Get rid of some old and crufty global variables in the planner. When

this code was last gone over, there wasn't really any alternative to
globals because we didn't have the PlannerInfo struct being passed all
through the planner code.  Now that we do, we can restructure things
to avoid non-reentrancy.  I'm fooling with this because otherwise I'd
have had to add another global variable for the planned compact
range table list.

src/include/nodes/primnodes.h

@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.124 2007/02/03 14:06:56 petere Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.125 2007/02/19 07:03:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -442,10 +442,9 @@ typedef struct SubPlan
 	List	   *paramIds;		/* IDs of Params embedded in the above */
 	/* The subselect, transformed to a Plan: */
 	struct Plan *plan;			/* subselect plan itself */
-	int			plan_id;		/* dummy thing because of we haven't equal
-								 * funcs for plan nodes... actually, we could
-								 * put *plan itself somewhere else (TopPlan
-								 * node ?)... */
+	int			plan_id;		/* kluge because we haven't equal-funcs for
+								 * plan nodes... we compare this instead of
+								 * subselect plan */
 	List	   *rtable;			/* range table for subselect */
 	/* Information about execution strategy: */
 	bool		useHashTable;	/* TRUE to store subselect output in a hash