Marko,
> But Tom's mail gave me impression core wants to wait until we get "perfect"
> read-only slave implementation so we wait with it until 8.6, which does
> not seem sensible. If we can do slightly inefficient (but simple)
> implementation
> right now, I see no reason to reject it, we can always improve it later.
That's incorrect. We're looking for a workable solution. If we could
get one for 8.4, that would be brilliant but we think it's going to be
harder than that.
Publishing the XIDs back to the master is one possibility. We also
looked at using "spillover segments" for vacuumed rows, but that seemed
even less viable.
I'm also thinking, for *async replication*, that we could simply halt
replication on the slave whenever a transaction passes minxid on the
master. However, the main focus will be on synchrounous hot standby.
--Josh