cannot use string() on <cdata 'char *' NULL> error when connecting to amazon redshift

[mwhooker]

I installed psycopg2cffi from git.

When I tried to connect to my redshift database, I got this error.

(venv)[mwhooker@Wolfe:dev/psycopg2cffi]$ python                                                                                                                                          [master] 17:37:04
Python 2.7.3 (7e4f0faa3d51, Nov 21 2012, 15:59:46)
[PyPy 2.0.0-beta1 with GCC 4.2.1] on darwin
Type "help", "copyright", "credits" or "license" for more information.
And now for something completely different: ``PyPy 1.6 released!''
>>>> from psycopg2cffi import compat
>>>> compat.register()
>>>> import psycopg2
>>>> conn = psycopg2.connect("dbname=*** host=*** port=5439 user=*** password=***")
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "psycopg2cffi/__init__.py", line 107, in connect
    connection_factory=connection_factory, async=async)
  File "psycopg2cffi/_impl/connection.py", line 793, in _connect
    return connection_factory(dsn)
  File "psycopg2cffi/_impl/connection.py", line 118, in __init__
    self._connect_sync()
  File "psycopg2cffi/_impl/connection.py", line 134, in _connect_sync
    self._setup()
  File "psycopg2cffi/_impl/connection.py", line 590, in _setup
    libpq.PQparameterStatus(self._pgconn, 'DateStyle'))
  File "/Users/mwhooker/dev/natty/kafka2redshift/venv/site-packages/cffi/api.py", line 220, in string
    return self._backend.string(cdata, maxlen)
RuntimeError: cannot use string() on <cdata 'char *' NULL>

I am able to connect using psycopg2 just fine.

Please let me know if I can provide more information.

[lopuhin]

The issue is fixed, I think, but I did not manage to write a test - maybe you can suggest how can I set NULL datestyle in postgres?

[mwhooker]

@lopuhin I can verify that this has been resolved. Unfortunately, I'm not sure what you mean by a NULL datastyle.

thanks very much for your quick response!

[lopuhin]

Thank you! The error was that libpq returned NULL when queried about current date style - this is the setting described here http://www.postgresql.org/docs/9.1/static/runtime-config-client.html - but I think that generally date style is not null. Are you fine with using github version for now? I can make a minor release if it is more convenient for you.

[mwhooker]

Thanks for clearing that up. For what it's worth, this is the result of show datestyle in redshift

show datestyle;
 datestyle
-----------
 ISO, MDY
(1 row)

weird that it's reported as NULL.

I'm fine using the github version. It'll be a couple more weeks before I need to use this in production.

Thanks again.