Re: [PATCHES] pg_freespacemap question - Mailing 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