Condition pushdown: why (=) is pushed down into join, but BETWEEN or >= is not?

From 62e161902bf5d77089af772e4f458f05df368585 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=8C=83?= <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 15:20:10 +0800
Subject: [PATCH v1 3/6] introduce RelOptInfo.filtered_rows.

---
 src/backend/optimizer/path/costsize.c | 21 ++++++++++++++++-----
 src/include/nodes/pathnodes.h         |  2 ++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 9e303877af7..b1117257a38 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -241,7 +241,7 @@ cost_seqscan(Path *path, PlannerInfo *root,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	if (!enable_seqscan)
 		startup_cost += disable_cost;
@@ -539,7 +539,7 @@ cost_index(IndexPath *path, PlannerInfo *root, double loop_count,
 	}
 	else
 	{
-		path->path.rows = baserel->rows;
+		path->path.rows = baserel->filtered_rows;
 		/* qpquals come from just the rel's restriction clauses */
 		qpquals = extract_nonindex_conditions(path->indexinfo->indrestrictinfo,
 											  path->indexclauses);
@@ -978,7 +978,7 @@ cost_bitmap_heap_scan(Path *path, PlannerInfo *root, RelOptInfo *baserel,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	if (!enable_bitmapscan)
 		startup_cost += disable_cost;
@@ -1209,7 +1209,7 @@ cost_tidscan(Path *path, PlannerInfo *root,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	/* Count how many tuples we expect to retrieve */
 	ntuples = 0;
@@ -1320,7 +1320,7 @@ cost_tidrangescan(Path *path, PlannerInfo *root,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	/* Count how many tuples and pages we expect to scan */
 	selectivity = clauselist_selectivity(root, tidrangequals, baserel->relid,
@@ -4938,6 +4938,17 @@ set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 
 	rel->rows = clamp_row_est(nrows);
 
+	nrows = rel->tuples *
+		clauselist_selectivity_ext(root,
+								   rel->baserestrictinfo,
+								   0,
+								   JOIN_INNER,
+								   NULL,
+								   true,
+								   true /* include_derived, for filtered rows */);
+
+	rel->filtered_rows = clamp_row_est(nrows);
+
 	cost_qual_eval(&rel->baserestrictcost, rel->baserestrictinfo, root);
 
 	set_rel_width(root, rel);
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 42368e10b8e..dbe1775f96d 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -683,6 +683,8 @@ typedef struct RelOptInfo
 	/* size estimates generated by planner */
 	Cardinality	rows;			/* estimated number of result tuples */
 
+	Cardinality filtered_rows;  /* filtered rows */
+
 	/* per-relation planner control flags */
 	bool		consider_startup;	/* keep cheap-startup-cost paths? */
 	bool		consider_param_startup; /* ditto, for parameterized paths? */
-- 
2.21.0

From dee63e6e198ecfe66638910b8764dc5ba6e96e7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=8C=83?= <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 20:56:40 +0800
Subject: [PATCH v1 1/6] Rebaee David's patch against the latest code.

---
 src/backend/nodes/outfuncs.c             |  14 ++
 src/backend/optimizer/path/equivclass.c  | 182 +++++++++++++++++++++++
 src/backend/optimizer/plan/initsplan.c   |  96 +++++++++---
 src/backend/utils/cache/lsyscache.c      |  28 ++++
 src/include/nodes/nodes.h                |   1 +
 src/include/nodes/pathnodes.h            |  37 +++++
 src/include/optimizer/paths.h            |   1 +
 src/include/utils/lsyscache.h            |   1 +
 src/test/regress/expected/equivclass.out |  45 ++++++
 9 files changed, 388 insertions(+), 17 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 2b0236937aa..504b805326f 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2504,6 +2504,17 @@ _outEquivalenceMember(StringInfo str, const EquivalenceMember *node)
 	WRITE_OID_FIELD(em_datatype);
 }
 
+static void
+_outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
+{
+	WRITE_NODE_TYPE("EQUIVALENCEFILTER");
+
+	WRITE_NODE_FIELD(ef_const);
+	WRITE_OID_FIELD(ef_opno);
+	WRITE_BOOL_FIELD(ef_const_is_left);
+	WRITE_UINT_FIELD(ef_source_rel);
+}
+
 static void
 _outPathKey(StringInfo str, const PathKey *node)
 {
@@ -4304,6 +4315,9 @@ outNode(StringInfo str, const void *obj)
 			case T_EquivalenceMember:
 				_outEquivalenceMember(str, obj);
 				break;
+			case T_EquivalenceFilter:
+				_outEquivalenceFilter(str, obj);
+				break;
 			case T_PathKey:
 				_outPathKey(str, obj);
 				break;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 8c6770de972..f9ae2785d60 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -19,6 +19,7 @@
 #include <limits.h>
 
 #include "access/stratnum.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
@@ -1250,6 +1251,37 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 	}
 }
 
+/*
+ * finds the opfamily and strategy number for the specified 'opno' and 'method'
+ * access method. Returns True if one is found and sets 'family' and
+ * 'amstrategy', or returns False if none are found.
+ */
+static bool
+find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+{
+	List *opfamilies;
+	ListCell *l;
+	int strategy;
+
+	opfamilies = get_opfamilies(opno, method);
+
+	foreach(l, opfamilies)
+	{
+		Oid opfamily = lfirst_oid(l);
+
+		strategy = get_op_opfamily_strategy(opno, opfamily);
+
+		if (strategy)
+		{
+			*amstrategy = strategy;
+			*family = opfamily;
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /*
  * generate_base_implied_equalities when EC contains no pseudoconstants
  */
@@ -1259,6 +1291,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 {
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
+	ListCell   *lc2;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1320,6 +1353,57 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+
+		/*
+		 * Also push any EquivalenceFilter clauses down into all relations
+		 * other than the one which the filter actually originated from.
+		 */
+		foreach(lc2, ec->ec_filters)
+		{
+			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+			Expr *leftexpr;
+			Expr *rightexpr;
+			int strategy;
+			Oid opno;
+			Oid family;
+
+			if (ef->ef_source_rel == relid)
+				continue;
+
+			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
+				&family, &strategy))
+				continue;
+
+			if (ef->ef_const_is_left)
+			{
+				leftexpr = (Expr *) ef->ef_const;
+				rightexpr = cur_em->em_expr;
+			}
+			else
+			{
+				leftexpr = cur_em->em_expr;
+				rightexpr = (Expr *) ef->ef_const;
+			}
+
+			opno = get_opfamily_member(family,
+										exprType((Node *) leftexpr),
+										exprType((Node *) rightexpr),
+										strategy);
+
+			if (opno == InvalidOid)
+				continue;
+
+			process_implied_equality(root, opno,
+										ec->ec_collation,
+										leftexpr,
+										rightexpr,
+										bms_copy(ec->ec_relids),
+										bms_copy(cur_em->em_nullable_relids),
+									 	ec->ec_min_security,
+										ec->ec_below_outer_join,
+										false);
+		}
+
 		prev_ems[relid] = cur_em;
 	}
 
@@ -1901,6 +1985,104 @@ create_join_clause(PlannerInfo *root,
 	return rinfo;
 }
 
+/*
+ * distribute_filter_quals_to_eclass
+ *		For each OpExpr in quallist look for an eclass which has an Expr
+ *		matching the Expr in the OpExpr. If a match is found we add a new
+ *		EquivalenceFilter to the eclass containing the filter details.
+ */
+void
+distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
+{
+	ListCell *l;
+
+	/* fast path for when no eclasses have been generated */
+	if (root->eq_classes == NIL)
+		return;
+
+	/*
+	 * For each qual in quallist try and find an eclass which contains the
+	 * non-Const part of the OpExpr. We'll tag any matches that we find onto
+	 * the correct eclass.
+	 */
+	foreach(l, quallist)
+	{
+		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
+		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		Const	   *constexpr;
+		Expr	   *varexpr;
+		Relids		exprrels;
+		int			relid;
+		bool		const_isleft;
+		ListCell *l2;
+
+		/*
+		 * Determine if the the OpExpr is in the form "expr op const" or
+		 * "const op expr".
+		 */
+		if (IsA(leftexpr, Const))
+		{
+			constexpr = (Const *) leftexpr;
+			varexpr = rightexpr;
+			const_isleft = true;
+		}
+		else
+		{
+			constexpr = (Const *) rightexpr;
+			varexpr = leftexpr;
+			const_isleft = false;
+		}
+
+		exprrels = pull_varnos(root, (Node *) varexpr);
+
+		/* should be filtered out, but we need to determine relid anyway */
+		if (!bms_get_singleton_member(exprrels, &relid))
+			continue;
+
+		/* search for a matching eclass member in all eclasses */
+		foreach(l2, root->eq_classes)
+		{
+			EquivalenceClass *ec = (EquivalenceClass *) lfirst(l2);
+			ListCell *l3;
+
+			if (ec->ec_broken || ec->ec_has_volatile)
+				continue;
+
+			/*
+			 * if the eclass has a const then that const will serve as the
+			 * filter, we needn't add any others.
+			 */
+			if (ec->ec_has_const)
+				continue;
+
+			/* skip this eclass no members exist which belong to this relid */
+			if (!bms_is_member(relid, ec->ec_relids))
+				continue;
+
+			foreach(l3, ec->ec_members)
+			{
+				EquivalenceMember *em = (EquivalenceMember *) lfirst(l3);
+
+				if (!bms_is_member(relid, em->em_relids))
+					continue;
+
+				if (equal(em->em_expr, varexpr))
+				{
+					EquivalenceFilter *efilter;
+					efilter = makeNode(EquivalenceFilter);
+					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const_is_left = const_isleft;
+					efilter->ef_opno = opexpr->opno;
+					efilter->ef_source_rel = relid;
+
+					ec->ec_filters = lappend(ec->ec_filters, efilter);
+					break;		/* Onto the next eclass */
+				}
+			}
+		}
+	}
+}
 
 /*
  * reconsider_outer_join_clauses
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 023efbaf092..b219bee8567 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -53,7 +53,7 @@ static void extract_lateral_references(PlannerInfo *root, RelOptInfo *brel,
 static List *deconstruct_recurse(PlannerInfo *root, Node *jtnode,
 								 bool below_outer_join,
 								 Relids *qualscope, Relids *inner_join_rels,
-								 List **postponed_qual_list);
+								 List **postponed_qual_list, List **filter_qual_list);
 static void process_security_barrier_quals(PlannerInfo *root,
 										   int rti, Relids qualscope,
 										   bool below_outer_join);
@@ -70,7 +70,8 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 									Relids qualscope,
 									Relids ojscope,
 									Relids outerjoin_nonnullable,
-									List **postponed_qual_list);
+									List **postponed_qual_list,
+									List **filter_qual_list);
 static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 								  Relids *nullable_relids_p, bool is_pushed_down);
 static bool check_equivalence_delay(PlannerInfo *root,
@@ -650,6 +651,43 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
+/*
+ * is_simple_filter_qual
+ *             Analyzes an OpExpr to determine if it may be useful as an
+ *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
+ *             false if it should not be used.
+ */
+static bool
+is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+{
+       Expr *leftexpr;
+       Expr *rightexpr;
+
+       if (!IsA(expr, OpExpr))
+               return false;
+
+       if (list_length(expr->args) != 2)
+               return false;
+
+       leftexpr = (Expr *) linitial(expr->args);
+       rightexpr = (Expr *) lsecond(expr->args);
+
+       /* XXX should we restrict these to simple Var op Const expressions? */
+       if (IsA(leftexpr, Const))
+       {
+		   if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
+			   !contain_volatile_functions((Node *) rightexpr))
+                       return true;
+       }
+       else if (IsA(rightexpr, Const))
+       {
+		   if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
+			   !contain_volatile_functions((Node *) leftexpr))
+                       return true;
+       }
+
+       return false;
+}
 
 /*****************************************************************************
  *
@@ -690,6 +728,7 @@ deconstruct_jointree(PlannerInfo *root)
 	Relids		qualscope;
 	Relids		inner_join_rels;
 	List	   *postponed_qual_list = NIL;
+	List	   *filter_qual_list = NIL;
 
 	/* Start recursion at top of jointree */
 	Assert(root->parse->jointree != NULL &&
@@ -700,11 +739,14 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list);
+								 &postponed_qual_list, &filter_qual_list);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
 
+	/* try and match each filter_qual_list item up with an eclass. */
+	distribute_filter_quals_to_eclass(root, filter_qual_list);
+
 	return result;
 }
 
@@ -725,6 +767,8 @@ deconstruct_jointree(PlannerInfo *root)
  *		or free this, either)
  *	*postponed_qual_list is a list of PostponedQual structs, which we can
  *		add quals to if they turn out to belong to a higher join level
+ *	*filter_qual_list is appended to with a list of quals which may be useful
+ *		include as EquivalenceFilters.
  *	Return value is the appropriate joinlist for this jointree node
  *
  * In addition, entries will be added to root->join_info_list for outer joins.
@@ -732,7 +776,7 @@ deconstruct_jointree(PlannerInfo *root)
 static List *
 deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 					Relids *qualscope, Relids *inner_join_rels,
-					List **postponed_qual_list)
+					List **postponed_qual_list, List **filter_qual_list)
 {
 	List	   *joinlist;
 
@@ -785,7 +829,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 											   below_outer_join,
 											   &sub_qualscope,
 											   inner_join_rels,
-											   &child_postponed_quals);
+											   &child_postponed_quals,
+											   filter_qual_list);
 			*qualscope = bms_add_members(*qualscope, sub_qualscope);
 			sub_members = list_length(sub_joinlist);
 			remaining--;
@@ -819,7 +864,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 										below_outer_join, JOIN_INNER,
 										root->qual_security_level,
 										*qualscope, NULL, NULL,
-										NULL);
+										NULL,
+										filter_qual_list);
 			else
 				*postponed_qual_list = lappend(*postponed_qual_list, pq);
 		}
@@ -835,7 +881,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									below_outer_join, JOIN_INNER,
 									root->qual_security_level,
 									*qualscope, NULL, NULL,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 	}
 	else if (IsA(jtnode, JoinExpr))
@@ -873,11 +920,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = *qualscope;
 				/* Inner join adds no restrictions for quals */
@@ -890,11 +939,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				nonnullable_rels = leftids;
@@ -904,11 +955,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* Semi join adds no restrictions for quals */
@@ -925,11 +978,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   true,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* each side is both outer and inner */
@@ -1013,7 +1068,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									root->qual_security_level,
 									*qualscope,
 									ojscope, nonnullable_rels,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 
 		/* Now we can add the SpecialJoinInfo to join_info_list */
@@ -1117,6 +1173,7 @@ process_security_barrier_quals(PlannerInfo *root,
 									qualscope,
 									qualscope,
 									NULL,
+									NULL,
 									NULL);
 		}
 		security_level++;
@@ -1610,7 +1667,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 						Relids qualscope,
 						Relids ojscope,
 						Relids outerjoin_nonnullable,
-						List **postponed_qual_list)
+						List **postponed_qual_list,
+						List **filter_qual_list)
 {
 	Relids		relids;
 	bool		is_pushed_down;
@@ -1964,6 +2022,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* No EC special case applies, so push it into the clause lists */
 	distribute_restrictinfo_to_rels(root, restrictinfo);
+
+	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
 /*
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index feef9998634..add2e7176ae 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -341,6 +341,34 @@ get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
 	return result;
 }
 
+/*
+ * get_opfamilies
+ *		Returns a list of Oids of each opfamily which 'opno' belonging to
+ *		'method' access method.
+ */
+List *
+get_opfamilies(Oid opno, Oid method)
+{
+	List	   *result = NIL;
+	CatCList   *catlist;
+	int			i;
+
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == method)
+			result = lappend_oid(result, aform->amopfamily);
+	}
+
+	ReleaseSysCacheList(catlist);
+
+	return result;
+}
+
 /*
  * get_mergejoin_opfamilies
  *		Given a putatively mergejoinable operator, return a list of the OIDs
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index da35f2c2722..3a9a235cd0e 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -265,6 +265,7 @@ typedef enum NodeTag
 	/* these aren't subclasses of Path: */
 	T_EquivalenceClass,
 	T_EquivalenceMember,
+	T_EquivalenceFilter,
 	T_PathKey,
 	T_PathTarget,
 	T_RestrictInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 1f3845b3fec..e73fef057a4 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -990,6 +990,7 @@ typedef struct EquivalenceClass
 	List	   *ec_members;		/* list of EquivalenceMembers */
 	List	   *ec_sources;		/* list of generating RestrictInfos */
 	List	   *ec_derives;		/* list of derived RestrictInfos */
+	List	   *ec_filters;
 	Relids		ec_relids;		/* all relids appearing in ec_members, except
 								 * for child members (see below) */
 	bool		ec_has_const;	/* any pseudoconstants in ec_members? */
@@ -1002,6 +1003,42 @@ typedef struct EquivalenceClass
 	struct EquivalenceClass *ec_merged; /* set if merged into another EC */
 } EquivalenceClass;
 
+/*
+ * EquivalenceFilter - List of filters on Consts which belong to the
+ * EquivalenceClass.
+ *
+ * When building the equivalence classes we also collected a list of quals in
+ * the form of; "Expr op Const" and "Const op Expr". These are collected in the
+ * hope that we'll later generate an equivalence class which contains the
+ * "Expr" part. For example, if we parse a query such as;
+ *
+ *		SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id WHERE t1.id < 10;
+ *
+ * then since we'll end up with an equivalence class containing {t1.id,t2.id},
+ * we'll tag the "< 10" filter onto the eclass. We are able to do this because
+ * the eclass proves equality between each class member, therefore all members
+ * must be below 10.
+ *
+ * EquivalenceFilters store the details required to allow us to push these
+ * filter clauses down into other relations which share an equivalence class
+ * containing a member which matches the expression of this EquivalenceFilter.
+ *
+ * ef_const is the Const value which this filter should filter against.
+ * ef_opno is the operator to filter on.
+ * ef_const_is_left marks if the OpExpr was in the form "Const op Expr" or
+ * "Expr op Const".
+ * ef_source_rel is the relation id of where this qual originated from.
+ */
+typedef struct EquivalenceFilter
+{
+	NodeTag		type;
+
+	Const	   *ef_const;		/* the constant expression to filter on */
+	Oid			ef_opno;		/* Operator Oid of filter operator */
+	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
+	Index		ef_source_rel;	/* relid of originating relation. */
+} EquivalenceFilter;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 0c3a0b90c85..ce2aac7d3aa 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -126,6 +126,7 @@ extern bool process_equivalence(PlannerInfo *root,
 extern Expr *canonicalize_ec_expression(Expr *expr,
 										Oid req_type, Oid req_collation);
 extern void reconsider_outer_join_clauses(PlannerInfo *root);
+extern void distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist);
 extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
 												  Expr *expr,
 												  Relids nullable_relids,
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index b8dd27d4a96..188d65faa0d 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -78,6 +78,7 @@ extern bool get_ordering_op_properties(Oid opno,
 									   Oid *opfamily, Oid *opcintype, int16 *strategy);
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
+extern List *get_opfamilies(Oid opno, Oid method);
 extern List *get_mergejoin_opfamilies(Oid opno);
 extern bool get_compatible_hash_operators(Oid opno,
 										  Oid *lhs_opno, Oid *rhs_opno);
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 126f7047fed..ce4c9b11748 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -451,3 +451,48 @@ explain (costs off)  -- this should not require a sort
    Filter: (f1 = 'foo'::name)
 (2 rows)
 
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Merge Join
+   Merge Cond: (ec0.ff = ec1.ff)
+   ->  Sort
+         Sort Key: ec0.ff
+         ->  Bitmap Heap Scan on ec0
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec0_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Sort
+         Sort Key: ec1.ff
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(14 rows)
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Merge Join
+   Merge Cond: (ec0.ff = ec1.ff)
+   ->  Sort
+         Sort Key: ec0.ff
+         ->  Bitmap Heap Scan on ec0
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec0_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Sort
+         Sort Key: ec1.ff
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(14 rows)
+
-- 
2.21.0

From f87f52db53b7caf56d0bb04138cb0357d2db2223 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=8C=83?= <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 20:58:07 +0800
Subject: [PATCH v1 5/6] Support ScalarArrayOpExpr and perudoconstant on
 ef_filter.

