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 0.10 Trac can use MySQL for its DatabaseBackend, but consider using at least 0.10.5 or, much better, 0.11.1.
Requirements
MySQL
Warning: The following applies to Trac starting with 0.11.1.
For earlier versions of Trac, please see MySqlDb@22#MySQL.
In short, up to 0.11 use utf8_general_ci collation type, but starting with 0.11.1, use utf_bin as explained below.
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 0.10.4. As a workaround it has been 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 0.11.1.
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 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 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 MySQL-python Bug Tracker.
Known Issues
Still Opened
- #3676
- MySQL: Primary keys are not well designed
- #4990
- release 0.10.4 with MySQL utf8 enforcement
- #6823
- trac crashing under mysql, w/ fix
- #5120
- mysql_backend should parse parameters
- #6986
- MySQL schema changes for performance
- #5556
- server "crash", restart, then cannot view tickets
- #6554
- trac-admin allows to init environment with errors
- #5255
- Trac resource leak?
Typical Problems
If you have some strange issues (typically OperationalError: (2006, 'MySQL server has gone away'), as in #3645, and your web frontend is Apache, you might have conflicting mysql libraries. Be sure to read: http://code.google.com/p/modwsgi/wiki/ApplicationIssues#MySQL_Shared_Library_Conflicts
- #3182
- Error when adding or viewing a ticket using MySQL
- #3723
- Problems with database encoding
- #3857
- Encoding problem with mysql
- #4017
- initenv problem with MySQL - Access Denied
- #4437
- install error (mysql)
- #4528
- TypeError: unhashable type when installing trac-0.10.3 with mysql
- #5012
- 'module' object has no attribute 'connect'
- #6787
- Trac 0.10.4 - ticket module provider fails in background
(corresponding custom query)
Conversion
While a more robust method may be created for 0.10.4 to allow easy conversion from SQLite to MySQL, users have reported success with the following method.
