RE: What is a technique to start a program periodically?

---
Scott Klement  http://www.scottklement.com


On Thu, 3 Nov 2005, Jevgeni Astanovski wrote:

I've asked this question once last year and got some proposals.
Letter below describes more or less these possibilities.

There was also Simon Coulter's comment:

Surely it would be better to start the program once and have it sleep
for n seconds between processing. That would avoid the overhead of
starting umpteen jobs as well as make it easier to locate problems.

But the problem is (I understood it now :-(((), that most of these are not what 
I've been looking for....

Imagine you need to START a process every minute, that is
......
7:00:00
7:01:00
7:02:00
7:03:00
......

And the process itself can take from 1 second to say 50 seconds - unpredictable.
Both methods (1) and (2) does not do the job at all - as obvious as it is. I 
need to guarantee, that the process is started with a fixed frequency, and the 
proposed guarantees, that system will rest guaranteed amount of time between 
process executions.

The only method, that actually does the job is (3), when I have an upper level 
C(L) program, that submits my process every fixed period.
But Simon says, that from the system point of view it is not very good.

Are there any other possibilities, or number (3) is the only one?

Jevgeni.

-----Original Message-----
From: Svensson, Joakim [mailto:joakim.svensson@xxxxxxxxxxxxx]
Sent: Friday, December 17, 2004 9:54 AM
To: C programming iSeries / AS400
Subject: RE: [C400-L] What is a technique to start a program
periodically?



Hmm, well, I actually did write a response but our web-mail
client seems
to have kept all the text... The text you see is added to all outgoing
mail totally out of my control.
Back to my answer:

You have several options to accomplish what you need:

1. Use a simple delay in a loop in your program.
C-pseudo code

do {
...stuff...
system("DLYJOB (60)");
} while (break_condition)

2. Use a time out on a data queue. This is nice since you can control
the program termination externally, by sending something via the data
queue and since it's consuming close to zero system resources.

timeout = 60;
do {
...stuff...
ReceiveFromDataqueue (myqueue, mydata, timeout);
} while (mydata <> "BREAK")

3. As suggested you can have another job submitting your program every
60 seconds, or you can do it from your program, but both options are
inefficient from a system point of view.


All these options would in practice require you to execute
your program
in a new job queue, or else your program would hog QBATCH all day long
which normally is not accepted.


Joakim
------------------------------------
Svensson, Joakim
Capgemini, Sweden
Certified Enterprise Architect / Principal
Joakim.Svensson@xxxxxxxxxxxxx
Sweden
------------------------------------

-----Original Message-----
From: c400-l-bounces+joakim.svensson=capgemini.com@xxxxxxxxxxxx
[mailto:c400-l-bounces+joakim.svensson=capgemini.com@xxxxxxxxxxxx] On
Behalf Of Peter Grace
Sent: den 16 december 2004 20:07
To: C programming iSeries / AS400
Subject: Re: [C400-L] What is a technique to start a program
periodically?

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OK, maybe not.  But it makes you wonder! <puts on tinfoil hat>

Pete



Jevgeni Astanovski wrote:
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