Python: MySQLdb and "Library not loaded: libmysqlclient.16.dylib"

##The setup... Trying to set up a clean Mac os X 10.6 install to develop python/django and I didn't remember running into this on 10.5.

After installing MySQL from the installer on mysql-5.5.8-osx10.6-x86_64.dmg I ran

$ sudo pip install MySQL-python

and it seemed to go smoothly (output below)

Downloading/unpacking MySQL-python
  Downloading MySQL-python-1.2.3.tar.gz (70Kb): 70Kb downloaded
  Running setup.py egg_info for package MySQL-python
    warning: no files found matching 'MANIFEST'
    warning: no files found matching 'ChangeLog'
    warning: no files found matching 'GPL'
Installing collected packages: MySQL-python
  Running setup.py install for MySQL-python
    building '_mysql' extension
    gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -pipe -Dversion_info=(1,2,3,'final',0) -D__version__=1.2.3 -I/usr/local/mysql/include -I/System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -c _mysql.c -o build/temp.macosx-10.6-universal-2.6/_mysql.o -Os -g -fno-common -fno-strict-aliasing -arch x86_64
    In file included from _mysql.c:36:
    /usr/local/mysql/include/my_config.h:325:1: warning: "SIZEOF_SIZE_T" redefined
    In file included from /System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6/Python.h:9,
                     from pymemcompat.h:10,
                     from _mysql.c:29:
    /System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6/pymacconfig.h:33:1: warning: this is the location of the previous definition
    In file included from _mysql.c:36:
    /usr/local/mysql/include/my_config.h:419:1: warning: "HAVE_WCSCOLL" redefined
    In file included from /System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6/Python.h:8,
                     from pymemcompat.h:10,
                     from _mysql.c:29:
    /System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6/pyconfig.h:803:1: warning: this is the location of the previous definition
    gcc-4.2 -Wl,-F. -bundle -undefined dynamic_lookup build/temp.macosx-10.6-universal-2.6/_mysql.o -L/usr/local/mysql/lib -lmysqlclient_r -lpthread -o build/lib.macosx-10.6-universal-2.6/_mysql.so -arch x86_64
    warning: no files found matching 'MANIFEST'
    warning: no files found matching 'ChangeLog'
    warning: no files found matching 'GPL'
Successfully installed MySQL-python
Cleaning up...

after this I tried:

$ python -c "import MySQLdb"

and it crapped out on me with:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Library/Python/2.6/site-packages/MySQLdb/__init__.py", line 19, in <module>
    import _mysql
ImportError: dlopen(/Library/Python/2.6/site-packages/_mysql.so, 2): Library not loaded: libmysqlclient.16.dylib
  Referenced from: /Library/Python/2.6/site-packages/_mysql.so
  Reason: image not found

##So on to my question...

What did I do wrong?/What else do I need to do?

Googling (and searching here) for this returns a lot of results getting this error message with Ruby not too many with Python tho.

Just set the DYLD_LIBRARY_PATH after running pip install or easy_install:

export DYLD_LIBRARY_PATH=/usr/local/mysql/lib/

Should do the job assuming your MySQL installation lives under /usr/local/mysql.

_mysql.so refers to libmysqlclient.16.dylib. That is, the shared library that serves as the bridge between Python and the MySQL client library, _mysql.so, refers to the dynamic library for the MySQL client library, and that library cannot be loaded for some reason.

Questions you need to answer:

• Is there a libmysqlclient.16.dylib anywhere on your system? If not, you need to install the MySQL client software.
• If so, is the directory containing that library in your DYLD_LIBRARY_PATH setting? If not, try adding it.
• If so, you'll have to ensure that the libmysqlclient.16.dylib file is not corrupt. My copy, installed in /opt/local/lib/mysql5/mysql/libmysqlclient.16.dylib, courtesy of MacPorts, has MD5 signature c79ee91af08057dfc269ee212915801a and is 1,462,376 bytes in size. What does your copy look like?

After easy_install, I create a soft link that solved the problem

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

It can also crop up if your MySQL client is newer than your MySQL-python package. In my case, I had a libmysqlclient_r.18.dylib on my machine, but not a libmysqlclient_r.16.dylib. Running pip search mysql revealed

> MySQL-python - Python > interface to MySQL INSTALLED: 1.2.3 > LATEST: 1.2.3c1

and running pip install --upgrade MySQL-python fixed my problem.

On my setup (mysql 5.7.x from brew, pyenv), I had a newer lib file libmysqlclient.20.dylib. What worked was to pip uninstall MySQL-python and pip install MySQL-python.

On the latest version of MySQL 5.7.9 it's no support from MySQL-python and I used the PyMySQL library instead. Also I added in manage.py (in Django project) these lines to emulate API of MySQL-python:

try:
    # load MySQLdb interface emulation
    import pymysql
    pymysql.install_as_MySQLdb()
except ImportError:
    pass

For those like me who need - or have - both MySQLdb & PyMySQL installed (in my case, I needed to have both installed because I use PyMySQL to connect to my local MySQL instances, and MySQLDb for remote/live instances):

Be sure you're using the right URI scheme. To access the local instances:

LOCAL_DATABASE_URI = 'mysql+pymysql://username:password@hostname/dbname'

and for live:

REMOTE_DATABASE_URI = 'mysql+mysqldb://username:password@hostname/dbname'

Making this distinction solved the issue for me