Hi.

I implement 2Q algorithm to PostgreSQL for buffer management , instead
of LRU.
It's known as low overhead and high performance than LRU. If you have
some interests , see following URL.

http://www.vldb.org/conf/1994/P439.PDF

In my test (pgbench -S) , it improves 4% cache hit rate and 2% up
performance comparing from LRU.

Do you have any interest about this patch?

-- 
Yutaka tanida <yutaka@nonsensecorner.com>
http://www.nonsensecorner.com/
Mon, 23 Jun 2003 14:41:59 +0900
Yutaka tanida <yutaka@nonsensecorner.com>
2Q implementaion for PostgreSQL buffer replacement.

Looks good to me --- we will include it in 7.4.

Your patch has been added to the PostgreSQL unapplied patches list at:

	http://momjian.postgresql.org/cgi-bin/pgpatches

I will try to apply it within the next 48 hours.

---------------------------------------------------------------------------


Yutaka tanida wrote:
> Hi.
> 
> I implement 2Q algorithm to PostgreSQL for buffer management , instead
> of LRU.
> It's known as low overhead and high performance than LRU. If you have
> some interests , see following URL.
> 
> http://www.vldb.org/conf/1994/P439.PDF
> 
> In my test (pgbench -S) , it improves 4% cache hit rate and 2% up
> performance comparing from LRU.
> 
> Do you have any interest about this patch?
> 
> -- 
> Yutaka tanida <yutaka@nonsensecorner.com>
> http://www.nonsensecorner.com/

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> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Mon, 23 Jun 2003 23:49:17 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: 2Q implementaion for PostgreSQL buffer replacement.

On Mon, 23 Jun 2003 23:49:17 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us> wrote:

> 
> Looks good to me --- we will include it in 7.4.

Thanks.But please note it is not completed yet. I must implement more ,
and move configurable parameter to postgresql.conf file.

-- 
Yutaka tanida <yutaka@nonsensecorner.com>
http://www.nonsensecorner.com/


Tue, 24 Jun 2003 21:12:08 +0900
Yutaka tanida <yutaka@nonsensecorner.com>
Re: 2Q implementaion for PostgreSQL buffer replacement.

OK, thanks. I will remove it from the queue, and someone suggested a
different algorithm today:

> I was researching on cache replacement strategy as well. 2Q has one
> disadvantage see this exellent paper:
> http://www.almaden.ibm.com/cs/people/dmodha/#ARC see the paper
> "ARC: A Self-Tuning, Low Overhead Replacement Cache" for theory and "One
> Up on LRU" for implementation details. ARC requires no tuning and can
> switch fast between chaging patterns. Best of all is it is resistant to a
> "sequential scan" pattern. and i think it's even easier to implement then
> 2q :)


---------------------------------------------------------------------------

Yutaka tanida wrote:
> 
> On Mon, 23 Jun 2003 23:49:17 -0400 (EDT)
> Bruce Momjian <pgman@candle.pha.pa.us> wrote:
> 
> > 
> > Looks good to me --- we will include it in 7.4.
> 
> Thanks.But please note it is not completed yet. I must implement more ,
> and move configurable parameter to postgresql.conf file.
> 
> -- 
> Yutaka tanida <yutaka@nonsensecorner.com>
> http://www.nonsensecorner.com/
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
>       joining column's datatypes do not match
> 

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Tue, 24 Jun 2003 09:54:04 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: 2Q implementaion for PostgreSQL buffer replacement.

Patch removed at author's request.

---------------------------------------------------------------------------

Yutaka tanida wrote:
> Hi.
> 
> I implement 2Q algorithm to PostgreSQL for buffer management , instead
> of LRU.
> It's known as low overhead and high performance than LRU. If you have
> some interests , see following URL.
> 
> http://www.vldb.org/conf/1994/P439.PDF
> 
> In my test (pgbench -S) , it improves 4% cache hit rate and 2% up
> performance comparing from LRU.
> 
> Do you have any interest about this patch?
> 
> -- 
> Yutaka tanida <yutaka@nonsensecorner.com>
> http://www.nonsensecorner.com/

[ Attachment, skipping... ]

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[ Attachment, skipping... ]

> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Tue, 24 Jun 2003 09:54:32 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: 2Q implementaion for PostgreSQL buffer replacement.