---
 src/backend/optimizer/path/equivclass.c | 110 +++++++++++++++++-------
 src/backend/optimizer/plan/initsplan.c  |  59 ++++++++-----
 src/include/nodes/pathnodes.h           |   3 +-
 3 files changed, 120 insertions(+), 52 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 9ce0249b10d..4271bacb070 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1386,23 +1386,55 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rightexpr = (Expr *) ef->ef_const;
 			}
 
-			opno = get_opfamily_member(family,
-										exprType((Node *) leftexpr),
-										exprType((Node *) rightexpr),
-										strategy);
+			if (ef->ef_expr_type == T_OpExpr)
+			{
+				opno = get_opfamily_member(family,
+										   exprType((Node *) leftexpr),
+										   exprType((Node *) rightexpr),
+										   strategy);
 
-			if (opno == InvalidOid)
-				continue;
+				if (opno == InvalidOid)
+					continue;
 
-			rinfo = process_implied_equality(root, opno,
-											 ec->ec_collation,
-											 leftexpr,
-											 rightexpr,
-											 bms_copy(ec->ec_relids),
-											 bms_copy(cur_em->em_nullable_relids),
-											 ec->ec_min_security,
-											 ec->ec_below_outer_join,
-											 false);
+				rinfo = process_implied_equality(root, opno,
+												 ec->ec_collation,
+												 leftexpr,
+												 rightexpr,
+												 bms_copy(ec->ec_relids),
+												 bms_copy(cur_em->em_nullable_relids),
+												 ec->ec_min_security,
+												 ec->ec_below_outer_join,
+												 false);
+			}
+			else
+			{
+				ScalarArrayOpExpr *arr_opexpr;
+				Relids relids;
+
+				Assert(ef->ef_expr_type == T_ScalarArrayOpExpr);
+				arr_opexpr = makeNode(ScalarArrayOpExpr);
+				arr_opexpr->opno = ef->ef_opno;
+				arr_opexpr->opfuncid = get_opcode(ef->ef_opno);
+				arr_opexpr->useOr = true; /* See is_simple_filter_qual */
+				arr_opexpr->args = list_make2(leftexpr, ef->ef_const);
+				arr_opexpr->inputcollid = ec->ec_collation;
+
+				relids = pull_varnos(root, (Node *)arr_opexpr);
+
+				rinfo = make_restrictinfo(root,
+										  (Expr *) arr_opexpr,
+										  true,
+										  false,
+										  false, /* perudoconstant */
+										  ec->ec_min_security,
+										  relids,
+										  NULL,
+										  bms_copy(cur_em->em_nullable_relids));
+
+				// check_mergejoinable(rinfo);
+
+				distribute_restrictinfo_to_rels(root, rinfo);
+			}
 			rinfo->derived = ec;
 		}
 
@@ -2009,29 +2041,48 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 	 */
 	foreach(l, quallist)
 	{
-		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
-		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
-		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
-		Const	   *constexpr;
-		Expr	   *varexpr;
+		Expr	*expr = lfirst(l);
+
+		List	*args;
+		Node	   *leftexpr;
+		Node	   *rightexpr;
+		Node	   *constexpr;
+		Node	   *varexpr;
+		Oid			opno;
+
 		Relids		exprrels;
 		int			relid;
 		bool		const_isleft;
 		ListCell *l2;
 
-		/*
-		 * Determine if the the OpExpr is in the form "expr op const" or
-		 * "const op expr".
-		 */
-		if (IsA(leftexpr, Const))
+		if (nodeTag(expr) == T_OpExpr)
+		{
+			OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+			args = opexpr->args;
+			opno = opexpr->opno;
+		}
+		else if (nodeTag(expr) == T_ScalarArrayOpExpr)
+		{
+			ScalarArrayOpExpr *arr_expr = (ScalarArrayOpExpr *) lfirst(l);
+			args = arr_expr->args;
+			opno = arr_expr->opno;
+		}
+		else
+		{
+			Assert(false);
+		}
+
+		leftexpr = linitial(args);
+		rightexpr = lsecond(args);
+		if (is_pseudo_constant_clause(leftexpr))
 		{
-			constexpr = (Const *) leftexpr;
+			constexpr = leftexpr;
 			varexpr = rightexpr;
 			const_isleft = true;
 		}
 		else
 		{
-			constexpr = (Const *) rightexpr;
+			constexpr = rightexpr;
 			varexpr = leftexpr;
 			const_isleft = false;
 		}
@@ -2073,10 +2124,11 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 				{
 					EquivalenceFilter *efilter;
 					efilter = makeNode(EquivalenceFilter);
-					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const = (Node *)copyObject(constexpr);
 					efilter->ef_const_is_left = const_isleft;
-					efilter->ef_opno = opexpr->opno;
+					efilter->ef_opno = opno;
 					efilter->ef_source_rel = relid;
+					efilter->ef_expr_type = nodeTag(expr);
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index b219bee8567..a0f12198b8c 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -656,33 +656,42 @@ create_lateral_join_info(PlannerInfo *root)
  *             Analyzes an OpExpr to determine if it may be useful as an
  *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
  *             false if it should not be used.
+ *
  */
 static bool
-is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+is_simple_filter_qual(PlannerInfo *root, Expr *expr)
 {
-       Expr *leftexpr;
-       Expr *rightexpr;
-
-       if (!IsA(expr, OpExpr))
-               return false;
-
-       if (list_length(expr->args) != 2)
-               return false;
-
-       leftexpr = (Expr *) linitial(expr->args);
-       rightexpr = (Expr *) lsecond(expr->args);
-
-       /* XXX should we restrict these to simple Var op Const expressions? */
-       if (IsA(leftexpr, Const))
+       Node *leftexpr;
+       Node *rightexpr;
+	   List	*args = NIL;
+
+       if (IsA(expr, OpExpr))
+		   args = castNode(OpExpr, expr)->args;
+	   else if (IsA(expr, ScalarArrayOpExpr))
+	   {
+		   ScalarArrayOpExpr *arr_opexpr = castNode(ScalarArrayOpExpr, expr);
+		   if (!arr_opexpr->useOr)
+			   /* Just support IN for now */
+			   return false;
+		   args = arr_opexpr->args;
+	   }
+
+       if (list_length(args) != 2)
+		   return false;
+
+       leftexpr = linitial(args);
+       rightexpr = lsecond(args);
+
+       if (is_pseudo_constant_clause(leftexpr))
        {
-		   if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
-			   !contain_volatile_functions((Node *) rightexpr))
+		   if (bms_membership(pull_varnos(root, rightexpr)) == BMS_SINGLETON &&
+			   !contain_volatile_functions(rightexpr))
                        return true;
        }
-       else if (IsA(rightexpr, Const))
+       else if (is_pseudo_constant_clause(rightexpr))
        {
-		   if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
-			   !contain_volatile_functions((Node *) leftexpr))
+		   if (bms_membership(pull_varnos(root, leftexpr)) == BMS_SINGLETON &&
+			   !contain_volatile_functions(leftexpr))
                        return true;
        }
 
@@ -739,7 +748,13 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list, &filter_qual_list);
+								 &postponed_qual_list,
+								 /*
+								  * geqo option here is just used for testing
+								  * during review stage, set enable_geqo to
+								  * false to disable this feature.
+								  */
+								 enable_geqo ? &filter_qual_list : NULL);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
@@ -2024,7 +2039,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	distribute_restrictinfo_to_rels(root, restrictinfo);
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
-	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (Expr *) clause))
 		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index dbe1775f96d..c1ef0066188 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1035,10 +1035,11 @@ typedef struct EquivalenceFilter
 {
 	NodeTag		type;
 
-	Const	   *ef_const;		/* the constant expression to filter on */
+	Node		*ef_const;		/* pseudo const */
 	Oid			ef_opno;		/* Operator Oid of filter operator */
 	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
 	Index		ef_source_rel;	/* relid of originating relation. */
+	NodeTag		ef_expr_type;
 } EquivalenceFilter;
 
 /*
-- 
2.21.0

From 9d8e8e11253e177f24436fbdbc8aff0715b5dd39 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=8C=83?= <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 17:37:27 +0800
Subject: [PATCH v1 4/6] remove duplicated qual executing.

---
 src/backend/optimizer/path/equivclass.c | 22 +++++++++++++++++++
 src/backend/optimizer/plan/createplan.c | 29 +++++++++++++++++++++++--
 src/include/optimizer/paths.h           |  2 ++
 src/test/regress/parallel_schedule      |  2 ++
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 6ed9e8c9064..9ce0249b10d 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -3350,6 +3350,28 @@ is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist)
 	return false;
 }
 
+
+bool
+is_correlated_derived_clause(RestrictInfo *rinfo, List *clauselist)
+{
+	EquivalenceClass *derived_ec = rinfo->derived;
+	ListCell   *lc;
+
+	/* Fail if it's not a potentially-derived clause from some EC */
+	if (derived_ec == NULL)
+		return false;
+
+	foreach(lc, clauselist)
+	{
+		RestrictInfo *otherrinfo = (RestrictInfo *) lfirst(lc);
+
+		if (otherrinfo->parent_ec == derived_ec)
+			return true;
+	}
+
+	return false;
+}
+
 /*
  * is_redundant_with_indexclauses
  *		Test whether rinfo is redundant with any clause in the IndexClause
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index cd6d72c7633..03c5207ede0 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -556,11 +556,14 @@ static Plan *
 create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 {
 	RelOptInfo *rel = best_path->parent;
-	List	   *scan_clauses;
+	List	   *scan_clauses = NIL;
 	List	   *gating_clauses;
 	List	   *tlist;
 	Plan	   *plan;
 
+	List	*ppi_clauses = best_path->param_info ? best_path->param_info->ppi_clauses : NIL;
+	ListCell	*lc;
+
 	/*
 	 * Extract the relevant restriction clauses from the parent relation. The
 	 * executor must apply all these restrictions during the scan, except for
@@ -591,8 +594,18 @@ create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 	 * For paranoia's sake, don't modify the stored baserestrictinfo list.
 	 */
 	if (best_path->param_info)
-		scan_clauses = list_concat_copy(scan_clauses,
+	{
+		List *stripped_quals = NIL;
+		foreach(lc, rel->baserestrictinfo)
+		{
+			RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
+
+			if (!is_correlated_derived_clause(rinfo, ppi_clauses))
+				stripped_quals = lappend(stripped_quals, rinfo);
+		}
+		scan_clauses = list_concat_copy(stripped_quals,
 										best_path->param_info->ppi_clauses);
+	}
 
 	/*
 	 * Detect whether we have any pseudoconstant quals to deal with.  Then, if
@@ -4912,6 +4925,7 @@ fix_indexqual_references(PlannerInfo *root, IndexPath *index_path,
 	List	   *stripped_indexquals;
 	List	   *fixed_indexquals;
 	ListCell   *lc;
+	List	*ppi_clauses = index_path->path.param_info ? index_path->path.param_info->ppi_clauses : NIL;
 
 	stripped_indexquals = fixed_indexquals = NIL;
 
@@ -4921,6 +4935,17 @@ fix_indexqual_references(PlannerInfo *root, IndexPath *index_path,
 		int			indexcol = iclause->indexcol;
 		ListCell   *lc2;
 
+		if (is_correlated_derived_clause(iclause->rinfo, ppi_clauses))
+		{
+			/*
+			 * bitmapscan will read this indexquals as well. so we can't just igrore
+			 * it for now. we can totally delete it.
+			 */
+			index_path->indexclauses = foreach_delete_current(index_path->indexclauses, lc);
+			continue;
+		}
+
+
 		foreach(lc2, iclause->indexquals)
 		{
 			RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc2);
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index ce2aac7d3aa..08d8612cdba 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -188,6 +188,8 @@ extern bool eclass_useful_for_merging(PlannerInfo *root,
 extern bool is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist);
 extern bool is_redundant_with_indexclauses(RestrictInfo *rinfo,
 										   List *indexclauses);
+extern bool is_correlated_derived_clause(RestrictInfo *rinfo, List *clauselist);
+
 
 /*
  * pathkeys.c
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 861c30a73ae..b071324b961 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -134,3 +134,5 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+test: ec_filter
\ No newline at end of file
-- 
2.21.0

From d34e73aad40e4b54ce61dce65da810abfb608b23 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=8C=83?= <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 14:54:07 +0800
Subject: [PATCH v1 2/6] support set_xxx_size with derived_clauses ignored.

---
 src/backend/optimizer/path/clausesel.c  | 34 +++++++++++++++++--------
 src/backend/optimizer/path/costsize.c   | 25 ++++++++++--------
 src/backend/optimizer/path/equivclass.c | 20 ++++++++-------
 src/backend/optimizer/util/inherit.c    | 31 ++++++++++++----------
 src/backend/statistics/dependencies.c   |  3 ++-
 src/backend/statistics/extended_stats.c |  5 ++--
 src/include/nodes/pathnodes.h           |  1 +
 src/include/optimizer/optimizer.h       |  6 +++--
 8 files changed, 77 insertions(+), 48 deletions(-)

diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c
index 06f836308d0..8961e66ea4e 100644
--- a/src/backend/optimizer/path/clausesel.c
+++ b/src/backend/optimizer/path/clausesel.c
@@ -106,7 +106,7 @@ clauselist_selectivity(PlannerInfo *root,
 					   SpecialJoinInfo *sjinfo)
 {
 	return clauselist_selectivity_ext(root, clauses, varRelid,
-									  jointype, sjinfo, true);
+									  jointype, sjinfo, true, true);
 }
 
 /*
@@ -121,7 +121,8 @@ clauselist_selectivity_ext(PlannerInfo *root,
 						   int varRelid,
 						   JoinType jointype,
 						   SpecialJoinInfo *sjinfo,
-						   bool use_extended_stats)
+						   bool use_extended_stats,
+						   bool include_derived)
 {
 	Selectivity s1 = 1.0;
 	RelOptInfo *rel;
@@ -137,7 +138,8 @@ clauselist_selectivity_ext(PlannerInfo *root,
 	if (list_length(clauses) == 1)
 		return clause_selectivity_ext(root, (Node *) linitial(clauses),
 									  varRelid, jointype, sjinfo,
-									  use_extended_stats);
+									  use_extended_stats,
+									  include_derived);
 
 	/*
 	 * Determine if these clauses reference a single relation.  If so, and if
@@ -183,7 +185,7 @@ clauselist_selectivity_ext(PlannerInfo *root,
 
 		/* Compute the selectivity of this clause in isolation */
 		s2 = clause_selectivity_ext(root, clause, varRelid, jointype, sjinfo,
-									use_extended_stats);
+									use_extended_stats, include_derived);
 
 		/*
 		 * Check for being passed a RestrictInfo.
@@ -412,7 +414,9 @@ clauselist_selectivity_or(PlannerInfo *root,
 			continue;
 
 		s2 = clause_selectivity_ext(root, (Node *) lfirst(lc), varRelid,
-									jointype, sjinfo, use_extended_stats);
+									jointype, sjinfo, use_extended_stats,
+									true /* we never push a derived under or clause */
+			);
 
 		s1 = s1 + s2 - s1 * s2;
 	}
@@ -694,7 +698,7 @@ clause_selectivity(PlannerInfo *root,
 				   SpecialJoinInfo *sjinfo)
 {
 	return clause_selectivity_ext(root, clause, varRelid,
-								  jointype, sjinfo, true);
+								  jointype, sjinfo, true, true);
 }
 
 /*
@@ -709,7 +713,8 @@ clause_selectivity_ext(PlannerInfo *root,
 					   int varRelid,
 					   JoinType jointype,
 					   SpecialJoinInfo *sjinfo,
-					   bool use_extended_stats)
+					   bool use_extended_stats,
+					   bool include_derived)
 {
 	Selectivity s1 = 0.5;		/* default for any unhandled clause type */
 	RestrictInfo *rinfo = NULL;
@@ -742,6 +747,9 @@ clause_selectivity_ext(PlannerInfo *root,
 		if (rinfo->norm_selec > 1)
 			return (Selectivity) 1.0;
 
+		if (rinfo->derived && !include_derived)
+			return (Selectivity) 1.0;
+
 		/*
 		 * If possible, cache the result of the selectivity calculation for
 		 * the clause.  We can cache if varRelid is zero or the clause
@@ -830,7 +838,8 @@ clause_selectivity_ext(PlannerInfo *root,
 										  varRelid,
 										  jointype,
 										  sjinfo,
-										  use_extended_stats);
+										  use_extended_stats,
+										  include_derived);
 	}
 	else if (is_andclause(clause))
 	{
@@ -840,7 +849,8 @@ clause_selectivity_ext(PlannerInfo *root,
 										varRelid,
 										jointype,
 										sjinfo,
-										use_extended_stats);
+										use_extended_stats,
+										include_derived);
 	}
 	else if (is_orclause(clause))
 	{
@@ -959,7 +969,8 @@ clause_selectivity_ext(PlannerInfo *root,
 									varRelid,
 									jointype,
 									sjinfo,
-									use_extended_stats);
+									use_extended_stats,
+									include_derived);
 	}
 	else if (IsA(clause, CoerceToDomain))
 	{
@@ -969,7 +980,8 @@ clause_selectivity_ext(PlannerInfo *root,
 									varRelid,
 									jointype,
 									sjinfo,
-									use_extended_stats);
+									use_extended_stats,
+									include_derived);
 	}
 	else
 	{
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 8dc7dd4ca26..9e303877af7 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -4928,11 +4928,13 @@ set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 	Assert(rel->relid > 0);
 
 	nrows = rel->tuples *
-		clauselist_selectivity(root,
-							   rel->baserestrictinfo,
-							   0,
-							   JOIN_INNER,
-							   NULL);
+		clauselist_selectivity_ext(root,
+								   rel->baserestrictinfo,
+								   0,
+								   JOIN_INNER,
+								   NULL,
+								   true,
+								   false /* include_derived */);
 
 	rel->rows = clamp_row_est(nrows);
 
@@ -4964,11 +4966,14 @@ get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
 	 */
 	allclauses = list_concat_copy(param_clauses, rel->baserestrictinfo);
 	nrows = rel->tuples *
-		clauselist_selectivity(root,
-							   allclauses,
-							   rel->relid,	/* do not use 0! */
-							   JOIN_INNER,
-							   NULL);
+		clauselist_selectivity_ext(root,
+								   allclauses,
+								   rel->relid,	/* do not use 0! */
+								   JOIN_INNER,
+								   NULL,
+								   true,
+								   false /* doesn't include the derived clause */
+			);
 	nrows = clamp_row_est(nrows);
 	/* For safety, make sure result is not more than the base estimate */
 	if (nrows > rel->rows)
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index f9ae2785d60..6ed9e8c9064 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1366,6 +1366,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			int strategy;
 			Oid opno;
 			Oid family;
+			RestrictInfo *rinfo;
 
 			if (ef->ef_source_rel == relid)
 				continue;
@@ -1393,15 +1394,16 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (opno == InvalidOid)
 				continue;
 
-			process_implied_equality(root, opno,
-										ec->ec_collation,
-										leftexpr,
-										rightexpr,
-										bms_copy(ec->ec_relids),
-										bms_copy(cur_em->em_nullable_relids),
-									 	ec->ec_min_security,
-										ec->ec_below_outer_join,
-										false);
+			rinfo = process_implied_equality(root, opno,
+											 ec->ec_collation,
+											 leftexpr,
+											 rightexpr,
+											 bms_copy(ec->ec_relids),
+											 bms_copy(cur_em->em_nullable_relids),
+											 ec->ec_min_security,
+											 ec->ec_below_outer_join,
+											 false);
+			rinfo->derived = ec;
 		}
 
 		prev_ems[relid] = cur_em;
diff --git a/src/backend/optimizer/util/inherit.c b/src/backend/optimizer/util/inherit.c
index 7e134822f36..8a5863c4da4 100644
--- a/src/backend/optimizer/util/inherit.c
+++ b/src/backend/optimizer/util/inherit.c
@@ -797,6 +797,7 @@ apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,
 		{
 			Node	   *onecq = (Node *) lfirst(lc2);
 			bool		pseudoconstant;
+			RestrictInfo		*child_rinfo;
 
 			/* check for pseudoconstant (no Vars or volatile functions) */
 			pseudoconstant =
@@ -807,15 +808,19 @@ apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,
 				/* tell createplan.c to check for gating quals */
 				root->hasPseudoConstantQuals = true;
 			}
+
+			child_rinfo =  make_restrictinfo(root,
+											 (Expr *) onecq,
+											 rinfo->is_pushed_down,
+											 rinfo->outerjoin_delayed,
+											 pseudoconstant,
+											 rinfo->security_level,
+											 NULL, NULL, NULL);
+
+			child_rinfo->derived = rinfo->derived;
 			/* reconstitute RestrictInfo with appropriate properties */
-			childquals = lappend(childquals,
-								 make_restrictinfo(root,
-												   (Expr *) onecq,
-												   rinfo->is_pushed_down,
-												   rinfo->outerjoin_delayed,
-												   pseudoconstant,
-												   rinfo->security_level,
-												   NULL, NULL, NULL));
+			childquals = lappend(childquals, child_rinfo);
+
 			/* track minimum security level among child quals */
 			cq_min_security = Min(cq_min_security, rinfo->security_level);
 		}
@@ -844,13 +849,13 @@ apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,
 			foreach(lc2, qualset)
 			{
 				Expr	   *qual = (Expr *) lfirst(lc2);
+				RestrictInfo *rinfo = make_restrictinfo(root, qual,
+														true, false, false,
+														security_level,
+														NULL, NULL, NULL);
 
