On Wed, Sep 08, 2010 at 03:22:46PM +0100, Simon Riggs wrote: > On Wed, 2010-09-08 at 09:50 -0400, Robert Haas wrote: > > > So that means we have to make sure that none of the effects of a > > transaction can be seen until WAL is fsync'd on the master AND the > > slave has acked. > > Yes, that's right. And I like your example; one for the docs. > > There is a slight complexity there: An application might connect to > the standby and see the changes made by the transaction, even though > the master has not yet been notified, but will be in a moment. I > don't see that as an issue though, but worth mentioning cos its just > the "Byzantine Generals" problem.
For completeness, a reference to the aforementioned Byzantine Generals: http://en.wikipedia.org/wiki/Byzantine_fault_tolerance Cheers, David. -- David Fetter <da...@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fet...@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
