Re: Possible performance improvement: buffer replacement policy

I added this too to TODO.detail/performance.

> On Fri, Jan 19, 2001 at 12:03:58PM -0500, Bruce Momjian wrote:
> > 
> > Tom, did we ever test this?  I think we did and found that it was the
> > same or worse, right?
> 
> (Funnily enough, I just read that message:)
> 
> To: Bruce Momjian <pgman@candle.pha.pa.us>
> cc: pgsql-hackers@postgreSQL.org
> Subject: Re: [HACKERS] Possible performance improvement: buffer replacement policy 
> In-reply-to: <200010161541.LAA06653@candle.pha.pa.us> 
> References: <200010161541.LAA06653@candle.pha.pa.us>
> Comments: In-reply-to Bruce Momjian <pgman@candle.pha.pa.us>
>     message dated "Mon, 16 Oct 2000 11:41:41 -0400"
> Date: Mon, 16 Oct 2000 11:49:52 -0400
> Message-ID: <26100.971711392@sss.pgh.pa.us>
> From: Tom Lane <tgl@sss.pgh.pa.us>
> X-Mailing-List: pgsql-hackers@postgresql.org
> Precedence: bulk
> Sender: pgsql-hackers-owner@hub.org
> Status: RO
> Content-Length: 947
> Lines: 19
> 
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >> It looks like it wouldn't take too much work to replace shared buffers
> >> on the basis of LRU-2 instead of LRU, so I'm thinking about trying it.
> >> 
> >> Has anyone looked into this area?  Is there a better method to try?
> 
> > Sounds like a perfect idea.  Good luck.  :-)
> 
> Actually, the idea went down in flames :-(, but I neglected to report
> back to pghackers about it.  I did do some code to manage buffers as
> LRU-2.  I didn't have any good performance test cases to try it with,
> but Richard Brosnahan was kind enough to re-run the TPC tests previously
> published by Great Bridge with that code in place.  Wasn't any faster,
> in fact possibly a little slower, likely due to the extra CPU time spent
> on buffer freelist management.  It's possible that other scenarios might
> show a better result, but right now I feel pretty discouraged about the
> LRU-2 idea and am not pursuing it.
> 
>             regards, tom lane
> 
> 


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