Re: Applying logical replication changes by more than one process

On 2016-03-21 14:18:27 +0100, Petr Jelinek wrote:
> On 21/03/16 14:15, Andres Freund wrote:
> >>Only when the origin is actually setup for the current session. You
> >>need
> >>to call the replorigin_advance yourself from your apply code.
> >
> >That's problematic from a durability POV.
> >
> 
> Huh? How come?

If you use the session mechanism the replication progress is synced with
the apply process, even if there are crashes. Crash recovery updates the
progress.  There's no such interlock with apply otherwise, and I don't
see how you can build one with reasonable effort.