aqo_pg13.patch

diff --git a/contrib/Makefile b/contrib/Makefile
index 1846d415b6..95519ac11d 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -7,6 +7,7 @@ include $(top_builddir)/src/Makefile.global
 SUBDIRS = \
 		adminpack	\
 		amcheck		\
+		aqo		\
 		auth_delay	\
 		auto_explain	\
 		bloom		\
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index bc05c96b4c..b6a3abe0d2 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -24,6 +24,7 @@
 #include "nodes/extensible.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
+#include "optimizer/cost.h"
 #include "parser/parsetree.h"
 #include "rewrite/rewriteHandler.h"
 #include "storage/bufmgr.h"
@@ -46,6 +47,12 @@ ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
 /* Hook for plugins to get control in explain_get_index_name() */
 explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 
+/* Hook for plugins to get control in ExplainOnePlan() */
+ExplainOnePlan_hook_type ExplainOnePlan_hook = NULL;
+
+/* Hook for plugins to get control in ExplainOnePlan() */
+ExplainOneNode_hook_type ExplainOneNode_hook = NULL;
+
 
 /* OR-able flags for ExplainXMLTag() */
 #define X_OPENING 0
@@ -638,6 +645,10 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 		ExplainPropertyFloat("Execution Time", "ms", 1000.0 * totaltime, 3,
 							 es);
 
+	if (ExplainOnePlan_hook)
+		ExplainOnePlan_hook(plannedstmt, into, es,
+							queryString, params, planduration, queryEnv);
+
 	ExplainCloseGroup("Query", NULL, true, es);
 }
 
@@ -1612,6 +1623,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		}
 	}
 
+	if (ExplainOneNode_hook)
+		ExplainOneNode_hook(es, planstate, plan);
+
 	/* in text format, first line ends here */
 	if (es->format == EXPLAIN_FORMAT_TEXT)
 		appendStringInfoChar(es->str, '\n');
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 692b6c1559..580d04d784 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -132,6 +132,7 @@ CopyPlanFields(const Plan *from, Plan *newnode)
 	COPY_NODE_FIELD(initPlan);
 	COPY_BITMAPSET_FIELD(extParam);
 	COPY_BITMAPSET_FIELD(allParam);
+	COPY_NODE_FIELD(ext_nodes);
 }
 
 /*
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 21ececf0c2..a0e7a7ebca 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -342,6 +342,7 @@ _outPlanInfo(StringInfo str, const Plan *node)
 	WRITE_NODE_FIELD(initPlan);
 	WRITE_BITMAPSET_FIELD(extParam);
 	WRITE_BITMAPSET_FIELD(allParam);
+	/*WRITE_NODE_FIELD(ext_nodes); */
 }
 
 /*
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 7976b369ba..604314e0b3 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1580,6 +1580,11 @@ ReadCommonPlan(Plan *local_node)
 	READ_NODE_FIELD(initPlan);
 	READ_BITMAPSET_FIELD(extParam);
 	READ_BITMAPSET_FIELD(allParam);
+	local_node->ext_nodes = NIL;
+	/* READ_NODE_FIELD(ext_nodes);
+	 * Don't serialize this field. It is required to serialize RestrictInfo and
+	 * EqualenceClass.
+	*/
 }
 
 /*
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 4edc859cb5..988f2e6ab7 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -98,6 +98,12 @@
 #include "utils/tuplesort.h"
 
 
+set_baserel_rows_estimate_hook_type set_baserel_rows_estimate_hook = NULL;
+set_foreign_rows_estimate_hook_type set_foreign_rows_estimate_hook = NULL;
+get_parameterized_baserel_size_hook_type get_parameterized_baserel_size_hook = NULL;
+get_parameterized_joinrel_size_hook_type get_parameterized_joinrel_size_hook = NULL;
+set_joinrel_size_estimates_hook_type set_joinrel_size_estimates_hook = NULL;
+
 /* source-code-compatibility hacks for pull_varnos() API change */
 #define pull_varnos(a,b) pull_varnos_new(a,b)
 
@@ -181,7 +187,6 @@ static Cost append_nonpartial_cost(List *subpaths, int numpaths,
 static void set_rel_width(PlannerInfo *root, RelOptInfo *rel);
 static double relation_byte_size(double tuples, int width);
 static double page_size(double tuples, int width);
-static double get_parallel_divisor(Path *path);
 
