Re: [PERFORM] how to plan for vacuum?

On Thu, Jan 25, 2007 at 07:52:50PM +0900, Galy Lee wrote:
> It is very hard for any normal user to set this correctly. I think the 
> experience / trial-and-error approach is awful for the user, every DBA 
> need to be an expert of vacuum to keep the system stable. For vacuum is 
> still a big threat to the performance, a more intelligent way is needed.

Agreed.

> So I have proposed the "vacuum in time" feature in previous; just let 
> vacuum know how long can it runs, and then it will minimize the impact 
> in the time span for you. Some argue that it should not have the 
> maintenance window assumption, but the most safely way is to run in the 
> maintenance window.

Most systems I work on don't have a maintenance window. For those that
do, the window is at best once a day, and that's nowhere near often
enough to be vacuuming any database I've run across. I'm not saying they
don't exist, but effort put into restricting vacuums to a maintenance
window would serve very few people. It'd be much better to put effort
into things like piggyback vacuum.
-- 
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)