On Sat, Oct 21, 2006 at 02:08:48PM -0300, Andrew And wrote:
> I am using Slony with 4 slaves, and I look that my CPU in master has with
> 25% - 40 % busy when slony is active (UP). When I stop Slony the CPU is less
> than 8% busy in Master.

It sounds like your replication tables need some attention. 40% busy
suggests to me that the system is doing a lot of sorting that it
shouldn't need to do, which tells me you may have some stats tuning
or vacuuming needed.  But. . .

> I will need to use 80 slaves in 2 months, then I am nervous with this.

. . .have you tested such a scenario?  80 replicas is a _lot_. 
There is a non-zero overhead per replica.  My guess is that 80 is
going to be a really significant burden.  I'd consider doing
something with cascaded replicas as well, but even so, it may be more
than is practical.

> My master is CPU Intel Pentium 4 (3.20GHz) with 1 Gb RAM.

And you can be sure that that machine is nowhere near enough for 80
replicas.  I'd have at least an 8-way system for that kind of load.

A

-- 
Andrew Sullivan  | ajs at crankycanuck.ca
Windows is a platform without soap, where rats run around 
in open sewers.
		--Daniel Eran