 
 /*
@@ -4632,6 +4637,58 @@ approx_tuple_count(PlannerInfo *root, JoinPath *path, List *quals)
 }
 
 
+void
+set_foreign_rows_estimate(PlannerInfo *root, RelOptInfo *rel)
+{
+	if (set_foreign_rows_estimate_hook)
+		(*set_foreign_rows_estimate_hook) (root, rel);
+	else
+		rel->rows = 1000;			/* entirely bogus default estimate */
+}
+
+/*
+ * set_baserel_rows_estimate
+ *		Set the rows estimate for the given base relation.
+ *
+ * Rows is the estimated number of output tuples after applying
+ * restriction clauses.
+ *
+ * To support loadable plugins that monitor or modify cardinality estimation,
+ * we provide a hook variable that lets a plugin get control before and
+ * after the cardinality estimation.
+ * The hook must set rel->rows.
+ */
+void
+set_baserel_rows_estimate(PlannerInfo *root, RelOptInfo *rel)
+{
+	if (set_baserel_rows_estimate_hook)
+		(*set_baserel_rows_estimate_hook) (root, rel);
+	else
+		set_baserel_rows_estimate_standard(root, rel);
+}
+
+/*
+ * set_baserel_rows_estimate
+ *		Set the rows estimate for the given base relation.
+ *
+ * Rows is the estimated number of output tuples after applying
+ * restriction clauses.
+ */
+void
+set_baserel_rows_estimate_standard(PlannerInfo *root, RelOptInfo *rel)
+{
+	double		nrows;
+
+	nrows = rel->tuples *
+		clauselist_selectivity(root,
+							   rel->baserestrictinfo,
+							   0,
+							   JOIN_INNER,
+							   NULL);
+
+	rel->rows = clamp_row_est(nrows);
+}
+
 /*
  * set_baserel_size_estimates
  *		Set the size estimates for the given base relation.
@@ -4648,19 +4705,10 @@ approx_tuple_count(PlannerInfo *root, JoinPath *path, List *quals)
 void
 set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 {
-	double		nrows;
-
 	/* Should only be applied to base relations */
 	Assert(rel->relid > 0);
 
-	nrows = rel->tuples *
-		clauselist_selectivity(root,
-							   rel->baserestrictinfo,
-							   0,
-							   JOIN_INNER,
-							   NULL);
-
-	rel->rows = clamp_row_est(nrows);
+	set_baserel_rows_estimate(root, rel);
 
 	cost_qual_eval(&rel->baserestrictcost, rel->baserestrictinfo, root);
 
