-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/plpython.sgml,v 1.14 2002/09/23 01:51:02 momjian Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/plpython.sgml,v 1.15 2002/10/21 20:34:09 momjian Exp $ -->
<chapter id="plpython">
<title>PL/Python - Python Procedural Language</title>
<para>
When you prepare a plan using the PL/Python module it is
automatically saved. Read the SPI documentation (<xref
- linkend="spi">) for a description of what this means. The take
- home message is if you do
+ linkend="spi">) for a description of what this means.
+ </para>
+
+ <para>
+ In order to make effective use of this across function calls
+ one needs to use one of the persistent storage dictionaries
+ <literal>SD</literal> or <literal>GD</literal>, see
+ <xref linkend="plpython-funcs">. For example:
<programlisting>
-plan = plpy.prepare("SOME QUERY")
-plan = plpy.prepare("SOME OTHER QUERY")
+CREATE FUNCTION usesavedplan ( ) RETURNS TRIGGER AS '
+ if SD.has_key("plan"):
+ plan = SD["plan"]
+ else:
+ plan = plpy.prepare("SELECT 1")
+ SD["plan"] = plan
+ # rest of function
+' LANGUAGE 'plpython';
</programlisting>
- you are leaking memory, as I know of no way to free a saved plan.
- The alternative of using unsaved plans it even more painful (for
- me).
</para>
</sect1>