Change MySQL default character set to UTF-8 in my.cnf?

Question

Currently we are using the following commands in PHP to set the character set to UTF-8 in our application.

Since this is a bit of overhead, we\'d like to set this a

Answer 1

MySQL v5.5.3 and greater:

Just add three lines only in the [mysqld] section:

[mysqld]
character-set-server = utf8
collation-server = utf8_unicode_ci
skip-character-set-client-handshake

Note: Including skip-character-set-client-handshake here obviates the need to include both init-connect in [mysqld] and default-character-set in the [client] and [mysql] sections.

Answer 2

MySQL versions and Linux distributions may matter when making configurations.

However, the changes under [mysqld] section is encouraged.

I want to give a short explanation of tomazzlender's answer:

[mysqld] 
init_connect='SET collation_connection = utf8_unicode_ci' 
init_connect='SET NAMES utf8' 
character-set-server=utf8 
collation-server=utf8_unicode_ci 
skip-character-set-client-handshake

[mysqld]

This will change collation_connection to utf8_unicode_ci

init_connect='SET collation_connection = utf8_unicode_ci'

Using SET NAMES:

init_connect='SET NAMES utf8'

The SET NAMES will influence three characters, that is:

character_set_client
character_set_results
character_set_connection

This will set character_set_database & character_set_server

character-set-server=utf8

This will only affect collation_database & collation_server

collation-server=utf8_unicode_ci

Sorry, I'm not so sure what is this for. I don't use it however:

skip-character-set-client-handshake

Answer 3

If you are confused by your setting for client and conn is reseted after restart mysql service. Try these steps (which worked for me):

1. vi /etc/my.cnf
2. add the contents blow and :wq [client] character-sets-dir=/usr/local/mysql/share/mysql/charsets
3. restart mysql and login mysql , use database, input command status;, you'll find the character-set for 'client' and 'conn' is set to 'utf8'.

Check the reference for more info.

Answer 4

Change MySQL character:

Client

default-character-set=utf8

mysqld

character_set_server=utf8

We should not write default-character-set=utf8 in mysqld, because that could result in an error like:

start: Job failed to start

At last:

 +--------------------------+----------------------------+
 | Variable_name            | Value                      |
 +--------------------------+----------------------------+
 | character_set_client     | utf8                       |
 | character_set_connection | utf8                       |
 | character_set_database   | utf8                       |
 | character_set_filesystem | binary                     |
 | character_set_results    | utf8                       |
 | character_set_server     | utf8                       |
 | character_set_system     | utf8                       |
 | character_sets_dir       | /usr/share/mysql/charsets/ |
 +--------------------------+----------------------------+

Answer 5

Under Xubuntu 12.04 I simply added

[mysqld]
character_set_server = utf8

to /etc/mysql/my.cnf

And the result is

mysql> show variables like "%character%";show variables like "%collation%";
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

+----------------------+-----------------+
| Variable_name        | Value           |
+----------------------+-----------------+
| collation_connection | utf8_general_ci |
| collation_database   | utf8_general_ci |
| collation_server     | utf8_general_ci |
+----------------------+-----------------+
3 rows in set (0.00 sec)

Also take a look at http://dev.mysql.com/doc/refman/5.6/en/charset-server.html

Answer 6

All settings listed here are correct, but here are the most optimal and sufficient solution:

[mysqld]
init_connect='SET collation_connection = utf8_unicode_ci'
character-set-server = utf8
collation-server = utf8_unicode_ci

[client]
default-character-set = utf8

Add these to /etc/mysql/my.cnf.

Please note, I choose utf8_unicode_ci type of collation due to the performance issue.

The result is:

mysql> SHOW VARIABLES LIKE 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

mysql> SHOW VARIABLES LIKE 'collation%';
+----------------------+-----------------+
| Variable_name        | Value           |
+----------------------+-----------------+
| collation_connection | utf8_unicode_ci |
| collation_database   | utf8_unicode_ci |
| collation_server     | utf8_unicode_ci |
+----------------------+-----------------+

And this is when you connect as non-SUPER user!

For example, the difference between connection as SUPER and non-SUPER user (of course in case of utf8_unicode_ci collation):

user with SUPER priv.:

mysql> SHOW VARIABLES LIKE 'collation%';
+----------------------+-----------------+
| Variable_name        | Value           |
+----------------------+-----------------+
| collation_connection | utf8_general_ci | <---
| collation_database   | utf8_unicode_ci |
| collation_server     | utf8_unicode_ci |
+----------------------+-----------------+

user with non-SUPER priv.:

mysql> SHOW VARIABLES LIKE 'collation%';
+----------------------+-----------------+
| Variable_name        | Value           |
+----------------------+-----------------+
| collation_connection | utf8_unicode_ci |
| collation_database   | utf8_unicode_ci |
| collation_server     | utf8_unicode_ci |
+----------------------+-----------------+

I wrote a comprehensive article (rus) explaining in details why you should use one or the other option. All types of Character Sets and Collations are considered: for server, for database, for connection, for table and even for column.

I hope this and the article will help to clarify unclear moments.