DB2 vs. VSAM

[login to unmask email]

DB2 vs. VSAM
I know this is a loaded question but.... Does anyone know of any
benchmarks that compare DB2 CPU usage to VSAM. I know this all depends on if VSAM
programs are converted to properly use DB2, the tables are properly designed, etc.
but is there any 'rule of thumb' for DB2 overhead when comparing to VSAM?
The reason I ask is that we are getting a lot of grief about how much CPU
overhead DB2 adds to processing. We did some benchmarks doing sequential and
random reads against a VSAM file and then simply converted the reads to DB2
singleton selects for comparison. DB2 uses between 2 and 4 times the CPU. Any
feedback would be appreciated.

Thanks
Dave.

---------------------------------------------------------------------------------
Welcome to the IDUG DB2-L list. To unsubscribe, go to the archives and home page at http://www.idugdb2-l.org/archives/db2-l.html. From that page select "Join or Leave the list". The IDUG DB2-L FAQ is at http://www.idugdb2-l.org. The IDUG List Admins can be reached at [login to unmask email] Find out the latest on IDUG conferences at http://conferences.idug.org/index.cfm

Joel Goldstein

Re: DB2 vs. VSAM
(in response to DPetro@AOL.COM)
You're comparing an apple and a football.
When you say "VSAM" your talking about the physical file structure and access.
When you say DB2, you're talking about a Database Management System.
The cost of an I/O is no different - it's all the other things that DB2 gives you, that adds the overhead.

Now saying the cost of using DB2 uses twice the CPU - sure. Four times the CPU, no way; or not on the
repeatable benchmarks I ran years ago.

Regards,
Joel
----- Original Message -----
From: [login to unmask email]
Newsgroups: bit.listserv.db2-l
To: [login to unmask email]
Sent: Tuesday, January 11, 2005 11:09 PM
Subject: [DB2-L] DB2 vs. VSAM


I know this is a loaded question but.... Does anyone know of any benchmarks that compare DB2 CPU usage to VSAM. I know this all depends on if VSAM programs are converted to properly use DB2, the tables are properly designed, etc. but is there any 'rule of thumb' for DB2 overhead when comparing to VSAM? The reason I ask is that we are getting a lot of grief about how much CPU overhead DB2 adds to processing. We did some benchmarks doing sequential and random reads against a VSAM file and then simply converted the reads to DB2 singleton selects for comparison. DB2 uses between 2 and 4 times the CPU. Any feedback would be appreciated.

Thanks
Dave.
--------------------------------------------------------------------------------- Welcome to the IDUG DB2-L list. To unsubscribe, go to the archives and home page at http://www.idugdb2-l.org/archives/db2-l.html. From that page select "Join or Leave the list". The IDUG DB2-L FAQ is at http://www.idugdb2-l.org. The IDUG List Admins can be reached at [login to unmask email] Find out the latest on IDUG conferences at http://conferences.idug.org/index.cfm

---------------------------------------------------------------------------------
Welcome to the IDUG DB2-L list. To unsubscribe, go to the archives and home page at http://www.idugdb2-l.org/archives/db2-l.html. From that page select "Join or Leave the list". The IDUG DB2-L FAQ is at http://www.idugdb2-l.org. The IDUG List Admins can be reached at [login to unmask email] Find out the latest on IDUG conferences at http://conferences.idug.org/index.cfm