Problem using MySQLdb: Symbol not found: _mysql_affected_rows

Question

A colleague got this error message when trying to use MySQLdb from Django:

[...] ImproperlyConfigured("Error loading MySQLdb module: %s" % e) django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: dlopen(/Users/roy/.python-eggs/MySQL_python-1.2.3c1-py2.5-macosx-10.5-i386.egg-tmp/_mysql.so, 2): Symbol not found: _mysql_affected_rows Referenced from: /Users/roy/.python-eggs/MySQL_python-1.2.3c1-py2.5-macosx-10.5-i386.egg-tmp/_mysql.so Expected in: dynamic lookup

He's using OS X 10.5, Python 2.5 (arriving with OS X), MySQL 5.1 & MySQLdb 1.2.3c1.

Any idea how to attack this?

Answer 1

Yes, the MySQLDb egg was compiled against a different version of libmysqlclient than the version present in the system. You need to either get a proper egg (uninstalling the previous) or to build MySQLDb from scratch to compile it against the library present in your system.

I don't know why but I think your colleague might be interested in this question:

http://stackoverflow.com/questions/1297917/configuring-django-to-use-remote-mysql-server

Answer 2

It might be best if you install mysql and it's Python bindings from scratch, I use the following steps whenever I need MySQLdb on OS X 10.4 or 10.5:

1. Install MySQL for your system, the dmg installer should be sufficient

2. The default location of MySQL will be somewhere around: /usr/local/mysql-5.0.45-osx10.4-i686. From /usr/local/mysql/lib, create a soft link:

   ln -s ../../mysql-5.0.45-osx10.4-i686/lib mysql

3. Download the MySQLdb source and unpack it

4. Edit the file site.cfg under your unpacked MySQLdb directory, comment out the registry_key and set mysql_config to:

   mysql_config = /usr/local/mysql-5.0.45-osx10.4-i686/bin/mysql_config

5. Carry on with the regular Python packages build from within MySQLdb directory:

   sudo python setup.py install

6. If everything is fine above, test MySQLdb in a new terminal:

   python -c "import MySQLdb"

The above should return nothing if successful. The above example shows OS 10.4 and MySQL 5.0, substitute them with the your proper tools version.