 				/* not likely that we'd see constants here, so no check */
-				childquals = lappend(childquals,
-									 make_restrictinfo(root, qual,
-													   true, false, false,
-													   security_level,
-													   NULL, NULL, NULL));
+				childquals = lappend(childquals, rinfo);
 				cq_min_security = Min(cq_min_security, security_level);
 			}
 			security_level++;
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index 34326d55619..838446a220d 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -1076,7 +1076,8 @@ clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
 		}
 
 		simple_sel = clauselist_selectivity_ext(root, attr_clauses, varRelid,
-												jointype, sjinfo, false);
+												jointype, sjinfo, false,
+												true /* probably no reasonable */);
 		attr_sel[attidx++] = simple_sel;
 	}
 
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index ca48395d5c5..38836f58c4e 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -1870,7 +1870,8 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
 				 * columns/clauses.
 				 */
 				simple_sel = clause_selectivity_ext(root, clause, varRelid,
-													jointype, sjinfo, false);
+													jointype, sjinfo, false,
+													true);
 
 				overlap_simple_sel = simple_or_sel * simple_sel;
 
@@ -1943,7 +1944,7 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
 			 */
 			simple_sel = clauselist_selectivity_ext(root, stat_clauses,
 													varRelid, jointype,
-													sjinfo, false);
+													sjinfo, false, true);
 
 			/*
 			 * Multi-column estimate using MCV statistics, along with base and
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index e73fef057a4..42368e10b8e 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -2165,6 +2165,7 @@ typedef struct RestrictInfo
 	/* hash equality operators used for memoize nodes, else InvalidOid */
 	Oid			left_hasheqoperator;
 	Oid			right_hasheqoperator;
+	EquivalenceClass *derived;
 } RestrictInfo;
 
 /*
diff --git a/src/include/optimizer/optimizer.h b/src/include/optimizer/optimizer.h
index 6b8ee0c69fa..a3385ae51ff 100644
--- a/src/include/optimizer/optimizer.h
+++ b/src/include/optimizer/optimizer.h
@@ -68,7 +68,8 @@ extern Selectivity clause_selectivity_ext(PlannerInfo *root,
 										  int varRelid,
 										  JoinType jointype,
 										  SpecialJoinInfo *sjinfo,
-										  bool use_extended_stats);
+										  bool use_extended_stats,
+										  bool include_derived);
 extern Selectivity clauselist_selectivity(PlannerInfo *root,
 										  List *clauses,
 										  int varRelid,
@@ -79,7 +80,8 @@ extern Selectivity clauselist_selectivity_ext(PlannerInfo *root,
 											  int varRelid,
 											  JoinType jointype,
 											  SpecialJoinInfo *sjinfo,
-											  bool use_extended_stats);
+											  bool use_extended_stats,
+											  bool include_derived);
 
 /* in path/costsize.c: */
 
-- 
2.21.0

From ce6623ac58687c67e3e7576c212b4e352bc786b9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=8C=83?= <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 22:57:13 +0800
Subject: [PATCH v1 6/6] adding some test cases for this feature and fix the
 existing case

because of this feature.
---
 src/test/regress/expected/equivclass.out      |  54 ++++-----
 src/test/regress/expected/join.out            |  33 +++---
 src/test/regress/expected/partition_join.out  | 106 ++++++++++--------
 src/test/regress/expected/partition_prune.out |  56 ++-------
 src/test/regress/sql/equivclass.sql           |  12 ++
 5 files changed, 118 insertions(+), 143 deletions(-)

diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index ce4c9b11748..a5042c3cbc3 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -456,43 +456,29 @@ explain (costs off)
   select * from ec0
   inner join ec1 on ec0.ff = ec1.ff
   where ec0.ff between 1 and 10;
-                         QUERY PLAN                         
-------------------------------------------------------------
- Merge Join
-   Merge Cond: (ec0.ff = ec1.ff)
-   ->  Sort
-         Sort Key: ec0.ff
-         ->  Bitmap Heap Scan on ec0
-               Recheck Cond: ((ff >= 1) AND (ff <= 10))
-               ->  Bitmap Index Scan on ec0_pkey
-                     Index Cond: ((ff >= 1) AND (ff <= 10))
-   ->  Sort
-         Sort Key: ec1.ff
-         ->  Bitmap Heap Scan on ec1
-               Recheck Cond: ((ff >= 1) AND (ff <= 10))
-               ->  Bitmap Index Scan on ec1_pkey
-                     Index Cond: ((ff >= 1) AND (ff <= 10))
-(14 rows)
+                            QUERY PLAN                            
+------------------------------------------------------------------
+ Nested Loop
+   ->  Bitmap Heap Scan on ec1
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec1_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Index Scan using ec0_pkey on ec0
+         Index Cond: ((ff = ec1.ff) AND (ff >= 1) AND (ff <= 10))
+(7 rows)
 
 explain (costs off)
   select * from ec0
   inner join ec1 on ec0.ff = ec1.ff
   where ec1.ff between 1 and 10;
-                         QUERY PLAN                         
-------------------------------------------------------------
- Merge Join
-   Merge Cond: (ec0.ff = ec1.ff)
-   ->  Sort
-         Sort Key: ec0.ff
-         ->  Bitmap Heap Scan on ec0
-               Recheck Cond: ((ff >= 1) AND (ff <= 10))
-               ->  Bitmap Index Scan on ec0_pkey
-                     Index Cond: ((ff >= 1) AND (ff <= 10))
-   ->  Sort
-         Sort Key: ec1.ff
-         ->  Bitmap Heap Scan on ec1
-               Recheck Cond: ((ff >= 1) AND (ff <= 10))
-               ->  Bitmap Index Scan on ec1_pkey
-                     Index Cond: ((ff >= 1) AND (ff <= 10))
-(14 rows)
+                            QUERY PLAN                            
+------------------------------------------------------------------
+ Nested Loop
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Index Scan using ec1_pkey on ec1
+         Index Cond: ((ff = ec0.ff) AND (ff >= 1) AND (ff <= 10))
+(7 rows)
 
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index d5b5b775fdd..7df4f93856e 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3337,7 +3337,7 @@ where t1.unique2 < 42 and t1.stringu1 > t2.stringu2;
    Join Filter: (t1.stringu1 > t2.stringu2)
    ->  Nested Loop
          ->  Seq Scan on int4_tbl i1
-               Filter: (f1 = 0)
+               Filter: ((f1 = 0) AND (11 < 42))
          ->  Index Scan using tenk1_unique2 on tenk1 t1
                Index Cond: ((unique2 = (11)) AND (unique2 < 42))
    ->  Index Scan using tenk1_unique1 on tenk1 t2
@@ -6496,9 +6496,10 @@ where j1.id1 % 1000 = 1 and j2.id1 % 1000 = 1 and j2.id1 = any (array[1]);
    Merge Cond: (j1.id1 = j2.id1)
    Join Filter: (j1.id2 = j2.id2)
    ->  Index Scan using j1_id1_idx on j1
+         Index Cond: (id1 = ANY ('{1}'::integer[]))
    ->  Index Scan using j2_id1_idx on j2
          Index Cond: (id1 = ANY ('{1}'::integer[]))
-(6 rows)
+(7 rows)
 
 select * from j1
 inner join j2 on j1.id1 = j2.id1 and j1.id2 = j2.id2
@@ -6513,16 +6514,17 @@ where j1.id1 % 1000 = 1 and j2.id1 % 1000 = 1 and j2.id1 = any (array[1]);
 explain (costs off) select * from j1
 inner join j2 on j1.id1 = j2.id1 and j1.id2 = j2.id2
 where j1.id1 % 1000 = 1 and j2.id1 % 1000 = 1 and j2.id1 >= any (array[1,5]);
-                      QUERY PLAN                       
--------------------------------------------------------
+                       QUERY PLAN                        
+---------------------------------------------------------
  Merge Join
-   Merge Cond: (j1.id1 = j2.id1)
-   Join Filter: (j1.id2 = j2.id2)
-   ->  Index Scan using j1_id1_idx on j1
+   Merge Cond: ((j1.id1 = j2.id1) AND (j1.id2 = j2.id2))
+   ->  Index Only Scan using j1_pkey on j1
+         Index Cond: (id1 >= ANY ('{1,5}'::integer[]))
+         Filter: ((id1 % 1000) = 1)
    ->  Index Only Scan using j2_pkey on j2
          Index Cond: (id1 >= ANY ('{1,5}'::integer[]))
          Filter: ((id1 % 1000) = 1)
-(7 rows)
+(8 rows)
 
 select * from j1
 inner join j2 on j1.id1 = j2.id1 and j1.id2 = j2.id2
@@ -6558,6 +6560,7 @@ where exists (select 1 from tenk1 t3
                Group Key: t3.thousand, t3.tenthous
                ->  Index Only Scan using tenk1_thous_tenthous on public.tenk1 t3
                      Output: t3.thousand, t3.tenthous
+                     Index Cond: (t3.thousand < 1)
          ->  Hash
                Output: t1.unique1
                ->  Index Only Scan using onek_unique1 on public.onek t1
@@ -6566,7 +6569,7 @@ where exists (select 1 from tenk1 t3
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = t3.tenthous)
-(18 rows)
+(19 rows)
 
 -- ... unless it actually is unique
 create table j3 as select unique1, tenthous from onek;
@@ -6578,18 +6581,18 @@ from onek t1, tenk1 t2
 where exists (select 1 from j3
               where j3.unique1 = t1.unique1 and j3.tenthous = t2.hundred)
       and t1.unique1 < 1;
-                               QUERY PLAN                               
-------------------------------------------------------------------------
+                                 QUERY PLAN                                 
+----------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
    ->  Nested Loop
          Output: t1.unique1, j3.tenthous
-         ->  Index Only Scan using onek_unique1 on public.onek t1
-               Output: t1.unique1
-               Index Cond: (t1.unique1 < 1)
          ->  Index Only Scan using j3_unique1_tenthous_idx on public.j3
                Output: j3.unique1, j3.tenthous
-               Index Cond: (j3.unique1 = t1.unique1)
+               Index Cond: (j3.unique1 < 1)
+         ->  Index Only Scan using onek_unique1 on public.onek t1
+               Output: t1.unique1
+               Index Cond: ((t1.unique1 = j3.unique1) AND (t1.unique1 < 1))
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = j3.tenthous)
diff --git a/src/test/regress/expected/partition_join.out b/src/test/regress/expected/partition_join.out
index bb5b7c47a45..c12351a3b0a 100644
--- a/src/test/regress/expected/partition_join.out
+++ b/src/test/regress/expected/partition_join.out
@@ -186,17 +186,17 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM (SELECT 50 phv, * FROM prt1 WHERE prt1.b = 0)
 -- Join with pruned partitions from joining relations
 EXPLAIN (COSTS OFF)
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
-                     QUERY PLAN                      
------------------------------------------------------
+                            QUERY PLAN                             
+-------------------------------------------------------------------
  Sort
    Sort Key: t1.a
    ->  Hash Join
          Hash Cond: (t2.b = t1.a)
          ->  Seq Scan on prt2_p2 t2
-               Filter: (b > 250)
+               Filter: ((b > 250) AND (b < 450))
          ->  Hash
                ->  Seq Scan on prt1_p2 t1
-                     Filter: ((a < 450) AND (b = 0))
+                     Filter: ((a < 450) AND (a > 250) AND (b = 0))
 (9 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
@@ -3100,16 +3100,18 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a < 300) AND (b = 0))
          ->  Hash Join
                Hash Cond: (t2_2.b = t1_2.a)
                ->  Seq Scan on prt2_adv_p2 t2_2
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a < 300) AND (b = 0))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -3139,16 +3141,19 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: ((b >= 100) AND (b < 300))
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-         ->  Hash Join
-               Hash Cond: (t2_2.b = t1_2.a)
-               ->  Seq Scan on prt2_adv_p2 t2_2
-               ->  Hash
+         ->  Merge Join
+               Merge Cond: (t2_2.b = t1_2.a)
+               ->  Index Scan using prt2_adv_p2_b_idx on prt2_adv_p2 t2_2
+                     Index Cond: ((b >= 100) AND (b < 300))
+               ->  Sort
+                     Sort Key: t1_2.a
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-(15 rows)
+(18 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a >= 100 AND t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -4444,16 +4449,18 @@ SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: ((t2_1.a = t1_1.a) AND (t2_1.c = t1_1.c))
                ->  Seq Scan on plt2_adv_p3 t2_1
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p3 t1_1
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
          ->  Hash Join
                Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.c = t1_2.c))
                ->  Seq Scan on plt2_adv_p4 t2_2
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p4 t1_2
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE t1.c IN ('0003', '0004', '0005') AND t1.b < 10 ORDER BY t1.a;
  a |  c   | a |  c   
@@ -4497,16 +4504,18 @@ SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: ((t2_1.a = t1_1.a) AND (t2_1.c = t1_1.c))
                ->  Seq Scan on plt2_adv_p3 t2_1
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p3 t1_1
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
          ->  Hash Join
                Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.c = t1_2.c))
                ->  Seq Scan on plt2_adv_p4 t2_2
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p4 t1_2
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE t1.c IN ('0003', '0004', '0005') AND t1.b < 10 ORDER BY t1.a;
  a |  c   | a |  c   
@@ -4692,27 +4701,32 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
                      Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Seq Scan on beta_neg_p1 t2_1
+                           Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.b = t1_2.b))
-               ->  Seq Scan on beta_neg_p2 t2_2
+               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b))
+               ->  Seq Scan on alpha_neg_p2 t1_2
+                     Filter: ((b >= 125) AND (b < 225))
                ->  Hash
-                     ->  Seq Scan on alpha_neg_p2 t1_2
+                     ->  Seq Scan on beta_neg_p2 t2_2
                            Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_4.a = t1_4.a) AND (t2_4.b = t1_4.b))
+               Hash Cond: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b))
                ->  Append
-                     ->  Seq Scan on beta_pos_p1 t2_4
-                     ->  Seq Scan on beta_pos_p2 t2_5
-                     ->  Seq Scan on beta_pos_p3 t2_6
+                     ->  Seq Scan on alpha_pos_p1 t1_4
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p2 t1_5
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p3 t1_6
+                           Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Append
-                           ->  Seq Scan on alpha_pos_p1 t1_4
+                           ->  Seq Scan on beta_pos_p1 t2_4
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p2 t1_5
+                           ->  Seq Scan on beta_pos_p2 t2_5
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p3 t1_6
+                           ->  Seq Scan on beta_pos_p3 t2_6
                                  Filter: ((b >= 125) AND (b < 225))
-(29 rows)
+(34 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b) WHERE t1.b >= 125 AND t1.b < 225 ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
@@ -4761,8 +4775,8 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
 
 EXPLAIN (COSTS OFF)
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b, t2.b;
-                                                              QUERY PLAN                                                              
---------------------------------------------------------------------------------------------------------------------------------------
+                                                                 QUERY PLAN                                                                 
+--------------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Sort Key: t1.a, t1.b, t2.b
    ->  Append
@@ -4776,21 +4790,21 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2
                ->  Hash
                      ->  Append
                            ->  Seq Scan on beta_neg_p1 t2_2
-                                 Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                                 Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                            ->  Seq Scan on beta_neg_p2 t2_3
-                                 Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                                 Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
          ->  Nested Loop
                Join Filter: ((t1_4.a = t2_4.a) AND (t1_4.c = t2_4.c))
                ->  Seq Scan on alpha_pos_p2 t1_4
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p2 t2_4
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
          ->  Nested Loop
                Join Filter: ((t1_5.a = t2_5.a) AND (t1_5.c = t2_5.c))
                ->  Seq Scan on alpha_pos_p3 t1_5
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p3 t2_5
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
 (28 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b, t2.b;
@@ -4816,38 +4830,40 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2
 
 EXPLAIN (COSTS OFF)
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b;
-                                                           QUERY PLAN                                                           
---------------------------------------------------------------------------------------------------------------------------------
+                                                              QUERY PLAN                                                              
+--------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Sort Key: t1.a, t1.b
    ->  Append
-         ->  Hash Join
-               Hash Cond: ((t1_1.a = t2_1.a) AND (t1_1.b = t2_1.b) AND (t1_1.c = t2_1.c))
-               ->  Seq Scan on alpha_neg_p1 t1_1
-                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
-               ->  Hash
+         ->  Merge Join
+               Merge Cond: ((t1_1.a = t2_1.a) AND (t1_1.b = t2_1.b) AND (t1_1.c = t2_1.c))
+               ->  Sort
+                     Sort Key: t1_1.a, t1_1.b, t1_1.c
+                     ->  Seq Scan on alpha_neg_p1 t1_1
+                           Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
+               ->  Sort
+                     Sort Key: t2_1.a, t2_1.b, t2_1.c
                      ->  Seq Scan on beta_neg_p1 t2_1
-                           Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
-         ->  Hash Join
-               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b) AND (t1_2.c = t2_2.c))
+                           Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
+         ->  Nested Loop
+               Join Filter: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b) AND (t1_2.c = t2_2.c))
+               ->  Seq Scan on beta_neg_p2 t2_2
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on alpha_neg_p2 t1_2
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
-               ->  Hash
-                     ->  Seq Scan on beta_neg_p2 t2_2
-                           Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
          ->  Nested Loop
                Join Filter: ((t1_3.a = t2_3.a) AND (t1_3.b = t2_3.b) AND (t1_3.c = t2_3.c))
                ->  Seq Scan on alpha_pos_p2 t1_3
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p2 t2_3
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
          ->  Nested Loop
                Join Filter: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b) AND (t1_4.c = t2_4.c))
                ->  Seq Scan on alpha_pos_p3 t1_4
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p3 t2_4
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
-(29 rows)
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
+(31 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 7555764c779..3fb515cdd9d 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -2104,19 +2104,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (never executed)
-                                 Index Cond: (a = a.a)
-(27 rows)
+(15 rows)
 
 -- Ensure the same partitions are pruned when we make the nested loop
 -- parameter an Expr rather than a plain Param.
@@ -2171,19 +2159,13 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (actual rows=N loops=N)
+                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_4 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (actual rows=N loops=N)
+                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_5 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (actual rows=N loops=N)
+                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_6 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-(27 rows)
+(21 rows)
 
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
                                         explain_parallel_append                                         
@@ -2204,19 +2186,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (never executed)
-                                 Index Cond: (a = a.a)
-(28 rows)
+(16 rows)
 
 delete from lprt_a where a = 1;
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
@@ -2238,19 +2208,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (never executed)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (never executed)
-                                 Index Cond: (a = a.a)
-(28 rows)
+(16 rows)
 
 reset enable_hashjoin;
 reset enable_mergejoin;
diff --git a/src/test/regress/sql/equivclass.sql b/src/test/regress/sql/equivclass.sql
index 247b0a31055..dae83c41965 100644
--- a/src/test/regress/sql/equivclass.sql
+++ b/src/test/regress/sql/equivclass.sql
@@ -269,3 +269,15 @@ create temp view overview as
   select f1::information_schema.sql_identifier as sqli, f2 from undername;
 explain (costs off)  -- this should not require a sort
   select * from overview where sqli = 'foo' order by sqli;
+
+
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
-- 
2.21.0

From 2875a76136293589b6e409cb6be4defab87ade59 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Wed, 2 Feb 2022 11:54:24 +0800
Subject: [PATCH v2 5/6] Support ScalarArrayOpExpr and perudoconstant on
 ef_filter.

