Re: Dtaq/ UsrQ Monitor

["Mark S. Waterbury" <mark.s.waterbury@xxxxxxx>]

Hi, All:

There is no need to create a separate object, like a *DTAARA, for this. 
The *PGM can issue ALCOBJ against the program object (itself).

Use the same logic as shown (below) for the *DTAARA, but use the 
"library/pgmname" of the *PGM itself, and "*PGM" for the object type.  :-)

But, you might not want to limit a "listener" to only one "instance" in 
this way when using a *DTAQ, because, as others have mentioned, it is 
often desirable to be able to start multiple instances of your server 
(listener) job to service a single request queue, depending on the 
frequency and volume of messages arriving in the message queue, to 
ensure that there is almost always a server job ready and waiting to 
service the next request as soon as it arrives (or soon thereafter).  
(This is a way of "tuning" your application performance.)

HTH,

Mark S. Waterbury

> Albert York wrote:
> This is what I do.
>
> The monitor program allocates a data area (usually the same name as the job) exclusively. Then other programs can determine if it is active by attemptnig to allocate it (with a wait time of 0).
>
> For example.
>
> The monitor program:
>
>                 CRTDTAARA DTAARA(QGPL/DTAQJOB) TYPE(*CHAR) LEN(1)
>                 MONMSG MSGID(CPF1023) /* already exists */
>                 ALCOBJ OBJ((QGPL/DTAQJOB *DTAARA *EXCL)) WAIT(0)
>                 MONMSG MSGID(CPF0000) EXEC(GOTO EOJ) /* Already active so end */
>
>
> Other jobs:
>                 ALCOBJ OBJ((QGPL/DTAQJOB *DTAARA *EXCL)) WAIT(0)
>                 MONMSG MSGID(CPF0000) EXEC(GOTO ACTIVE)
> /* if the data area can be allocated then the monitor job is not active */
>                 DLCOBJ OBJ((QGPL/DTAQJOB *DTAARA *EXCL))
>                 SBMJOB CMD(CALL PGM(DTAQPGM)) JOB(DTAQMON)
>       ACTIVE:
>
>   
> > ----- Original Message -----
> > From: "Bob Bledsoe" <bledsoe.bob@xxxxxxxxx>
> > To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
> > Subject: Re: Dtaq/ UsrQ Monitor
> > Date: Mon, 16 Mar 2009 10:24:19 -0700
> >
> >
> > Well I need a lot of education on queues. But that said I think Albert
> > somehow came up with what I'm looking for. How do I tell if the program that
> > which monitors the queue is active?
> >
> > Thanks
> > Bob B
> >
> >
> > On Mon, Mar 16, 2009 at 10:05 AM, Albert York <albertyork@xxxxxxxxx> wrote:
> >
> >     
> > > If the queue exists then it is active. You don't have to start it.
> > >
> > > To check if the queue exists use the CHKOBJ command.
> > >
> > > Do you mean that you want to know if the program which monitors the queue
> > > is active?
> > >
> > > Albetr
> > >
> > >       
> > > > ----- Original Message -----
> > > > From: "Bob Bledsoe" <bledsoe.bob@xxxxxxxxx>
> > > > To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
> > > > Subject: Re: Dtaq/ UsrQ Monitor
> > > > Date: Mon, 16 Mar 2009 09:41:55 -0700
> > > >
> > > >
> > > > The problem here is that I'm not sure what I mean. I have not done
> > > >         
> > > anywork
> > >       
> > > > with the datq or usrq before. The program is calling another progran that
> > > >         
> > > is
> > >       
> > > > used to start the queue. I don't want to start the queue if it is already
> > > > there and active. How do I know if the queue is there and active?
> > > >
> > > > Thanks,
> > > > Bob
> > > >
> > > >
> > > >
> > > > On Mon, Mar 16, 2009 at 9:36 AM, Alan Campin <alan0307d@xxxxxxxxx>
> > > >         
> > > wrote:
> > >       
> > > > > Not sure what you mean by instance? Do you mean a message in the queue?
> > > > >           
> > > Do
> > >       
> > > > > you mean how do you monitor for a message in a Data Queue or User
> > > > >           
> > > Queue?
> > >       
> > > > > I have a service program that implements functions that read and write
> > > > >           
> > > to
> > >       
> > > > > user queues if that is what you need.
> > > > >
> > > > > On Mon, Mar 16, 2009 at 10:22 AM, Bob Bledsoe <bledsoe.bob@xxxxxxxxx>
> > > > > wrote:
> > > > >
> > > > >           
> > > > > > Good Morning,
> > > > > >  I am writing a RPGLE program where I will be starting Dtaq's and
> > > > > >             
> > > usrq's.
> > >       
> > > > > I
> > > > >           
> > > > > > want to monitor so that I only start up an instance when there are no
> > > > > > instances currently. I have looked around but can't find anything
> > > > > >             
> > > that
> > >       
> > > > > > shows
> > > > > > how to do the monitor. Can someone please give me a push in the right
> > > > > > direction?
> > > > > >
> > > > > > Thank you,
> > > > > >
> > > > > > Bob B
> > > > > > --
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