Document that Python 2.3 requires cdecimal module for full functionality.

This has been true for some time, but we were leaving users to discover it
the hard way.

Back-patch to 9.2.  It might've been true before that, but we were claiming
Python 2.2 compatibility before that, so I won't guess at the exact
requirements back then.

diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index 673ec243eaa5b93f13aafc6fa713709418cd93ff..1dee8f4ccba1470a0a1c2e77c0ae64a9bbe76a4b 100644 (file)
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -203,8 +203,12 @@ su - postgres
       language, you need a Python
       installation with the header files and
       the distutils module.  The minimum
-      required version is Python
-      2.3.  Python 3 is supported if it's
+      required version is Python 2.3.
+      For full functionality, a 2.3.x installation must include the
+      separately-available cdecimal module; in particular
+      the PL/Python regression tests will not pass if that
+      is missing.
+      Python 3 is supported if it's
       version 3.1 or later; but see
       PL/Python documentation]]>
       ]]>