---
 src/backend/optimizer/path/equivclass.c | 110 +++++++++++++++++-------
 src/backend/optimizer/plan/initsplan.c  |  48 +++++++----
 src/include/nodes/pathnodes.h           |   3 +-
 3 files changed, 114 insertions(+), 47 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 9ce0249b10d..4271bacb070 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1386,23 +1386,55 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rightexpr = (Expr *) ef->ef_const;
 			}
 
-			opno = get_opfamily_member(family,
-										exprType((Node *) leftexpr),
-										exprType((Node *) rightexpr),
-										strategy);
+			if (ef->ef_expr_type == T_OpExpr)
+			{
+				opno = get_opfamily_member(family,
+										   exprType((Node *) leftexpr),
+										   exprType((Node *) rightexpr),
+										   strategy);
 
-			if (opno == InvalidOid)
-				continue;
+				if (opno == InvalidOid)
+					continue;
 
-			rinfo = process_implied_equality(root, opno,
-											 ec->ec_collation,
-											 leftexpr,
-											 rightexpr,
-											 bms_copy(ec->ec_relids),
-											 bms_copy(cur_em->em_nullable_relids),
-											 ec->ec_min_security,
-											 ec->ec_below_outer_join,
-											 false);
+				rinfo = process_implied_equality(root, opno,
+												 ec->ec_collation,
+												 leftexpr,
+												 rightexpr,
+												 bms_copy(ec->ec_relids),
+												 bms_copy(cur_em->em_nullable_relids),
+												 ec->ec_min_security,
+												 ec->ec_below_outer_join,
+												 false);
+			}
+			else
+			{
+				ScalarArrayOpExpr *arr_opexpr;
+				Relids relids;
+
+				Assert(ef->ef_expr_type == T_ScalarArrayOpExpr);
+				arr_opexpr = makeNode(ScalarArrayOpExpr);
+				arr_opexpr->opno = ef->ef_opno;
+				arr_opexpr->opfuncid = get_opcode(ef->ef_opno);
+				arr_opexpr->useOr = true; /* See is_simple_filter_qual */
+				arr_opexpr->args = list_make2(leftexpr, ef->ef_const);
+				arr_opexpr->inputcollid = ec->ec_collation;
+
+				relids = pull_varnos(root, (Node *)arr_opexpr);
+
+				rinfo = make_restrictinfo(root,
+										  (Expr *) arr_opexpr,
+										  true,
+										  false,
+										  false, /* perudoconstant */
+										  ec->ec_min_security,
+										  relids,
+										  NULL,
+										  bms_copy(cur_em->em_nullable_relids));
+
+				// check_mergejoinable(rinfo);
+
+				distribute_restrictinfo_to_rels(root, rinfo);
+			}
 			rinfo->derived = ec;
 		}
 
@@ -2009,29 +2041,48 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 	 */
 	foreach(l, quallist)
 	{
-		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
-		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
-		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
-		Const	   *constexpr;
-		Expr	   *varexpr;
+		Expr	*expr = lfirst(l);
+
+		List	*args;
+		Node	   *leftexpr;
+		Node	   *rightexpr;
+		Node	   *constexpr;
+		Node	   *varexpr;
+		Oid			opno;
+
 		Relids		exprrels;
 		int			relid;
 		bool		const_isleft;
 		ListCell *l2;
 
-		/*
-		 * Determine if the the OpExpr is in the form "expr op const" or
-		 * "const op expr".
-		 */
-		if (IsA(leftexpr, Const))
+		if (nodeTag(expr) == T_OpExpr)
+		{
+			OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+			args = opexpr->args;
+			opno = opexpr->opno;
+		}
+		else if (nodeTag(expr) == T_ScalarArrayOpExpr)
+		{
+			ScalarArrayOpExpr *arr_expr = (ScalarArrayOpExpr *) lfirst(l);
+			args = arr_expr->args;
+			opno = arr_expr->opno;
+		}
+		else
+		{
+			Assert(false);
+		}
+
+		leftexpr = linitial(args);
+		rightexpr = lsecond(args);
+		if (is_pseudo_constant_clause(leftexpr))
 		{
-			constexpr = (Const *) leftexpr;
+			constexpr = leftexpr;
 			varexpr = rightexpr;
 			const_isleft = true;
 		}
 		else
 		{
-			constexpr = (Const *) rightexpr;
+			constexpr = rightexpr;
 			varexpr = leftexpr;
 			const_isleft = false;
 		}
@@ -2073,10 +2124,11 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 				{
 					EquivalenceFilter *efilter;
 					efilter = makeNode(EquivalenceFilter);
-					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const = (Node *)copyObject(constexpr);
 					efilter->ef_const_is_left = const_isleft;
-					efilter->ef_opno = opexpr->opno;
+					efilter->ef_opno = opno;
 					efilter->ef_source_rel = relid;
+					efilter->ef_expr_type = nodeTag(expr);
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index b5204b3c4f4..120380ea3ae 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -658,31 +658,39 @@ create_lateral_join_info(PlannerInfo *root)
  *             false if it should not be used.
  */
 static bool
-is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+is_simple_filter_qual(PlannerInfo *root, Expr *expr)
 {
-	Expr *leftexpr;
-	Expr *rightexpr;
+	Node *leftexpr;
+	Node *rightexpr;
+	List *args = NIL;
 
-	if (!IsA(expr, OpExpr))
+	if (IsA(expr, OpExpr))
+		args = castNode(OpExpr, expr)->args;
+	else if (IsA(expr, ScalarArrayOpExpr))
+	{
+		ScalarArrayOpExpr *arr_opexpr = castNode(ScalarArrayOpExpr, expr);
+		if (!arr_opexpr->useOr)
+			/* Just support IN for now */
 			return false;
+		args = arr_opexpr->args;
+	}
 
-	if (list_length(expr->args) != 2)
-			return false;
+	if (list_length(args) != 2)
+		return false;
 
-	leftexpr = (Expr *) linitial(expr->args);
-	rightexpr = (Expr *) lsecond(expr->args);
+	leftexpr = linitial(args);
+	rightexpr = lsecond(args);
 
-	/* XXX should we restrict these to simple Var op Const expressions? */
-	if (IsA(leftexpr, Const))
+	if (is_pseudo_constant_clause(leftexpr))
 	{
-		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) rightexpr))
+		if (bms_membership(pull_varnos(root, rightexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions(rightexpr))
 			return true;
 	}
-	else if (IsA(rightexpr, Const))
+	else if (is_pseudo_constant_clause(rightexpr))
 	{
-		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) leftexpr))
+		if (bms_membership(pull_varnos(root, leftexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions(leftexpr))
 			return true;
 	}
 
@@ -739,7 +747,13 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list, &filter_qual_list);
+								 &postponed_qual_list,
+								 /*
+								  * geqo option here is just used for testing
+								  * during review stage, set enable_geqo to
+								  * false to disable this feature.
+								  */
+								 enable_geqo ? &filter_qual_list : NULL);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
@@ -2024,7 +2038,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	distribute_restrictinfo_to_rels(root, restrictinfo);
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
-	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (Expr *) clause))
 		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index dbe1775f96d..c1ef0066188 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1035,10 +1035,11 @@ typedef struct EquivalenceFilter
 {
 	NodeTag		type;
 
-	Const	   *ef_const;		/* the constant expression to filter on */
+	Node		*ef_const;		/* pseudo const */
 	Oid			ef_opno;		/* Operator Oid of filter operator */
 	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
 	Index		ef_source_rel;	/* relid of originating relation. */
+	NodeTag		ef_expr_type;
 } EquivalenceFilter;
 
 /*
-- 
2.21.0

From 8439b4818410d860a4ca4be3458b54c04c6f8648 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 15:20:10 +0800
Subject: [PATCH v2 3/6] Introduce RelOptInfo.filtered_rows.

Previously the Path.rows (shown in the explain output) and RelOptInfo.rows
which would be used to calculating joinrel's estimated rows. They are same
at many scan paths, like SeqScan, IndexScan, BitmapHeapScan and so on. But
they would be different after distributing a new restrictinfo from ec_filter.
So I developed RelOptInfo.filtered_rows to take the duty out of RelOptInfo.rows.
---
 src/backend/optimizer/path/costsize.c | 21 ++++++++++++++++-----
 src/include/nodes/pathnodes.h         |  2 ++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 9e303877af7..b1117257a38 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -241,7 +241,7 @@ cost_seqscan(Path *path, PlannerInfo *root,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	if (!enable_seqscan)
 		startup_cost += disable_cost;
@@ -539,7 +539,7 @@ cost_index(IndexPath *path, PlannerInfo *root, double loop_count,
 	}
 	else
 	{
-		path->path.rows = baserel->rows;
+		path->path.rows = baserel->filtered_rows;
 		/* qpquals come from just the rel's restriction clauses */
 		qpquals = extract_nonindex_conditions(path->indexinfo->indrestrictinfo,
 											  path->indexclauses);
@@ -978,7 +978,7 @@ cost_bitmap_heap_scan(Path *path, PlannerInfo *root, RelOptInfo *baserel,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	if (!enable_bitmapscan)
 		startup_cost += disable_cost;
@@ -1209,7 +1209,7 @@ cost_tidscan(Path *path, PlannerInfo *root,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	/* Count how many tuples we expect to retrieve */
 	ntuples = 0;
@@ -1320,7 +1320,7 @@ cost_tidrangescan(Path *path, PlannerInfo *root,
 	if (param_info)
 		path->rows = param_info->ppi_rows;
 	else
-		path->rows = baserel->rows;
+		path->rows = baserel->filtered_rows;
 
 	/* Count how many tuples and pages we expect to scan */
 	selectivity = clauselist_selectivity(root, tidrangequals, baserel->relid,
@@ -4938,6 +4938,17 @@ set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 
 	rel->rows = clamp_row_est(nrows);
 
+	nrows = rel->tuples *
+		clauselist_selectivity_ext(root,
+								   rel->baserestrictinfo,
+								   0,
+								   JOIN_INNER,
+								   NULL,
+								   true,
+								   true /* include_derived, for filtered rows */);
+
+	rel->filtered_rows = clamp_row_est(nrows);
+
 	cost_qual_eval(&rel->baserestrictcost, rel->baserestrictinfo, root);
 
 	set_rel_width(root, rel);
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 42368e10b8e..dbe1775f96d 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -683,6 +683,8 @@ typedef struct RelOptInfo
 	/* size estimates generated by planner */
 	Cardinality	rows;			/* estimated number of result tuples */
 
+	Cardinality filtered_rows;  /* filtered rows */
+
 	/* per-relation planner control flags */
 	bool		consider_startup;	/* keep cheap-startup-cost paths? */
 	bool		consider_param_startup; /* ditto, for parameterized paths? */
-- 
2.21.0

From 73f52d0909374446cd689457f0a4ef52addb035e Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 14:54:07 +0800
Subject: [PATCH v2 2/6] After distributing the new derived RestrictInfo into
 RelOptInfo, then the rows

estimation is wrong at the joinrel part. The reason is well described at [1] and
[2],  To fix this issue, I added a new field "EquivalenceClass *derived" in
RestrictInfo struct to indicate how this qual is generated. we would ignore such
qual during estimate the rows size. All the set_xx_size should be take care, but
for now, just set_plain_rel_size is taken care for the PoC purpose.

[1]
https://www.postgresql.org/message-id/flat/CAKJS1f9FK_X_5HKcPcSeimy16Owe3EmPmmGsGWLcKkj_rW9s6A%40mail.gmail.com
[2]
https://www.postgresql.org/message-id/flat/1727507.1620948117%40sss.pgh.pa.us#52ac3f46cf614acb0bdbddb7128f5bd2
---
 src/backend/optimizer/path/clausesel.c  | 34 +++++++++++++++++--------
 src/backend/optimizer/path/costsize.c   | 25 ++++++++++--------
 src/backend/optimizer/path/equivclass.c | 20 ++++++++-------
 src/backend/optimizer/util/inherit.c    | 31 ++++++++++++----------
 src/backend/statistics/dependencies.c   |  3 ++-
 src/backend/statistics/extended_stats.c |  5 ++--
 src/include/nodes/pathnodes.h           |  1 +
 src/include/optimizer/optimizer.h       |  6 +++--
 8 files changed, 77 insertions(+), 48 deletions(-)

diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c
index 06f836308d0..8961e66ea4e 100644
--- a/src/backend/optimizer/path/clausesel.c
+++ b/src/backend/optimizer/path/clausesel.c
@@ -106,7 +106,7 @@ clauselist_selectivity(PlannerInfo *root,
 					   SpecialJoinInfo *sjinfo)
 {
 	return clauselist_selectivity_ext(root, clauses, varRelid,
-									  jointype, sjinfo, true);
+									  jointype, sjinfo, true, true);
 }
 
 /*
@@ -121,7 +121,8 @@ clauselist_selectivity_ext(PlannerInfo *root,
 						   int varRelid,
 						   JoinType jointype,
 						   SpecialJoinInfo *sjinfo,
-						   bool use_extended_stats)
+						   bool use_extended_stats,
+						   bool include_derived)
 {
 	Selectivity s1 = 1.0;
 	RelOptInfo *rel;
@@ -137,7 +138,8 @@ clauselist_selectivity_ext(PlannerInfo *root,
 	if (list_length(clauses) == 1)
 		return clause_selectivity_ext(root, (Node *) linitial(clauses),
 									  varRelid, jointype, sjinfo,
-									  use_extended_stats);
+									  use_extended_stats,
+									  include_derived);
 
 	/*
 	 * Determine if these clauses reference a single relation.  If so, and if
@@ -183,7 +185,7 @@ clauselist_selectivity_ext(PlannerInfo *root,
 
 		/* Compute the selectivity of this clause in isolation */
 		s2 = clause_selectivity_ext(root, clause, varRelid, jointype, sjinfo,
-									use_extended_stats);
+									use_extended_stats, include_derived);
 
 		/*
 		 * Check for being passed a RestrictInfo.
@@ -412,7 +414,9 @@ clauselist_selectivity_or(PlannerInfo *root,
 			continue;
 
 		s2 = clause_selectivity_ext(root, (Node *) lfirst(lc), varRelid,
-									jointype, sjinfo, use_extended_stats);
+									jointype, sjinfo, use_extended_stats,
+									true /* we never push a derived under or clause */
+			);
 
 		s1 = s1 + s2 - s1 * s2;
 	}
@@ -694,7 +698,7 @@ clause_selectivity(PlannerInfo *root,
 				   SpecialJoinInfo *sjinfo)
 {
 	return clause_selectivity_ext(root, clause, varRelid,
-								  jointype, sjinfo, true);
+								  jointype, sjinfo, true, true);
 }
 
 /*
@@ -709,7 +713,8 @@ clause_selectivity_ext(PlannerInfo *root,
 					   int varRelid,
 					   JoinType jointype,
 					   SpecialJoinInfo *sjinfo,
-					   bool use_extended_stats)
+					   bool use_extended_stats,
+					   bool include_derived)
 {
 	Selectivity s1 = 0.5;		/* default for any unhandled clause type */
 	RestrictInfo *rinfo = NULL;
@@ -742,6 +747,9 @@ clause_selectivity_ext(PlannerInfo *root,
 		if (rinfo->norm_selec > 1)
 			return (Selectivity) 1.0;
 
+		if (rinfo->derived && !include_derived)
+			return (Selectivity) 1.0;
+
 		/*
 		 * If possible, cache the result of the selectivity calculation for
 		 * the clause.  We can cache if varRelid is zero or the clause
@@ -830,7 +838,8 @@ clause_selectivity_ext(PlannerInfo *root,
 										  varRelid,
 										  jointype,
 										  sjinfo,
-										  use_extended_stats);
+										  use_extended_stats,
+										  include_derived);
 	}
 	else if (is_andclause(clause))
 	{
@@ -840,7 +849,8 @@ clause_selectivity_ext(PlannerInfo *root,
 										varRelid,
 										jointype,
 										sjinfo,
-										use_extended_stats);
+										use_extended_stats,
+										include_derived);
 	}
 	else if (is_orclause(clause))
 	{
@@ -959,7 +969,8 @@ clause_selectivity_ext(PlannerInfo *root,
 									varRelid,
 									jointype,
 									sjinfo,
-									use_extended_stats);
+									use_extended_stats,
+									include_derived);
 	}
 	else if (IsA(clause, CoerceToDomain))
 	{
@@ -969,7 +980,8 @@ clause_selectivity_ext(PlannerInfo *root,
 									varRelid,
 									jointype,
 									sjinfo,
-									use_extended_stats);
+									use_extended_stats,
+									include_derived);
 	}
 	else
 	{
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 8dc7dd4ca26..9e303877af7 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -4928,11 +4928,13 @@ set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 	Assert(rel->relid > 0);
 
 	nrows = rel->tuples *
-		clauselist_selectivity(root,
-							   rel->baserestrictinfo,
-							   0,
-							   JOIN_INNER,
-							   NULL);
+		clauselist_selectivity_ext(root,
+								   rel->baserestrictinfo,
+								   0,
+								   JOIN_INNER,
+								   NULL,
+								   true,
+								   false /* include_derived */);
 
 	rel->rows = clamp_row_est(nrows);
 
@@ -4964,11 +4966,14 @@ get_parameterized_baserel_size(PlannerInfo *root, RelOptInfo *rel,
 	 */
 	allclauses = list_concat_copy(param_clauses, rel->baserestrictinfo);
 	nrows = rel->tuples *
-		clauselist_selectivity(root,
-							   allclauses,
-							   rel->relid,	/* do not use 0! */
-							   JOIN_INNER,
-							   NULL);
+		clauselist_selectivity_ext(root,
+								   allclauses,
+								   rel->relid,	/* do not use 0! */
+								   JOIN_INNER,
+								   NULL,
+								   true,
+								   false /* doesn't include the derived clause */
+			);
 	nrows = clamp_row_est(nrows);
 	/* For safety, make sure result is not more than the base estimate */
 	if (nrows > rel->rows)
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index f9ae2785d60..6ed9e8c9064 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1366,6 +1366,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			int strategy;
 			Oid opno;
 			Oid family;
+			RestrictInfo *rinfo;
 
 			if (ef->ef_source_rel == relid)
 				continue;
@@ -1393,15 +1394,16 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (opno == InvalidOid)
 				continue;
 
-			process_implied_equality(root, opno,
-										ec->ec_collation,
-										leftexpr,
-										rightexpr,
-										bms_copy(ec->ec_relids),
-										bms_copy(cur_em->em_nullable_relids),
-									 	ec->ec_min_security,
-										ec->ec_below_outer_join,
-										false);
+			rinfo = process_implied_equality(root, opno,
+											 ec->ec_collation,
+											 leftexpr,
+											 rightexpr,
+											 bms_copy(ec->ec_relids),
+											 bms_copy(cur_em->em_nullable_relids),
+											 ec->ec_min_security,
+											 ec->ec_below_outer_join,
+											 false);
+			rinfo->derived = ec;
 		}
 
 		prev_ems[relid] = cur_em;
diff --git a/src/backend/optimizer/util/inherit.c b/src/backend/optimizer/util/inherit.c
index 7e134822f36..8a5863c4da4 100644
--- a/src/backend/optimizer/util/inherit.c
+++ b/src/backend/optimizer/util/inherit.c
@@ -797,6 +797,7 @@ apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,
 		{
 			Node	   *onecq = (Node *) lfirst(lc2);
 			bool		pseudoconstant;
+			RestrictInfo		*child_rinfo;
 
 			/* check for pseudoconstant (no Vars or volatile functions) */
 			pseudoconstant =
@@ -807,15 +808,19 @@ apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,
 				/* tell createplan.c to check for gating quals */
 				root->hasPseudoConstantQuals = true;
 			}
+
+			child_rinfo =  make_restrictinfo(root,
+											 (Expr *) onecq,
+											 rinfo->is_pushed_down,
+											 rinfo->outerjoin_delayed,
+											 pseudoconstant,
+											 rinfo->security_level,
+											 NULL, NULL, NULL);
+
+			child_rinfo->derived = rinfo->derived;
 			/* reconstitute RestrictInfo with appropriate properties */
-			childquals = lappend(childquals,
-								 make_restrictinfo(root,
-												   (Expr *) onecq,
-												   rinfo->is_pushed_down,
-												   rinfo->outerjoin_delayed,
-												   pseudoconstant,
-												   rinfo->security_level,
-												   NULL, NULL, NULL));
+			childquals = lappend(childquals, child_rinfo);
+
 			/* track minimum security level among child quals */
 			cq_min_security = Min(cq_min_security, rinfo->security_level);
 		}
@@ -844,13 +849,13 @@ apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,
 			foreach(lc2, qualset)
 			{
 				Expr	   *qual = (Expr *) lfirst(lc2);
+				RestrictInfo *rinfo = make_restrictinfo(root, qual,
+														true, false, false,
+														security_level,
+														NULL, NULL, NULL);
 
 				/* not likely that we'd see constants here, so no check */
-				childquals = lappend(childquals,
-									 make_restrictinfo(root, qual,
-													   true, false, false,
-													   security_level,
-													   NULL, NULL, NULL));
+				childquals = lappend(childquals, rinfo);
 				cq_min_security = Min(cq_min_security, security_level);
 			}
 			security_level++;
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index 34326d55619..838446a220d 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -1076,7 +1076,8 @@ clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
 		}
 
 		simple_sel = clauselist_selectivity_ext(root, attr_clauses, varRelid,
-												jointype, sjinfo, false);
+												jointype, sjinfo, false,
+												true /* probably no reasonable */);
 		attr_sel[attidx++] = simple_sel;
 	}
 
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index ca48395d5c5..38836f58c4e 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -1870,7 +1870,8 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
 				 * columns/clauses.
 				 */
 				simple_sel = clause_selectivity_ext(root, clause, varRelid,
-													jointype, sjinfo, false);
+													jointype, sjinfo, false,
+													true);
 
 				overlap_simple_sel = simple_or_sel * simple_sel;
 
@@ -1943,7 +1944,7 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
 			 */
 			simple_sel = clauselist_selectivity_ext(root, stat_clauses,
 													varRelid, jointype,
-													sjinfo, false);
+													sjinfo, false, true);
 
 			/*
 			 * Multi-column estimate using MCV statistics, along with base and
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index e73fef057a4..42368e10b8e 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -2165,6 +2165,7 @@ typedef struct RestrictInfo
 	/* hash equality operators used for memoize nodes, else InvalidOid */
 	Oid			left_hasheqoperator;
 	Oid			right_hasheqoperator;
+	EquivalenceClass *derived;
 } RestrictInfo;
 
 /*
diff --git a/src/include/optimizer/optimizer.h b/src/include/optimizer/optimizer.h
index 6b8ee0c69fa..a3385ae51ff 100644
--- a/src/include/optimizer/optimizer.h
+++ b/src/include/optimizer/optimizer.h
@@ -68,7 +68,8 @@ extern Selectivity clause_selectivity_ext(PlannerInfo *root,
 										  int varRelid,
 										  JoinType jointype,
 										  SpecialJoinInfo *sjinfo,
-										  bool use_extended_stats);
+										  bool use_extended_stats,
+										  bool include_derived);
 extern Selectivity clauselist_selectivity(PlannerInfo *root,
 										  List *clauses,
 										  int varRelid,
@@ -79,7 +80,8 @@ extern Selectivity clauselist_selectivity_ext(PlannerInfo *root,
 											  int varRelid,
 											  JoinType jointype,
 											  SpecialJoinInfo *sjinfo,
-											  bool use_extended_stats);
+											  bool use_extended_stats,
+											  bool include_derived);
 
 /* in path/costsize.c: */
 
-- 
2.21.0

From 11b3395bb5bcc4a2bcff6fed8078dbbf3cda81b1 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Tue, 1 Feb 2022 17:37:27 +0800
Subject: [PATCH v2 4/6] Remove duplicated qual executing for executor.

