Hi and welcome Lwoo,

We just installed psycopg2 v2.4.4 on server1 for give support to you. If you need some other module, just let me know.

When you write "import psycopg2" you need set previously the enviroment variable PYTHON_EGG_CACHE, for example:

import os
os.environ['PYTHON_EGG_CACHE'] = '/home/youruser/tmp/trac-eggs'

import psycopg2
It is important that you must set PYTHON_EGG_CACHE under you username folder. The folder /tmp is not writeable for some reason to python when it loads internal imports and you could get a error similar to (or error 500):

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/site-packages/psycopg2-2.4.4-py2.7-linux-x86_64.egg/psycopg2/__init__.py", line 67, in <module>
    from psycopg2._psycopg import BINARY, NUMBER, STRING, DATETIME, ROWID
ImportError: /usr/local/lib/python2.7/site-packages/psycopg2-2.4.4-py2.7-linux-x86_64.egg/psycopg2/_psycopg.so: undefined symbol: lo_truncate
Regarding to error 500, the error_log by apache for cPanel is general, so the only way that I know to catch 500 errors is wrapper the code with a try/catch exception like:

filename = 'error_log.txt'
f = open(filename, 'w')
try:
  # Do something with your code here
  f.write('Ok')
except:
  traceback.print_exc(file=f) 
f.close()

Also searching on the general error_log I see this error for your site:

[Thu Mar 08 23:36:18 2012] [alert] [client XXX.XXX.XXX.XXX] /home/monfloo/public_html/monfloo-landing/.htaccess: Invalid command 'PythonHandler', perhaps misspelled or defined by a module not included in the server configuration
[Thu Mar 08 23:36:18 2012] [alert] [client XXX.XXX.XXX.XXX] /home/monfloo/public_html/monfloo-landing/.htaccess: Invalid command 'PythonHandler', perhaps misspelled or defined by a module not included in the server configuration
[Thu Mar 08 23:36:18 2012] [error] Optional hook test said: GET / HTTP/1.0
[Thu Mar 08 23:36:18 2012] [error] Optional function test said: GET / HTTP/1.0
[Thu Mar 08 19:36:19 2012] [alert] [client XXX.XXX.XXX.XXX] /home/monfloo/public_html/monfloo-landing/.htaccess: Invalid command 'PythonHandler', perhaps misspelled or defined by a module not included in the server configuration
[Thu Mar 08 19:36:19 2012] [alert] [client XXX.XXX.XXX.XXX] /home/monfloo/public_html/monfloo-landing/.htaccess: Invalid command 'PythonHandler', perhaps misspelled or defined by a module not included in the server configuration

Note that PythonHandler directive is only for mod_python and we are using mod_wsgi for python scripts that works with "SetHandler wsgi-script"

Please fix that and back to me again if you need more assistance.

I test on our sandbox example too http://quijost.com/sandbox/index.py

And I am getting a error like:
/usr/local/lib/python2.7/site-packages/psycopg2-2.4.4-py2.7-linux-x86_64.egg/psycopg2/_psycopg.so: undefined symbol: lo_truncate

On google a lot people complains about the error, but without a workaround. The most precise info that I could get was:

http://archives.postgresql.org/psycopg/2011-10/msg00020.php

lo_truncate is available after postgres 8.3. Psycopg is being compiled
again libpq 8.4, so the function is included. Looks like at runtime it
tries to dynamically link with an older libpq: you can check with ldd
which one.

So I gonna try debug and search on source code for make some changes on psycopg2 ang get it make available on postgres 9.1. But I cannot guarantee that I can make it work, seems a bug related with psycopg2.

While I try to fix, you could use MySqldb as a fallback alternative.

I finally solve the problem, it seems a bug on psycopg 2.4.4 on the file psycopg/lobject_int.c:

.psycopg/lobject_int.c:478:    retvalue = lo_truncate(self->conn->pgconn, self->fd, len);

http://www.postgresql.org/docs/9.0/static/lo-interfaces.html#LO-TRUNCATE

I install the development version that fix the bug, so now it is working:

# python -c "import psycopg2; print psycopg2.__version__"
2.4.5.dev0 (dt dec pq3 ext)

Try now with psycopg2 and manage.py if solves your problem and post here again your result.

