Re: Add visibility map information to pg_freespace.

I'm looking into this patch as a reviewer.

(2013/06/19 18:03), Simon Riggs wrote:
> On 19 June 2013 09:19, Kyotaro HORIGUCHI
> <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>
>> It should useful in other aspects but it seems a bit complicated
>> just to know about visibility bits for certain blocks.
>
> With your current patch you can only see the visibility info for
> blocks in cache, not for all blocks. So while you may think it is
> useful, it is also unnecessarily limited in scope.
>
> Let's just have something that is easy to use that lets us see the
> visibility state for a block, not just blocks in freespace.

I think we can have this visibility map statistics also
in pgstattuple function (as a new column) for this purpose.

IMHO, we have several modules for different purposes.

- pageinspect provies several functions for debugging purpose.
- pg_freespace provies a view for monitoring purpose.
- pgstattuple provies several functions for collecting
specific table/index statistics.

So, we can have similar feature in different modules.

Any comments?

Regards,
--
Satoshi Nagayasu <snaga(at)uptime(dot)jp>
Uptime Technologies, LLC. http://www.uptime.jp