Re: Synchronous Log Shipping Replication

On Wed, 2008-09-10 at 13:28 +0900, Fujii Masao wrote:
> On Tue, Sep 9, 2008 at 8:38 PM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com> wrote:
> > There's one thing I haven't figured out in this discussion. Does the write
> > to the disk happen before or after the write to the slave? Can you guarantee
> > that if a transaction is committed in the master, it's also committed in the
> > slave, or vice versa?
> 

The write happens concurrently and independently on both.

Yes, you wait for the write *and* send pointer to be "flushed" before
you allow a synch commit with synch replication. (Definition of flushed
is changeable by parameters).

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support