On Fri, Mar 11, 2011 at 09:03:33AM -0500, Robert Haas wrote:
> On Fri, Mar 11, 2011 at 8:21 AM, Fujii Masao <masao.fujii@gmail.com> wrote:
> >
> > In that case, the last write WAL timestamp would become equal to the
> > last replay WAL timestamp. So we can see that there is no lag.
>
> Oh, I see (I think). You're talking about write/replay lag, but I was
> thinking of master/slave transmission lag.
>
Which are both useful numbers to know: the first tells you how "stale"
queries from a Hot Standby will be, the second tells you the maximum
data loss from a "meteor hits the master" scenario where that slave is
promoted, if I understand all the interactions correctly.
Ross
--
Ross Reedstrom, Ph.D. reedstrm@rice.edu
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