aqo_pg11.patch

diff --git a/contrib/Makefile b/contrib/Makefile
index 92184ed487..9b91ad1952 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 799a22e9d5..ece4ffffd9 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -47,6 +47,9 @@ 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;
+
 
 /* OR-able flags for ExplainXMLTag() */
 #define X_OPENING 0
@@ -594,6 +597,10 @@ 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);
+
 	ExplainCloseGroup("Query", NULL, true, es);
 }
 
@@ -1448,6 +1455,24 @@ ExplainNode(PlanState *planstate, List *ancestors,
 				appendStringInfo(es->str,
 								 " (actual rows=%.0f loops=%.0f)",
 								 rows, nloops);
+#ifdef AQO_EXPLAIN
+			if (es->verbose && plan)
+			{
+				int wrkrs = 1;
+				double error = -1.;
+
+				if (planstate->worker_instrument && plan->parallel_aware)
+					wrkrs = planstate->worker_instrument->num_workers + 1;
+
+				if (plan->predicted_cardinality > 0.)
+				{
+					error = 100. * (plan->predicted_cardinality-(rows*wrkrs)) / (rows * wrkrs);
+					appendStringInfo(es->str,
+							" (AQO predicted: cardinality=%.0lf, error=%.0lf%%, fss=%d)",
+							plan->predicted_cardinality, error, plan->fss_hash);
+				}
+			}
+#endif
 		}
 		else
 		{
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 648758de4a..5cc1491507 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -127,6 +127,12 @@ CopyPlanFields(const Plan *from, Plan *newnode)
 	COPY_NODE_FIELD(lefttree);
 	COPY_NODE_FIELD(righttree);
 	COPY_NODE_FIELD(initPlan);
+	COPY_SCALAR_FIELD(had_path);
+	COPY_NODE_FIELD(path_clauses);
+	COPY_NODE_FIELD(path_relids);
+	COPY_SCALAR_FIELD(path_jointype);
+	COPY_SCALAR_FIELD(path_parallel_workers);
+	COPY_SCALAR_FIELD(was_parametrized);
 	COPY_BITMAPSET_FIELD(extParam);
 	COPY_BITMAPSET_FIELD(allParam);
 }
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index c7400941ee..a07c1551dc 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -97,6 +97,10 @@
 #include "utils/spccache.h"
 #include "utils/tuplesort.h"
 
+set_baserel_rows_estimate_hook_type set_baserel_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;
 
 #define LOG2(x)  (log(x) / 0.693147180559945)
 
@@ -4283,6 +4287,49 @@ approx_tuple_count(PlannerInfo *root, JoinPath *path, List *quals)
 }
 
 
+/*
+ * 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.
@@ -4299,19 +4346,10 @@ 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);
 
@@ -4322,13 +4360,33 @@ 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;
@@ -4358,6 +4416,36 @@ 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.
@@ -4377,11 +4465,11 @@ 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,
@@ -4397,6 +4485,35 @@ 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.
@@ -4409,11 +4526,11 @@ 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;
 
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 5f6d2bad7b..eecdf53c21 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -71,6 +71,8 @@
 #define CP_LABEL_TLIST		0x0004	/* tlist must contain sortgrouprefs */
 #define CP_IGNORE_TLIST		0x0008	/* caller will replace tlist */
 
+/* Hook for plugins to get control in creating plan from path */
+copy_generic_path_info_hook_type copy_generic_path_info_hook = NULL;
 
 static Plan *create_plan_recurse(PlannerInfo *root, Path *best_path,
 					int flags);
@@ -157,7 +159,7 @@ static List *fix_indexorderby_references(PlannerInfo *root, IndexPath *index_pat
 static Node *fix_indexqual_operand(Node *node, IndexOptInfo *index, int indexcol);
 static List *get_switched_clauses(List *clauses, Relids outerrelids);
 static List *order_qual_clauses(PlannerInfo *root, List *clauses);
-static void copy_generic_path_info(Plan *dest, Path *src);
+static void copy_generic_path_info(PlannerInfo *root, Plan *dest, Path *src);
 static void copy_plan_costsize(Plan *dest, Plan *src);
 static void label_sort_with_costsize(PlannerInfo *root, Sort *plan,
 						 double limit_tuples);
@@ -1052,7 +1054,7 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path)
 																	  false)),
 									NULL);
 
