What is a technique to start a program periodically?

Well, if you can guarantee that the processing always takes less than 60
seconds you could do something like

do {
        clock1 = now();
        ...stuff...
        clock2 = now();
        timeout = 60 - clock2 - clock1;
        ReceiveFromDataqueue (myqueue, mydata, timeout); } while (mydata
<> "BREAK")

But I can't stop thinking you have some flaw in the design; why do you
have to start every 60 seconds? A polling solution is always using more
resources and always have an upper scaling limit. A solution that uses
event triggers are close to always more efficient.


/Joakim

-----Original Message-----
From: c400-l-bounces+joakim.svensson=capgemini.com@xxxxxxxxxxxx
[mailto:c400-l-bounces+joakim.svensson=capgemini.com@xxxxxxxxxxxx] On
Behalf Of Jevgeni Astanovski
Sent: den 3 november 2005 16:35
To: C programming iSeries / AS400
Subject: RE: [C400-L] What is a technique to start a program
periodically?


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?
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> It's a new kind of e-mail where only the person it's addressed to can
> actually see the message!
>
> OK, maybe not.  But it makes you wonder! <puts on tinfoil hat>
>
> Pete
>
>
>
> Jevgeni Astanovski wrote:
> | Hm-m-m....
> | Does it really contain anything confidential?
>
> /------------------------------------------------\
> |Peter Grace                  Phone: 484-875-9462
> |Technology Analyst             Fax: 484-875-9461
> |RealTime Technologies, Inc.
> |835 Springdale Drive, Suite 101
> |Exton, PA  19341
> \------------------------------------------------/

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