The error that the trace shows:

File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/uti
ls/simplejson/__init__.py", line 111, in <module>
    import simplejson
  File "/usr/local/lib/python2.7/site-packages/simplejson-2.3.0-py2.7-linux-x86_
64.egg/simplejson/__init__.py", line 111, in <module>
    from decoder import JSONDecoder, JSONDecodeError
MemoryError
Seems more a bug (memory leak) on Django or simplejson module reading your settings.py. The server1 has 8 GB of Ram and normally used 2-4 GB, so it is pretty weird that you receive a MemoryError exception.

Try again and keep me aware of you results. Soon Django 1.4 would be released so maybe we can update soon for fix this.

Hi again Lwoo,

Sorry for the delay.

This appears on root error log:

[Wed Mar 14 00:57:15 2012] [error] [client XX.XX.XX.XX] mod_wsgi (pid=12662): Target WSGI script '/home/monfloo/public_html/monfloo-landing/django.wsgi' cannot be loaded as Python module.
[Wed Mar 14 00:57:15 2012] [error] [client XX.XX.XX.XX] mod_wsgi (pid=12662): Exception occurred processing WSGI script '/home/monfloo/public_html/monfloo-landing/django.wsgi'.
[Wed Mar 14 00:57:15 2012] [error] [client XX.XX.XX.XX] Traceback (most recent call last):
[Wed Mar 14 00:57:15 2012] [error] [client XX.XX.XX.XX]   File "/home/monfloo/public_html/monfloo-landing/django.wsgi", line 9, in <module>
[Wed Mar 14 00:57:15 2012] [error] [client XX.XX.XX.XX]     f = open(filename, 'w')
[Wed Mar 14 00:57:15 2012] [error] [client XX.XX.XX.XX] IOError: [Errno 13] Permission denied: 'error_log.txt'
[Wed Mar 14 00:57:15 2012] [warn] [client XX.XX.XX.XX] mod_include: Options +Includes (or IncludesNoExec) wasn't set, INCLUDES filter removed
Seems that you need set previously a the write permissions on error_log.txt and also complains about "Options +Includes"

Note too that sys.path.append('/home/monfloo/monfloo-lp/monfloo_lp') is wrong. You should put with public_html sys.path.append('/home/monfloo/public_html/monfloo-lp/')

I will check this for try to find a solution, but it could be that a owner file permissions. I mean user/group options as running as apache (nobody/nobody). And Django runs then as Apache application too handled by ws-script

But write a file should could make easily, because Django write files without problems but no running as apache user (nobody/nobody).

You could try use logging module or even more advanced solutions for fetch the exceptions:

http://www.davidcramer.net/code/502/debugging-django-errors.html
http://lucumr.pocoo.org/2007/5/21/getting-started-with-wsgi

Hi Lwoo,

Entering to http://monfloo.quijost.com/monfloo-landing/ appear this on general error log:

[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX] mod_wsgi (pid=24275): Exception occurred processing WSGI script '/home/monfloo/public_html/django.wsgi'.
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX] Traceback (most recent call last):
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/core/handlers/wsgi.py", line 272, in __call__
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     response = self.get_response(request)
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/core/handlers/base.py", line 153, in get_response
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/core/handlers/base.py", line 218, in handle_uncaught_exception
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     return callback(request, **param_dict)
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/utils/decorators.py", line 93, in _wrapped_view
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     response = view_func(request, *args, **kwargs)
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/views/defaults.py", line 30, in server_error
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     t = loader.get_template(template_name) # You need to create a 500.html template.
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/template/loader.py", line 157, in get_template
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     template, origin = find_template(template_name)
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]   File "/usr/local/lib/python2.7/site-packages/Django-1.3.1-py2.7.egg/django/template/loader.py", line 138, in find_template
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX]     raise TemplateDoesNotExist(name)
[Thu Mar 15 10:54:22 2012] [error] [client XX.XX.XX.XX] TemplateDoesNotExist: 500.html

So, you are getting a exception TemplateDoesNotExist. Try checking the current paths on django project and catch the exception when you import the template.