-		copy_generic_path_info(plan, (Path *) best_path);
+		copy_generic_path_info(root, plan, (Path *) best_path);
 
 		return plan;
 	}
@@ -1119,7 +1121,7 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path)
 					   tlist, best_path->partitioned_rels,
 					   partpruneinfo);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return (Plan *) plan;
 }
@@ -1150,7 +1152,7 @@ create_merge_append_plan(PlannerInfo *root, MergeAppendPath *best_path,
 	 * prepare_sort_from_pathkeys on it before we do so on the individual
 	 * child plans, to make cross-checking the sort info easier.
 	 */
-	copy_generic_path_info(plan, (Path *) best_path);
+	copy_generic_path_info(root, plan, (Path *) best_path);
 	plan->targetlist = tlist;
 	plan->qual = NIL;
 	plan->lefttree = NULL;
@@ -1274,7 +1276,7 @@ create_result_plan(PlannerInfo *root, ResultPath *best_path)
 
 	plan = make_result(tlist, (Node *) quals, NULL);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1299,7 +1301,7 @@ create_project_set_plan(PlannerInfo *root, ProjectSetPath *best_path)
 
 	plan = make_project_set(tlist, subplan);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1327,7 +1329,7 @@ create_material_plan(PlannerInfo *root, MaterialPath *best_path, int flags)
 
 	plan = make_material(subplan);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1521,7 +1523,7 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path, int flags)
 	}
 
 	/* Copy cost data from Path to Plan */
-	copy_generic_path_info(plan, &best_path->path);
+	copy_generic_path_info(root, plan, &best_path->path);
 
 	return plan;
 }
@@ -1554,7 +1556,7 @@ create_gather_plan(PlannerInfo *root, GatherPath *best_path)
 							  best_path->single_copy,
 							  subplan);
 
-	copy_generic_path_info(&gather_plan->plan, &best_path->path);
+	copy_generic_path_info(root, &gather_plan->plan, &best_path->path);
 
 	/* use parallel mode for parallel plans. */
 	root->glob->parallelModeNeeded = true;
@@ -1583,7 +1585,7 @@ create_gather_merge_plan(PlannerInfo *root, GatherMergePath *best_path)
 	gm_plan = makeNode(GatherMerge);
 	gm_plan->plan.targetlist = tlist;
 	gm_plan->num_workers = best_path->num_workers;
-	copy_generic_path_info(&gm_plan->plan, &best_path->path);
+	copy_generic_path_info(root, &gm_plan->plan, &best_path->path);
 
 	/* Assign the rescan Param. */
 	gm_plan->rescan_param = assign_special_exec_param(root);
@@ -1711,7 +1713,7 @@ create_projection_plan(PlannerInfo *root, ProjectionPath *best_path, int flags)
 		/* We need a Result node */
 		plan = (Plan *) make_result(tlist, NULL, subplan);
 
-		copy_generic_path_info(plan, (Path *) best_path);
+		copy_generic_path_info(root, plan, (Path *) best_path);
 	}
 
 	return plan;
@@ -1812,7 +1814,7 @@ create_sort_plan(PlannerInfo *root, SortPath *best_path, int flags)
 								   IS_OTHER_REL(best_path->subpath->parent) ?
 								   best_path->path.parent->relids : NULL);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1849,7 +1851,7 @@ create_group_plan(PlannerInfo *root, GroupPath *best_path)
 					  extract_grouping_ops(best_path->groupClause),
 					  subplan);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1877,7 +1879,7 @@ create_upper_unique_plan(PlannerInfo *root, UpperUniquePath *best_path, int flag
 									 best_path->path.pathkeys,
 									 best_path->numkeys);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1918,7 +1920,7 @@ create_agg_plan(PlannerInfo *root, AggPath *best_path)
 					best_path->numGroups,
 					subplan);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2117,7 +2119,7 @@ create_groupingsets_plan(PlannerInfo *root, GroupingSetsPath *best_path)
 						subplan);
 