@@ -4671,13 +4719,33 @@ set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
  * get_parameterized_baserel_size
  *		Make a size estimate for a parameterized scan of a base relation.
  *
+ * To support loadable plugins that monitor or modify cardinality estimation,
+ * we provide a hook variable that lets a plugin get control before and
+ * after the cardinality estimation.
+ */
+double
+get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
+							   List *param_clauses)
+{
+	if (get_parameterized_baserel_size_hook)
+		return (*get_parameterized_baserel_size_hook) (root, rel,
+													   param_clauses);
+	else
+		return get_parameterized_baserel_size_standard(root, rel,
+													   param_clauses);
+}
+
+/*
+ * get_parameterized_baserel_size_standard
+ *		Make a size estimate for a parameterized scan of a base relation.
+ *
  * 'param_clauses' lists the additional join clauses to be used.
  *
  * set_baserel_size_estimates must have been applied already.
  */
 double
-get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
-							   List *param_clauses)
+get_parameterized_baserel_size_standard(PlannerInfo *root, RelOptInfo *rel,
+										List *param_clauses)
 {
 	List	   *allclauses;
 	double		nrows;
@@ -4706,6 +4774,36 @@ get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
  * set_joinrel_size_estimates
  *		Set the size estimates for the given join relation.
  *
+ * To support loadable plugins that monitor or modify cardinality estimation,
+ * we provide a hook variable that lets a plugin get control before and
+ * after the cardinality estimation.
+ * The hook must set rel->rows value.
+ */
+void
+set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
+						   RelOptInfo *outer_rel,
+						   RelOptInfo *inner_rel,
+						   SpecialJoinInfo *sjinfo,
+						   List *restrictlist)
+{
+	if (set_joinrel_size_estimates_hook)
+		(*set_joinrel_size_estimates_hook) (root, rel,
+											outer_rel,
+											inner_rel,
+											sjinfo,
+											restrictlist);
+	else
+		set_joinrel_size_estimates_standard(root, rel,
+											outer_rel,
+											inner_rel,
+											sjinfo,
+											restrictlist);
+}
+
+/*
+ * set_joinrel_size_estimates_standard
+ *		Set the size estimates for the given join relation.
+ *
  * The rel's targetlist must have been constructed already, and a
  * restriction clause list that matches the given component rels must
  * be provided.
@@ -4725,11 +4823,11 @@ get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
  * build_joinrel_tlist, and baserestrictcost is not used for join rels.
  */
 void
-set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
-						   RelOptInfo *outer_rel,
-						   RelOptInfo *inner_rel,
-						   SpecialJoinInfo *sjinfo,
-						   List *restrictlist)
+set_joinrel_size_estimates_standard(PlannerInfo *root, RelOptInfo *rel,
+									RelOptInfo *outer_rel,
+									RelOptInfo *inner_rel,
+									SpecialJoinInfo *sjinfo,
+									List *restrictlist)
 {
 	rel->rows = calc_joinrel_size_estimate(root,
 										   rel,
@@ -4745,6 +4843,35 @@ set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
  * get_parameterized_joinrel_size
  *		Make a size estimate for a parameterized scan of a join relation.
  *
+ * To support loadable plugins that monitor or modify cardinality estimation,
+ * we provide a hook variable that lets a plugin get control before and
+ * after the cardinality estimation.
+ */
+double
+get_parameterized_joinrel_size(PlannerInfo *root, RelOptInfo *rel,
+							   Path *outer_path,
+							   Path *inner_path,
+							   SpecialJoinInfo *sjinfo,
+							   List *restrict_clauses)
+{
+	if (get_parameterized_joinrel_size_hook)
+		return (*get_parameterized_joinrel_size_hook) (root, rel,
+													   outer_path,
+													   inner_path,
+													   sjinfo,
+													   restrict_clauses);
+	else
+		return get_parameterized_joinrel_size_standard(root, rel,
+													   outer_path,
+													   inner_path,
+													   sjinfo,
+													   restrict_clauses);
+}
+
+/*
+ * get_parameterized_joinrel_size_standard
+ *		Make a size estimate for a parameterized scan of a join relation.
+ *
  * 'rel' is the joinrel under consideration.
  * 'outer_path', 'inner_path' are (probably also parameterized) Paths that
  *		produce the relations being joined.
@@ -4757,11 +4884,11 @@ set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
  * set_joinrel_size_estimates must have been applied already.
  */
 double
-get_parameterized_joinrel_size(PlannerInfo *root, RelOptInfo *rel,
-							   Path *outer_path,
-							   Path *inner_path,
-							   SpecialJoinInfo *sjinfo,
-							   List *restrict_clauses)
+get_parameterized_joinrel_size_standard(PlannerInfo *root, RelOptInfo *rel,
+										Path *outer_path,
+										Path *inner_path,
+										SpecialJoinInfo *sjinfo,
+										List *restrict_clauses)
 {
 	double		nrows;
 
@@ -5430,7 +5557,7 @@ set_foreign_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 	/* Should only be applied to base relations */
 	Assert(rel->relid > 0);
 
-	rel->rows = 1000;			/* entirely bogus default estimate */
+	set_foreign_rows_estimate(root, rel);
 
 	cost_qual_eval(&rel->baserestrictcost, rel->baserestrictinfo, root);
 
@@ -5716,7 +5843,7 @@ page_size(double tuples, int width)
  * Estimate the fraction of the work that each worker will do given the
  * number of workers budgeted for the path.
  */
-static double
+double
 get_parallel_divisor(Path *path)
 {
 	double		parallel_divisor = path->parallel_workers;
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 917713c163..5b7bf1cec6 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -70,6 +70,7 @@
 #define CP_LABEL_TLIST		0x0004	/* tlist must contain sortgrouprefs */
 #define CP_IGNORE_TLIST		0x0008	/* caller will replace tlist */
 
+create_plan_hook_type create_plan_hook = NULL;
 
 static Plan *create_plan_recurse(PlannerInfo *root, Path *best_path,
 								 int flags);
@@ -524,6 +525,10 @@ create_plan_recurse(PlannerInfo *root, Path *best_path, int flags)
 			break;
 	}
 
