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.

Author: tglsfdc

src/backend/nodes/outfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.298 2007/02/19 02:23:12 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.299 2007/02/19 07:03:27 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -1225,14 +1225,27 @@ _outHashPath(StringInfo str, HashPath *node)
 	WRITE_NODE_FIELD(path_hashclauses);
 }
 
+static void
+_outPlannerGlobal(StringInfo str, PlannerGlobal *node)
+{
+	WRITE_NODE_TYPE("PLANNERGLOBAL");
+
+	/* NB: this isn't a complete set of fields */
+	WRITE_NODE_FIELD(paramlist);
+	WRITE_INT_FIELD(next_plan_id);
+}
+
 static void
 _outPlannerInfo(StringInfo str, PlannerInfo *node)
 {
 	WRITE_NODE_TYPE("PLANNERINFO");
 
 	/* NB: this isn't a complete set of fields */
 	WRITE_NODE_FIELD(parse);
+	WRITE_NODE_FIELD(glob);
+	WRITE_UINT_FIELD(query_level);
 	WRITE_NODE_FIELD(join_rel_list);
+	WRITE_NODE_FIELD(init_plans);
 	WRITE_NODE_FIELD(eq_classes);
 	WRITE_NODE_FIELD(canon_pathkeys);
 	WRITE_NODE_FIELD(left_join_clauses);
@@ -1416,6 +1429,15 @@ _outAppendRelInfo(StringInfo str, AppendRelInfo *node)
 	WRITE_OID_FIELD(parent_reloid);
 }
 
+static void
+_outPlannerParamItem(StringInfo str, PlannerParamItem *node)
+{
+	WRITE_NODE_TYPE("PLANNERPARAMITEM");
+
+	WRITE_NODE_FIELD(item);
+	WRITE_UINT_FIELD(abslevel);
+}
+
 /*****************************************************************************
  *
  *	Stuff from parsenodes.h.
@@ -2195,6 +2217,9 @@ _outNode(StringInfo str, void *obj)
 			case T_HashPath:
 				_outHashPath(str, obj);
 				break;
+			case T_PlannerGlobal:
+				_outPlannerGlobal(str, obj);
+				break;
 			case T_PlannerInfo:
 				_outPlannerInfo(str, obj);
 				break;
@@ -2228,6 +2253,9 @@ _outNode(StringInfo str, void *obj)
 			case T_AppendRelInfo:
 				_outAppendRelInfo(str, obj);
 				break;
+			case T_PlannerParamItem:
+				_outPlannerParamItem(str, obj);
+				break;
 
 			case T_CreateStmt:
 				_outCreateStmt(str, obj);

src/backend/optimizer/README

@@ -317,7 +317,10 @@ planner()
 Optimizer Data Structures
 -------------------------
 
-PlannerInfo     - global information for planning a particular Query
+PlannerGlobal   - global information for a single planner invocation
+
+PlannerInfo     - information for planning a particular Query (we make
+                  a separate PlannerInfo node for each sub-Query)
 
 RelOptInfo      - a relation or joined relations
 

src/backend/optimizer/path/allpaths.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.158 2007/01/28 18:50:40 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.159 2007/02/19 07:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -517,7 +517,9 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
 		tuple_fraction = root->tuple_fraction;
 
 	/* Generate the plan for the subquery */
-	rel->subplan = subquery_planner(subquery, tuple_fraction,
+	rel->subplan = subquery_planner(root->glob, subquery,
+									root->query_level + 1,
+									tuple_fraction,
 									&subquery_pathkeys);
 
 	/* Copy number of output rows from subplan */

src/backend/optimizer/path/clausesel.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.83 2007/01/05 22:19:31 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.84 2007/02/19 07:03:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -537,7 +537,7 @@ clause_selectivity(PlannerInfo *root,
 	else if (IsA(clause, Param))
 	{
 		/* see if we can replace the Param */
-		Node	   *subst = estimate_expression_value(clause);
+		Node	   *subst = estimate_expression_value(root, clause);
 
 		if (IsA(subst, Const))
 		{

src/backend/optimizer/plan/planagg.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planagg.c,v 1.26 2007/02/06 06:50:26 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planagg.c,v 1.27 2007/02/19 07:03:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -450,6 +450,7 @@ make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info)
 	 */
 	memcpy(&subroot, root, sizeof(PlannerInfo));
 	subroot.parse = subparse = (Query *) copyObject(root->parse);
+	subroot.init_plans = NIL;
 	subparse->commandType = CMD_SELECT;
 	subparse->resultRelation = 0;
 	subparse->resultRelations = NIL;
@@ -524,6 +525,9 @@ make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info)
 	info->param = SS_make_initplan_from_plan(&subroot, plan,
 											 exprType((Node *) tle->expr),
 											 -1);
+
+	/* Make sure the InitPlan gets into the outer list */
+	root->init_plans = list_concat(root->init_plans, subroot.init_plans);
 }
 
