Understanding the Scheduler Server
The Scheduler server is a process that performs two distinct functions: it launches all jobs at the scheduled times, and it monitors each job's progress and ending state. These functions are started by a JDENET message, as defined in the following kernel type in the jde.ini file:
[JDENET_KERNEL_DEF10] dispatchDLLName=jdekrnl.dll dispatchDLLFunction=_JDEK_DispatchScheduler@24 maxNumberOfProcesses=1 beginningMsgTypeRange=2001 endingMsgTypeRange=2256 newProcessThresholdRequests=0 numberOfAutoStartProcesses=1
The Scheduler launches batch processes in a server, environment, and user combination, based on the information in the F91300 table. After the Scheduler is started, JDENET keeps it in a wait state by calling the Scheduler dispatch function every minute with an idle message. This idle message enables the Scheduler process to check whether it should launch a job or monitor the jobs that are running. In addition, JDENET sends the Scheduler any message sent from the workstation (for example, messages that new job schedules were added).
You can stop, reset, restart, and refresh the Scheduler server. For example, if the server goes offline, it needs to be reset. You can also modify the server and monitor sleep time, specifying how many seconds you want JDENET to wait until it checks to see if it needs to initialize, or wake up, the Scheduler server.
You also might encounter situations for which you need to activate or deactivate the Job Launcher or Job Monitor. For example, you might need to take down the servers to which you submit jobs and for which you want to avoid unnecessary connection errors when jobs are submitted.
You can also change the jde.ini file to enable the Scheduler to restart automatically by
changing the numberOfAutoStartProcesses line. If you enable this
feature, and the server on which the Scheduler server is running comes down, the
Scheduler server automatically restarts when the server comes back up, instead of having
to be restarted manually. When the Scheduler server restarts, the Scheduler checks the
F91320 table to determine if it should restart on that server. If not, the Scheduler
shuts down.
JDENET handles the calls to initialize the Scheduler server. The JDENET process either sends a message to initialize the Scheduler to launch a job if it receives a message that table F91320 has changed, or it sends an idle message if no change is detected. For faster response time, you can decrease the number of seconds that you want JDENET to wait until it checks to see if table F91320 has changed.