Re: Core team statement on replication in PostgreSQL

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