Re: [PATCHES] pg_freespacemap question - Mailing list pgsql-hackers

From Mark Kirkwood
Subject Re: [PATCHES] pg_freespacemap question
Date
Msg-id 4414A541.1080909@paradise.net.nz
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In response to Re: [PATCHES] pg_freespacemap question  (Tatsuo Ishii <ishii@sraoss.co.jp>)
Responses Re: [PATCHES] pg_freespacemap question
List pgsql-hackers
Tatsuo Ishii wrote:
> BTW, I noticed difference of outputs from pg_freespacemap and
> pgstattuple.
>
> I ran pgbench and inspected "accounts" table by using these tools.
>
> pg_freespacemap:
>     sum of bytes: 250712
>
> pgstattuple:
>     free_space: 354880
>
> Shouldn't they be identical?

I would have thought so - unless there are not enough pages left in the
FSM...

pg_freespacemap is reporting on what gets into the FSM - so provided I
haven't put a bug in there somewhere (!) - we need to look at how VACUUM
reports free space to the FSM....

cheers

Mark

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