RE: Paging option of *FIXED vs *CALC -- MIDRANGE-L

Jim,

Thanks for SQL tip.
We use very little SQL, but that could change.

Question, if QPFRADJ off, how does memory get moved back and forth between batch and interactive? We all know batch will take as much as it can.
It doesn't make sense to have large amounts in both, then when that pool is least used, a waste of memory.

I remembered the setting requires *CALC, Expert cache.

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jim Oberholtzer
Sent: Tuesday, December 30, 2014 12:52 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: Paging option of *FIXED vs *CALC

Paul,

I suggest you consider your use of the automatic tuning function (QPFRADJ).
For more traditional applications and batch processing this is a good setting. It will migrate memory from pool to pool as needed, with some limitations.

However if your application suite uses SQL in any meaningful way, then it's likely that setting is hurting more than helping. One of the things the SQL optimizer looks at when starting the optimization process is "did my environment change?". If not run the query, if it did, then optimize to be sure the query runs as fast as possible. QPFRADJ almost forces every query to optimize every time since the environment by definition is changing. In an environment where quite a bit of SQL and particularly remote SQL (Zend, WAS, and several other ways of doing remote SQL) then a steady environment
will make these queries more efficient.

I would say that 90% of my customers run better with QPFRADJ off, and an occasional (meaning weekly) look at the performance statistics to see if there is an adjustment needed.

--
Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Steinmetz, Paul
Sent: Tuesday, December 30, 2014 11:19 AM
To: 'Midrange Systems Technical Discussion'
Subject: RE: Paging option of *FIXED vs *CALC

*CALC for all, machine cannot be changed, forced to *fixed.
QPFRADJ = 2

During the day, most memory is moved to *interact for users.
During evening and night hours, memory moved to *SHRPOOL1 for large batch processing.

There is also a setting or feature that added improved performance if set to *CALC.
I can't remember what this was called.

Work with Shared Pools

System:
PENCOR05
Main storage size (M) . : 200704.00

Type changes (if allowed), press Enter.

Defined Max Allocated Pool -Paging Option--

Pool Size (M) Active Size (M) ID Defined Current

*MACHINE 22077.42 +++++ 22077.42 1 *FIXED *FIXED

*BASE 18888.82 1714 18888.82 2 *CALC *CALC

*INTERACT 92082.62 3999 92082.62 4 *CALC *CALC

*SPOOL 3010.55 30 3010.55 3 *CALC *CALC

*SHRPOOL1 64644.56 30 64644.56 5 *CALC *CALC

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Mike Cunningham
Sent: Tuesday, December 30, 2014 11:26 AM
To: Midrange Systems Technical Discussion
Subject: Paging option of *FIXED vs *CALC

It has been some time since we have looked at this option so I decided to review this setting for storage pools. We have always found in the past that *FIXED performed better for us and that is how we have all pools set at the moment. I think the last time we evaluated this setting was back pm V5R4 and we are now at 7.1 (we skipped 6). We have 7 pools setup. Besides *MACHINE and *BASE we have *INTERACT , *SPOOL and three Shared Pools. *INTERACT is mostly traditional 5250 but also some jobs that we run all day doing
interactive type transactions. One shared pool runs only ODBC/JDBC tasks
from a system running on Linux but using DB2 as its database. Second shared pool is for QBATCH work. Third shared pool is for WTR jobs. *BASE runs everything else. (HTTP, Websphere, Zend, QCTL, QSERVER, QSYSWRK, QUSRWRK and a few 3rd party tools - Curbstone, Websmart, GoAnywhere.

We do not have any real performance issues with the exception of an occasional SQL requests coming on from the Linux systems via ODBC, where it will spike the CPU for a 4-5 seconds. And some outgoing JDBC requests from a job running on the i OS and getting data from a MS SQL system.

I have not seen many articles after 2010 on this setting and those I did find say to use *FIXED for 5250 work and *MACHINE and *CALC for anything doing only database (aka ODBC) tasks or do batch type work. "back in the day" IBM's recommendation was to try each setting and see which performed better and use that one. We found that *FIXED worked better for us.

QPFRADJ is setup to No Adjustment.

What do others run for these settings and for what type of workload?

Thanks

Mike Cunningham
VP of Information Technology Services/CIO Pennsylvania College of Technology

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