Loading timezones into MySQL or InfiniDB

If you are running queries or reports that utilize mysql timezone convertion function (CONVERT_TZ) make sure that you have run mysql utility (mysql_tzinfo_to_sql) that loads timezone information from the system into mysql server first. Without having loaded the timezone information one will simply get NULL return value and no message or error. This is expected behavior because the required tables for MySQL already exist but they are not populated!

In many threads and forums I have seen developers asking question on how to convert one timezone to another while all they get is null return value.  I myself have bitten by it couple of times when I moved to new MySQL servers where the following steps were not done.

Here I am using Ubuntu which has timezone files under /usr/share/zoneinfo directory. In many flavors of unix including Mac OS you will find it there, if not search for it with find command 😉

Also, note you can load all timezones of the world in one go. The SQL created by this utility is large with more than 142K lines of SQL code! After completing the task the following tables must have been populated.

  1. mysql.time_zone
  2. mysql.time_zone_name
  3. mysql.time_zone_transition
  4. mysql.time_zone_transition_type

There is another related table mysql.time_zone_leap_second which we don’t need at this point.

# To load all timezone
shell> mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql

# You may see output like:
Warning: Unable to load '/usr/share/zoneinfo/Asia/Riyadh87' as time zone. Skipping it.
Warning: Unable to load '/usr/share/zoneinfo/Asia/Riyadh88' as time zone. Skipping it.
Warning: Unable to load '/usr/share/zoneinfo/Asia/Riyadh89' as time zone. Skipping it.
# On my system some specific timezone of Riyadh are not defined. And you can ignore these warnings.

Restart mysql or infinidb server to bring in the timezones and run a test.

# In case of infinidb idbmysql is just an alias
shell> alias idbmysql
alias idbmysql='/usr/local/Calpont/mysql/bin/mysql --defaults-file=/usr/local/Calpont/mysql/my.cnf -u root'

shell> idbmysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 16
Server version: 5.1.39 MySQL Community / Calpont InfiniDB Community 2.2-2 Final (COSS LA)

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. 

mysql> SELECT utc_timestamp(), CONVERT_TZ(utc_timestamp(),'UTC','MET');
| utc_timestamp() | CONVERT_TZ(utc_timestamp(),'UTC','MET') |
| 2011-07-29 01:14:40 | 2011-07-29 03:14:40 |
1 row in set (0.00 sec)

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