+	if (create_plan_hook)
+		/* Give an extension a chance to do something */
+		(*create_plan_hook)(root, best_path, &plan);
+
 	return plan;
 }
 
@@ -5163,6 +5168,7 @@ copy_generic_path_info(Plan *dest, Path *src)
 	dest->plan_width = src->pathtarget->width;
 	dest->parallel_aware = src->parallel_aware;
 	dest->parallel_safe = src->parallel_safe;
+	dest->ext_nodes = NIL;
 }
 
 /*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 27c665ac12..f599fba755 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -145,7 +145,8 @@ static List *extract_rollup_sets(List *groupingSets);
 static List *reorder_grouping_sets(List *groupingSets, List *sortclause);
 static void standard_qp_callback(PlannerInfo *root, void *extra);
 static double get_number_of_groups(PlannerInfo *root,
-								   double path_rows,
+								   Path *subpath,
+								   RelOptInfo *grouped_rel,
 								   grouping_sets_data *gd,
 								   List *target_list);
 static RelOptInfo *create_grouping_paths(PlannerInfo *root,
@@ -3686,7 +3687,8 @@ standard_qp_callback(PlannerInfo *root, void *extra)
  */
 static double
 get_number_of_groups(PlannerInfo *root,
-					 double path_rows,
+					 Path *subpath,
+					 RelOptInfo *grouped_rel,
 					 grouping_sets_data *gd,
 					 List *target_list)
 {
@@ -3723,7 +3725,7 @@ get_number_of_groups(PlannerInfo *root,
 					GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
 					double		numGroups = estimate_num_groups(root,
 																groupExprs,
-																path_rows,
+																subpath->rows,
 																&gset);
 
 					gs->numGroups = numGroups;
@@ -3748,7 +3750,7 @@ get_number_of_groups(PlannerInfo *root,
 					GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
 					double		numGroups = estimate_num_groups(root,
 																groupExprs,
-																path_rows,
+																subpath->rows,
 																&gset);
 
 					gs->numGroups = numGroups;
@@ -3764,8 +3766,8 @@ get_number_of_groups(PlannerInfo *root,
 			groupExprs = get_sortgrouplist_exprs(parse->groupClause,
 												 target_list);
 
-			dNumGroups = estimate_num_groups(root, groupExprs, path_rows,
-											 NULL);
+			dNumGroups = estimate_num_groups_ext(root, groupExprs, subpath,
+												 grouped_rel, NULL);
 		}
 	}
 	else if (parse->groupingSets)
@@ -4151,7 +4153,8 @@ create_ordinary_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,
 	 * Estimate number of groups.
 	 */
 	dNumGroups = get_number_of_groups(root,
-									  cheapest_path->rows,
+									  cheapest_path,
+									  grouped_rel,
 									  gd,
 									  extra->targetList);
 
@@ -6935,13 +6938,15 @@ create_partial_grouping_paths(PlannerInfo *root,
 	if (cheapest_total_path != NULL)
 		dNumPartialGroups =
 			get_number_of_groups(root,
-								 cheapest_total_path->rows,
+								 cheapest_total_path,
+								 partially_grouped_rel,
 								 gd,
 								 extra->targetList);
 	if (cheapest_partial_path != NULL)
 		dNumPartialPartialGroups =
 			get_number_of_groups(root,
-								 cheapest_partial_path->rows,
+								 cheapest_partial_path,
+								 partially_grouped_rel,
 								 gd,
 								 extra->targetList);
 
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index a203e6f1ff..d31bf5bae6 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -258,6 +258,7 @@ build_simple_rel(PlannerInfo *root, int relid, RelOptInfo *parent)
 	rel->partexprs = NULL;
 	rel->nullable_partexprs = NULL;
 	rel->partitioned_child_rels = NIL;
+	rel->ext_nodes = NULL;
 
 	/*
 	 * Pass assorted information down the inheritance hierarchy.
@@ -383,7 +384,6 @@ find_base_rel(PlannerInfo *root, int relid)
 		if (rel)
 			return rel;
 	}
-
 	elog(ERROR, "no relation entry for relid %d", relid);
 
 	return NULL;				/* keep compiler quiet */
@@ -673,6 +673,7 @@ build_join_rel(PlannerInfo *root,
 	joinrel->partexprs = NULL;
 	joinrel->nullable_partexprs = NULL;
 	joinrel->partitioned_child_rels = NIL;
+	joinrel->ext_nodes = NULL;
 