 		/* Copy cost data from Path to Plan */
-		copy_generic_path_info(&plan->plan, &best_path->path);
+		copy_generic_path_info(root, &plan->plan, &best_path->path);
 	}
 
 	return (Plan *) plan;
@@ -2173,7 +2175,7 @@ create_minmaxagg_plan(PlannerInfo *root, MinMaxAggPath *best_path)
 
 	plan = make_result(tlist, (Node *) best_path->quals, NULL);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	/*
 	 * During setrefs.c, we'll need to replace references to the Agg nodes
@@ -2281,7 +2283,7 @@ create_windowagg_plan(PlannerInfo *root, WindowAggPath *best_path)
 						  wc->inRangeNullsFirst,
 						  subplan);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2317,7 +2319,7 @@ create_setop_plan(PlannerInfo *root, SetOpPath *best_path, int flags)
 					  best_path->firstFlag,
 					  numGroups);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2353,7 +2355,7 @@ create_recursiveunion_plan(PlannerInfo *root, RecursiveUnionPath *best_path)
 								best_path->distinctList,
 								numGroups);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2376,7 +2378,7 @@ create_lockrows_plan(PlannerInfo *root, LockRowsPath *best_path,
 
 	plan = make_lockrows(subplan, best_path->rowMarks, best_path->epqParam);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2437,7 +2439,7 @@ create_modifytable_plan(PlannerInfo *root, ModifyTablePath *best_path)
 							best_path->onconflict,
 							best_path->epqParam);
 
-	copy_generic_path_info(&plan->plan, &best_path->path);
+	copy_generic_path_info(root, &plan->plan, &best_path->path);
 
 	return plan;
 }
@@ -2461,7 +2463,7 @@ create_limit_plan(PlannerInfo *root, LimitPath *best_path, int flags)
 					  best_path->limitOffset,
 					  best_path->limitCount);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2507,7 +2509,7 @@ create_seqscan_plan(PlannerInfo *root, Path *best_path,
 							 scan_clauses,
 							 scan_relid);
 
-	copy_generic_path_info(&scan_plan->plan, best_path);
+	copy_generic_path_info(root, &scan_plan->plan, best_path);
 
 	return scan_plan;
 }
@@ -2553,7 +2555,7 @@ create_samplescan_plan(PlannerInfo *root, Path *best_path,
 								scan_relid,
 								tsc);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -2734,7 +2736,7 @@ create_indexscan_plan(PlannerInfo *root,
 											indexorderbyops,
 											best_path->indexscandir);
 
-	copy_generic_path_info(&scan_plan->plan, &best_path->path);
+	copy_generic_path_info(root, &scan_plan->plan, &best_path->path);
 
 	return scan_plan;
 }
@@ -2849,7 +2851,7 @@ create_bitmap_scan_plan(PlannerInfo *root,
 									 bitmapqualorig,
 									 baserelid);
 
-	copy_generic_path_info(&scan_plan->scan.plan, &best_path->path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, &best_path->path);
 
 	return scan_plan;
 }
@@ -3114,7 +3116,7 @@ create_tidscan_plan(PlannerInfo *root, TidPath *best_path,
 							 scan_relid,
 							 tidquals);
 
-	copy_generic_path_info(&scan_plan->scan.plan, &best_path->path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, &best_path->path);
 
 	return scan_plan;
 }
@@ -3164,7 +3166,7 @@ create_subqueryscan_plan(PlannerInfo *root, SubqueryScanPath *best_path,
 								  scan_relid,
 								  subplan);
 
