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Re: Load Distributed Checkpoints, take 3

From: Greg Smith <gsmith(at)gregsmith(dot)com>
To: Patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: Load Distributed Checkpoints, take 3
Date: 2007-06-25 21:45:37
Message-ID: Pine.GSO.4.64.0706251743540.2936@westnet.com (view raw or flat)
Thread:
Lists: pgsql-patches
On Mon, 25 Jun 2007, Heikki Linnakangas wrote:

> It only scans bgwriter_lru_percent buffers ahead of the clock hand. If the 
> hand isn't moving, it keeps scanning the same buffers over and over again. 
> You can crank it all the way up to 100%, though, in which case it would work, 
> but that starts to get expensive CPU-wise.

In addition to being a CPU pig, that still won't necessarily work because 
the way the LRU writer ignores things with a non-zero usage_count.  If 
it's dirty, it's probably been used recently as well.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD

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