Added FAQ entry about the PYTHON_EGG_CACHE problem

doc/src/faq.rst

@@ -107,6 +107,7 @@ Transferring binary data from PostgreSQL 9.0 doesn't work.
     .. __: http://www.postgresql.org/docs/9.0/static/datatype-binary.html
     .. __: http://www.postgresql.org/docs/9.0/static/runtime-config-client.html#GUC-BYTEA-OUTPUT
 
+
 Best practices
 --------------
 
@@ -138,8 +139,8 @@ What are the advantages or disadvantages of using named cursors?
     little memory on the client and to skip or discard parts of the result set.
 
 
-Problems compiling Psycopg from source
---------------------------------------
+Problems compiling and deploying psycopg2
+-----------------------------------------
 
 .. cssclass:: faq
 
@@ -151,3 +152,14 @@ I can't compile `!psycopg2`: the compiler says *error: libpq-fe.h: No such file
     You need to install the development version of the libpq: the package is
     usually called ``libpq-dev``.
 
+Psycopg raises *ImportError: cannot import name tz* on import in mod_wsgi / ASP, but it works fine otherwise.
+    If `!psycopg2` is installed in an egg_ (e.g. because installed by
+    :program:`easy_install`), the user running the program may be unable to
+    write in the `eggs cache`__. Set the env variable
+    :envvar:`PYTHON_EGG_CACHE` to a writable directory. With modwsgi you can
+    use the WSGIPythonEggs__ directive.
+
+    .. _egg: http://peak.telecommunity.com/DevCenter/PythonEggs
+    .. __: http://stackoverflow.com/questions/2192323/what-is-the-python-egg-cache-python-egg-cache
+    .. __: http://code.google.com/p/modwsgi/wiki/ConfigurationDirectives#WSGIPythonEggs
+