run a command, but that might change
with a longer explanation of what you're thinking. I wouldn't rule out
adding something like that in this release, but I'm not around for the
next week to add it.

-- Simon Riggs           http://www.2ndQuadrant.com/books/PostgreSQL Development, 24x7 Support, Training and Services