Date: Mon, 7 Jul 2003 13:58:24 -0600 (MDT)
From: "scott.marlowe" <scott.marlowe@ihs.com>
To: Brian Tarbox <btarbox@world.std.com>
Cc: Brian Tarbox <btarbox@theworld.com>,
	<michael.mattox@verideon.com>, Rafal Kedziorski <rafcio@polonium.de>,
	<pgsql-performance@postgresql.org>
Subject: Re: PostgreSQL vs. MySQL
In-Reply-To: <000d01c344b3$db2add00$01000001@trouble>
Message-ID: <Pine.LNX.4.33.0307071355150.4823-100000@css120.ihs.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Mon, 7 Jul 2003, Brian Tarbox wrote:

> Oddly enough, the particular application in question will have an extremely
> small user base...perhaps a few simultainous users at most.
> 
> As to the testing, I neglected to say early in this thread that my manager
> instructed me _not_ to do further performance testing...so as a good
> consultant I complied.  I'm not going to touch if that was a smart
> instruction to give :-)

But remember, you can always rename your performance testing as 
compliance testing and then it's ok, as long as you don't keep any 
detailed records about the time it took to run the "compliance testing" 
queries.

Definitely look at the output from explain analyze select ... to see what 
the planner THINKS the query is gonna cost versus what it really costs.  
If you see a huge difference between, say estimated rows and actual rows, 
or some other value, it points to the analyzer not getting the right data 
for the planner.  You can adjust the percentage of a table sampled with 
alter table to force more data into analyze.