This is why when you order a new machine (or upgrade) always get as much
memory as you can afford, because from all my performance tuning work over
the years, NOTHING helps like lots and lots of memory.
Pete
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of David FOXWELL
Sent: Friday, March 13, 2009 4:26 AM
To: Midrange Systems Technical Discussion
Subject: AS400/i5 etc general behaviour
Hi,
I wondered if I could start a new thread using Alan's reply to the dataq
problem.
----- Original Message -----
From: "Alan Campin" <alan0307d@xxxxxxxxx>
To: "Midrange Systems Technical Discussion"
<midrange-l@xxxxxxxxxxxx>
Subject: Re: Multiple Jobs reading from same data queue-who's turn is
it?Job swapping.
If a job is sitting and waiting and gets no activity it is going to swap out
to disk and when the request comes in it goes to the job and the job is not
available so it swaps it back in memory which takes time. Same problem you
run into with Client Access SQL jobs. User stops to take check a figure and
when they come back and make another call, the job has been swapped and now
they have to wait for it to get swapped back. On a very heavily load system,
it is a really big problem.
On a general note :
Alan, how do you get to learn this kind of thing? I'd like to know more
about how the system functions, for example, how a program is activated or
shared.
As for the example above, I thought that the unique storage address meant
that you never knew if main or secondary storage was being used. How would
you know for sure that a job got swapped out to disk? Is this information
recorded somewhere? How can you manage it? I'm thinking of a program that we
have that uses an SQL request that functions normally then suddenly takes a
long time to execute.
midrange.com
