= MySQL and the MySQLdb Python bindings for MySQL =

 ''It is somewhat supported by Trac since 0.10, but there are some limitations (see [#KnownIssues]). Use this only if you don't have other choice, and be warned that there can be many issues, in particular related to the unicode support and the repository cache support. Some users are nevertheless using MySQL successfully, so it ''might'' work for you. The primary supported backends though are PostgreSQL and SQLite.''

Starting with [milestone:0.10] Trac can use MySQL for its DatabaseBackend, but consider using at least [milestone:0.10.4], [milestone:0.10.5]dev or [milestone:0.11]dev.


== Requirements ==
=== MySQL ===

In order to avoid several issues with unicode and international characters throughout Trac (e.g., international characters turning into question marks with mysterious "Incorrect string value" errors logged), we '''''strongly''''' advise MySQL users to only use databases having the ''`utf8`'' character set and the ''`utf8_bin`'' collation type. However, changing collation to ''utf8'' makes MySQL fail in 4.1.x and 5.0.x versions on MyISAM table type, because some Trac tables indexes become "too big". This will be (hopefully) addressed in [milestone:0.10.4]. As a workaround it has been [comment:ticket:3659:5 recommended] to use InnoDB tables instead of MyISAM where this limitation is absent.

Such databases can be created with the MySQL monitor, like that:
{{{
CREATE DATABASE trac DEFAULT CHARACTER SET utf8 COLLATE utf8_bin; 
}}}

Some unicode related MySQL-python bugs were worked around in r7286 so if you're experiencing problems with non-ascii text you should consider upgrading to Trac 0.11-stable or wait until Trac 0.11.1 is released.

To check character set settings for your database, issue command:
{{{
mysql> USE trac;
Database changed
mysql> SHOW VARIABLES LIKE '%character%';
+--------------------------+--------------------
| Variable_name            | Value
+--------------------------+--------------------
| character_set_client     | cp1251
| character_set_connection | cp1251
| character_set_database   | utf8
| character_set_filesystem | binary
| character_set_results    | cp1251
| character_set_server     | utf8
| character_set_system     | utf8
| character_sets_dir       | C:\DevServer\Instal
+--------------------------+--------------------
8 rows in set (0.00 sec)
mysql>
}}}

See also #3884.

Usually, you also want to create a user and give this user access to the database created above:
{{{
CREATE USER tracuser IDENTIFIED BY 'password';
GRANT ALL ON trac.* TO tracuser;
}}}
The connection string will then be:
{{{
mysql://tracuser:password@localhost/trac
}}}
=== MySQLdb ===
The recommended version is MySQL-python 1.2.2.

See http://cheeseshop.python.org/pypi/MySQL-python/1.2.2, which contains links to the .tar.gz source distribution as well as pre-built Windows eggs.

Older versions can be found at the [https://sourceforge.net/projects/mysql-python/ mysql-python] sourceforge project:
 - MySQL-python 1.2.1_p2 was the previously recommended version
 - MySQL-python 1.2.0-3.2.2, MySQL-python 1.2.2b2) were reported to have issues (see #3645).  
 - MySQL-python-1.2.2b2 was [googlegroups:trac-users:e291b3ecb4a990a1 reported] to solve an `AttributeError: 'array.array' object has no attribute 'startswith'` error seen when viewing a changeset... These problems ought to be fixed in 1.2.2b3; if they are not, or if you have other issues, please file a bug in the [https://sourceforge.net/tracker/?group_id=22307&atid=374932 MySQL-python Bug Tracker].

== Known Issues ==
=== Still Opened ===
[[TicketQuery(keywords=~mysql&status=!closed&group=milestone)]]

=== Typical Problems ===
[[TicketQuery(keywords=~mysql&resolution=worksforme)]]

(corresponding [query:keywords=~mysql&status=!closed custom query])

== Conversion ==

While a more robust method may be created for [milestone:0.10.4] to allow easy conversion from SQLite to MySQL, users have reported success with the [wiki:SqLiteToMySql following method].