 /*

src/backend/optimizer/plan/planner.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.212 2007/01/20 20:45:39 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.213 2007/02/19 07:03:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,9 +42,6 @@
 #include "utils/syscache.h"
 
 
-ParamListInfo PlannerBoundParamList = NULL;		/* current boundParams */
-
-
 /* Expression kind codes for preprocess_expression */
 #define EXPRKIND_QUAL		0
 #define EXPRKIND_TARGET		1
@@ -86,35 +83,21 @@ Plan *
 planner(Query *parse, bool isCursor, int cursorOptions,
 		ParamListInfo boundParams)
 {
+	PlannerGlobal *glob;
 	double		tuple_fraction;
 	Plan	   *result_plan;
-	Index		save_PlannerQueryLevel;
-	List	   *save_PlannerParamList;
-	ParamListInfo save_PlannerBoundParamList;
 
 	/*
-	 * The planner can be called recursively (an example is when
-	 * eval_const_expressions tries to pre-evaluate an SQL function). So,
-	 * these global state variables must be saved and restored.
-	 *
-	 * Query level and the param list cannot be moved into the per-query
-	 * PlannerInfo structure since their whole purpose is communication across
-	 * multiple sub-queries. Also, boundParams is explicitly info from outside
-	 * the query, and so is likewise better handled as a global variable.
-	 *
-	 * Note we do NOT save and restore PlannerPlanId: it exists to assign
-	 * unique IDs to SubPlan nodes, and we want those IDs to be unique for the
-	 * life of a backend.  Also, PlannerInitPlan is saved/restored in
-	 * subquery_planner, not here.
+	 * Set up global state for this planner invocation.  This data is needed
+	 * across all levels of sub-Query that might exist in the given command,
+	 * so we keep it in a separate struct that's linked to by each per-Query
+	 * PlannerInfo.
 	 */
-	save_PlannerQueryLevel = PlannerQueryLevel;
-	save_PlannerParamList = PlannerParamList;
-	save_PlannerBoundParamList = PlannerBoundParamList;
+	glob = makeNode(PlannerGlobal);
 
-	/* Initialize state for handling outer-level references and params */
-	PlannerQueryLevel = 0;		/* will be 1 in top-level subquery_planner */
-	PlannerParamList = NIL;
-	PlannerBoundParamList = boundParams;
+	glob->boundParams = boundParams;
+	glob->paramlist = NIL;
+	glob->next_plan_id = 0;
 
 	/* Determine what fraction of the plan is likely to be scanned */
 	if (isCursor)
@@ -134,10 +117,7 @@ planner(Query *parse, bool isCursor, int cursorOptions,
 	}
 
 	/* primary planning entry point (may recurse for subqueries) */
-	result_plan = subquery_planner(parse, tuple_fraction, NULL);
-
-	/* check we popped out the right number of levels */
-	Assert(PlannerQueryLevel == 0);
+	result_plan = subquery_planner(glob, parse, 1, tuple_fraction, NULL);
 
 	/*
 	 * If creating a plan for a scrollable cursor, make sure it can run
@@ -153,12 +133,7 @@ planner(Query *parse, bool isCursor, int cursorOptions,
 	result_plan = set_plan_references(result_plan, parse->rtable);
 
 	/* executor wants to know total number of Params used overall */
-	result_plan->nParamExec = list_length(PlannerParamList);
-
-	/* restore state for outer planner, if any */
-	PlannerQueryLevel = save_PlannerQueryLevel;
-	PlannerParamList = save_PlannerParamList;
-	PlannerBoundParamList = save_PlannerBoundParamList;
+	result_plan->nParamExec = list_length(glob->paramlist);
 
 	return result_plan;
 }
@@ -169,7 +144,9 @@ planner(Query *parse, bool isCursor, int cursorOptions,
  *	  Invokes the planner on a subquery.  We recurse to here for each
  *	  sub-SELECT found in the query tree.
  *
+ * glob is the global state for the current planner run.
  * parse is the querytree produced by the parser & rewriter.
+ * level is the current recursion depth (1 at the top-level Query).
  * tuple_fraction is the fraction of tuples we expect will be retrieved.
  * tuple_fraction is interpreted as explained for grouping_planner, below.
  *
@@ -189,24 +166,23 @@ planner(Query *parse, bool isCursor, int cursorOptions,
  *--------------------
  */
 Plan *
-subquery_planner(Query *parse, double tuple_fraction,
+subquery_planner(PlannerGlobal *glob, Query *parse,
+				 Index level, double tuple_fraction,
 				 List **subquery_pathkeys)
 {
-	List	   *saved_initplan = PlannerInitPlan;
-	int			saved_planid = PlannerPlanId;
+	int			saved_plan_id = glob->next_plan_id;
 	PlannerInfo *root;
 	Plan	   *plan;
 	List	   *newHaving;
 	ListCell   *l;
 
