Message-ID: <46780A5D.50006@archonet.com>
Date: Tue, 19 Jun 2007 17:54:53 +0100
From: Richard Huxton <dev@archonet.com>
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To: "Campbell, Lance" <lance@uiuc.edu>
Cc: pgsql-performance@postgresql.org
Subject: Re: PostgreSQL Configuration Tool for Dummies
References: <A3AC4FA47DC0B1458C3E5396E685E63302395E5D@SAB-DC1.sab.uiuc.edu>
In-Reply-To: <A3AC4FA47DC0B1458C3E5396E685E63302395E5D@SAB-DC1.sab.uiuc.edu>
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Campbell, Lance wrote:
> Please think simple.  I stress the word simple.  The real challenge here
> is getting the formulas correct.  Someone mentioned to not focus on the
> values but just get something out there for everyone to help tweak.  I
> agree!
> 
> What questions do you think should be asked in order to figure out what
> values should go into the formulas for the configuration suggestions?  
> 
> My thoughts:
> 
> What version of PostgreSQL are you using?

OK, obviously not needed if embedded in the manuals.

 > How many connections will be made to PostgreSQL?
OK (but changed order)

> How much memory will be available to PostgreSQL?
Would structure it like:
- What is total memory of your machine?
- How much do you want to reserve for other apps (e.g. apache/java)?

Also:
- How many disks will PG be using?
- How much data do you think you'll store?
- Will your usage be: mostly reads|balance of read+write|mostly writes
- Are your searches: all very simple|few complex|lots of complex queries

Then, with the output provide a commentary stating reasons why for the 
chosen values. e.g.
   random_page_cost = 1.0
   Because you have [effective_cache_size = 1GB] and [total db size = 
0.5GB] the cost of fetching a page is the same no matter what order you 
fetch them in.

-- 
   Richard Huxton
   Archonet Ltd