Take the SELECT * FROM t1, t2 WHERE t1.a = t2.a and t2.a > 3 for example,
we can derive t1.a > 3 with EC filter infrastructure.  However if it generate a
plan like below, the new generated qual does not deserve to execute.

Nest Loop
   Seq Scan (t1.a > 3)
   Index Scan t2_a
      (a = t1.a) (t2.a > 3)

This patch remove the "t2.a > 3" for the above case.
---
 src/backend/optimizer/path/equivclass.c | 22 +++++++++++++++++++
 src/backend/optimizer/plan/createplan.c | 29 +++++++++++++++++++++++--
 src/include/optimizer/paths.h           |  2 ++
 src/test/regress/parallel_schedule      |  2 ++
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 6ed9e8c9064..9ce0249b10d 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -3350,6 +3350,28 @@ is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist)
 	return false;
 }
 
+
+bool
+is_correlated_derived_clause(RestrictInfo *rinfo, List *clauselist)
+{
+	EquivalenceClass *derived_ec = rinfo->derived;
+	ListCell   *lc;
+
+	/* Fail if it's not a potentially-derived clause from some EC */
+	if (derived_ec == NULL)
+		return false;
+
+	foreach(lc, clauselist)
+	{
+		RestrictInfo *otherrinfo = (RestrictInfo *) lfirst(lc);
+
+		if (otherrinfo->parent_ec == derived_ec)
+			return true;
+	}
+
+	return false;
+}
+
 /*
  * is_redundant_with_indexclauses
  *		Test whether rinfo is redundant with any clause in the IndexClause
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index cd6d72c7633..03c5207ede0 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -556,11 +556,14 @@ static Plan *
 create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 {
 	RelOptInfo *rel = best_path->parent;
-	List	   *scan_clauses;
+	List	   *scan_clauses = NIL;
 	List	   *gating_clauses;
 	List	   *tlist;
 	Plan	   *plan;
 
+	List	*ppi_clauses = best_path->param_info ? best_path->param_info->ppi_clauses : NIL;
+	ListCell	*lc;
+
 	/*
 	 * Extract the relevant restriction clauses from the parent relation. The
 	 * executor must apply all these restrictions during the scan, except for
@@ -591,8 +594,18 @@ create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 	 * For paranoia's sake, don't modify the stored baserestrictinfo list.
 	 */
 	if (best_path->param_info)
-		scan_clauses = list_concat_copy(scan_clauses,
+	{
+		List *stripped_quals = NIL;
+		foreach(lc, rel->baserestrictinfo)
+		{
+			RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
+
+			if (!is_correlated_derived_clause(rinfo, ppi_clauses))
+				stripped_quals = lappend(stripped_quals, rinfo);
+		}
+		scan_clauses = list_concat_copy(stripped_quals,
 										best_path->param_info->ppi_clauses);
+	}
 
 	/*
 	 * Detect whether we have any pseudoconstant quals to deal with.  Then, if
@@ -4912,6 +4925,7 @@ fix_indexqual_references(PlannerInfo *root, IndexPath *index_path,
 	List	   *stripped_indexquals;
 	List	   *fixed_indexquals;
 	ListCell   *lc;
+	List	*ppi_clauses = index_path->path.param_info ? index_path->path.param_info->ppi_clauses : NIL;
 
 	stripped_indexquals = fixed_indexquals = NIL;
 
@@ -4921,6 +4935,17 @@ fix_indexqual_references(PlannerInfo *root, IndexPath *index_path,
 		int			indexcol = iclause->indexcol;
 		ListCell   *lc2;
 
+		if (is_correlated_derived_clause(iclause->rinfo, ppi_clauses))
+		{
+			/*
+			 * bitmapscan will read this indexquals as well. so we can't just igrore
+			 * it for now. we can totally delete it.
+			 */
+			index_path->indexclauses = foreach_delete_current(index_path->indexclauses, lc);
+			continue;
+		}
+
+
 		foreach(lc2, iclause->indexquals)
 		{
 			RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc2);
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index ce2aac7d3aa..08d8612cdba 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -188,6 +188,8 @@ extern bool eclass_useful_for_merging(PlannerInfo *root,
 extern bool is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist);
 extern bool is_redundant_with_indexclauses(RestrictInfo *rinfo,
 										   List *indexclauses);
+extern bool is_correlated_derived_clause(RestrictInfo *rinfo, List *clauselist);
+
 
 /*
  * pathkeys.c
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 861c30a73ae..b071324b961 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -134,3 +134,5 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+test: ec_filter
\ No newline at end of file
-- 
2.21.0

From e0a7838a09e73f831eecb23b5e7884cc34d71301 Mon Sep 17 00:00:00 2001
From: David Rowley <dgrowleyml@gmail.com>
Date: Tue, 1 Feb 2022 20:56:40 +0800
Subject: [PATCH v2 1/6] Introudce ec_filters in EquivalenceClass struct, the
 semantics is the quals can

be applied to any EquivalenceMember in this EC. Later this information is used
to generate new RestrictInfo and was distributed to related RelOptInfo very
soon.

Author: David Rowley at 2015-12 [1]
Andy Fan rebase this patch to current latest code.

https://www.postgresql.org/message-id/CAKJS1f9FK_X_5HKcPcSeimy16Owe3EmPmmGsGWLcKkj_rW9s6A%40mail.gmail.com
---
 .../postgres_fdw/expected/postgres_fdw.out    |  36 ++--
 src/backend/nodes/outfuncs.c                  |  14 ++
 src/backend/optimizer/path/equivclass.c       | 182 ++++++++++++++++++
 src/backend/optimizer/plan/initsplan.c        |  96 +++++++--
 src/backend/utils/cache/lsyscache.c           |  28 +++
 src/include/nodes/nodes.h                     |   1 +
 src/include/nodes/pathnodes.h                 |  37 ++++
 src/include/optimizer/paths.h                 |   1 +
 src/include/utils/lsyscache.h                 |   1 +
 src/test/regress/expected/equivclass.out      |  45 ++++-
 src/test/regress/expected/join.out            |  22 +--
 src/test/regress/expected/partition_join.out  |  52 +++--
 src/test/regress/sql/equivclass.sql           |  12 ++
 13 files changed, 457 insertions(+), 70 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index b2e02caefe4..d89fd4e11ab 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1545,12 +1545,12 @@ SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNE
 -- full outer join + inner join
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
-                                                                                                                                                 QUERY PLAN                                                                                                                                                 
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: t1.c1, t2.c1, t3.c1
    Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
-   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND (((r2.c1 + 1) >= 50)) AND (((r2.c1 + 1) <= 60)) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
 (4 rows)
 
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
@@ -2335,12 +2335,12 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                QUERY PLAN                                                                                                                                 
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                    QUERY PLAN                                                                                                                                                     
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
    Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
 (4 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
@@ -2362,8 +2362,8 @@ SET enable_hashjoin TO false;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
     AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
-                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                      QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  LockRows
    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
    ->  Merge Join
@@ -2373,7 +2373,7 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
          ->  Foreign Scan
                Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
-               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
                ->  Merge Join
                      Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                      Merge Cond: (ft1.c2 = ft5.c1)
@@ -2391,12 +2391,12 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
                                              Sort Key: ft1.c1
                                              ->  Foreign Scan on public.ft1
                                                    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) FOR UPDATE
                                        ->  Materialize
                                              Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
                                              ->  Foreign Scan on public.ft2
                                                    Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
                            ->  Sort
                                  Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
                                  Sort Key: ft4.c1
@@ -5685,25 +5685,25 @@ UPDATE ft2 AS target SET (c2) = (
 EXPLAIN (VERBOSE, COSTS OFF)
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
   FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
-                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Update on public.ft2 d
    Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
    ->  Foreign Scan
          Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
          Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
-         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
-         ->  Hash Join
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" > 1000)) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Merge Join
                Output: d.c2, d.ctid, d.*, t.*
-               Hash Cond: (d.c1 = t.c1)
+               Merge Cond: (d.c1 = t.c1)
                ->  Foreign Scan on public.ft2 d
                      Output: d.c2, d.ctid, d.*, d.c1
                      Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
-               ->  Hash
+               ->  Materialize
                      Output: t.*, t.c1
                      ->  Foreign Scan on public.ft2 t
                            Output: t.*, t.c1
-                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST
 (17 rows)
 
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 2b0236937aa..504b805326f 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2504,6 +2504,17 @@ _outEquivalenceMember(StringInfo str, const EquivalenceMember *node)
 	WRITE_OID_FIELD(em_datatype);
 }
 
+static void
+_outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
+{
+	WRITE_NODE_TYPE("EQUIVALENCEFILTER");
+
+	WRITE_NODE_FIELD(ef_const);
+	WRITE_OID_FIELD(ef_opno);
+	WRITE_BOOL_FIELD(ef_const_is_left);
+	WRITE_UINT_FIELD(ef_source_rel);
+}
+
 static void
 _outPathKey(StringInfo str, const PathKey *node)
 {
@@ -4304,6 +4315,9 @@ outNode(StringInfo str, const void *obj)
 			case T_EquivalenceMember:
 				_outEquivalenceMember(str, obj);
 				break;
+			case T_EquivalenceFilter:
+				_outEquivalenceFilter(str, obj);
+				break;
 			case T_PathKey:
 				_outPathKey(str, obj);
 				break;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 8c6770de972..f9ae2785d60 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -19,6 +19,7 @@
 #include <limits.h>
 
 #include "access/stratnum.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
@@ -1250,6 +1251,37 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 	}
 }
 
+/*
+ * finds the opfamily and strategy number for the specified 'opno' and 'method'
+ * access method. Returns True if one is found and sets 'family' and
+ * 'amstrategy', or returns False if none are found.
+ */
+static bool
+find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+{
+	List *opfamilies;
+	ListCell *l;
+	int strategy;
+
+	opfamilies = get_opfamilies(opno, method);
+
+	foreach(l, opfamilies)
+	{
+		Oid opfamily = lfirst_oid(l);
+
+		strategy = get_op_opfamily_strategy(opno, opfamily);
+
+		if (strategy)
+		{
+			*amstrategy = strategy;
+			*family = opfamily;
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /*
  * generate_base_implied_equalities when EC contains no pseudoconstants
  */
@@ -1259,6 +1291,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 {
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
+	ListCell   *lc2;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1320,6 +1353,57 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+
+		/*
+		 * Also push any EquivalenceFilter clauses down into all relations
+		 * other than the one which the filter actually originated from.
+		 */
+		foreach(lc2, ec->ec_filters)
+		{
+			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+			Expr *leftexpr;
+			Expr *rightexpr;
+			int strategy;
+			Oid opno;
+			Oid family;
+
+			if (ef->ef_source_rel == relid)
+				continue;
+
+			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
+				&family, &strategy))
+				continue;
+
+			if (ef->ef_const_is_left)
+			{
+				leftexpr = (Expr *) ef->ef_const;
+				rightexpr = cur_em->em_expr;
+			}
+			else
+			{
+				leftexpr = cur_em->em_expr;
+				rightexpr = (Expr *) ef->ef_const;
+			}
+
+			opno = get_opfamily_member(family,
+										exprType((Node *) leftexpr),
+										exprType((Node *) rightexpr),
+										strategy);
+
+			if (opno == InvalidOid)
+				continue;
+
+			process_implied_equality(root, opno,
+										ec->ec_collation,
+										leftexpr,
+										rightexpr,
+										bms_copy(ec->ec_relids),
+										bms_copy(cur_em->em_nullable_relids),
+									 	ec->ec_min_security,
+										ec->ec_below_outer_join,
+										false);
+		}
+
 		prev_ems[relid] = cur_em;
 	}
 
@@ -1901,6 +1985,104 @@ create_join_clause(PlannerInfo *root,
 	return rinfo;
 }
 
+/*
+ * distribute_filter_quals_to_eclass
+ *		For each OpExpr in quallist look for an eclass which has an Expr
+ *		matching the Expr in the OpExpr. If a match is found we add a new
+ *		EquivalenceFilter to the eclass containing the filter details.
+ */
+void
+distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
+{
+	ListCell *l;
+
+	/* fast path for when no eclasses have been generated */
+	if (root->eq_classes == NIL)
+		return;
+
+	/*
+	 * For each qual in quallist try and find an eclass which contains the
+	 * non-Const part of the OpExpr. We'll tag any matches that we find onto
+	 * the correct eclass.
+	 */
+	foreach(l, quallist)
+	{
+		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
+		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		Const	   *constexpr;
+		Expr	   *varexpr;
+		Relids		exprrels;
+		int			relid;
+		bool		const_isleft;
+		ListCell *l2;
+
+		/*
+		 * Determine if the the OpExpr is in the form "expr op const" or
+		 * "const op expr".
+		 */
+		if (IsA(leftexpr, Const))
+		{
+			constexpr = (Const *) leftexpr;
+			varexpr = rightexpr;
+			const_isleft = true;
+		}
+		else
+		{
+			constexpr = (Const *) rightexpr;
+			varexpr = leftexpr;
+			const_isleft = false;
+		}
+
+		exprrels = pull_varnos(root, (Node *) varexpr);
+
+		/* should be filtered out, but we need to determine relid anyway */
+		if (!bms_get_singleton_member(exprrels, &relid))
+			continue;
+
+		/* search for a matching eclass member in all eclasses */
+		foreach(l2, root->eq_classes)
+		{
+			EquivalenceClass *ec = (EquivalenceClass *) lfirst(l2);
+			ListCell *l3;
+
+			if (ec->ec_broken || ec->ec_has_volatile)
+				continue;
+
+			/*
+			 * if the eclass has a const then that const will serve as the
+			 * filter, we needn't add any others.
+			 */
+			if (ec->ec_has_const)
+				continue;
+
+			/* skip this eclass no members exist which belong to this relid */
+			if (!bms_is_member(relid, ec->ec_relids))
+				continue;
+
+			foreach(l3, ec->ec_members)
+			{
+				EquivalenceMember *em = (EquivalenceMember *) lfirst(l3);
+
+				if (!bms_is_member(relid, em->em_relids))
+					continue;
+
+				if (equal(em->em_expr, varexpr))
+				{
+					EquivalenceFilter *efilter;
+					efilter = makeNode(EquivalenceFilter);
+					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const_is_left = const_isleft;
+					efilter->ef_opno = opexpr->opno;
+					efilter->ef_source_rel = relid;
+
+					ec->ec_filters = lappend(ec->ec_filters, efilter);
+					break;		/* Onto the next eclass */
+				}
+			}
+		}
+	}
+}
 
 /*
  * reconsider_outer_join_clauses
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 023efbaf092..b5204b3c4f4 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -53,7 +53,7 @@ static void extract_lateral_references(PlannerInfo *root, RelOptInfo *brel,
 static List *deconstruct_recurse(PlannerInfo *root, Node *jtnode,
 								 bool below_outer_join,
 								 Relids *qualscope, Relids *inner_join_rels,
-								 List **postponed_qual_list);
+								 List **postponed_qual_list, List **filter_qual_list);
 static void process_security_barrier_quals(PlannerInfo *root,
 										   int rti, Relids qualscope,
 										   bool below_outer_join);
@@ -70,7 +70,8 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 									Relids qualscope,
 									Relids ojscope,
 									Relids outerjoin_nonnullable,
-									List **postponed_qual_list);
+									List **postponed_qual_list,
+									List **filter_qual_list);
 static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 								  Relids *nullable_relids_p, bool is_pushed_down);
 static bool check_equivalence_delay(PlannerInfo *root,
@@ -650,6 +651,43 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
+/*
+ * is_simple_filter_qual
+ *             Analyzes an OpExpr to determine if it may be useful as an
+ *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
+ *             false if it should not be used.
+ */
+static bool
+is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+{
+	Expr *leftexpr;
+	Expr *rightexpr;
+
+	if (!IsA(expr, OpExpr))
+			return false;
+
+	if (list_length(expr->args) != 2)
+			return false;
+
+	leftexpr = (Expr *) linitial(expr->args);
+	rightexpr = (Expr *) lsecond(expr->args);
+
+	/* XXX should we restrict these to simple Var op Const expressions? */
+	if (IsA(leftexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) rightexpr))
+			return true;
+	}
+	else if (IsA(rightexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) leftexpr))
+			return true;
+	}
+
+	return false;
+}
 
 /*****************************************************************************
  *
@@ -690,6 +728,7 @@ deconstruct_jointree(PlannerInfo *root)
 	Relids		qualscope;
 	Relids		inner_join_rels;
 	List	   *postponed_qual_list = NIL;
+	List	   *filter_qual_list = NIL;
 
 	/* Start recursion at top of jointree */
 	Assert(root->parse->jointree != NULL &&
@@ -700,11 +739,14 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list);
+								 &postponed_qual_list, &filter_qual_list);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
 
+	/* try and match each filter_qual_list item up with an eclass. */
+	distribute_filter_quals_to_eclass(root, filter_qual_list);
+
 	return result;
 }
 
@@ -725,6 +767,8 @@ deconstruct_jointree(PlannerInfo *root)
  *		or free this, either)
  *	*postponed_qual_list is a list of PostponedQual structs, which we can
  *		add quals to if they turn out to belong to a higher join level
+ *	*filter_qual_list is appended to with a list of quals which may be useful
+ *		include as EquivalenceFilters.
  *	Return value is the appropriate joinlist for this jointree node
  *
  * In addition, entries will be added to root->join_info_list for outer joins.
@@ -732,7 +776,7 @@ deconstruct_jointree(PlannerInfo *root)
 static List *
 deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 					Relids *qualscope, Relids *inner_join_rels,
-					List **postponed_qual_list)
+					List **postponed_qual_list, List **filter_qual_list)
 {
 	List	   *joinlist;
 
@@ -785,7 +829,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 											   below_outer_join,
 											   &sub_qualscope,
 											   inner_join_rels,
-											   &child_postponed_quals);
+											   &child_postponed_quals,
+											   filter_qual_list);
 			*qualscope = bms_add_members(*qualscope, sub_qualscope);
 			sub_members = list_length(sub_joinlist);
 			remaining--;
@@ -819,7 +864,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 										below_outer_join, JOIN_INNER,
 										root->qual_security_level,
 										*qualscope, NULL, NULL,
-										NULL);
+										NULL,
+										filter_qual_list);
 			else
 				*postponed_qual_list = lappend(*postponed_qual_list, pq);
 		}
@@ -835,7 +881,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									below_outer_join, JOIN_INNER,
 									root->qual_security_level,
 									*qualscope, NULL, NULL,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 	}
 	else if (IsA(jtnode, JoinExpr))
@@ -873,11 +920,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = *qualscope;
 				/* Inner join adds no restrictions for quals */
@@ -890,11 +939,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				nonnullable_rels = leftids;
@@ -904,11 +955,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* Semi join adds no restrictions for quals */
@@ -925,11 +978,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   true,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* each side is both outer and inner */
@@ -1013,7 +1068,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									root->qual_security_level,
 									*qualscope,
 									ojscope, nonnullable_rels,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 
 		/* Now we can add the SpecialJoinInfo to join_info_list */
@@ -1117,6 +1173,7 @@ process_security_barrier_quals(PlannerInfo *root,
 									qualscope,
 									qualscope,
 									NULL,
+									NULL,
 									NULL);
 		}
 		security_level++;
@@ -1610,7 +1667,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 						Relids qualscope,
 						Relids ojscope,
 						Relids outerjoin_nonnullable,
-						List **postponed_qual_list)
+						List **postponed_qual_list,
+						List **filter_qual_list)
 {
 	Relids		relids;
 	bool		is_pushed_down;
@@ -1964,6 +2022,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* No EC special case applies, so push it into the clause lists */
 	distribute_restrictinfo_to_rels(root, restrictinfo);
+
+	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
 /*
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index feef9998634..add2e7176ae 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -341,6 +341,34 @@ get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
 	return result;
 }
 
