RE: Best options for polling a file

First off, what are you attempting to accomplish?

Secondly, why have you ruled out the use of data queues?

Charles Wilt
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
 

> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of
> pascal.jacquemain@xxxxxxxxxxxxxx
> Sent: Monday, May 23, 2005 12:57 PM
> To: rpg400-l@xxxxxxxxxxxx
> Subject: Best options for polling a file
> 
> 
> Hello,
> 
> Imagine a file where records are created by jobs and are 
> processed by other
> jobs. The processing jobs do not access all records but only 
> those with the
> right key field. There are several solutions to get data from 
> the file and
> to "wake up" the processing job.
> 
> - Use of data queue or message queue to tell the processing 
> job to "wake
> up". While not a bad idea, it means programs that create 
> records in the file
> must also call a program to generate the data queue message 
> or the message.
> This may be done via a trigger but this adds processing time 
> every time a
> record is created.
> 
> - Use a delay wait method (in this case, waiting 0.1 second 
> each time) and
> check with SETLL or CHAIN that at least 1 record is awaiting 
> processing.
> This is a "lighter" option than the above on the jobs that 
> create data but
> can lead to unnecessary use of CPU or I/O (although while 
> running on our
> system, the CPU and I/O of jobs that have nothing to process 
> are very low if
> not negligible).
> 
> Can you make comments or are there other more desirable 
> methods? (We do not
> want to use either data queues or MQ queues or message queues 
> to store the
> temporary data).
> 
> Thanks
> 
> Pascal
> 
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