Re: More buffers used than a relation's relpages

On Tue, Jun 4, 2013 at 12:17 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> On Monday, June 3, 2013, Amit Langote wrote:
>>
>> Hello,
>>
>> In what cases can a relation use more buffers (in shared memory) than
>> its pg_class.relpages?
>
>
> I think relpages only counts pages in the main fork, while the buffer cache
> will also have buffers for the other forks (visibility map, free space map).
> Also, relpages can be out of date if the table has grown since the last
> vac/analyze.
>

Is there a way to refer to pages of these other forks like
pg_class.relpages is for referring to relation's disk pages as of the
last analyze (is that right?)

--
Amit Langote