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.

1 files changed, 64 insertions, 1 deletions

diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index dac7d959bbd..6de06ebc918 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.135 2007/02/16 20:57:19 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.136 2007/02/19 07:03:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,6 +16,7 @@
 
 #include "access/sdir.h"
 #include "nodes/bitmapset.h"
+#include "nodes/params.h"
 #include "nodes/parsenodes.h"
 #include "storage/block.h"
 
@@ -47,6 +48,27 @@ typedef struct QualCost
 
 
 /*----------
+ * PlannerGlobal
+ *		Global information for planning/optimization
+ *
+ * PlannerGlobal holds state for an entire planner invocation; this state
+ * is shared across all levels of sub-Queries that exist in the command being
+ * planned.
+ *----------
+ */
+typedef struct PlannerGlobal
+{
+	NodeTag		type;
+
+	ParamListInfo boundParams;	/* Param values provided to planner() */
+
+	List	   *paramlist;		/* to keep track of cross-level Params */
+
+	int			next_plan_id;	/* hack for distinguishing SubPlans */
+} PlannerGlobal;
+
+
+/*----------
  * PlannerInfo
  *		Per-query information for planning/optimization
  *
@@ -62,6 +84,10 @@ typedef struct PlannerInfo
 
 	Query	   *parse;			/* the Query being planned */
 
+	PlannerGlobal *glob;		/* global info for current planner run */
+
+	Index		query_level;	/* 1 at the outermost Query */
+
 	/*
 	 * simple_rel_array holds pointers to "base rels" and "other rels" (see
 	 * comments for RelOptInfo for more info).	It is indexed by rangetable
@@ -84,6 +110,8 @@ typedef struct PlannerInfo
 	List	   *join_rel_list;	/* list of join-relation RelOptInfos */
 	struct HTAB *join_rel_hash; /* optional hashtable for join relations */
 
+	List	   *init_plans;				/* init subplans for query */
+
 	List	   *eq_classes;				/* list of active EquivalenceClasses */
 
 	List	   *canon_pathkeys;			/* list of "canonical" PathKeys */
@@ -1109,4 +1137,39 @@ typedef struct AppendRelInfo
 	Oid			parent_reloid;	/* OID of parent relation */
 } AppendRelInfo;
 
+/*
+ * glob->paramlist keeps track of the PARAM_EXEC slots that we have decided
+ * we need for the query.  At runtime these slots are used to pass values
+ * either down into subqueries (for outer references in subqueries) or up out
+ * of subqueries (for the results of a subplan).  The n'th entry in the list
+ * (n counts from 0) corresponds to Param->paramid = n.
+ *
+ * Each paramlist item shows the absolute query level it is associated with,
+ * where the outermost query is level 1 and nested subqueries have higher
+ * numbers.  The item the parameter slot represents can be one of three kinds:
+ *
+ * A Var: the slot represents a variable of that level that must be passed
+ * down because subqueries have outer references to it.  The varlevelsup
+ * value in the Var will always be zero.
+ *
+ * An Aggref (with an expression tree representing its argument): the slot
+ * represents an aggregate expression that is an outer reference for some
+ * subquery.  The Aggref itself has agglevelsup = 0, and its argument tree
+ * is adjusted to match in level.
+ *
+ * A Param: the slot holds the result of a subplan (it is a setParam item
+ * for that subplan).  The absolute level shown for such items corresponds
+ * to the parent query of the subplan.
+ *
+ * Note: we detect duplicate Var parameters and coalesce them into one slot,
+ * but we do not do this for Aggref or Param slots.
+ */
+typedef struct PlannerParamItem
+{
+	NodeTag		type;
+
+	Node	   *item;			/* the Var, Aggref, or Param */
+	Index		abslevel;		/* its absolute query level */
+} PlannerParamItem;
+
 #endif   /* RELATION_H */