Beginning in 2007, daylight saving time (DST) will be extended in the United States. DST will start three weeks earlier on March 11, 2007, and end one week later on November 4, 2007. This results in a new DST period that is four weeks longer than previously observed.

How that does affect SQL Server users? Since the SQL Server engine takes time from the Windows operating system, SQL Server users will not be directly affected. As long as their Windows system is updated with the appropriate patches the SQL Server engine will be fine. However, users that utilize the Notification Services for SQL Server will be affected. They need to apply the update script from this KB article: http://support.microsoft.com/?id=931815.

To determine if Notification Services is installed users can check Add/Remove Programs for SQL Server 2000 (since Notification Services is installed as a separate product) or certain registry keys can be verified for both SQL Server 2000 and 2005. Also, the existence of the NS services or databases named like NS* will be an indication for existence of Notification Services. See the section “How to determine whether Notification Services is installed” in the above KB article for more details.

Important notes:

– The update script needs to be applied only if a Notification Services instance has been deployed, since only the NS application instance database is affected. By default when Notification Services is installed it installs only the binary files (which do not need to be updated).
– New instances created after SQL Server 2005 SP2 is installed do not need to be patched (however, SQL Server SP2 does not fix existing instances, so they have to be patched).

Additional resources:

2007 time zone update for Microsoft Windows operating systems
http://support.microsoft.com/kb/928388/

Daylight Saving Time Help and Support Center
http://support.microsoft.com/gp/cp_dst

2007 time zone update for SQL Server 2005 Notification Services and for SQL Server 2000 Notification Services
http://support.microsoft.com/?id=931815

How to prepare SQL Server 2005 and SQL Server 2000 for changes to daylight saving time in 2007
http://support.microsoft.com/?kbid=931975

February 2007 cumulative time zone update for Microsoft Windows operating systems
http://support.microsoft.com/kb/931836/