CA Process Automation and Leap Seconds

Document ID : KB000047003
Last Modified Date : 14/02/2018
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Right out of the gate, will this affect CA Process Automation? -- No.

CA Process Automation does not fire any events on the strike of a second. Processes, schedules, tasks, etc. will not be affected.


If you want to be cautious, we can suggest modifying any schedules you may have that fire on the hour to be moved by a couple minutes either before or after the hour. But again, the way those are handled is not dependent on a specific second, they just execute as soon after the expiration of the schedule as possible. 


Here is some additional information regarding the leap second if you are interested.


Windows systems are not affected by the leap second, this is because time servers for Windows are updated about once a week, so this is a non-issue in any Windows environment.

The Windows Time service does not indicate the value of the Leap Indicator when the Windows Time service receives a packet that includes a leap second. (The Leap Indicator indicates whether an impending leap second is to be inserted or deleted in the last minute of the current day.) Therefore, after the leap second occurs, the NTP client that is running Windows Time service is one second faster than the actual time. This time difference is resolved at the next time synchronization.


More information on the Windows Time Service can be found here: --- How the Windows Time Service Works.


For Unix and Linux systems however, it can be critical. Here is a link to some information for RedHat:


The key to this is the explanation:


If the system clock is kept in TAI and a right/* timezone is used then 23:59:60 may be listed; however, as 23:59:60 does not exist in Unix's implementation of UTC then the linux kernel inserts the leap second by stepping the system clock back by one second on the first clock update after 0:00 UTC.


This is what caused the Qantas Airlines outage in 2012, along with other web sites like Reddit and Mozilla.


Again, this was all due to the underlying Linux OS issue – and it’s not the fault of the OS. Unix was created WAY before the first insertion of “Leap Second” in 1972. There have been 26 since then, and the one for 2016 DEC 31 23:59:59 UTC / 2016 DEC 31 23:59:60 UTC is number 27.


Finally, here is the link to the IERS Bulletin:


Select bulletin C.