 	/* Compute information relevant to the foreign relations. */
 	set_foreign_rel_properties(joinrel, outer_rel, inner_rel);
@@ -851,6 +852,7 @@ build_child_join_rel(PlannerInfo *root, RelOptInfo *outer_rel,
 	joinrel->partexprs = NULL;
 	joinrel->nullable_partexprs = NULL;
 	joinrel->partitioned_child_rels = NIL;
+	joinrel->ext_nodes = NULL;
 
 	joinrel->top_parent_relids = bms_union(outer_rel->top_parent_relids,
 										   inner_rel->top_parent_relids);
@@ -1264,6 +1266,7 @@ find_childrel_parents(PlannerInfo *root, RelOptInfo *rel)
 }
 
 
+set_parampathinfo_postinit_hook_type parampathinfo_postinit_hook = NULL;
 /*
  * get_baserel_parampathinfo
  *		Get the ParamPathInfo for a parameterized path for a base relation,
@@ -1332,6 +1335,10 @@ get_baserel_parampathinfo(PlannerInfo *root, RelOptInfo *baserel,
 	ppi->ppi_req_outer = required_outer;
 	ppi->ppi_rows = rows;
 	ppi->ppi_clauses = pclauses;
+
+	if (parampathinfo_postinit_hook)
+		(*parampathinfo_postinit_hook)(ppi);
+
 	baserel->ppilist = lappend(baserel->ppilist, ppi);
 
 	return ppi;
@@ -1557,6 +1564,10 @@ get_joinrel_parampathinfo(PlannerInfo *root, RelOptInfo *joinrel,
 	ppi->ppi_req_outer = required_outer;
 	ppi->ppi_rows = rows;
 	ppi->ppi_clauses = NIL;
+
+	if (parampathinfo_postinit_hook)
+			(*parampathinfo_postinit_hook)(ppi);
+
 	joinrel->ppilist = lappend(joinrel->ppilist, ppi);
 
 	return ppi;
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 37458da096..248a1875a1 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -147,6 +147,7 @@
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
 get_index_stats_hook_type get_index_stats_hook = NULL;
+estimate_num_groups_hook_type estimate_num_groups_hook = NULL;
 
 static double eqsel_internal(PG_FUNCTION_ARGS, bool negate);
 static double eqjoinsel_inner(Oid opfuncoid, Oid collation,
@@ -3295,6 +3296,19 @@ add_unique_group_var(PlannerInfo *root, List *varinfos,
 	return varinfos;
 }
 
+double
+estimate_num_groups_ext(PlannerInfo *root, List *groupExprs, Path *subpath,
+						RelOptInfo *grouped_rel, List **pgset)
+{
+	double input_rows = subpath->rows;
+
+	if (estimate_num_groups_hook != NULL)
+		return (*estimate_num_groups_hook)(root, groupExprs, subpath,
+										   grouped_rel, pgset);
+
+	return estimate_num_groups(root, groupExprs, input_rows, pgset);
+}
+
 /*
  * estimate_num_groups		- Estimate number of groups in a grouped query
  *
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index ba661d32a6..09d0abe58b 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -75,6 +75,18 @@ extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
 typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
 extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
 
+/* Hook for plugins to get control in ExplainOnePlan() */
+typedef void (*ExplainOnePlan_hook_type) (PlannedStmt *plannedstmt, IntoClause *into,
+			   ExplainState *es, const char *queryString,
+			   ParamListInfo params, const instr_time *planduration,
+			   QueryEnvironment *queryEnv);
+extern PGDLLIMPORT ExplainOnePlan_hook_type ExplainOnePlan_hook;
+
+/* Explain a node info */
+typedef void (*ExplainOneNode_hook_type) (ExplainState *es,
+										 PlanState *ps,
+										 Plan *plan);
+extern PGDLLIMPORT ExplainOneNode_hook_type ExplainOneNode_hook;
 
 extern void ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 						 ParamListInfo params, DestReceiver *dest);
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 5ebf070979..5b2acd7de2 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -739,6 +739,10 @@ typedef struct RelOptInfo
 	Relids		top_parent_relids;	/* Relids of topmost parents (if "other"
 									 * rel) */
 
