Time Event shifts in time

Products

• CA Automic Workload Automation - Automation Engine

Issue/Introduction

When observing the Start Time of Time Events during a period, a shift of seconds is observed compared to the expected schedules duration.

For instance a TIme Event that runs every 30 minutes can have the following Start Times:

Expected (hh:mm:ss)	Real (hh:mm:ss)
00:00:00	00:00:44
00:30:00	00:30:47
01:00:00	01:00:48
01:30:00	01:30:52
02:00:00	02:00:52
02:30:00	02:30:53
...	...

Environment

Release : v12.2 / v12.3

Component : AUTOMATION ENGINE

Cause

The delays are caused by 4 factors:

1. The initial delay (44 seconds in the example) is caused by the recalculation of jobs at the period turnaround. 
2. The Automation Engine checks each 20 seconds (by default) if there are Events to be launched, if yes a request is posted in the MQWP queue, this can lead to delays of up to 20 seconds
3. It takes between 0 and x seconds before the WP picks up the request and launches the job, this can lead to a delays of x seconds. Depending on the speed of the database this should limited to 1-2 seconds.
4. After the check the Automation Engines sets EH_NextCheck at the current time + one period later (so 30 minutes=1800 seconds later, in the example)

Factor (1) depends on number of jobs to be calculated at Period Turnaround and thus the database performance. Because of (2) and (3) small additional delays can build up. Lastly, because of (3) the delays are pushed forward and can never go down. 

Resolution

If very precise scheduling is needed it is recommended to use the C_PERIOD. This will put the request to launch of the job at the required launch time.

The job will be launched max. 20 seconds after the scheduled launch time.