Re: Hot Standby (v9d)

On Wed, 2009-01-28 at 22:47 +0200, Heikki Linnakangas wrote:
> It's not quite that simple. Setting max_standby_delay=5mins means that 
> you're willing to wait 5 minutes for each query to die. Which means that 
> in worst case you have to stop for 5 minutes at every single vacuum 
> record, and fall behind much more than 5 minutes.

Just trying to follow along: are you talking about the situation where
there are (for example) a continuous stream of "select pg_sleep(600)" on
the standby, and a series of rapid VACUUMs on the primary?

This situation might be more likely now that we have partial VACUUMs.

> It should also be noted that the control functions allow you to connect 
> to the database and manually pause/resume the replay. So you can for 
> example set max_standby_delay=0 during the day, but pause the replay 
> manually before starting a nightly report.
> 

That's a very cool feature.

Regards,
	Jeff Davis