pg_buffercache description

Hi,

I found that the manual page for pg_buffercache module explains
"usagecount" as "Page LRU count".

http://www.postgresql.org/docs/devel/static/pgbuffercache.html

However, AFAIK, "usagecount" is not a LRU count nowadays, because
LRU is no longer used for the buffer management algorithm.

I think it should be described as "Clock-sweep count" or something
like that.

And I'd like to add some additional explanation for the "forknumber"
as below:

"0 for heap file, 1 for FreeSpaceMap, and 2 for VisibilityMap".

Any comments?

Regards,
--
Satoshi Nagayasu <snaga@uptime.jp>
Uptime Technologies, LLC. http://www.uptime.jp