All,
> > For the slave to not interfere with the master at all, we would need to
> > delay application of WAL files on each slave until visibility on that
> > slave allows the WAL to be applied, but in that case we would have
> > long-running transactions delay data visibility of all slave sessions.
>
> Right, but you could segregate out long-running queries to one slave
> server that could be further behind than the others.
I still see having 2 different settings:
Synchronous: XID visibility is pushed to the master. Maintains synchronous
failover, and users are expected to run *1* master to *1* slave for most
installations.
Asynchronous: replication stops on the slave whenever minxid gets out of
synch. Could have multiple slaves, but noticeable lag between master and
slave.
--
Josh Berkus
PostgreSQL @ Sun
San Francisco
