Re: Performance tuning

Until it's not.......

If you have heavy SQL, them that setting can, not always certainly, and usually does, bollox things up. It forces the optimizer to run for every query. Sometimes it'll do a table scan, other times it'll build an index. It may or may not use existing index objects.

Mean time you're sitting there trying to understand why things run differently every day.

Bottom line is, performance is as much art as science, and a solid understanding of the application is a good starting point.

Jim Oberholtzer
Agile Technology Architects

On Nov 30, 2018, at 12:19 PM, Roger Harman <roger.harman@xxxxxxxxxxx> wrote:

When I had that responsibility, I just set QPFRADJ to '3' and was a happy camper. Figured the machine was smart enough.

Roger Harman
COMMON Certified Application Developer - ILE RPG on IBM i on Power







From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxx> on behalf of Rob Berendt <rob@xxxxxxxxx>
Sent: Friday, November 30, 2018 10:13 AM
To: Midrange Systems Technical Discussion
Subject: Re: Performance tuning

We just buy more than enough horsepower to keep the users happy and us
working on other stuff than mucking around with performance.


Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1
Group Dekko
Dept 1600
Mail to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





From: "Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>
To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
Date: 11/30/2018 01:08 PM
Subject: Performance tuning
Sent by: "MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx>



How do folks here analyze and tune their IBM i systems? I'm looking for
broad recommendations as to:

1. Do it myself? Are there enough tools available in the base O/S to do
so, and where would I start?

2. Additional IBM i licensed program options that would help with option
1.

3. Third party utilities. I have no idea if these exist; a cursory
Google turned up nothing.

4. Third party consulting.

Please note that I don't want to use David's list to solicit for
services. I'm just trying to get a feel for how it's done. The last
box I tuned was a model 270 and things have evolved a little since
then. If, though, you are someone who wishes to throw a hat in the ring
(yours or someone else's) then please feel free to send me an email
directly.

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