Re: Determining right size for max_fsm_pages on large setup?

On Sep 8, 2006, at 4:29 PM, Francisco Reyes wrote:

> I have a database that I started with 1,000,000 max_fsm_pages and I
> was doing vacuum analyze verboze daily. Checked every couple of
> days to make sure we had the right amount of fsm pages.
> A few days ago I noticed that we got the notice "Consider
> increasing the configuration parameter" and it recommended
> 1,216,864. So I first increased it to 1.5 Million and changed to do
> two vacuum analyze per day.
> Ever since I have been gradually increasing the numbers of
> max_fsm_pages and every time we get about 200,000 over what I have
> set. Finally tried going from 3 Millinon to 5 Million at it still
> suggests that I need about 200K more than what I have.

how many actual pages of data (and index) do you have? you want to
see how many relpages you're relations are using in the pg_class
view. i would venture to say if you have deleted rows in every
single page, you'd want at least one entry per page of your table(s).

once you're done with your migration, you should consider running a
cluster on the big tables to pack them more tightly and get rid of
some of your pages with empty space.