+/*
+ * get_opfamilies
+ *		Returns a list of Oids of each opfamily which 'opno' belonging to
+ *		'method' access method.
+ */
+List *
+get_opfamilies(Oid opno, Oid method)
+{
+	List	   *result = NIL;
+	CatCList   *catlist;
+	int			i;
+
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == method)
+			result = lappend_oid(result, aform->amopfamily);
+	}
+
+	ReleaseSysCacheList(catlist);
+
+	return result;
+}
+
 /*
  * get_mergejoin_opfamilies
  *		Given a putatively mergejoinable operator, return a list of the OIDs
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index da35f2c2722..3a9a235cd0e 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -265,6 +265,7 @@ typedef enum NodeTag
 	/* these aren't subclasses of Path: */
 	T_EquivalenceClass,
 	T_EquivalenceMember,
+	T_EquivalenceFilter,
 	T_PathKey,
 	T_PathTarget,
 	T_RestrictInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 1f3845b3fec..e73fef057a4 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -990,6 +990,7 @@ typedef struct EquivalenceClass
 	List	   *ec_members;		/* list of EquivalenceMembers */
 	List	   *ec_sources;		/* list of generating RestrictInfos */
 	List	   *ec_derives;		/* list of derived RestrictInfos */
+	List	   *ec_filters;
 	Relids		ec_relids;		/* all relids appearing in ec_members, except
 								 * for child members (see below) */
 	bool		ec_has_const;	/* any pseudoconstants in ec_members? */
@@ -1002,6 +1003,42 @@ typedef struct EquivalenceClass
 	struct EquivalenceClass *ec_merged; /* set if merged into another EC */
 } EquivalenceClass;
 
+/*
+ * EquivalenceFilter - List of filters on Consts which belong to the
+ * EquivalenceClass.
+ *
+ * When building the equivalence classes we also collected a list of quals in
+ * the form of; "Expr op Const" and "Const op Expr". These are collected in the
+ * hope that we'll later generate an equivalence class which contains the
+ * "Expr" part. For example, if we parse a query such as;
+ *
+ *		SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id WHERE t1.id < 10;
+ *
+ * then since we'll end up with an equivalence class containing {t1.id,t2.id},
+ * we'll tag the "< 10" filter onto the eclass. We are able to do this because
+ * the eclass proves equality between each class member, therefore all members
+ * must be below 10.
+ *
+ * EquivalenceFilters store the details required to allow us to push these
+ * filter clauses down into other relations which share an equivalence class
+ * containing a member which matches the expression of this EquivalenceFilter.
+ *
+ * ef_const is the Const value which this filter should filter against.
+ * ef_opno is the operator to filter on.
+ * ef_const_is_left marks if the OpExpr was in the form "Const op Expr" or
+ * "Expr op Const".
+ * ef_source_rel is the relation id of where this qual originated from.
+ */
+typedef struct EquivalenceFilter
+{
+	NodeTag		type;
+
+	Const	   *ef_const;		/* the constant expression to filter on */
+	Oid			ef_opno;		/* Operator Oid of filter operator */
+	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
+	Index		ef_source_rel;	/* relid of originating relation. */
+} EquivalenceFilter;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 0c3a0b90c85..ce2aac7d3aa 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -126,6 +126,7 @@ extern bool process_equivalence(PlannerInfo *root,
 extern Expr *canonicalize_ec_expression(Expr *expr,
 										Oid req_type, Oid req_collation);
 extern void reconsider_outer_join_clauses(PlannerInfo *root);
+extern void distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist);
 extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
 												  Expr *expr,
 												  Relids nullable_relids,
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index b8dd27d4a96..188d65faa0d 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -78,6 +78,7 @@ extern bool get_ordering_op_properties(Oid opno,
 									   Oid *opfamily, Oid *opcintype, int16 *strategy);
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
+extern List *get_opfamilies(Oid opno, Oid method);
 extern List *get_mergejoin_opfamilies(Oid opno);
 extern bool get_compatible_hash_operators(Oid opno,
 										  Oid *lhs_opno, Oid *rhs_opno);
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 126f7047fed..92fcec1158b 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                 QUERY PLAN                  
----------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: (f1 < '5'::int8alias1)
+         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
 (6 rows)
 
 reset session authorization;
@@ -451,3 +451,42 @@ explain (costs off)  -- this should not require a sort
    Filter: (f1 = 'foo'::name)
 (2 rows)
 
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index d5b5b775fdd..b20de6a505f 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3337,7 +3337,7 @@ where t1.unique2 < 42 and t1.stringu1 > t2.stringu2;
    Join Filter: (t1.stringu1 > t2.stringu2)
    ->  Nested Loop
          ->  Seq Scan on int4_tbl i1
-               Filter: (f1 = 0)
+               Filter: ((f1 = 0) AND (11 < 42))
          ->  Index Scan using tenk1_unique2 on tenk1 t1
                Index Cond: ((unique2 = (11)) AND (unique2 < 42))
    ->  Index Scan using tenk1_unique1 on tenk1 t2
@@ -6550,23 +6550,22 @@ where exists (select 1 from tenk1 t3
 ---------------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
-   ->  Hash Join
+   ->  Nested Loop
          Output: t1.unique1, t3.tenthous
-         Hash Cond: (t3.thousand = t1.unique1)
+         Join Filter: (t1.unique1 = t3.thousand)
+         ->  Index Only Scan using onek_unique1 on public.onek t1
+               Output: t1.unique1
+               Index Cond: (t1.unique1 < 1)
          ->  HashAggregate
                Output: t3.thousand, t3.tenthous
                Group Key: t3.thousand, t3.tenthous
                ->  Index Only Scan using tenk1_thous_tenthous on public.tenk1 t3
                      Output: t3.thousand, t3.tenthous
-         ->  Hash
-               Output: t1.unique1
-               ->  Index Only Scan using onek_unique1 on public.onek t1
-                     Output: t1.unique1
-                     Index Cond: (t1.unique1 < 1)
+                     Index Cond: (t3.thousand < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = t3.tenthous)
-(18 rows)
+(17 rows)
 
 -- ... unless it actually is unique
 create table j3 as select unique1, tenthous from onek;
@@ -6584,15 +6583,16 @@ where exists (select 1 from j3
    Output: t1.unique1, t2.hundred
    ->  Nested Loop
          Output: t1.unique1, j3.tenthous
+         Join Filter: (t1.unique1 = j3.unique1)
          ->  Index Only Scan using onek_unique1 on public.onek t1
                Output: t1.unique1
                Index Cond: (t1.unique1 < 1)
          ->  Index Only Scan using j3_unique1_tenthous_idx on public.j3
                Output: j3.unique1, j3.tenthous
-               Index Cond: (j3.unique1 = t1.unique1)
+               Index Cond: (j3.unique1 < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = j3.tenthous)
-(13 rows)
+(14 rows)
 
 drop table j3;
diff --git a/src/test/regress/expected/partition_join.out b/src/test/regress/expected/partition_join.out
index bb5b7c47a45..5a2923bac6c 100644
--- a/src/test/regress/expected/partition_join.out
+++ b/src/test/regress/expected/partition_join.out
@@ -186,17 +186,17 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM (SELECT 50 phv, * FROM prt1 WHERE prt1.b = 0)
 -- Join with pruned partitions from joining relations
 EXPLAIN (COSTS OFF)
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
-                     QUERY PLAN                      
------------------------------------------------------
+                            QUERY PLAN                             
+-------------------------------------------------------------------
  Sort
    Sort Key: t1.a
    ->  Hash Join
          Hash Cond: (t2.b = t1.a)
          ->  Seq Scan on prt2_p2 t2
-               Filter: (b > 250)
+               Filter: ((b > 250) AND (b < 450))
          ->  Hash
                ->  Seq Scan on prt1_p2 t1
-                     Filter: ((a < 450) AND (b = 0))
+                     Filter: ((a < 450) AND (a > 250) AND (b = 0))
 (9 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
@@ -3100,16 +3100,18 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a < 300) AND (b = 0))
          ->  Hash Join
                Hash Cond: (t2_2.b = t1_2.a)
                ->  Seq Scan on prt2_adv_p2 t2_2
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a < 300) AND (b = 0))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -3139,16 +3141,19 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: ((b >= 100) AND (b < 300))
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-         ->  Hash Join
-               Hash Cond: (t2_2.b = t1_2.a)
-               ->  Seq Scan on prt2_adv_p2 t2_2
-               ->  Hash
+         ->  Merge Join
+               Merge Cond: (t2_2.b = t1_2.a)
+               ->  Index Scan using prt2_adv_p2_b_idx on prt2_adv_p2 t2_2
+                     Index Cond: ((b >= 100) AND (b < 300))
+               ->  Sort
+                     Sort Key: t1_2.a
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-(15 rows)
+(18 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a >= 100 AND t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -4692,27 +4697,32 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
                      Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Seq Scan on beta_neg_p1 t2_1
+                           Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.b = t1_2.b))
-               ->  Seq Scan on beta_neg_p2 t2_2
+               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b))
+               ->  Seq Scan on alpha_neg_p2 t1_2
+                     Filter: ((b >= 125) AND (b < 225))
                ->  Hash
-                     ->  Seq Scan on alpha_neg_p2 t1_2
+                     ->  Seq Scan on beta_neg_p2 t2_2
                            Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_4.a = t1_4.a) AND (t2_4.b = t1_4.b))
+               Hash Cond: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b))
                ->  Append
-                     ->  Seq Scan on beta_pos_p1 t2_4
-                     ->  Seq Scan on beta_pos_p2 t2_5
-                     ->  Seq Scan on beta_pos_p3 t2_6
+                     ->  Seq Scan on alpha_pos_p1 t1_4
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p2 t1_5
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p3 t1_6
+                           Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Append
-                           ->  Seq Scan on alpha_pos_p1 t1_4
+                           ->  Seq Scan on beta_pos_p1 t2_4
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p2 t1_5
+                           ->  Seq Scan on beta_pos_p2 t2_5
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p3 t1_6
+                           ->  Seq Scan on beta_pos_p3 t2_6
                                  Filter: ((b >= 125) AND (b < 225))
-(29 rows)
+(34 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b) WHERE t1.b >= 125 AND t1.b < 225 ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
diff --git a/src/test/regress/sql/equivclass.sql b/src/test/regress/sql/equivclass.sql
index 247b0a31055..dae83c41965 100644
--- a/src/test/regress/sql/equivclass.sql
+++ b/src/test/regress/sql/equivclass.sql
@@ -269,3 +269,15 @@ create temp view overview as
   select f1::information_schema.sql_identifier as sqli, f2 from undername;
 explain (costs off)  -- this should not require a sort
   select * from overview where sqli = 'foo' order by sqli;
+
+
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
-- 
2.21.0

From a4b21ab6fd0fd57902f5471ec962a77b59085158 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Wed, 2 Feb 2022 11:59:53 +0800
Subject: [PATCH v2 6/6] Added the testcase for this feature and fix the
 previous test case

as well. The new added test case needs outputting some runtime
statistics, which probably be different at each run. I can think
of a way to make the test case stable if the patchsets is not wrong
at the first step.
---
 .../postgres_fdw/expected/postgres_fdw.out    |  15 +-
 src/test/regress/expected/ec_filter.out       | 137 ++++++++++++++++++
 src/test/regress/expected/equivclass.out      |  38 ++---
 src/test/regress/expected/join.out            |  43 +++---
 src/test/regress/expected/partition_join.out  |  54 ++++---
 src/test/regress/expected/partition_prune.out |  56 +------
 src/test/regress/sql/ec_filter.sql            |  46 ++++++
 7 files changed, 267 insertions(+), 122 deletions(-)
 create mode 100644 src/test/regress/expected/ec_filter.out
 create mode 100644 src/test/regress/sql/ec_filter.sql

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index d89fd4e11ab..41d0cd414cd 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -2335,13 +2335,16 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                                    QUERY PLAN                                                                                                                                                     
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
- Foreign Scan
+                                                                                                                                        QUERY PLAN                                                                                                                                         
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Sort
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
-   Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
-(4 rows)
+   Sort Key: ft5.c1
+   ->  Foreign Scan
+         Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
+         Relations: (public.ft5) INNER JOIN (public.ft4)
+         Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30))))
+(7 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
       ft5       | c1 | c2 |   c3   | c1 | c2 
diff --git a/src/test/regress/expected/ec_filter.out b/src/test/regress/expected/ec_filter.out
new file mode 100644
index 00000000000..2ee670af1ec
--- /dev/null
+++ b/src/test/regress/expected/ec_filter.out
@@ -0,0 +1,137 @@
+-- THIS TEST IS JUST FOW REVIEW PURPOSE, IT CONTAINS TOO MANY RUNTIME STATS.
+set enable_hashjoin to off;
+set enable_mergejoin to off;
+set enable_seqscan to on;
+-- 1. The joinrel.rows should be correct.
+-- 2. The path estimated rows for b should be correct.
+-- 3. the estimated rows from a in wrong, but that is not the fault of this patch.
+explain analyze select * from tenk1 a, tenk1 b where a.thousand = b.thousand and a.thousand < 100;
+                                                                  QUERY PLAN                                                                   
+-----------------------------------------------------------------------------------------------------------------------------------------------
+ Nested Loop  (cost=24.90..459.16 rows=10740 width=488) (actual time=0.418..15.061 rows=10000 loops=1)
+   ->  Bitmap Heap Scan on tenk1 b  (cost=24.61..383.03 rows=1074 width=244) (actual time=0.368..1.427 rows=1000 loops=1)
+         Recheck Cond: (thousand < 100)
+         Heap Blocks: exact=324
+         ->  Bitmap Index Scan on tenk1_thous_tenthous  (cost=0.00..24.34 rows=1074 width=0) (actual time=0.256..0.257 rows=1000 loops=1)
+               Index Cond: (thousand < 100)
+   ->  Memoize  (cost=0.30..0.47 rows=1 width=244) (actual time=0.002..0.006 rows=10 loops=1000)
+         Cache Key: b.thousand
+         Cache Mode: logical
+         Hits: 900  Misses: 100  Evictions: 0  Overflows: 0  Memory Usage: 277kB
+         ->  Index Scan using tenk1_thous_tenthous on tenk1 a  (cost=0.29..0.46 rows=1 width=244) (actual time=0.010..0.030 rows=10 loops=100)
+               Index Cond: ((thousand = b.thousand) AND (thousand < 100))
+ Planning Time: 2.314 ms
+ Execution Time: 16.022 ms
+(14 rows)
+
+create table d_tenk2 as select * from tenk1 union all select * from tenk1;
+create index on d_tenk2(thousand);
+analyze d_tenk2 ;
+set enable_seqscan to off;
+drop index tenk1_thous_tenthous;
+-- 1. The parameterized path of b shows the correct rows estimation as well.
+-- 2. The new added qual is fully duplicated with the join clause, so it should be removed.
+explain analyze select * from tenk1 a join d_tenk2 b on a.thousand = b.thousand and a.thousand < 100;
+                                                                    QUERY PLAN                                                                    
+--------------------------------------------------------------------------------------------------------------------------------------------------
+ Nested Loop  (cost=10000000000.30..10000002799.78 rows=20020 width=488) (actual time=0.045..26.640 rows=20000 loops=1)
+   ->  Seq Scan on tenk1 a  (cost=10000000000.00..10000000470.00 rows=1001 width=244) (actual time=0.015..3.923 rows=1000 loops=1)
+         Filter: (thousand < 100)
+         Rows Removed by Filter: 9000
+   ->  Memoize  (cost=0.30..3.18 rows=20 width=244) (actual time=0.002..0.008 rows=20 loops=1000)
+         Cache Key: a.thousand
+         Cache Mode: logical
+         Hits: 900  Misses: 100  Evictions: 0  Overflows: 0  Memory Usage: 546kB
+         ->  Index Scan using d_tenk2_thousand_idx on d_tenk2 b  (cost=0.29..3.17 rows=20 width=244) (actual time=0.008..0.038 rows=20 loops=100)
+               Index Cond: (thousand = a.thousand)
+ Planning Time: 0.829 ms
+ Execution Time: 28.033 ms
+(12 rows)
+
+create index tenk1_thous_tenthous on tenk1(thousand, tenthous);
+-- test ef filter with partition prune.
+create table p (a int, b int) partition by range(a);
+select 'create table p_' || i || ' partition of p  for values from (' || (i-1) * 100000 || ') to (' || i * 100000 || ');' from generate_series(1, 5)i;  \gexec
+                                ?column?                                
+------------------------------------------------------------------------
+ create table p_1 partition of p  for values from (0) to (100000);
+ create table p_2 partition of p  for values from (100000) to (200000);
+ create table p_3 partition of p  for values from (200000) to (300000);
+ create table p_4 partition of p  for values from (300000) to (400000);
+ create table p_5 partition of p  for values from (400000) to (500000);
+(5 rows)
+
+create table p_1 partition of p  for values from (0) to (100000);
+create table p_2 partition of p  for values from (100000) to (200000);
+create table p_3 partition of p  for values from (200000) to (300000);
+create table p_4 partition of p  for values from (300000) to (400000);
+create table p_5 partition of p  for values from (400000) to (500000);
+insert into p select i, i from generate_series(1, 5 * 100000 -1) i;
+create table q (a int, b int) partition by range(a);
+select 'create table q_' || i || ' partition of q  for values from (' || (i-1) * 100000 || ') to (' || i * 100000 || ');' from generate_series(1, 5)i;  \gexec
+                                ?column?                                
+------------------------------------------------------------------------
+ create table q_1 partition of q  for values from (0) to (100000);
+ create table q_2 partition of q  for values from (100000) to (200000);
+ create table q_3 partition of q  for values from (200000) to (300000);
+ create table q_4 partition of q  for values from (300000) to (400000);
+ create table q_5 partition of q  for values from (400000) to (500000);
+(5 rows)
+
+create table q_1 partition of q  for values from (0) to (100000);
+create table q_2 partition of q  for values from (100000) to (200000);
+create table q_3 partition of q  for values from (200000) to (300000);
+create table q_4 partition of q  for values from (300000) to (400000);
+create table q_5 partition of q  for values from (400000) to (500000);
+insert into q select * from p;
+create index on q(a);
+select * from p, q where p.a = q.a and p.a > 5 * 100000 - 3;
+   a    |   b    |   a    |   b    
+--------+--------+--------+--------
+ 499998 | 499998 | 499998 | 499998
+ 499999 | 499999 | 499999 | 499999
+(2 rows)
+
+set plan_cache_mode to force_generic_plan ;
+prepare s as select * from p, q where p.a = q.a and p.a > $1;
+explain (costs off) execute s(5 * 100000 - 3);
+                    QUERY PLAN                     
+---------------------------------------------------
+ Nested Loop
+   ->  Append
+         Subplans Removed: 4
+         ->  Seq Scan on p_5 p_1
+               Filter: (a > $1)
+   ->  Append
+         Subplans Removed: 4
+         ->  Index Scan using q_5_a_idx on q_5 q_1
+               Index Cond: (a = p.a)
+(9 rows)
+
+-- support perudo const.
+prepare s2 as select * from p, q where p.a = q.a and p.a > abs($1::integer);
+explain (costs off) execute s2(5 * 100000 - 3);
+                    QUERY PLAN                     
+---------------------------------------------------
+ Nested Loop
+   ->  Append
+         Subplans Removed: 4
+         ->  Seq Scan on p_5 p_1
+               Filter: (a > abs($1))
+   ->  Append
+         Subplans Removed: 4
+         ->  Index Scan using q_5_a_idx on q_5 q_1
+               Index Cond: (a = p.a)
+(9 rows)
+
+-- test the IN Expr.
+explain (costs off) select * from p, q where p.a = q.a and p.a in (30, 5000000 -3);
+                      QUERY PLAN                       
+-------------------------------------------------------
+ Nested Loop
+   ->  Seq Scan on p_1 p
+         Filter: (a = ANY ('{30,4999997}'::integer[]))
+   ->  Index Scan using q_1_a_idx on q_1 q
+         Index Cond: (a = p.a)
+(5 rows)
+
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 92fcec1158b..a5042c3cbc3 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                              QUERY PLAN                              
-----------------------------------------------------------------------
+                 QUERY PLAN                  
+---------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
+         Filter: (f1 < '5'::int8alias1)
 (6 rows)
 
 reset session authorization;
@@ -456,37 +456,29 @@ explain (costs off)
   select * from ec0
   inner join ec1 on ec0.ff = ec1.ff
   where ec0.ff between 1 and 10;
-                         QUERY PLAN                         
-------------------------------------------------------------
+                            QUERY PLAN                            
+------------------------------------------------------------------
  Nested Loop
-   Join Filter: (ec0.ff = ec1.ff)
-   ->  Bitmap Heap Scan on ec0
+   ->  Bitmap Heap Scan on ec1
          Recheck Cond: ((ff >= 1) AND (ff <= 10))
-         ->  Bitmap Index Scan on ec0_pkey
+         ->  Bitmap Index Scan on ec1_pkey
                Index Cond: ((ff >= 1) AND (ff <= 10))
-   ->  Materialize
-         ->  Bitmap Heap Scan on ec1
-               Recheck Cond: ((ff >= 1) AND (ff <= 10))
-               ->  Bitmap Index Scan on ec1_pkey
-                     Index Cond: ((ff >= 1) AND (ff <= 10))
-(11 rows)
+   ->  Index Scan using ec0_pkey on ec0
+         Index Cond: ((ff = ec1.ff) AND (ff >= 1) AND (ff <= 10))
+(7 rows)
 
 explain (costs off)
   select * from ec0
   inner join ec1 on ec0.ff = ec1.ff
   where ec1.ff between 1 and 10;
-                         QUERY PLAN                         
-------------------------------------------------------------
+                            QUERY PLAN                            
+------------------------------------------------------------------
  Nested Loop
-   Join Filter: (ec0.ff = ec1.ff)
    ->  Bitmap Heap Scan on ec0
          Recheck Cond: ((ff >= 1) AND (ff <= 10))
          ->  Bitmap Index Scan on ec0_pkey
                Index Cond: ((ff >= 1) AND (ff <= 10))
-   ->  Materialize
-         ->  Bitmap Heap Scan on ec1
-               Recheck Cond: ((ff >= 1) AND (ff <= 10))
-               ->  Bitmap Index Scan on ec1_pkey
-                     Index Cond: ((ff >= 1) AND (ff <= 10))
-(11 rows)
+   ->  Index Scan using ec1_pkey on ec1
+         Index Cond: ((ff = ec0.ff) AND (ff >= 1) AND (ff <= 10))
+(7 rows)
 