+	/* For Adaptive optimization DEBUG purposes */
+	double		predicted_cardinality;
+	int			fss_hash;
+
 	/* used for partitioned relations: */
 	PartitionScheme part_scheme;	/* Partitioning scheme */
 	int			nparts;			/* Number of partitions; -1 if not yet set; in
@@ -754,6 +758,12 @@ typedef struct RelOptInfo
 	List	  **partexprs;		/* Non-nullable partition key expressions */
 	List	  **nullable_partexprs; /* Nullable partition key expressions */
 	List	   *partitioned_child_rels; /* List of RT indexes */
+
+	/*
+	 * At this list an extension can add additional nodes to pass an info along
+	 * the planning and executing stages.
+	 */
+	List		*ext_nodes;
 } RelOptInfo;
 
 /*
@@ -1105,6 +1115,10 @@ typedef struct ParamPathInfo
 	Relids		ppi_req_outer;	/* rels supplying parameters used by path */
 	double		ppi_rows;		/* estimated number of result tuples */
 	List	   *ppi_clauses;	/* join clauses available from outer rels */
+
+	/* AQO DEBUG purposes */
+	double predicted_ppi_rows;
+	double fss_ppi_hash;
 } ParamPathInfo;
 
 
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 90f02ce6fd..88c332164d 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -159,6 +159,9 @@ typedef struct Plan
 	 */
 	Bitmapset  *extParam;
 	Bitmapset  *allParam;
+
+	/* Additional field for an extension purposes. */
+	List		*ext_nodes;
 } Plan;
 
 /* ----------------
diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h
index 6141654e47..e6b28cbb05 100644
--- a/src/include/optimizer/cost.h
+++ b/src/include/optimizer/cost.h
@@ -39,6 +39,37 @@ typedef enum
 }			ConstraintExclusionType;
 
 
+/* Hook for plugins to get control of cardinality estimation */
+typedef void (*set_baserel_rows_estimate_hook_type) (PlannerInfo *root,
+															RelOptInfo *rel);
+typedef void (*set_foreign_rows_estimate_hook_type) (PlannerInfo *root,
+													RelOptInfo *rel);
+extern PGDLLIMPORT set_baserel_rows_estimate_hook_type
+			set_baserel_rows_estimate_hook;
+extern PGDLLIMPORT set_foreign_rows_estimate_hook_type
+												set_foreign_rows_estimate_hook;
+typedef double (*get_parameterized_baserel_size_hook_type) (PlannerInfo *root,
+															 RelOptInfo *rel,
+														List *param_clauses);
+extern PGDLLIMPORT get_parameterized_baserel_size_hook_type
+			get_parameterized_baserel_size_hook;
+typedef double (*get_parameterized_joinrel_size_hook_type) (PlannerInfo *root,
+															 RelOptInfo *rel,
+															Path *outer_path,
+															Path *inner_path,
+													 SpecialJoinInfo *sjinfo,
+													 List *restrict_clauses);
+extern PGDLLIMPORT get_parameterized_joinrel_size_hook_type
+			get_parameterized_joinrel_size_hook;
+typedef void (*set_joinrel_size_estimates_hook_type) (PlannerInfo *root,
+															 RelOptInfo *rel,
+													   RelOptInfo *outer_rel,
+													   RelOptInfo *inner_rel,
+													 SpecialJoinInfo *sjinfo,
+														 List *restrictlist);
+extern PGDLLIMPORT set_joinrel_size_estimates_hook_type
+			set_joinrel_size_estimates_hook;
+
 /*
  * prototypes for costsize.c
  *	  routines to compute costs and sizes
@@ -175,10 +206,22 @@ extern void compute_semi_anti_join_factors(PlannerInfo *root,
 										   SpecialJoinInfo *sjinfo,
 										   List *restrictlist,
 										   SemiAntiJoinFactors *semifactors);
+extern void set_foreign_rows_estimate(PlannerInfo *root, RelOptInfo *rel);
+extern void set_baserel_rows_estimate(PlannerInfo *root, RelOptInfo *rel);
+extern void set_baserel_rows_estimate_standard(PlannerInfo *root, RelOptInfo *rel);
 extern void set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel);
 extern double get_parameterized_baserel_size(PlannerInfo *root,
 											 RelOptInfo *rel,
 											 List *param_clauses);
+extern double get_parameterized_baserel_size_standard(PlannerInfo *root,
+										RelOptInfo *rel,
+										List *param_clauses);
+extern double get_parameterized_joinrel_size_standard(PlannerInfo *root,
+										RelOptInfo *rel,
+										Path *outer_path,
+										Path *inner_path,
+										SpecialJoinInfo *sjinfo,
+										List *restrict_clauses);
 extern double get_parameterized_joinrel_size(PlannerInfo *root,
 											 RelOptInfo *rel,
 											 Path *outer_path,
@@ -190,6 +233,11 @@ extern void set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 									   RelOptInfo *inner_rel,
 									   SpecialJoinInfo *sjinfo,
 									   List *restrictlist);
+extern void set_joinrel_size_estimates_standard(PlannerInfo *root, RelOptInfo *rel,
+									RelOptInfo *outer_rel,
+									RelOptInfo *inner_rel,
+									SpecialJoinInfo *sjinfo,
+									List *restrictlist);
 extern void set_subquery_size_estimates(PlannerInfo *root, RelOptInfo *rel);
 extern void set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel);
 extern void set_values_size_estimates(PlannerInfo *root, RelOptInfo *rel);
@@ -202,5 +250,6 @@ extern void set_foreign_size_estimates(PlannerInfo *root, RelOptInfo *rel);
 extern PathTarget *set_pathtarget_cost_width(PlannerInfo *root, PathTarget *target);
 extern double compute_bitmap_pages(PlannerInfo *root, RelOptInfo *baserel,
 								   Path *bitmapqual, int loop_count, Cost *cost, double *tuple);
+extern double get_parallel_divisor(Path *path);
 
