Python mysqldb: Library not loaded: libmysqlclient.18.dylib

Question

I solved the problem by creating a symbolic link to the library. I.e.

The actual library resides in

/usr/local/mysql/lib

And then I created a symbolic link in

/usr/lib

Using the command:

sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib

so that I have the following mapping:

ls -l libmysqlclient.18.dylib 
lrwxr-xr-x  1 root  wheel  44 16 Jul 14:01 libmysqlclient.18.dylib -> /usr/local/mysql/lib/libmysqlclient.18.dylib

That was it. After that everything worked fine.

EDIT:

Notice, that since MacOS El Capitan the System Integrity Protection (SIP, also known as "rootless") will prevent you from creating links in /usr/lib/. You could disable SIP by following these instructions, but you can create a link in /usr/local/lib/ instead:

sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/local/lib/libmysqlclient.18.dylib

My preferred method is to actually fix the library rather than playing with environment variables that may or may not actually be in scope depending on how the application is run. This is actually a fairly simple process.

First, look at the error output to see where the offending python module is located:

ImportError: dlopen(/Library/Python/2.7/site-packages/_mysql.so, 2): Library not loaded: libmysqlclient.18.dylib Referenced from: /Library/Python/2.7/site-packages/_mysql.so Reason: image not found

Okay, so the offending file is /Library/Python/2.7/site-packages/_mysql.so

Next, figure out where _mysql.so thinks it should find libmysqlclient.18.dylib:

% otool -L /Library/Python/2.7/site-packages/_mysql.so
/Library/Python/2.7/site-packages/_mysql.so:
    libmysqlclient.18.dylib (compatibility version 18.0.0, current version 18.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 169.3.0)

So, it's looking for libmysqlclient.18.dylib with no path information, let's fix that:

% sudo install_name_tool -change libmysqlclient.18.dylib /usr/local/mysql/lib/libmysqlclient.18.dylib /Library/Python/2.7/site-packages/_mysql.so

Now _mysql.so knows the full path to the library and everything works, regardless of environment variables.

% otool -L /Library/Python/2.7/site-packages/_mysql.so                                                                                           
/Library/Python/2.7/site-packages/_mysql.so:
    /usr/local/mysql/lib/libmysqlclient.18.dylib (compatibility version 18.0.0, current version 18.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 169.3.0)

I found there was another solution for this problem rather than creating a symbolic link.

You set the path to your directory, where libmysqlclient.18.dylib resides, to DYLD_LIBRARY_PATH environment variable. What I did is to put following line in my .bash_profile:

export DYLD_LIBRARY_PATH=/usr/local/mysql-5.5.15-osx10.6-x86/lib/:$DYLD_LIBRARY_PATH

That's it.

In my case, I was getting the error with Mac OS X 10.9 Mavericks. I installed MySQL Community Server directly from the Oracle/MySQL Website from DMG.

All I needed to do was symlink the lib files to the /usr/local/lib directory.

mkdir -p /usr/local/lib   
ln -s /usr/local/mysql/lib/libmysql* /usr/local/lib

Bonus: If you're running Mac OS X as well, there is a great tool to finding files like the libmysqlclient.18.dylib file, http://apps.tempel.org/FindAnyFile. This is how I originally found the location of the dylib file.