-	copy_generic_path_info(&scan_plan->scan.plan, &best_path->path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, &best_path->path);
 
 	return scan_plan;
 }
@@ -3207,7 +3209,7 @@ create_functionscan_plan(PlannerInfo *root, Path *best_path,
 	scan_plan = make_functionscan(tlist, scan_clauses, scan_relid,
 								  functions, rte->funcordinality);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -3250,7 +3252,7 @@ create_tablefuncscan_plan(PlannerInfo *root, Path *best_path,
 	scan_plan = make_tablefuncscan(tlist, scan_clauses, scan_relid,
 								   tablefunc);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -3294,7 +3296,7 @@ create_valuesscan_plan(PlannerInfo *root, Path *best_path,
 	scan_plan = make_valuesscan(tlist, scan_clauses, scan_relid,
 								values_lists);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -3387,7 +3389,7 @@ create_ctescan_plan(PlannerInfo *root, Path *best_path,
 	scan_plan = make_ctescan(tlist, scan_clauses, scan_relid,
 							 plan_id, cte_param_id);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -3426,7 +3428,7 @@ create_namedtuplestorescan_plan(PlannerInfo *root, Path *best_path,
 	scan_plan = make_namedtuplestorescan(tlist, scan_clauses, scan_relid,
 										 rte->enrname);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -3486,7 +3488,7 @@ create_worktablescan_plan(PlannerInfo *root, Path *best_path,
 	scan_plan = make_worktablescan(tlist, scan_clauses, scan_relid,
 								   cteroot->wt_param_id);
 
-	copy_generic_path_info(&scan_plan->scan.plan, best_path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, best_path);
 
 	return scan_plan;
 }
@@ -3546,7 +3548,7 @@ create_foreignscan_plan(PlannerInfo *root, ForeignPath *best_path,
 												outer_plan);
 
 	/* Copy cost data from Path to Plan; no need to make FDW do this */
-	copy_generic_path_info(&scan_plan->scan.plan, &best_path->path);
+	copy_generic_path_info(root, &scan_plan->scan.plan, &best_path->path);
 
 	/* Copy foreign server OID; likewise, no need to make FDW do this */
 	scan_plan->fs_server = rel->serverid;
@@ -3680,7 +3682,7 @@ create_customscan_plan(PlannerInfo *root, CustomPath *best_path,
 	 * Copy cost data from Path to Plan; no need to make custom-plan providers
 	 * do this
 	 */
-	copy_generic_path_info(&cplan->scan.plan, &best_path->path);
+	copy_generic_path_info(root, &cplan->scan.plan, &best_path->path);
 
 	/* Likewise, copy the relids that are represented by this custom scan */
 	cplan->custom_relids = best_path->path.parent->relids;
@@ -3782,7 +3784,7 @@ create_nestloop_plan(PlannerInfo *root,
 							  best_path->jointype,
 							  best_path->inner_unique);
 
-	copy_generic_path_info(&join_plan->join.plan, &best_path->path);
+	copy_generic_path_info(root, &join_plan->join.plan, &best_path->path);
 
 	return join_plan;
 }
@@ -4089,7 +4091,7 @@ create_mergejoin_plan(PlannerInfo *root,
 							   best_path->skip_mark_restore);
 
 	/* Costs of sort and material steps are included in path cost already */
-	copy_generic_path_info(&join_plan->join.plan, &best_path->jpath.path);
+	copy_generic_path_info(root, &join_plan->join.plan, &best_path->jpath.path);
 
 	return join_plan;
 }
@@ -4235,7 +4237,7 @@ create_hashjoin_plan(PlannerInfo *root,
 							  best_path->jpath.jointype,
 							  best_path->jpath.inner_unique);
 
-	copy_generic_path_info(&join_plan->join.plan, &best_path->jpath.path);
+	copy_generic_path_info(root, &join_plan->join.plan, &best_path->jpath.path);
 
 	return join_plan;
 }
@@ -4781,7 +4783,7 @@ order_qual_clauses(PlannerInfo *root, List *clauses)
  * Also copy the parallel-related flags, which the executor *will* use.
  */
 static void
-copy_generic_path_info(Plan *dest, Path *src)
+copy_generic_path_info(PlannerInfo *root, Plan *dest, Path *src)
 {
 	dest->startup_cost = src->startup_cost;
 	dest->total_cost = src->total_cost;
@@ -4789,6 +4791,9 @@ 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;
+
+	if (copy_generic_path_info_hook)
+		(*copy_generic_path_info_hook) (root, dest, src);
 }
 