 #endif							/* COST_H */
diff --git a/src/include/optimizer/pathnode.h b/src/include/optimizer/pathnode.h
index 3bd7072ae8..21bbaba11c 100644
--- a/src/include/optimizer/pathnode.h
+++ b/src/include/optimizer/pathnode.h
@@ -18,6 +18,10 @@
 #include "nodes/pathnodes.h"
 
 
+typedef void (*set_parampathinfo_postinit_hook_type) (ParamPathInfo *ppi);
+
+extern PGDLLIMPORT set_parampathinfo_postinit_hook_type parampathinfo_postinit_hook;
+
 /*
  * prototypes for pathnode.c
  */
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 8ce60e202e..75415102c2 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -24,6 +24,12 @@ extern double cursor_tuple_fraction;
 /* query_planner callback to compute query_pathkeys */
 typedef void (*query_pathkeys_callback) (PlannerInfo *root, void *extra);
 
+
+/* Hook for plugins to get control in ExecutorRun() */
+typedef void (*create_plan_hook_type) (PlannerInfo *root,
+									   Path *best_path,
+									   Plan **plan);
+extern PGDLLIMPORT create_plan_hook_type create_plan_hook;
 /*
  * prototypes for plan/planmain.c
  */
diff --git a/src/include/utils/selfuncs.h b/src/include/utils/selfuncs.h
index 7ac4a06391..def3522881 100644
--- a/src/include/utils/selfuncs.h
+++ b/src/include/utils/selfuncs.h
@@ -127,6 +127,12 @@ typedef bool (*get_index_stats_hook_type) (PlannerInfo *root,
 										   AttrNumber indexattnum,
 										   VariableStatData *vardata);
 extern PGDLLIMPORT get_index_stats_hook_type get_index_stats_hook;
+typedef double (*estimate_num_groups_hook_type) (PlannerInfo *root,
+												 List *groupExprs,
+												 Path *subpath,
+												 RelOptInfo *grouped_rel,
+												 List **pgset);
+extern PGDLLIMPORT estimate_num_groups_hook_type estimate_num_groups_hook;
 
 /* Functions in selfuncs.c */
 
@@ -195,6 +201,9 @@ extern void mergejoinscansel(PlannerInfo *root, Node *clause,
 
 extern double estimate_num_groups(PlannerInfo *root, List *groupExprs,
 								  double input_rows, List **pgset);
+extern double estimate_num_groups_ext(PlannerInfo *root, List *groupExprs,
+									  Path *subpath, RelOptInfo *grouped_rel,
+									  List **pgset);
 
 extern void estimate_hash_bucket_stats(PlannerInfo *root,
 									   Node *hashkey, double nbuckets,