RE: Performance problems using dataqueues to NT.

A comment - the latest versions of both Domino and WebSphere Application
Server on AS/400 *still* have their classes shipped with PURGE(*YES), which
is quite extraordinary in my view since both products involve very large
numbers of Act->Wait transitions and our experience has shown that it is
essential to switch both, straight away, to using PURGE(*NO). It is
essential to have sufficient main storage for either product, but people
who are deploying them, by and large, know that. I do suspect that there
are a lot of people out there using PURGE(*YES) for things simply because
it's the default.
Mandy





"Richard Jackson" <richardjackson@richardjackson.net> on 28/09/2000
20:31:31

Please respond to JAVA400-L@midrange.com

To:   JAVA400-L@midrange.com
cc:    (bcc: Mandy Shaw/Pacific/UK)
Subject:  RE: Performance problems using dataqueues to NT.




Fred:

On a RISC machine with adequate memory, it is irresponsible to use process
purge on an AS/400.  Between 1996 and 1998, purge(*yes) was the IBM/JDE
guideline for ODBC server jobs (QZDASOINIT).  In December 1998, Debbie Hatt
and Alan Wallet discovered the problem and the guideline changed.  Setting
those jobs to purge(*yes) was a very bad idea but we didn't know it at the
time.  I can speak here because it was my decision, after consultation with
the IBM ODBC database guys, to recommend that it be set that way in 1996.
I
made a mistake.  In 1998 and 1999, I spread the word to change the setting.
It took between 6 and 9 months to get the word out to everyone.

I believe that makes highly questionable any assumption on the part of IBM
developers that customers use purge.  If SLIC retains that anachronism, it
should be purged :)

Contact me offline if you want to discuss this further.  You can call
Debbie
Hatt on an inside line.

Richard Jackson
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Voice: 1 (303) 808-8058
Fax:   1 (303) 663-4325

> |-----Original Message-----
> |From: owner-java400-l@midrange.com
> |[mailto:owner-java400-l@midrange.com]On Behalf Of kulack@us.ibm.com
> |Sent: Thursday, September 28, 2000 8:23 AM
> |To: JAVA400-L@midrange.com
> |Subject: Re: Performance problems using dataqueues to NT.
> |
> |
> |
> |Many waiting primitives in the bowels OS/400 have options coded
> |in them to
> |help overall performance in the system. The optiosn tell SLIC whether a
> |wait is expected to be long > 2 seconds or short < 2 seconds.
> |This has a direct effect on how the scheduler treats the waiter, on
> |priority of the waiter, and on whether the waiter is immediately
> |paged out
> |or what. There's a significant transition that occurs in SLIC at the 2
> |second mark.
> |I suspect is related to this in some fashion.
> |
> |"Do you believe that my being stronger or faster has anything
> | to do with my muscles in this place?" ... "Free your mind."
> |Laurence Fishburne as Morpheus in 'The Matrix'.
> |
> |Fred A. Kulack  -  AS/400e  Java and Java DB2 access, Jdbc, JTA, etc...
> |IBM in Rochester, MN  (Phone: 507.253.5982   T/L 553-5982)
> |mailto:kulack@us.ibm.com   Personal: mailto:kulack@bresnanlink.net
> |AOL Instant Messenger: Home:FKulack  Work:FKulackWrk
> |
> |
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      Regards,
      Mandy Shaw

      Catalyst Solutions plc
      Kingfisher House
      Frimley Business Park
      Camberley
      Surrey
      GU16 5SG
      UK

      http://www.catalyst-solutions.com
      Email: Mandy.Shaw@uk.catalyst-solutions.com

      Telephone: +44 (0)870 166 1000
      DDI: +44 870 166 1324
      Facsimile: +44 870 168 3920
      Mobile: +44 410 447966
      Email to mobile 'phone: mandyshaw@sms.genie.co.uk





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