On 4 October 2012 05:32, Mark Kirkwood <mark.kirkwood@catalyst.net.nz> wrote:
> I am seeing the situation where the reported flush location for the sync
> standby (standby1 below) is *behind* the reported current xlog location of
> the primary. This is Postgres 9.1.5 , and I was under the impression that
> transactions initiated on the master do not commit until the corresponding
> wal is flushed on the sync standby.
>
> Now the standby is definitely working in sync mode, because stopping it
> halts all write transactions on the primary (sync_standby_names contains
> only standby1). So is the reported lag in flush location merely an artifact
> of timing in the query, or is there something else going on? [1]
The writing of new WAL is independent of the wait that occurs on
commit, so it is entirely possible, even desirable, that the observed
effect occurs.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