 /*
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index 284215a717..f5249aca95 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -1226,6 +1226,7 @@ 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,
@@ -1294,6 +1295,10 @@ 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;
@@ -1519,6 +1524,10 @@ 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/include/commands/explain.h b/src/include/commands/explain.h
index d3f70fda08..2dd4200282 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -61,6 +61,12 @@ 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);
+extern PGDLLIMPORT ExplainOnePlan_hook_type ExplainOnePlan_hook;
+
 
 extern void ExplainQuery(ParseState *pstate, ExplainStmt *stmt, const char *queryString,
 			 ParamListInfo params, QueryEnvironment *queryEnv, DestReceiver *dest);
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 249aa6520a..13d0961ed7 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -151,6 +151,19 @@ typedef struct Plan
 	List	   *initPlan;		/* Init Plan nodes (un-correlated expr
 								 * subselects) */
 
+	/*
+	 * information for adaptive query optimization
+	 */
+	bool		had_path;
+	List	   *path_clauses;
+	List	   *path_relids;
+	JoinType	path_jointype;
+	int			path_parallel_workers;
+	bool		was_parametrized;
+	/* For Adaptive optimization DEBUG purposes */
+	double		predicted_cardinality;
+	int			fss_hash;
+
 	/*
 	 * Information for management of parameter-change-driven rescanning
 	 *
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index e61c1a2a29..2be4cad86b 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -694,6 +694,10 @@ 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 */
@@ -1048,6 +1052,10 @@ 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/optimizer/cost.h b/src/include/optimizer/cost.h
index 77ca7ff837..f95ea34063 100644
--- a/src/include/optimizer/cost.h
+++ b/src/include/optimizer/cost.h
@@ -39,6 +39,34 @@ typedef enum
 }			ConstraintExclusionType;
 
 
+/* Hook for plugins to get control of cardinality estimation */
+typedef void (*set_baserel_rows_estimate_hook_type) (PlannerInfo *root,
+															RelOptInfo *rel);
+extern PGDLLIMPORT set_baserel_rows_estimate_hook_type
+			set_baserel_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
@@ -174,21 +202,37 @@ extern void compute_semi_anti_join_factors(PlannerInfo *root,
 							   SpecialJoinInfo *sjinfo,
 							   List *restrictlist,
 							   SemiAntiJoinFactors *semifactors);
+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(PlannerInfo *root,
 							   RelOptInfo *rel,
 							   Path *outer_path,
 							   Path *inner_path,
 							   SpecialJoinInfo *sjinfo,
 							   List *restrict_clauses);
+extern double get_parameterized_joinrel_size_standard(PlannerInfo *root,
+										RelOptInfo *rel,
+										Path *outer_path,
+										Path *inner_path,
+										SpecialJoinInfo *sjinfo,
+										List *restrict_clauses);
 extern void set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 						   RelOptInfo *outer_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);
diff --git a/src/include/optimizer/pathnode.h b/src/include/optimizer/pathnode.h
index 7c5ff22650..178e7888af 100644
--- a/src/include/optimizer/pathnode.h
+++ b/src/include/optimizer/pathnode.h
@@ -17,6 +17,9 @@
 #include "nodes/bitmapset.h"
 #include "nodes/relation.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 a081ca689a..d42da2980f 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -34,6 +34,12 @@ extern bool parallel_leader_participation;
 /* query_planner callback to compute query_pathkeys */
 typedef void (*query_pathkeys_callback) (PlannerInfo *root, void *extra);
 
+/* hook for plugins to get control in creating plan from path */
+typedef void (*copy_generic_path_info_hook_type) (PlannerInfo *root,
+													  Plan *dest, Path *src);
+
+extern PGDLLIMPORT copy_generic_path_info_hook_type copy_generic_path_info_hook;
+
 /*
  * prototypes for plan/planmain.c
  */