Re: 8.x Vaccum/Autovacuum settings

[Jim Nasby <jnasby(at)pervasive(dot)com>]

On Jun 24, 2006, at 5:03 PM, Chris Hoover wrote:
> What are most of you setting your vacuum and autovacuum parameters  
> to for your 8.x databases.  I just turned on autovacuuming on one  
> of my db servers and went with a very conservative  
> vacuum_cost_delay of 200 and vacuum_cost_limit of 50.  I am  
> wondering if anyone else has tested to find out just how far you  
> can push your vacuum/autovacuum before you start to feel  
> performance hits from running it?

It's highly, highly dependent on both your hardware and your  
workload. If you have some kind of metric for how well your app is  
performing, you can fire off a vacuum with different settings and see  
when it starts to slow down your application.

If you're more write-constrained than read constrained, you'll want  
to bump up the cost of dirty pages, probably bumping up  
vacuum_cost_limit at the same time.
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby(at)pervasive(dot)com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461