Re: VACUUM on duplicate DB gives FSM and total pages discrepancies

From: Alvaro Herrera
Subject: Re: VACUUM on duplicate DB gives FSM and total pages discrepancies
Date: ,
Msg-id: 20050330151903.GD32434@dcc.uchile.cl
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In response to: VACUUM on duplicate DB gives FSM and total pages discrepancies  (Karim Nassar)
List: pgsql-performance

On Tue, Mar 29, 2005 at 05:52:58PM -0700, Karim Nassar wrote:
> I recently pg_dumpall'd my DB from a (used for testing) v20z install of
> postgresql 8.0.1, and restored it to my production (but not yet in
> service) v40z running the same version. The test DB has had multiple
> millions of rows created/dropped during testing. The results of VACUUM
> VERBOSE are giving me pause:

The FSM only stores pages that have some free space.  If the database
has only been through a restore, then probably there aren't many of
those.  After you start playing with the data some more pages will need
registering.  So the behavior you are seeing is expected.

--
Alvaro Herrera (<alvherre[@]dcc.uchile.cl>)
"We are who we choose to be", sang the goldfinch
when the sun is high (Sandman)


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