For some reason, the OSX version of MySQL can’t find its own libraries.
If you’re trying to connect to MySQL from code (in this case, Python, and the MySQLdb library), you’ll typically see something like this:
Traceback (most recent call last):
File “demo.py”, line 3, in <module>
python2.7/site-packages/MySQLdb/__init__.py”, line 19, in <module>
python2.7/site-packages/_mysql.so, 2): Library not loaded: libmysqlclient.18.dylib
Referenced from: /Library/Frameworks/Python.framework/Versions/2.7/lib/
Reason: image not found
Which basically translates to “Duh, I can’t find myself.”
Specifically, it’s looking for the file libmysqlclient.18.dylib in /usr/lib, and not finding it – why? Because it installed it in /usr/local/mysql/lib. It’s been broken a few years.
Yay open source!
Anyway, there are several fixes out there, with varying levels of crapness.
The standard recommendation is to put this in your .bashrc (or .bash_profile) in your home dir:
Which fixes the problem, except then every time you try to run anything that isn’t MySQL related from the command line, you get a stupid message like this:
dyld: DYLD_ environment variables being ignored because main executable…
(/usr/bin/su) is setuid or setgid
This gets old and boring verrrrry quickly.
Another suggestion is to put the export statement at the start of any script that uses MySQL, followed by an equivalent unset command at the end (so you’re not polluting the environment).
Now, have a quick think about how many different places you’d have to put this in (ie, any script or code that connects, accesses or uses any code at all that talks to MySQL). BORING.
After I’d edited 5 or 6 scripts I decided “ok, this is crap, there must be a better way.”
So, what’s the cleanest solution? Specifically, one that avoids having to alter everything you ever write, just to get around a (hopefully soon fixed) bug in the MySQL installation?
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
In other words, create a link from /usr/local/mysql/lib (actual location) to /usr/lib (the place MySQL goes looking).
No coding around the bug, no spurious and/or dangerous environment variables. Simple, clean, with minimal or zero side effects.
[update: It’s been further suggested, by Gary Allen Vollink, below, that linking to /usr/local/lib might be more upgrade friendly – and thus safer – than /usr/lib. Please read his comments. I’m inclined to agree]