Unicenter CA-Scheduler Job Management for VSE User Guide

3.1 Defining Schedules
3.1.4.2 When Will a Schedule's Jobs Actually Run?
As Unicenter CA-Scheduler selects the day's workload, it organizes the work,
grouping each schedule's jobs together, but it does not line schedules up in the
order they are selected. Instead, Unicenter CA-Scheduler allows you to control
the work sequence with several schedule parameters:
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SCR predecessors
USE SIMTIME
EARLIEST START TIME
SRC start times
COMPLETION DEADLINE TIME
SCHD PRIORITY
Defining predecessors forces Unicenter CA-Scheduler to witness a specific
event before starting any jobs in that schedule. Predecessors can be a variety of
events such as
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The start or end of another schedule or job
The close of an output data set or generation data group
A user-defined event that you can control using a global parameter
An event that occurred sometime in the past
When schedules must run in a certain order, define schedules as predecessors
to one another using the schedule criteria record (SCR). See the chapter
"Criteria Language" for instructions on how that is done.
When Unicenter CA-Scheduler lines up the work to be processed during the
day, the first factor it considers is each schedule's predecessors. Then
Unicenter CA-Scheduler compares the start times for schedules, putting those
that can start earliest ahead of ones that start later. Schedules without
predecessors and start times go to the top of the list because nothing is
delaying them, so they start right after autoscan. SCHD PRIORITY is the last
factor Unicenter CA-Scheduler considers when organizing the workload and
only serves to sort schedules that have equivalent values for all the other
factors.
Unicenter CA-Scheduler gives you three ways of specifying when jobs start.
To see which method you chose, Unicenter CA-Scheduler checks the value of
USE SIMTIME. A value of YES causes Unicenter CA-Scheduler to start that
schedule at the time shown on the Simulated Execution Schedule.
If you set USE SIMTIME=YES, Unicenter CA-Scheduler ignores any other start
times you may have specified. Unicenter CA-Scheduler sites that have defined
their resources in great detail and run the vast majority of their production
load under Unicenter CA-Scheduler control could set USE SIMTIME=YES. The
accuracy of their history data and resource definitions would result in
simulations that project optimal start times for schedules. However, most
Unicenter CA-Scheduler sites leave USE SIMTIME=NO.
Chapter 3. Maintaining the Database 3-11