-	/* Set up for a new level of subquery */
-	PlannerQueryLevel++;
-	PlannerInitPlan = NIL;
-
 	/* Create a PlannerInfo data structure for this subquery */
 	root = makeNode(PlannerInfo);
 	root->parse = parse;
+	root->glob = glob;
+	root->query_level = level;
 	root->planner_cxt = CurrentMemoryContext;
+	root->init_plans = NIL;
 	root->eq_classes = NIL;
 	root->in_info_list = NIL;
 	root->append_rel_list = NIL;
@@ -396,18 +372,13 @@ subquery_planner(Query *parse, double tuple_fraction,
 	 * initPlan list and extParam/allParam sets for plan nodes, and attach the
 	 * initPlans to the top plan node.
 	 */
-	if (PlannerPlanId != saved_planid || PlannerQueryLevel > 1)
-		SS_finalize_plan(plan, parse->rtable);
+	if (root->glob->next_plan_id != saved_plan_id || root->query_level > 1)
+		SS_finalize_plan(root, plan);
 
 	/* Return sort ordering info if caller wants it */
 	if (subquery_pathkeys)
 		*subquery_pathkeys = root->query_pathkeys;
 
-	/* Return to outer subquery context */
-	PlannerQueryLevel--;
-	PlannerInitPlan = saved_initplan;
-	/* we do NOT restore PlannerPlanId; that's not an oversight! */
-
 	return plan;
 }
 
@@ -460,7 +431,7 @@ preprocess_expression(PlannerInfo *root, Node *expr, int kind)
 	if (kind != EXPRKIND_VALUES &&
 		(root->parse->jointree->fromlist != NIL ||
 		 kind == EXPRKIND_QUAL ||
-		 PlannerQueryLevel > 1))
+		 root->query_level > 1))
 		expr = eval_const_expressions(expr);
 
 	/*
@@ -478,16 +449,16 @@ preprocess_expression(PlannerInfo *root, Node *expr, int kind)
 
 	/* Expand SubLinks to SubPlans */
 	if (root->parse->hasSubLinks)
-		expr = SS_process_sublinks(expr, (kind == EXPRKIND_QUAL));
+		expr = SS_process_sublinks(root, expr, (kind == EXPRKIND_QUAL));
 
 	/*
 	 * XXX do not insert anything here unless you have grokked the comments in
 	 * SS_replace_correlation_vars ...
 	 */
 
 	/* Replace uplevel vars with Param nodes (this IS possible in VALUES) */
-	if (PlannerQueryLevel > 1)
-		expr = SS_replace_correlation_vars(expr);
+	if (root->query_level > 1)
+		expr = SS_replace_correlation_vars(root, expr);
 
 	/*
 	 * If it's a qual or havingQual, convert it to implicit-AND format. (We
@@ -590,6 +561,7 @@ inheritance_planner(PlannerInfo *root)
 		subroot.in_info_list = (List *)
 			adjust_appendrel_attrs((Node *) root->in_info_list,
 								   appinfo);
+		subroot.init_plans = NIL;
 		/* There shouldn't be any OJ info to translate, as yet */
 		Assert(subroot.oj_info_list == NIL);
 
@@ -612,6 +584,9 @@ inheritance_planner(PlannerInfo *root)
 
 		subplans = lappend(subplans, subplan);
 
+		/* Make sure any initplans from this rel get into the outer list */
+		root->init_plans = list_concat(root->init_plans, subroot.init_plans);
+
 		/* Build target-relations list for the executor */
 		resultRelations = lappend_int(resultRelations, appinfo->child_relid);
 
@@ -1201,7 +1176,7 @@ preprocess_limit(PlannerInfo *root, double tuple_fraction,
 	 */
 	if (parse->limitCount)
 	{
-		est = estimate_expression_value(parse->limitCount);
+		est = estimate_expression_value(root, parse->limitCount);
 		if (est && IsA(est, Const))
 		{
 			if (((Const *) est)->constisnull)
@@ -1224,7 +1199,7 @@ preprocess_limit(PlannerInfo *root, double tuple_fraction,
 
 	if (parse->limitOffset)
 	{
-		est = estimate_expression_value(parse->limitOffset);
+		est = estimate_expression_value(root, parse->limitOffset);
 		if (est && IsA(est, Const))
 		{
 			if (((Const *) est)->constisnull)