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index b20de6a505f..7df4f93856e 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -6496,9 +6496,10 @@ where j1.id1 % 1000 = 1 and j2.id1 % 1000 = 1 and j2.id1 = any (array[1]);
    Merge Cond: (j1.id1 = j2.id1)
    Join Filter: (j1.id2 = j2.id2)
    ->  Index Scan using j1_id1_idx on j1
+         Index Cond: (id1 = ANY ('{1}'::integer[]))
    ->  Index Scan using j2_id1_idx on j2
          Index Cond: (id1 = ANY ('{1}'::integer[]))
-(6 rows)
+(7 rows)
 
 select * from j1
 inner join j2 on j1.id1 = j2.id1 and j1.id2 = j2.id2
@@ -6513,16 +6514,17 @@ where j1.id1 % 1000 = 1 and j2.id1 % 1000 = 1 and j2.id1 = any (array[1]);
 explain (costs off) select * from j1
 inner join j2 on j1.id1 = j2.id1 and j1.id2 = j2.id2
 where j1.id1 % 1000 = 1 and j2.id1 % 1000 = 1 and j2.id1 >= any (array[1,5]);
-                      QUERY PLAN                       
--------------------------------------------------------
+                       QUERY PLAN                        
+---------------------------------------------------------
  Merge Join
-   Merge Cond: (j1.id1 = j2.id1)
-   Join Filter: (j1.id2 = j2.id2)
-   ->  Index Scan using j1_id1_idx on j1
+   Merge Cond: ((j1.id1 = j2.id1) AND (j1.id2 = j2.id2))
+   ->  Index Only Scan using j1_pkey on j1
+         Index Cond: (id1 >= ANY ('{1,5}'::integer[]))
+         Filter: ((id1 % 1000) = 1)
    ->  Index Only Scan using j2_pkey on j2
          Index Cond: (id1 >= ANY ('{1,5}'::integer[]))
          Filter: ((id1 % 1000) = 1)
-(7 rows)
+(8 rows)
 
 select * from j1
 inner join j2 on j1.id1 = j2.id1 and j1.id2 = j2.id2
@@ -6550,22 +6552,24 @@ where exists (select 1 from tenk1 t3
 ---------------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
-   ->  Nested Loop
+   ->  Hash Join
          Output: t1.unique1, t3.tenthous
-         Join Filter: (t1.unique1 = t3.thousand)
-         ->  Index Only Scan using onek_unique1 on public.onek t1
-               Output: t1.unique1
-               Index Cond: (t1.unique1 < 1)
+         Hash Cond: (t3.thousand = t1.unique1)
          ->  HashAggregate
                Output: t3.thousand, t3.tenthous
                Group Key: t3.thousand, t3.tenthous
                ->  Index Only Scan using tenk1_thous_tenthous on public.tenk1 t3
                      Output: t3.thousand, t3.tenthous
                      Index Cond: (t3.thousand < 1)
+         ->  Hash
+               Output: t1.unique1
+               ->  Index Only Scan using onek_unique1 on public.onek t1
+                     Output: t1.unique1
+                     Index Cond: (t1.unique1 < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = t3.tenthous)
-(17 rows)
+(19 rows)
 
 -- ... unless it actually is unique
 create table j3 as select unique1, tenthous from onek;
@@ -6577,22 +6581,21 @@ from onek t1, tenk1 t2
 where exists (select 1 from j3
               where j3.unique1 = t1.unique1 and j3.tenthous = t2.hundred)
       and t1.unique1 < 1;
-                               QUERY PLAN                               
-------------------------------------------------------------------------
+                                 QUERY PLAN                                 
+----------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
    ->  Nested Loop
          Output: t1.unique1, j3.tenthous
-         Join Filter: (t1.unique1 = j3.unique1)
-         ->  Index Only Scan using onek_unique1 on public.onek t1
-               Output: t1.unique1
-               Index Cond: (t1.unique1 < 1)
          ->  Index Only Scan using j3_unique1_tenthous_idx on public.j3
                Output: j3.unique1, j3.tenthous
                Index Cond: (j3.unique1 < 1)
+         ->  Index Only Scan using onek_unique1 on public.onek t1
+               Output: t1.unique1
+               Index Cond: ((t1.unique1 = j3.unique1) AND (t1.unique1 < 1))
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = j3.tenthous)
-(14 rows)
+(13 rows)
 
 drop table j3;
diff --git a/src/test/regress/expected/partition_join.out b/src/test/regress/expected/partition_join.out
index 5a2923bac6c..c12351a3b0a 100644
--- a/src/test/regress/expected/partition_join.out
+++ b/src/test/regress/expected/partition_join.out
@@ -4449,16 +4449,18 @@ SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: ((t2_1.a = t1_1.a) AND (t2_1.c = t1_1.c))
                ->  Seq Scan on plt2_adv_p3 t2_1
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p3 t1_1
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
          ->  Hash Join
                Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.c = t1_2.c))
                ->  Seq Scan on plt2_adv_p4 t2_2
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p4 t1_2
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE t1.c IN ('0003', '0004', '0005') AND t1.b < 10 ORDER BY t1.a;
  a |  c   | a |  c   
@@ -4502,16 +4504,18 @@ SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: ((t2_1.a = t1_1.a) AND (t2_1.c = t1_1.c))
                ->  Seq Scan on plt2_adv_p3 t2_1
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p3 t1_1
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
          ->  Hash Join
                Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.c = t1_2.c))
                ->  Seq Scan on plt2_adv_p4 t2_2
+                     Filter: (c = ANY ('{0003,0004,0005}'::text[]))
                ->  Hash
                      ->  Seq Scan on plt1_adv_p4 t1_2
                            Filter: ((b < 10) AND (c = ANY ('{0003,0004,0005}'::text[])))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.a, t2.c FROM plt1_adv t1 INNER JOIN plt2_adv t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE t1.c IN ('0003', '0004', '0005') AND t1.b < 10 ORDER BY t1.a;
  a |  c   | a |  c   
@@ -4771,8 +4775,8 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
 
 EXPLAIN (COSTS OFF)
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b, t2.b;
-                                                              QUERY PLAN                                                              
---------------------------------------------------------------------------------------------------------------------------------------
+                                                                 QUERY PLAN                                                                 
+--------------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Sort Key: t1.a, t1.b, t2.b
    ->  Append
@@ -4786,21 +4790,21 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2
                ->  Hash
                      ->  Append
                            ->  Seq Scan on beta_neg_p1 t2_2
-                                 Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                                 Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                            ->  Seq Scan on beta_neg_p2 t2_3
-                                 Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                                 Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
          ->  Nested Loop
                Join Filter: ((t1_4.a = t2_4.a) AND (t1_4.c = t2_4.c))
                ->  Seq Scan on alpha_pos_p2 t1_4
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p2 t2_4
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
          ->  Nested Loop
                Join Filter: ((t1_5.a = t2_5.a) AND (t1_5.c = t2_5.c))
                ->  Seq Scan on alpha_pos_p3 t1_5
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p3 t2_5
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
 (28 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b, t2.b;
@@ -4826,38 +4830,40 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.c = t2
 
 EXPLAIN (COSTS OFF)
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b;
-                                                           QUERY PLAN                                                           
---------------------------------------------------------------------------------------------------------------------------------
+                                                              QUERY PLAN                                                              
+--------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Sort Key: t1.a, t1.b
    ->  Append
-         ->  Hash Join
-               Hash Cond: ((t1_1.a = t2_1.a) AND (t1_1.b = t2_1.b) AND (t1_1.c = t2_1.c))
-               ->  Seq Scan on alpha_neg_p1 t1_1
-                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
-               ->  Hash
+         ->  Merge Join
+               Merge Cond: ((t1_1.a = t2_1.a) AND (t1_1.b = t2_1.b) AND (t1_1.c = t2_1.c))
+               ->  Sort
+                     Sort Key: t1_1.a, t1_1.b, t1_1.c
+                     ->  Seq Scan on alpha_neg_p1 t1_1
+                           Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
+               ->  Sort
+                     Sort Key: t2_1.a, t2_1.b, t2_1.c
                      ->  Seq Scan on beta_neg_p1 t2_1
-                           Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
-         ->  Hash Join
-               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b) AND (t1_2.c = t2_2.c))
+                           Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
+         ->  Nested Loop
+               Join Filter: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b) AND (t1_2.c = t2_2.c))
+               ->  Seq Scan on beta_neg_p2 t2_2
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on alpha_neg_p2 t1_2
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
-               ->  Hash
-                     ->  Seq Scan on beta_neg_p2 t2_2
-                           Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
          ->  Nested Loop
                Join Filter: ((t1_3.a = t2_3.a) AND (t1_3.b = t2_3.b) AND (t1_3.c = t2_3.c))
                ->  Seq Scan on alpha_pos_p2 t1_3
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p2 t2_3
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
          ->  Nested Loop
                Join Filter: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b) AND (t1_4.c = t2_4.c))
                ->  Seq Scan on alpha_pos_p3 t1_4
                      Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
                ->  Seq Scan on beta_pos_p3 t2_4
-                     Filter: (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210)))
-(29 rows)
+                     Filter: ((c = ANY ('{0004,0009}'::text[])) AND (((b >= 100) AND (b < 110)) OR ((b >= 200) AND (b < 210))))
+(31 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b AND t1.c = t2.c) WHERE ((t1.b >= 100 AND t1.b < 110) OR (t1.b >= 200 AND t1.b < 210)) AND ((t2.b >= 100 AND t2.b < 110) OR (t2.b >= 200 AND t2.b < 210)) AND t1.c IN ('0004', '0009') ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 7555764c779..3fb515cdd9d 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -2104,19 +2104,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (never executed)
-                                 Index Cond: (a = a.a)
-(27 rows)
+(15 rows)
 
 -- Ensure the same partitions are pruned when we make the nested loop
 -- parameter an Expr rather than a plain Param.
@@ -2171,19 +2159,13 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (actual rows=N loops=N)
+                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_4 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (actual rows=N loops=N)
+                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_5 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (actual rows=N loops=N)
+                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_6 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-(27 rows)
+(21 rows)
 
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
                                         explain_parallel_append                                         
@@ -2204,19 +2186,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (actual rows=N loops=N)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (never executed)
-                                 Index Cond: (a = a.a)
-(28 rows)
+(16 rows)
 
 delete from lprt_a where a = 1;
 select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
@@ -2238,19 +2208,7 @@ select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on
                                  Index Cond: (a = a.a)
                            ->  Index Scan using ab_a1_b3_a_idx on ab_a1_b3 ab_3 (never executed)
                                  Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b1_a_idx on ab_a2_b1 ab_4 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b2_a_idx on ab_a2_b2 ab_5 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a2_b3_a_idx on ab_a2_b3 ab_6 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b1_a_idx on ab_a3_b1 ab_7 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b2_a_idx on ab_a3_b2 ab_8 (never executed)
-                                 Index Cond: (a = a.a)
-                           ->  Index Scan using ab_a3_b3_a_idx on ab_a3_b3 ab_9 (never executed)
-                                 Index Cond: (a = a.a)
-(28 rows)
+(16 rows)
 
 reset enable_hashjoin;
 reset enable_mergejoin;
diff --git a/src/test/regress/sql/ec_filter.sql b/src/test/regress/sql/ec_filter.sql
new file mode 100644
index 00000000000..f79e4206c50
--- /dev/null
+++ b/src/test/regress/sql/ec_filter.sql
@@ -0,0 +1,46 @@
+-- THIS TEST IS JUST FOW REVIEW PURPOSE, IT CONTAINS TOO MANY RUNTIME STATS.
+set enable_hashjoin to off;
+set enable_mergejoin to off;
+set enable_seqscan to on;
+-- 1. The joinrel.rows should be correct.
+-- 2. The path estimated rows for b should be correct.
+-- 3. the estimated rows from a in wrong, but that is not the fault of this patch.
+explain analyze select * from tenk1 a, tenk1 b where a.thousand = b.thousand and a.thousand < 100;
+
+create table d_tenk2 as select * from tenk1 union all select * from tenk1;
+create index on d_tenk2(thousand);
+analyze d_tenk2 ;
+
+set enable_seqscan to off;
+drop index tenk1_thous_tenthous;
+-- 1. The parameterized path of b shows the correct rows estimation as well.
+-- 2. The new added qual is fully duplicated with the join clause, so it should be removed.
+explain analyze select * from tenk1 a join d_tenk2 b on a.thousand = b.thousand and a.thousand < 100;
+
+create index tenk1_thous_tenthous on tenk1(thousand, tenthous);
+
+-- test ef filter with partition prune.
+
+create table p (a int, b int) partition by range(a);
+select 'create table p_' || i || ' partition of p  for values from (' || (i-1) * 100000 || ') to (' || i * 100000 || ');' from generate_series(1, 5)i;  \gexec
+insert into p select i, i from generate_series(1, 5 * 100000 -1) i;
+
+create table q (a int, b int) partition by range(a);
+select 'create table q_' || i || ' partition of q  for values from (' || (i-1) * 100000 || ') to (' || i * 100000 || ');' from generate_series(1, 5)i;  \gexec
+insert into q select * from p;
+create index on q(a);
+
+select * from p, q where p.a = q.a and p.a > 5 * 100000 - 3;
+
+set plan_cache_mode to force_generic_plan ;
+prepare s as select * from p, q where p.a = q.a and p.a > $1;
+explain (costs off) execute s(5 * 100000 - 3);
+
+-- support perudo const.
+prepare s2 as select * from p, q where p.a = q.a and p.a > abs($1::integer);
+explain (costs off) execute s2(5 * 100000 - 3);
+
+-- test the IN Expr.
+explain (costs off) select * from p, q where p.a = q.a and p.a in (30, 5000000 -3);
+
+
-- 
2.21.0

From ad2b12e2fb96a950cb97f8251a7825f061da16ef Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Sun, 6 Mar 2022 14:20:55 +0800
Subject: [PATCH v3 3/5] Reduce some planning cost for deriving qual for EC
 filter feature.

Mainly changes includes:
1. Check if the qual is simple enough by checking rinfo->right_relids and
info->right_relids, save the pull_varnos of rinfo->clause calls.
2. check contain_volatile_functions against RestrictInfo, so that
the result can be shared with following calls.
3. By employing the RestictInfo->btreeineqfamility which is calculating.
with same round of calculating  RestrictInfo->mergeopfamilies. In this
way we save the some calls for syscache.
4. Calculating the opfamility and amstrategy at
distribute_filter_quals_to_eclass and cache the results in EquivalenceFilter.
if no suitable opfamility and amstrategy are found, bypass the qual immediately
and at last using the cached value generate_base_implied_equalities_no_const.

After this change, there is an testcase changed unexpectedly in equivclass.out
(compared with David's expectation file.)

create user regress_user_ectest;
grant select on ec0 to regress_user_ectest;
grant select on ec1 to regress_user_ectest;

set session authorization regress_user_ectest;

-- with RLS active, the non-leakproof a.ff = 43 clause is not treated
-- as a suitable source for an EquivalenceClass; currently, this is true
-- even though the RLS clause has nothing to do directly with the EC
explain (costs off)
regression->   select * from ec0 a, ec1 b
regression->   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;

The b.ff = 43 is disappeared from ec1 b. But since it even didn't shown
before the EC filter, so I'm not sure my changes here make something wrong,
maybe fix a issue by accidental?
---
 src/backend/nodes/outfuncs.c             |  2 +
 src/backend/optimizer/path/equivclass.c  | 59 +++++++++++++-----------
 src/backend/optimizer/plan/initsplan.c   | 50 ++++----------------
 src/include/nodes/pathnodes.h            |  2 +
 src/test/regress/expected/equivclass.out |  6 +--
 5 files changed, 48 insertions(+), 71 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 4c384511c39..d29b64eb918 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2513,6 +2513,8 @@ _outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
 	WRITE_OID_FIELD(ef_opno);
 	WRITE_BOOL_FIELD(ef_const_is_left);
 	WRITE_UINT_FIELD(ef_source_rel);
+	WRITE_OID_FIELD(opfamily);
+	WRITE_INT_FIELD(amstrategy);
 }
 
 static void
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index f9ae2785d60..915888a8486 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1252,19 +1252,17 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 }
 
 /*
- * finds the opfamily and strategy number for the specified 'opno' and 'method'
- * access method. Returns True if one is found and sets 'family' and
- * 'amstrategy', or returns False if none are found.
+ * finds the operator id for the specified 'opno' and 'method' and 'opfamilies'
+ * Returns True if one is found and sets 'opfamily_p' and 'amstrategy_p' or returns
+ * False if none are found.
  */
 static bool
-find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+find_am_family_and_stategy(Oid opno, Oid method, List *opfamilies,
+						   Oid *opfamily_p, int *amstrategy_p)
 {
-	List *opfamilies;
 	ListCell *l;
 	int strategy;
 
-	opfamilies = get_opfamilies(opno, method);
-
 	foreach(l, opfamilies)
 	{
 		Oid opfamily = lfirst_oid(l);
@@ -1273,8 +1271,8 @@ find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
 
 		if (strategy)
 		{
-			*amstrategy = strategy;
-			*family = opfamily;
+			*opfamily_p = opfamily;
+			*amstrategy_p = strategy;
 			return true;
 		}
 	}
@@ -1363,17 +1361,11 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
 			Expr *leftexpr;
 			Expr *rightexpr;
-			int strategy;
 			Oid opno;
-			Oid family;
 
 			if (ef->ef_source_rel == relid)
 				continue;
 
-			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
-				&family, &strategy))
-				continue;
-
 			if (ef->ef_const_is_left)
 			{
 				leftexpr = (Expr *) ef->ef_const;
@@ -1385,10 +1377,10 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rightexpr = (Expr *) ef->ef_const;
 			}
 
-			opno = get_opfamily_member(family,
+			opno = get_opfamily_member(ef->opfamily,
 										exprType((Node *) leftexpr),
 										exprType((Node *) rightexpr),
-										strategy);
+										ef->amstrategy);
 
 			if (opno == InvalidOid)
 				continue;
@@ -1399,7 +1391,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 										rightexpr,
 										bms_copy(ec->ec_relids),
 										bms_copy(cur_em->em_nullable_relids),
-									 	ec->ec_min_security,
+										ec->ec_min_security,
 										ec->ec_below_outer_join,
 										false);
 		}
@@ -2007,9 +1999,12 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 	 */
 	foreach(l, quallist)
 	{
-		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
-		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
-		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
+		OpExpr *opexpr = (OpExpr *)(rinfo->clause);
+
+		Oid opfamily;
+		int amstrategy;
+
 		Const	   *constexpr;
 		Expr	   *varexpr;
 		Relids		exprrels;
@@ -2021,25 +2016,31 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 		 * Determine if the the OpExpr is in the form "expr op const" or
 		 * "const op expr".
 		 */
-		if (IsA(leftexpr, Const))
+		if (bms_is_empty(rinfo->left_relids))
 		{
-			constexpr = (Const *) leftexpr;
-			varexpr = rightexpr;
+			constexpr = (Const *) get_leftop(rinfo->clause);
+			varexpr = (Expr *) get_rightop(rinfo->clause);
 			const_isleft = true;
+			exprrels = rinfo->right_relids;
 		}
 		else
 		{
-			constexpr = (Const *) rightexpr;
-			varexpr = leftexpr;
+			constexpr = (Const *) get_rightop(rinfo->clause);
+			varexpr = (Expr *) get_leftop(rinfo->clause);
 			const_isleft = false;
+			exprrels = rinfo->left_relids;
 		}
 
