Re: Hot Standby remaining issues

On Fri, 2009-12-04 at 10:37 +0200, Heikki Linnakangas wrote:
> Regarding this item from the wiki page:
> > The "standby delay" is measured as current timestamp - timestamp of last replayed commit record. If there's little
activityin the master, that can lead to surprising results. For example, imagine that max_standby_delay is set to 8
hours.The standby is fully up-to-date with the master, and there's no write activity in master. After 10 hours, a long
reportingquery is started in the standby. Ten minutes later, a small transaction is executed in the master that
conflictswith the reporting query. I would expect the reporting query to be canceled 8 hours after the conflicting
transactionbegan, but it is in fact canceled immediately, because it's over 8 hours since the last commit record was
replayed.
> > 
> >     * Simon says... changed to allow checkpoints to update recoveryLastXTime (Simon DONE) 
> 
> Update recoveryLastXTime at checkpoints doesn't help when the master is
> completely idle, because we skip checkpoints in that case. It's better
> than nothing, of course.

Not if archive_timeout is set, which it would be in warm standby case.
We can do even better than this with SR.

-- Simon Riggs           www.2ndQuadrant.com