Django MySQL throws an error, Library not loaded: /usr/local/opt/mysql@5.6/lib/libmysqlclient.18.dylib When I upgraded from 5.6 to 5.7 mysql

Question

Yes, this seems like a common error. But something else is wrong with my environment. I have upgraded from MySQL 5.6 version to 5.7.

I can access mysql5.7 by typing mysql into the console.

I have updated the DYLD_LIBRARY_PATH to reflect new 5.7 location

git:(parent-child) ✗ echo $DYLD_LIBRARY_PATH
/usr/local/opt/mysql@5.7/lib/:

But the error for reason still says it is trying to load from 5.6 version.

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/Users/vineeth/envs/automize2.0/lib/python3.7/site-packages/django/db/backends/mysql/base.py", line 16, in <module>
    import MySQLdb as Database
  File "/Users/vineeth/envs/automize2.0/lib/python3.7/site-packages/MySQLdb/__init__.py", line 18, in <module>
    from . import _mysql
ImportError: dlopen(/Users/vineeth/envs/automize2.0/lib/python3.7/site-packages/MySQLdb/_mysql.cpython-37m-darwin.so, 2): Library not loaded: /usr/local/opt/mysql@5.6/lib/libmysqlclient.18.dylib
  Referenced from: /Users/vineeth/envs/automize2.0/lib/python3.7/site-packages/MySQLdb/_mysql.cpython-37m-darwin.so
  Reason: image not found

Notice the error says it still is trying locate /usr/local/opt/mysql@5.6/lib/libmysqlclient.18.dylib

I have reinstalled almost everything since this error came.

Tried several solutions

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

rails + MySQL on OSX: Library not loaded: libmysqlclient.18.dylib

Nothing seems to change its reference.

How do I make it refer to the newer one which is in /usr/local/opt/mysql@5.7/lib/

Also reinstalled mysqlclient with pip but still no luck.

Help is welcome. Been struggling since a day.

Have you also recreated that virtualenv, ensuring a new version of the MySQLdb binary module (`_mysql`) gets compiled? — AKX, May 07 '20 at 10:49
Yes, I have tried to run the project in a new environment with a fresh project. Same error. — Vineeth Sai, May 07 '20 at 10:57
Are you using `mysqlclient` or the old and busted `MySQL-python`? — AKX, May 07 '20 at 11:03
And when you install it, does it compile from source or is it maybe using a cached wheel? — AKX, May 07 '20 at 11:16
@AKX Thank you, man. This seems to have solve the problem. I never knew this was decided during the time of pip install and cached inside. — Vineeth Sai, May 07 '20 at 11:48

score 1 · Accepted Answer · answered May 07 '20 at 12:09

To expand my comment as an answer:

Pip compiles source packages into wheels that get cached into your local Pip cache. However, it has no knowledge of the "ambient" dependencies that may affect how the binary package gets compiled, in this case the MySQL shared library.

Recreating the virtualenv won't directly help, since Pip will use the cached binary wheel (to save you from a recompilation).

You could:

use pip install --no-cache-dir to have Pip not use the cache at all (though the "tainted" wheel will remain in your cache)
nuke the whole Pip cache from orbit
see what comes out of https://github.com/pypa/pip/issues/2882 / https://github.com/pypa/pip/issues/4685 ...

I had no clue that such details are stored inside the cache. I spend almost a day trying to figure out reinstalling stuff, completely oblivious to the fact that this was installing the same stored configurations. Running `pip install --no-cache-dir mysqlclient` fixed the problem. Thank you — Vineeth Sai, May 07 '20 at 12:23

Django MySQL throws an error, Library not loaded: /usr/local/opt/mysql@5.6/lib/libmysqlclient.18.dylib When I upgraded from 5.6 to 5.7 mysql

1 Answers1