aqo_pg9_6.patch

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 3244c76..8229702 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -121,6 +121,12 @@ 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 2a49639..7b9bdef 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -100,6 +100,10 @@
 
 #define LOG2(x)  (log(x) / 0.693147180559945)
 
+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;
 
 double		seq_page_cost = DEFAULT_SEQ_PAGE_COST;
 double		random_page_cost = DEFAULT_RANDOM_PAGE_COST;
@@ -3754,6 +3758,49 @@ 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.
  *
@@ -3769,19 +3816,10 @@ 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);
 
@@ -3792,13 +3830,33 @@ 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;
@@ -3828,6 +3886,36 @@ 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.
@@ -3847,11 +3935,11 @@ 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,
 										   outer_rel,
@@ -3866,6 +3954,35 @@ 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.
@@ -3878,11 +3995,11 @@ 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 54d601f..b212325 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -67,6 +67,8 @@
 #define CP_SMALL_TLIST		0x0002		/* Prefer narrower tlists */
 #define CP_LABEL_TLIST		0x0004		/* tlist must contain sortgrouprefs */
 
+/* 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);
@@ -154,7 +156,7 @@ 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);
@@ -977,7 +979,7 @@ 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;
 	}
@@ -1003,7 +1005,7 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path)
 
 	plan = make_append(subplans, tlist);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return (Plan *) plan;
 }
@@ -1031,7 +1033,7 @@ 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;
@@ -1136,7 +1138,7 @@ 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;
 }
@@ -1164,7 +1166,7 @@ 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;
 }
@@ -1367,7 +1369,7 @@ 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;
 }
@@ -1399,7 +1401,7 @@ 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;
@@ -1460,7 +1462,7 @@ create_projection_plan(PlannerInfo *root, ProjectionPath *best_path)
 		/* 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;
@@ -1515,7 +1517,7 @@ create_sort_plan(PlannerInfo *root, SortPath *best_path, int flags)
 
 	plan = make_sort_from_pathkeys(subplan, best_path->path.pathkeys);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -1552,7 +1554,7 @@ 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;
 }
@@ -1580,7 +1582,7 @@ 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;
 }
@@ -1621,7 +1623,7 @@ 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;
 }
@@ -1809,7 +1811,7 @@ 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;
@@ -1864,7 +1866,7 @@ 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
@@ -1958,7 +1960,7 @@ create_windowagg_plan(PlannerInfo *root, WindowAggPath *best_path)
 						  wc->endOffset,
 						  subplan);
 
-	copy_generic_path_info(&plan->plan, (Path *) best_path);
+	copy_generic_path_info(root, &plan->plan, (Path *) best_path);
 
 	return plan;
 }
@@ -2100,7 +2102,7 @@ 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;
 }
@@ -2136,7 +2138,7 @@ 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;
 }
@@ -2159,7 +2161,7 @@ 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;
 }
@@ -2217,7 +2219,7 @@ 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;
 }
@@ -2241,7 +2243,7 @@ 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;
 }
@@ -2287,7 +2289,7 @@ 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;
 }
@@ -2333,7 +2335,7 @@ 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;
 }
@@ -2514,7 +2516,7 @@ 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;
 }
@@ -2627,7 +2629,7 @@ 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;
 }
@@ -2888,7 +2890,7 @@ 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;
 }
@@ -2938,7 +2940,7 @@ 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;
 }
@@ -2981,7 +2983,7 @@ 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;
 }
@@ -3025,7 +3027,7 @@ 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;
 }
@@ -3118,7 +3120,7 @@ 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;
 }
@@ -3178,7 +3180,7 @@ 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;
 }
@@ -3238,7 +3240,7 @@ 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;
@@ -3365,7 +3367,7 @@ 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;
@@ -3496,7 +3498,7 @@ create_nestloop_plan(PlannerInfo *root,
 							  inner_plan,
 							  best_path->jointype);
 
-	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;
 }
@@ -3800,7 +3802,7 @@ create_mergejoin_plan(PlannerInfo *root,
 							   best_path->jpath.jointype);
 
 	/* 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;
 }
@@ -3939,7 +3941,7 @@ create_hashjoin_plan(PlannerInfo *root,
 							  (Plan *) hash_plan,
 							  best_path->jpath.jointype);
 
-	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;
 }
@@ -4578,13 +4580,16 @@ order_qual_clauses(PlannerInfo *root, List *clauses)
  * Also copy the parallel-aware flag, 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;
 	dest->plan_rows = src->rows;
 	dest->plan_width = src->pathtarget->width;
 	dest->parallel_aware = src->parallel_aware;
+
+	if (copy_generic_path_info_hook)
+		(*copy_generic_path_info_hook) (root, dest, src);
 }
 
 /*
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 369179f..6e81ae8 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -125,6 +125,16 @@ typedef struct Plan
 								 * 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;
+
+	/*
 	 * Information for management of parameter-change-driven rescanning
 	 *
 	 * extParam includes the paramIDs of all external PARAM_EXEC params
diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h
index 2a4df2f..64994a7 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
@@ -161,21 +189,37 @@ 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/planmain.h b/src/include/optimizer/planmain.h
index 4fbb6cc..def55e5 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -33,6 +33,12 @@ extern int	force_parallel_mode;
 /* 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
  */
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 7a6545f..42b58c0 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -46,6 +46,9 @@ 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
@@ -558,6 +561,10 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 								 3, es);
 	}
 
+	if (ExplainOnePlan_hook)
+		ExplainOnePlan_hook(plannedstmt, into, es,
+							queryString, params, planduration);
+
 	ExplainCloseGroup("Query", NULL, true, es);
 }
 
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 1f0bde7..9ca637c 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -58,6 +58,12 @@ 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(ExplainStmt *stmt, const char *queryString,
 			 ParamListInfo params, DestReceiver *dest);