pyhon导入psycopg2模块，提示undefined symbol: PQconninfo

问题描述：

pyhon导入psycopg2模块，提示undefined symbol: PQconninfo

[root@hd02 ~]# python
Python 2.7.15 (default, Apr  1 2019, 00:00:00)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>>
>>>
>>> import psycopg2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "build/bdist.linux-aarch64/egg/psycopg2/__init__.py", line 50, in <module>
  File "build/bdist.linux-aarch64/egg/psycopg2/_psycopg.py", line 7, in <module>
  File "build/bdist.linux-aarch64/egg/psycopg2/_psycopg.py", line 6, in __bootstrap__
ImportError: /root/.cache/Python-Eggs/psycopg2-2.8.3-py2.7-linux-aarch64.egg-tmp/psycopg2/_psycopg.so: undefined symbol: PQconninfo

定位过程：

1. 查询PQconninfo属于那个so文件

   find -name /  *.so|xargs -n 1 nm -AD |grep PQconninfo

   输出结果：/lib64/libpq.so

2. ldd _psycopg.so文件，确认 /lib64/libpq.so 是否包含在如下输出中，输出如附件图

  ldd /root/.cache/Python-Eggs/psycopg2-2.8.3-py2.7-linux-aarch64.egg-tmp/psycopg2/_psycopg.so

3. 发现libpq.so被链到了另外一路径下的 libpq.so  
 
4. 执行如下命令，修改其优先链接路径

   export LD_LIBRARY_PATH=/usr/lib64/

 问题原因：

动态链接库路径不正确，通过设置LD_LIBRARY_PATH，使其链接正确的动态库

解决办法：

执行如下命令：

export LD_LIBRARY_PATH=/usr/lib64/