More DST and Database Systems

Thursday, January 25, 2007

I gathered some notes in an earlier post on how the new Daylight Savings Time change effected my Oracle database systems. Now I had to do the research for MySQL and MS SQL Server.

MySQL
Found this forum thread which references this link. Whether you need to perform any actions is dependent upon whether your OS includes zoneinfo files or not (e.g. Microsoft Windows, HP-UX). My database installations appear to use the system to obtain the time information. I don’t believe there is a need for me to populate the MySQL time zone tables using the mysql_tzinfo_to_sql utility.

mysql> SELECT @@global.time_zone, @@session.time_zone;
+------------------------------------------------------------+---------------------------------------------------------------+
| @@global.time_zone | @@session.time_zone |
+------------------------------------------------------------+---------------------------------------------------------------+
| SYSTEM             | SYSTEM              |
+------------------------------------------------------------+---------------------------------------------------------------+
1 row in set (0.02 sec)

MySQL documentation about timezones can be found here for 4.1 and here for 5.0.

MS SQL Server
Found this link for Microsoft products, but SQL Server does not appear to be listed as an affected product. An MSDN forum posting has a response saying SQL Server is not affected because it uses time information from the OS. This reason is also mentioned on Chad Boyd’s blog post.