This blog explains the root cause why an ABAP application server instance shutdown itself, because of a time difference of 1 hour to the database. But on OS level, there is no time difference at this point in time?
A SAP system is started on 7th of February. At this point in time, the Windows OS was configured to switch to DST time in the United States at 12th of March.
The ABAP application server caches the timezone and DST settings of the Windows OS at 7th of February.
Let's assume, somebody decided not to switch to DST at 12th of March? The necessary changes will be made on Windows OS level. Windows will not switch to DST on 12th of March.
What will happen at 12th of March, at 2:00 AM?
A few minutes later, when any work process (disp+work.exe) will check the time against the database time, it will recognize that it is 3600 seconds (= 1 hour) away. This will lead to an emergency shutdown of the whole instance to prevent data inconsistency.
In dev_w* trace you see the emergency shutdown information and the time drift of 3600 seconds.
Whenever you plan to change timezone or DST settings on Windows Server hosts which run ABAP application server instances, make sure to restart the instances!
Scenario
A SAP system is started on 7th of February. At this point in time, the Windows OS was configured to switch to DST time in the United States at 12th of March.
The ABAP application server caches the timezone and DST settings of the Windows OS at 7th of February.
Let's assume, somebody decided not to switch to DST at 12th of March? The necessary changes will be made on Windows OS level. Windows will not switch to DST on 12th of March.
What will happen at 12th of March, at 2:00 AM?
- Windows remains on the winter time, no time change on OS level
- the database recognized the change on OS level at 5th of March and will not change the time
- the ABAP application server still has the old timezone and DST settings cached. It will switch "internally" to DST, which means: plus one hour
A few minutes later, when any work process (disp+work.exe) will check the time against the database time, it will recognize that it is 3600 seconds (= 1 hour) away. This will lead to an emergency shutdown of the whole instance to prevent data inconsistency.
In dev_w* trace you see the emergency shutdown information and the time drift of 3600 seconds.
Lessions learned
Whenever you plan to change timezone or DST settings on Windows Server hosts which run ABAP application server instances, make sure to restart the instances!
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