| From: | "Greg Stark" <stark(at)enterprisedb(dot)com> |
|---|---|
| To: | "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com> |
| Cc: | "Phillip Berry" <pberry(at)stellaconcepts(dot)com>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Maximum reasonable free space map |
| Date: | 2008-12-17 13:28:14 |
| Message-ID: | 4136ffa0812170528t440d9fael2903129795798c51@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
On Wed, Dec 17, 2008 at 5:45 AM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
>
> If you've got 40M rows and 10% are updated each day, then it's likely
> you'll want 4M fsm entries avaialble for those dead rows.
FWIW you only need an entry for each *page* of the table, not every
row. Of course if you have 40M rows and 10% are updated each day they
might all be on different pages. Also, it's not really the end of the
world if the FSM doesn't track every single page with free space -- as
long as it tracks enough to cover your usage until the next vacuum.
Thankfully all this is gone in 8.4.
--
greg
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Shahbaz A. Tyagi | 2008-12-17 13:45:53 | Re: PostgreSQL installation |
| Previous Message | Dave Page | 2008-12-17 12:48:33 | Re: [GENERAL] A bit confused about Postgres Plus |