Clean up various memory leaks within plpgsql, and re-enable the

exec_eval_simple_expr shortcut, which was diked out in 7.1 because it
leaked too much space.  CVS tip now leaks no memory in Chris Ruprecht's
example, which formerly leaked to the tune of 500 MB.  (Much of this
is work that Jan already did; this commit just cleans up around the
edges.)

src/pl/plpgsql/src/plpgsql.h

@@ -3,7 +3,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.16 2001/07/12 17:42:08 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.17 2001/08/02 21:31:23 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -502,6 +502,12 @@ typedef struct
 	int			found_varno;
 	int			ndatums;
 	PLpgSQL_datum **datums;
+
+	/* temporary state for results from evaluation of query or expr */
+	SPITupleTable *eval_tuptable;
+	uint32		eval_processed;
+	Oid			eval_lastoid;
+	ExprContext *eval_econtext;
 }			PLpgSQL_execstate;