docs: clarify plpython SD and GD dictionary behavior

Reported-by: Adam Bielański
Discussion: https://postgr.es/m/153484305538.1370.7605856225879294548@wrigleys.postgresql.org

Backpatch-through: 9.3

diff --git a/doc/src/sgml/plpython.sgml b/doc/src/sgml/plpython.sgml
index 98f5ed3ec0797ec888edd6a3220b8e497e83f05a..3019235fcb418bf8593a594521dffb8d8e9a3a25 100644 (file)
--- a/doc/src/sgml/plpython.sgml
+++ b/doc/src/sgml/plpython.sgml
@@ -720,9 +720,9 @@ SELECT * FROM multiout_simple_setof(3);
   <title>Sharing Data</title>
   <para>
    The global dictionary <varname>SD</varname> is available to store
-   data between function calls.  This variable is private static data.
+   private data between repeated calls to the same function.
    The global dictionary <varname>GD</varname> is public data,
-   available to all Python functions within a session.  Use with
+   that is available to all Python functions within a session;  use with
    care.<indexterm><primary>global data</>
    <secondary>in PL/Python</></indexterm>
   </para>