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MySQL/MariaDB and the MySQLdb Python bindings for MySQL/MariaDB
The primary supported backends are PostgreSQL and SQLite. MySQL/MariaDB is supported by Trac with limitations (see #KnownIssues). Use this only if you don't have other choice, and be warned that there can be issues unicode support and the repository cache. Some users are nevertheless using MySQL/MariaDB successfully, so it might work for you.
Requirements
MySQL/MariaDB
Warning: The following applies to Trac starting with 0.11.1.
For earlier versions of Trac, please see MySqlDb@22#MySQL.
To avoid unicode and international characters problems in Trac (e.g., international characters turning into question marks with mysterious "Incorrect string value" errors logged), we strongly advise MySQL users to use only databases with the utf8
character set and the utf8_bin
collation type. All tables should be created as InnoDB or NDB type tables, because Trac uses transaction mechanism that not supported by MyISAM tables (see ticket:8067:5 and MySQL docs).
Proper database can be created with the MySQL monitor, like that:
CREATE DATABASE trac DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
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. - NOTE: On FreeBSD this package is called py-MySQLdb (in ports)
Troubleshooting
If you get an error from python when using trac-admin like this:
OperationalError: (1045, "Access denied for user 'tracuser'@'localhost' (using password: YES)")
There are a few possibilities:
- Try first to login on the command-line using the user tracuser (mysql -p -h localhost -u tracuser)
- Created user is not yet used by MySQL (Login to the MySQL server(as root): mysql -p and type FLUSH PRIVILEGES;)
- The user is added but the host does not match in the mysql user table (I had this on my FreeBSD setup). mysql -p; use mysql; UPDATE user SET Host="localhost" WHERE User="tracuser"; FLUSH PRIVILEGES;)
Known Issues
Still Opened
next-dev-1.7.x milestone tickets:
- #13080
- Add [trac] mysql_storage_engine option instead of editting my.cnf
next-major-releases milestone tickets:
- #6986
- MySQL schema changes for performance
- #11206
- Reduce join in query process
- #12390
- Attachment table primary key not unique when migrating from SQLite to MySQL
next-stable-1.6.x milestone tickets:
- #12097
- Add a script to contrib for converting MySQL storage engine
- #12363
- Support ucs2/utf16/utf32 charset and utf16_bin/utf32_bin collation in MySQL
unscheduled milestone tickets:
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: mod_wsgi:ApplicationIssues#MySQL_Shared_Library_Conflicts. Another possibility is that you've hit MySQL bug 36639, as explained in ticket:3645#comment:48.
When changing collation to utf8 MySQL may fail in 4.1.x and 5.0.x versions on MyISAM table type. It will complain about "too big" indexes in some Trac tables. 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.
- #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'
- #6237
- InterfaceError: (0, '') after idle period with mod_wsgi 1.1/Apache 2.2.3
- #6554
- trac-admin allows to init environment with mysql errors
- #6787
- Trac 0.10.4 - ticket module provider fails in background
- #8279
- IntegrityError when not logged in
- #8552
- Formatted time via SQL command FROM_UNIXTIME fails to replace %*
- #9696
- OperationalError: (2002, "Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (13)")
- #9983
- TypeError: int() argument must be a string or a number
- #10287
- TypeError: unsupported type for timedelta microseconds component: unicode
- #10511
- OperationalError: (1030, 'Got error 28 from storage engine')
- #11727
- Problem with synchronizing svn commits to MySQL database
- #12409
- The $ character must be URL encoded if used as a database password
(corresponding custom query)
Conversion
MyISAM to InnoDB
Check that tables are not already converted:
SELECT table_name, engine FROM information_schema.tables WHERE table_schema=DATABASE();
For every table in Trac database issue:
ALTER TABLE `table_name` ENGINE = InnoDB;
Collation from "whatever" to "utf8_bin"
First modify DB collation:
ALTER DATABASE `trac_database` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
Then modify tables - issue the following for every table:
ALTER TABLE `table_name` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
From SQLite
Users have reported success with the following method.