Python: MySQLdb和"未加载库: libmysqlclient.16.dylib

Question

设置环境...

我正在尝试在一台全新的 Mac OS X 10.6 上安装环境，以便开发 Python 和 Django，但我不记得在 10.5 上遇到过这个问题。

我从 mysql-5.5.8-osx10.6-x86_64.dmg 安装了 MySQL，然后我运行了：

$ sudo pip install MySQL-python

看起来一切都很顺利（下面是输出结果）

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...

之后我尝试了：

$ python -c "import MySQLdb"

结果却出现了问题，显示：

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

所以我想问...

我哪里做错了？/我还需要做什么？

在网上搜索这个问题（包括这里的搜索）发现很多人遇到这个错误信息，主要是和 Ruby 有关，而和 Python 相关的却不多。

Answer 1

在使用easy_install之后，我创建了一个软链接，这样就解决了问题。

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

Answer 2

只需要在运行完 pip install 或 easy_install 之后，设置一下 DYLD_LIBRARY_PATH 就可以了：

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

这样做应该没问题，前提是你的 MySQL 安装在 /usr/local/mysql 这个路径下。

Answer 3

_mysql.so 是指 libmysqlclient.16.dylib。也就是说，_mysql.so 是一个共享库，它充当了 Python 和 MySQL 客户端库之间的桥梁，而这个库的动态链接库由于某种原因无法加载。

你需要回答以下问题：

• 你的系统上有没有 libmysqlclient.16.dylib 这个文件？如果没有，你需要安装 MySQL 客户端软件。
• 如果有，这个库所在的文件夹是否在你的 DYLD_LIBRARY_PATH 设置中？如果没有，试着把它加进去。
• 如果有，你还需要确保 libmysqlclient.16.dylib 这个文件没有损坏。我在 /opt/local/lib/mysql5/mysql/libmysqlclient.16.dylib 安装的版本，来自 MacPorts，MD5 校验码是 c79ee91af08057dfc269ee212915801a，文件大小是 1,462,376 字节。你的文件是什么样的？