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Date: Tue, 17 Mar 2009 19:54:54 -0400
From: "Jignesh K. Shah" <J.K.Shah@Sun.COM>
Subject: Re: Proposal of tunable fix for scalability of 8.4
In-reply-to: <1237330778.3953.139.camel@ebony.2ndQuadrant>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>,
 Kevin Grittner <Kevin.Grittner@wicourts.gov>,
	pgsql-performance@postgresql.org
Message-id: <49C0384E.2020707@sun.com>
References: <49B824DD.7090302@sun.com> <49B7F470.EE98.0025.0@wicourts.gov>
	<29080.1236821556@sss.pgh.pa.us> <49B87161.10201@sun.com>
	<1237225198.3963.60.camel@ebony.2ndQuadrant> <49C01900.5030406@sun.com>
	<1237330778.3953.139.camel@ebony.2ndQuadrant>
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Simon Riggs wrote:
> On Tue, 2009-03-17 at 17:41 -0400, Jignesh K. Shah wrote:
>
>   
>> I did a quick test with patch. Unfortunately it improves my number
>> even with default setting 0 (not sure whether I should be pleased or
>> sad - Definitely no overhead infact seems to help performance a bit.
>> NOTE: Logic is same, implementation is slightly different for default
>> set)
>>     
>
> OK, I bite. 25% gain from doing nothing??? You're stretching my... err,
> credulity.
>
> I like the train of thought for setting 1 and it is worth investigating,
> but something feels wrong somewhere.
>
>   
Actually I think I am hurting my credibility here  since I cannot 
explain the improvement with the patch but still using default logic 
(thought different way I compare sequential using fields from the 
previous proc structure  instead of comparing with constant boolean)  
But the change was necessary to allow it to handle multiple algorithms 
and yet be sleek and not bloated.

 In next couple of weeks I plan to test the patch on a different x64 
based system to do a sanity testing on lower number of cores and also 
try out other workloads ...

Regards,
Jignesh