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From: Satoshi Nagayasu <[email protected]>
To: [email protected]
Subject: pg_buffercache description
Date: Sat, 24 Nov 2012 11:57:51 +0900
Message-ID: <[email protected]> (raw)

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 <[email protected]>
Uptime Technologies, LLC. http://www.uptime.jp

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