Please test psycopg 2.4 beta2

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Daniele Varrazzo

Feb 14, 2011, 8:42:38 PM2/14/11
to modwsgi

Jason Erickson has addressed the problem with python 2.6/2.7 + modwsgi
+ psycopg2. His fixes are available in psycopg 2.4 beta2.

He has made available the packages at <
projects/python/win-psycopg/devel/>. It would be great if you could
test them and report success/failure with the problematic combination.


-- Daniele

Graham Dumpleton

Feb 14, 2011, 8:54:11 PM2/14/11

To clarify for those not following this issue, this is a Windows
specific issue and so if you are using a UNIX type system you can
ignore it.

As to the problem being solved, this is the problem whereby although
Python command line links certain Windows DLLs, the Apache executable
doesn't. This means that certain DLL functionality required by Windows
pyscopg2 module is not present when run under Apache/mod_wsgi and
pyscopg2 fails to load/run.

I am not sure of the change made in pyscopg2 to address the issue, but
could be pyscopg2 itself having a dependency on the DLL so it is
loaded, or using alternate function APIs that don't require the DLL in
the first place.

Thanks for Daniele for pursuing this and keeping us up to date.


Daniele Varrazzo

Feb 15, 2011, 3:56:23 AM2/15/11
to modwsgi
On Feb 15, 1:54 am, Graham Dumpleton <>

> To clarify for those not following this issue, this is a Windows
> specific issue and so if you are using a UNIX type system you can
> ignore it.

Yes, sorry: I missed the "windows" part in the description.

For more information about the issue, there is plenty of details in
the psycopg ticket #20 <

-- Daniele

Graham Dumpleton

Feb 15, 2011, 8:38:41 PM2/15/11

I take it from reading that description that it will not help for to embed manifest with reference to the DLL as needs to be
either in the executable or the originating DLL.

So, seems that nothing that I can do in mod_wsgi itself to avoid
distinct extension modules from needing to reference the DLL

Does this also mean that another extension module, eg., PILs, if it requires it would still in parallel need to
reference it in its manifest even though pyscopg2 may have already
done that and is loaded?


Paul Préfontaine

Feb 28, 2011, 11:47:41 AM2/28/11

"Daniele Varrazzo" <> a écrit, le 2011-02-14 à
17 h 42 :

Until now, I have been unable to move from the Windows psycopg2 build
installed by psycopg2-2.0.14.win32-py2.6-pg8.4.3-release.exe (from
Jason’s site), for the reasons listed elsewhere.

I downloaded and installed psycopg2-2.4-beta2.win32-py2.6.exe from the
link above over the weekend. My installation details:

- Windows Server 2008 R2 (no service packs)
- Python 2.6.6 (x86)
- Official Apache httpd+SSL build

This server is used fairly lightly, though it’s being used more and
more. We have 100 potential users, and we’re running an instance of the
Roundup issue tracking web app and a MoinMoin wiki.

After installing psycopg2 2.4 beta 2, Apache started up with no problems
(contrary to every other version since the one mentioned above), I
tested the functionality that I’ve seen break in the past for various
reasons, and things are looking good. I’ve kept the beta in place, and
I’m keeping an eye on the error logs. Things are looking great this
morning, and I’m looking forward to the final release!

Daniele, would you like me to post something to the psycopg2 list as


P.-S. modwsgi and psycopg2 and have made this kind of setup ridiculously
easy, so here’s a big thank you from a grateful user.

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