psycopg2 installation problem on OSX Lion

Question

I used PIP to install psycopg2 on OSX Lion. But when I try to import from python I get the following errors:

Python 2.7.1 (r271:86832, Jun 16 2011, 16:59:05) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import psycopg2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/psycopg2/__init__.py", line 67, in <module>
    from psycopg2._psycopg import BINARY, NUMBER, STRING, DATETIME, ROWID
ImportError: dlopen(/Library/Python/2.7/site-packages/psycopg2/_psycopg.so, 2): Symbol not found: _PQbackendPID
  Referenced from: /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
  Expected in: flat namespace
 in /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
>>> 

Does anyone know how to fix this?

Thanks!

Mosko

Answer 1

Step 1.

Install Mac Ports ( www.macports.org ) using the Lion dmg.

Step 2.

sudo port install postgresql91

Step 3.

export PATH=/opt/local/lib/postgresql91/bin:$PATH

Step 4.

pip install psycopg2

if in a virtualenv environment or

sudo port install psycopg2

if not.