Re: Prestart jobs... how does it work ?

[Alan Campin <alan0307d@xxxxxxxxx>]

I did not say the programs ended. They crashed with a message saying that
they crashed and to see the job log for why but there is no message I can
find that explains the crash.

I think you are mis-understanding what a pre-start job does. It does not
actually run a program. A job is created and then the system puts the job
into a Pre-start wait(PSW). When you issue the spawn is when it actually
calls the program. Nothing gets called until you run the spawn.

The manual for the pre-start job entry seemed to imply that if you used
some other name than the two programs names for spawn that when a job was
submitted, the system would use the program name to look up in the
pre-start list and run the program in the pre-start job but that did not
work because of the crash.



On Wed, Sep 21, 2016 at 12:29 AM, D*B <dieter.bender@xxxxxxxxxxxx> wrote:

> <Alan>
> I did a quick test. Created a program that did nothing. Added as a
> pre-start job to my subsystem and started up. All the pre-start jobs
> crashed. Job log does not say why, just that they crashed. . Called the
> program directly I and it runs fine. My only guess is that program name is
> not QP0ZSPWP or QP0ZSPWT.
> </Alan>
>
> ... this is happening simply, because your job is doing nothing!!! (=>
> it's ended before you could catch it and you don't find "nothing")
> Add a DLYJOB to your CL and you will see, that there is a JOB in DLY
> status. If you do the following:
> ADDPJE SBSD(...) PGM(.../...) USER(...) INLJOBS(2) THRESHOLD(1) ADLJOBS(1)
> MAXJOBS(2)
> you will see 2 Jobs in DLY status and if you kick out one of the jobs, a
> new one will arise by automatic.
> (BTW: I did not succeed to have one automagic starting job, THRESHOLD
> didn't allow 0)
>
> So your prestarted clients would have to do something (waiting on a DtaQ
> or Socket) and your dispatcher has to fire the asynchronous channel to
> bring them to work. You could use spawn() or sbmjob to create your workers.
> spawn should perform better (it's using BCI). For the socket variant
> sendmsg() rcvmsg() would be easier to handle than givedescriptor()
> takedescriptor() (you will find examples). You don't really need prestarted
> jobs to do so, the performance diffrence should be neglectable, as long as
> the startup of your (!!!) programm isn't heavy.
>
> D*B
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