V8 Z/OS Bufferpool Statistics

John Higgins

V8 Z/OS Bufferpool Statistics
Hello, List

Can anyone tell me why I see so many more "prefetch requests" than
"prefetch I/O Operations" in these stats?

I picked a sample 15 minute interval; most of the other intervals look
similar.


Pages Read via Seq Prefetch 1421298
Seq Prefetch I/O Operations 48168
Sequential Prefetch Requests 71118

Pages Read via List Prefetch 358707
List Prefetch I/O Operations 14472
List Prefetch Requests 25918

Pages Read via Dyn Prefetch 1214026
Dyn Prefetch I/O Operations 49302
Dyn Prefetch Requests 81340

John

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Joel Goldstein

Re: V8 Z/OS Bufferpool Statistics
(in response to John Higgins)
V8 Z/OS Bufferpool StatisticsHi John,
This means that the I/O was not necessary because all the pages necessary for the prefetch request were
already in the pool.

Regards,
Joel
----- Original Message -----
From: Higgins John
Newsgroups: bit.listserv.db2-l
To: [login to unmask email]
Sent: Tuesday, November 29, 2005 4:05 PM
Subject: [DB2-L] V8 Z/OS Bufferpool Statistics


Hello, List

Can anyone tell me why I see so many more "prefetch requests" than "prefetch I/O Operations" in these stats?

I picked a sample 15 minute interval; most of the other intervals look similar.



Pages Read via Seq Prefetch 1421298
Seq Prefetch I/O Operations 48168
Sequential Prefetch Requests 71118

Pages Read via List Prefetch 358707
List Prefetch I/O Operations 14472
List Prefetch Requests 25918

Pages Read via Dyn Prefetch 1214026
Dyn Prefetch I/O Operations 49302
Dyn Prefetch Requests 81340

John

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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