RE: Best options for polling a file

[Rich Duzenbury <rduz-midrange@xxxxxxxxxxxxxxxxxxx>]

On Mon, 2005-05-23 at 14:08 -0700, Alan Campin wrote:

> or using EOFDLY which again takes all kinds of resources. 
EOFDLY doesn't consume large amounts of resources.  The job goes to
sleep until a record appears in the file.  EOFDLY has been around since
system/38 (perhaps before that), and it *couldn't* use much in the way
of resources because there weren't that many to consume.

The drawback to EOFDLY is that a database write must be made in order to
signal the listening job to do something.

> Data queues are just about as perfect as anything can be on the AS/400. 
The problem with data queues is that they are transient.  If the system
goes down while there are (perhaps *important*) messages in the data
queue, you kiss them goodbye.  

When the system is IPL'd, one of the things it does is to initialize
(read 'empty') the queues.

Regards,
Rich