Add note that using PL/Python 2 and 3 in the same session will probably crash

diff --git a/doc/src/sgml/plpython.sgml b/doc/src/sgml/plpython.sgml
index 8b58a95a006f752b66e9df616049df57795408a3..3f924e6cbf1af1f50b52ba24eeffca28aa44b933 100644 (file)
--- a/doc/src/sgml/plpython.sgml
+++ b/doc/src/sgml/plpython.sgml
@@ -1,4 +1,4 @@
-
+
 
 
  PL/Python - Python Procedural Language
@@ -152,6 +152,15 @@
    New In Python 3.0 for more information about porting to
    Python 3.
   
+
+  
+   On most (possibly all) platforms, it is not possible to use
+   PL/Python based on Python 2 and PL/Python based on Python 3 in the
+   same session, because the symbols in the dynamic modules will
+   clash, which will result in crashes of the PostgreSQL server
+   process.  It is possible, however, to use both PL/Python variants
+   in the same database, from separate sessions.
+