-		exprrels = pull_varnos(root, (Node *) varexpr);
-
 		/* should be filtered out, but we need to determine relid anyway */
 		if (!bms_get_singleton_member(exprrels, &relid))
 			continue;
 
+		if (!find_am_family_and_stategy(opexpr->opno, BTREE_AM_OID,
+										rinfo->btreeineqopfamilies,
+										&opfamily,
+										&amstrategy))
+			continue;
+
 		/* search for a matching eclass member in all eclasses */
 		foreach(l2, root->eq_classes)
 		{
@@ -2075,6 +2076,8 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 					efilter->ef_const_is_left = const_isleft;
 					efilter->ef_opno = opexpr->opno;
 					efilter->ef_source_rel = relid;
+					efilter->opfamily = opfamily;
+					efilter->amstrategy = amstrategy;
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 7e355c94362..5a32c3987a0 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -651,44 +651,6 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
-/*
- * is_simple_filter_qual
- *             Analyzes an OpExpr to determine if it may be useful as an
- *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
- *             false if it should not be used.
- */
-static bool
-is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
-{
-	Expr *leftexpr;
-	Expr *rightexpr;
-
-	if (!IsA(expr, OpExpr))
-			return false;
-
-	if (list_length(expr->args) != 2)
-			return false;
-
-	leftexpr = (Expr *) linitial(expr->args);
-	rightexpr = (Expr *) lsecond(expr->args);
-
-	/* XXX should we restrict these to simple Var op Const expressions? */
-	if (IsA(leftexpr, Const))
-	{
-		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) rightexpr))
-			return true;
-	}
-	else if (IsA(rightexpr, Const))
-	{
-		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) leftexpr))
-			return true;
-	}
-
-	return false;
-}
-
 /*****************************************************************************
  *
  *	  JOIN TREE PROCESSING
@@ -1678,6 +1640,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	bool		maybe_outer_join;
 	Relids		nullable_relids;
 	RestrictInfo *restrictinfo;
+	int	relid;
 
 	/*
 	 * Retrieve all relids mentioned within the clause.
@@ -2027,8 +1990,15 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	distribute_restrictinfo_to_rels(root, restrictinfo);
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
-	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
-		*filter_qual_list = lappend(*filter_qual_list, clause);
+	if (filter_qual_list != NULL &&
+		is_opclause(restrictinfo->clause) &&
+		!contain_volatile_functions((Node *)restrictinfo) && // Cachable
+		restrictinfo->btreeineqopfamilies != NIL &&  /* ineq expression */
+		/* simple & common enough filter, one side references one relation and the other one is a constant */
+		((bms_is_empty(restrictinfo->left_relids) && bms_get_singleton_member(restrictinfo->right_relids, &relid)) ||
+		 (bms_is_empty(restrictinfo->right_relids) && bms_get_singleton_member(restrictinfo->left_relids, &relid)))
+		)
+		*filter_qual_list = lappend(*filter_qual_list, restrictinfo);
 }
 
 /*
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index dcae69635ce..e7b04211839 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1037,6 +1037,8 @@ typedef struct EquivalenceFilter
 	Oid			ef_opno;		/* Operator Oid of filter operator */
 	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
 	Index		ef_source_rel;	/* relid of originating relation. */
+	Oid			opfamily;
+	int			amstrategy;
 } EquivalenceFilter;
 
 /*
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 92fcec1158b..980bd3817d3 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                              QUERY PLAN                              
-----------------------------------------------------------------------
+                 QUERY PLAN                  
+---------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
+         Filter: (f1 < '5'::int8alias1)
 (6 rows)
 
 reset session authorization;
-- 
2.21.0

From 732f6a9a4b4f702d46866c7441b7addedcc0c00d Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Mon, 7 Mar 2022 20:17:42 +0800
Subject: [PATCH v3 4/5] Prepare the code for CorrectiveQual structure.

Just refactor the method for 2-level loop in
generate_base_implied_equalities_no_const, no other things is changed.
---
 src/backend/optimizer/path/equivclass.c | 61 +++++++++++++++----------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 915888a8486..6b638d184aa 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1351,17 +1351,33 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+		prev_ems[relid] = cur_em;
+	}
 
-		/*
-		 * Also push any EquivalenceFilter clauses down into all relations
-		 * other than the one which the filter actually originated from.
-		 */
-		foreach(lc2, ec->ec_filters)
+	pfree(prev_ems);
+
+
+	/*
+	 * Also push any EquivalenceFilter clauses down into all relations
+	 * other than the one which the filter actually originated from.
+	 */
+	foreach(lc2, ec->ec_filters)
+	{
+		EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+		Expr *leftexpr;
+		Expr *rightexpr;
+		Oid opno;
+		int relid;
+
+		if (ec->ec_broken)
+			break;
+
+		foreach(lc, ec->ec_members)
 		{
-			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
-			Expr *leftexpr;
-			Expr *rightexpr;
-			Oid opno;
+			EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
+
+			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
+				continue;
 
 			if (ef->ef_source_rel == relid)
 				continue;
@@ -1378,29 +1394,26 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			}
 
 			opno = get_opfamily_member(ef->opfamily,
-										exprType((Node *) leftexpr),
-										exprType((Node *) rightexpr),
-										ef->amstrategy);
+									   exprType((Node *) leftexpr),
+									   exprType((Node *) rightexpr),
+									   ef->amstrategy);
 
 			if (opno == InvalidOid)
 				continue;
 
+
 			process_implied_equality(root, opno,
-										ec->ec_collation,
-										leftexpr,
-										rightexpr,
-										bms_copy(ec->ec_relids),
-										bms_copy(cur_em->em_nullable_relids),
-										ec->ec_min_security,
-										ec->ec_below_outer_join,
-										false);
+									 ec->ec_collation,
+									 leftexpr,
+									 rightexpr,
+									 bms_copy(ec->ec_relids),
+									 bms_copy(cur_em->em_nullable_relids),
+									 ec->ec_min_security,
+									 ec->ec_below_outer_join,
+									 false);
 		}
-
-		prev_ems[relid] = cur_em;
 	}
 
-	pfree(prev_ems);
-
 	/*
 	 * We also have to make sure that all the Vars used in the member clauses
 	 * will be available at any join node we might try to reference them at.
-- 
2.21.0

From 067a720aeb273372aa536f0620ec53f022d40d85 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Mon, 7 Mar 2022 10:07:44 +0800
Subject: [PATCH v3 1/5] expand the duties of check_mergejoinable to check
 non-equal btree

operator as well to support the EC Filter function.  A new filed
named btreeineqopfamilies is added in RestictInfo and it is set
with the same round syscache search for check_mergejoinable. because
of this, check_mergejoinable is renamed to check_btreeable.

The bad part of this is it only works for opclause so far.
---
 src/backend/optimizer/plan/initsplan.c    | 33 ++++++++++-----------
 src/backend/optimizer/util/restrictinfo.c |  1 +
 src/backend/utils/cache/lsyscache.c       | 35 +++++++++++++++++++++++
 src/include/nodes/pathnodes.h             |  1 +
 src/include/utils/lsyscache.h             |  1 +
 5 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 023efbaf092..d61419f61a5 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -76,7 +76,7 @@ static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 static bool check_equivalence_delay(PlannerInfo *root,
 									RestrictInfo *restrictinfo);
 static bool check_redundant_nullability_qual(PlannerInfo *root, Node *clause);
-static void check_mergejoinable(RestrictInfo *restrictinfo);
+static void check_btreeable(RestrictInfo *restrictinfo);
 static void check_hashjoinable(RestrictInfo *restrictinfo);
 static void check_memoizable(RestrictInfo *restrictinfo);
 
@@ -1874,8 +1874,11 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	 * We check "mergejoinability" of every clause, not only join clauses,
 	 * because we want to know about equivalences between vars of the same
 	 * relation, or between vars and consts.
+	 *
+	 * We also checked the btree-able properity at the same round of checking
+	 * mergejoinability to support ec filter function.
 	 */
-	check_mergejoinable(restrictinfo);
+	check_btreeable(restrictinfo);
 
 	/*
 	 * If it is a true equivalence clause, send it to the EquivalenceClass
@@ -2389,7 +2392,7 @@ process_implied_equality(PlannerInfo *root,
 	 * from an EquivalenceClass; but we could have reduced the original clause
 	 * to a constant.
 	 */
-	check_mergejoinable(restrictinfo);
+	check_btreeable(restrictinfo);
 
 	/*
 	 * Note we don't do initialize_mergeclause_eclasses(); the caller can
@@ -2456,8 +2459,8 @@ build_implied_join_equality(PlannerInfo *root,
 									 NULL,	/* outer_relids */
 									 nullable_relids);	/* nullable_relids */
 
-	/* Set mergejoinability/hashjoinability flags */
-	check_mergejoinable(restrictinfo);
+	/* Set btreeability/hashjoinability flags */
+	check_btreeable(restrictinfo);
 	check_hashjoinable(restrictinfo);
 	check_memoizable(restrictinfo);
 
@@ -2641,16 +2644,13 @@ match_foreign_keys_to_quals(PlannerInfo *root)
  *****************************************************************************/
 
 /*
- * check_mergejoinable
- *	  If the restrictinfo's clause is mergejoinable, set the mergejoin
- *	  info fields in the restrictinfo.
- *
- *	  Currently, we support mergejoin for binary opclauses where
- *	  the operator is a mergejoinable operator.  The arguments can be
- *	  anything --- as long as there are no volatile functions in them.
+ * check_btreeable
+ *	  If the restrictinfo's clause is btreeable, set the mergejoin
+ *	  info field and btreeineq info field in the restrictinfo. btreeable
+ *	  now is a superset of mergeable.
  */
 static void
-check_mergejoinable(RestrictInfo *restrictinfo)
+check_btreeable(RestrictInfo *restrictinfo)
 {
 	Expr	   *clause = restrictinfo->clause;
 	Oid			opno;
@@ -2666,9 +2666,10 @@ check_mergejoinable(RestrictInfo *restrictinfo)
 	opno = ((OpExpr *) clause)->opno;
 	leftarg = linitial(((OpExpr *) clause)->args);
 
-	if (op_mergejoinable(opno, exprType(leftarg)) &&
-		!contain_volatile_functions((Node *) restrictinfo))
-		restrictinfo->mergeopfamilies = get_mergejoin_opfamilies(opno);
+	if (!contain_volatile_functions((Node *) restrictinfo))
+		get_btree_opfamilies(opno,
+							 &restrictinfo->mergeopfamilies,
+							 &restrictinfo->btreeineqopfamilies);
 
 	/*
 	 * Note: op_mergejoinable is just a hint; if we fail to find the operator
diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c
index ef8df3d098e..e09196d26f6 100644
--- a/src/backend/optimizer/util/restrictinfo.c
+++ b/src/backend/optimizer/util/restrictinfo.c
@@ -201,6 +201,7 @@ make_restrictinfo_internal(PlannerInfo *root,
 	restrictinfo->outer_selec = -1;
 
 	restrictinfo->mergeopfamilies = NIL;
+	restrictinfo->btreeineqopfamilies = NIL;
 
 	restrictinfo->left_ec = NULL;
 	restrictinfo->right_ec = NULL;
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index feef9998634..92c34ed8a49 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -389,6 +389,41 @@ get_mergejoin_opfamilies(Oid opno)
 	return result;
 }
 
+/*
+ * TODO:  get_mergejoin_opfamilies shoud be replaced with this function.
+ */
+void
+get_btree_opfamilies(Oid opno,
+					 List **mergeable_opfamilies,
+					 List **unmergeable_btree_opfamilies)
+{
+	CatCList   *catlist;
+	int			i;
+
+	/*
+	 * Search pg_amop to see find out all the btree opfamilies.
+	 */
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == BTREE_AM_OID)
+		{
+			if (aform->amopstrategy == BTEqualStrategyNumber)
+				*mergeable_opfamilies = lappend_oid(*mergeable_opfamilies,
+													aform->amopfamily);
+			else
+				*unmergeable_btree_opfamilies = lappend_oid(*unmergeable_btree_opfamilies,
+															aform->amopfamily);
+		}
+	}
+
+	ReleaseSysCacheList(catlist);
+}
+
 /*
  * get_compatible_hash_operators
  *		Get the OID(s) of hash equality operator(s) compatible with the given
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 1f3845b3fec..3b95e4a8eae 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -2105,6 +2105,7 @@ typedef struct RestrictInfo
 
 	/* valid if clause is mergejoinable, else NIL */
 	List	   *mergeopfamilies;	/* opfamilies containing clause operator */
+	List		*btreeineqopfamilies; /* btree families except the mergeable ones */
 
 	/* cache space for mergeclause processing; NULL if not yet set */
 	EquivalenceClass *left_ec;	/* EquivalenceClass containing lefthand */
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index b8dd27d4a96..5b5fac0397c 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -79,6 +79,7 @@ extern bool get_ordering_op_properties(Oid opno,
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
 extern List *get_mergejoin_opfamilies(Oid opno);
+extern void get_btree_opfamilies(Oid opno, List **mergeable_opfamilies, List **unmergeable_btree_opfamilies);
 extern bool get_compatible_hash_operators(Oid opno,
 										  Oid *lhs_opno, Oid *rhs_opno);
 extern bool get_op_hash_functions(Oid opno,
-- 
2.21.0

From 11204bfa8471e50c9ab3f379fe3a28329eeec841 Mon Sep 17 00:00:00 2001
From: David Rowley <dgrowleyml@gmail.com>
Date: Tue, 1 Feb 2022 20:56:40 +0800
Subject: [PATCH v3 2/5] Introudce ec_filters in EquivalenceClass struct, the
 semantics is the quals can

be applied to any EquivalenceMember in this EC. Later this information is used
to generate new RestrictInfo and was distributed to related RelOptInfo very
soon.  There are 3 major steps here:

a). In distribute_qual_to_rels to gather the ineq quallist.
b). After deconstruct_jointree, distribute_filter_quals_to_eclass distribute
these ineq-quallist to the related EC's ef_filters.
c). generate_base_implied_equalities_no_const scan the ec_filters and distriubte
the restrictinfo to related RelOptInfo.

Author: David Rowley at 2015-12 [1]
Andy Fan rebases this patch to current latest code.

https://www.postgresql.org/message-id/CAKJS1f9FK_X_5HKcPcSeimy16Owe3EmPmmGsGWLcKkj_rW9s6A%40mail.gmail.com
---
 .../postgres_fdw/expected/postgres_fdw.out    |  36 ++--
 src/backend/nodes/outfuncs.c                  |  14 ++
 src/backend/optimizer/path/equivclass.c       | 182 ++++++++++++++++++
 src/backend/optimizer/plan/initsplan.c        |  96 +++++++--
 src/backend/utils/cache/lsyscache.c           |  28 +++
 src/include/nodes/nodes.h                     |   1 +
 src/include/nodes/pathnodes.h                 |  37 ++++
 src/include/optimizer/paths.h                 |   1 +
 src/include/utils/lsyscache.h                 |   1 +
 src/test/regress/expected/equivclass.out      |  45 ++++-
 src/test/regress/expected/join.out            |  22 +--
 src/test/regress/expected/partition_join.out  |  52 +++--
 src/test/regress/sql/equivclass.sql           |  12 ++
 13 files changed, 457 insertions(+), 70 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f210f911880..ce102abe5d5 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1545,12 +1545,12 @@ SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNE
 -- full outer join + inner join
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
-                                                                                                                                                 QUERY PLAN                                                                                                                                                 
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: t1.c1, t2.c1, t3.c1
    Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
-   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND (((r2.c1 + 1) >= 50)) AND (((r2.c1 + 1) <= 60)) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
 (4 rows)
 
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
@@ -2335,12 +2335,12 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                QUERY PLAN                                                                                                                                 
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                    QUERY PLAN                                                                                                                                                     
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
    Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
 (4 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
@@ -2362,8 +2362,8 @@ SET enable_hashjoin TO false;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
     AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
-                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                      QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  LockRows
    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
    ->  Merge Join
@@ -2373,7 +2373,7 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
          ->  Foreign Scan
                Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
-               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
                ->  Merge Join
                      Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                      Merge Cond: (ft1.c2 = ft5.c1)
@@ -2391,12 +2391,12 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
                                              Sort Key: ft1.c1
                                              ->  Foreign Scan on public.ft1
                                                    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) FOR UPDATE
                                        ->  Materialize
                                              Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
                                              ->  Foreign Scan on public.ft2
                                                    Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
                            ->  Sort
                                  Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
                                  Sort Key: ft4.c1
@@ -5685,25 +5685,25 @@ UPDATE ft2 AS target SET (c2) = (
 EXPLAIN (VERBOSE, COSTS OFF)
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
   FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
-                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Update on public.ft2 d
    Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
    ->  Foreign Scan
          Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
          Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
-         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
-         ->  Hash Join
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" > 1000)) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Merge Join
                Output: d.c2, d.ctid, d.*, t.*
-               Hash Cond: (d.c1 = t.c1)
+               Merge Cond: (d.c1 = t.c1)
                ->  Foreign Scan on public.ft2 d
                      Output: d.c2, d.ctid, d.*, d.c1
                      Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
-               ->  Hash
+               ->  Materialize
                      Output: t.*, t.c1
                      ->  Foreign Scan on public.ft2 t
                            Output: t.*, t.c1
-                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST
 (17 rows)
 
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 6bdad462c78..4c384511c39 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2504,6 +2504,17 @@ _outEquivalenceMember(StringInfo str, const EquivalenceMember *node)
 	WRITE_OID_FIELD(em_datatype);
 }
 
+static void
+_outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
+{
+	WRITE_NODE_TYPE("EQUIVALENCEFILTER");
+
+	WRITE_NODE_FIELD(ef_const);
+	WRITE_OID_FIELD(ef_opno);
+	WRITE_BOOL_FIELD(ef_const_is_left);
+	WRITE_UINT_FIELD(ef_source_rel);
+}
+
 static void
 _outPathKey(StringInfo str, const PathKey *node)
 {
@@ -4306,6 +4317,9 @@ outNode(StringInfo str, const void *obj)
 			case T_EquivalenceMember:
 				_outEquivalenceMember(str, obj);
 				break;
+			case T_EquivalenceFilter:
+				_outEquivalenceFilter(str, obj);
+				break;
 			case T_PathKey:
 				_outPathKey(str, obj);
 				break;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 8c6770de972..f9ae2785d60 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -19,6 +19,7 @@
 #include <limits.h>
 
 #include "access/stratnum.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
@@ -1250,6 +1251,37 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 	}
 }
 
+/*
+ * finds the opfamily and strategy number for the specified 'opno' and 'method'
+ * access method. Returns True if one is found and sets 'family' and
+ * 'amstrategy', or returns False if none are found.
+ */
+static bool
+find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+{
+	List *opfamilies;
+	ListCell *l;
+	int strategy;
+
+	opfamilies = get_opfamilies(opno, method);
+
+	foreach(l, opfamilies)
+	{
+		Oid opfamily = lfirst_oid(l);
+
+		strategy = get_op_opfamily_strategy(opno, opfamily);
+
+		if (strategy)
+		{
+			*amstrategy = strategy;
+			*family = opfamily;
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /*
  * generate_base_implied_equalities when EC contains no pseudoconstants
  */
@@ -1259,6 +1291,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 {
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
+	ListCell   *lc2;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1320,6 +1353,57 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+
+		/*
+		 * Also push any EquivalenceFilter clauses down into all relations
+		 * other than the one which the filter actually originated from.
+		 */
+		foreach(lc2, ec->ec_filters)
+		{
+			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+			Expr *leftexpr;
+			Expr *rightexpr;
+			int strategy;
+			Oid opno;
+			Oid family;
+
+			if (ef->ef_source_rel == relid)
+				continue;
+
+			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
+				&family, &strategy))
+				continue;
+
+			if (ef->ef_const_is_left)
+			{
+				leftexpr = (Expr *) ef->ef_const;
+				rightexpr = cur_em->em_expr;
+			}
+			else
+			{
+				leftexpr = cur_em->em_expr;
+				rightexpr = (Expr *) ef->ef_const;
+			}
+
+			opno = get_opfamily_member(family,
+										exprType((Node *) leftexpr),
+										exprType((Node *) rightexpr),
+										strategy);
+
+			if (opno == InvalidOid)
+				continue;
+
+			process_implied_equality(root, opno,
+										ec->ec_collation,
+										leftexpr,
+										rightexpr,
+										bms_copy(ec->ec_relids),
+										bms_copy(cur_em->em_nullable_relids),
+									 	ec->ec_min_security,
+										ec->ec_below_outer_join,
+										false);
+		}
+
 		prev_ems[relid] = cur_em;
 	}
 
@@ -1901,6 +1985,104 @@ create_join_clause(PlannerInfo *root,
 	return rinfo;
 }
 
+/*
+ * distribute_filter_quals_to_eclass
+ *		For each OpExpr in quallist look for an eclass which has an Expr
+ *		matching the Expr in the OpExpr. If a match is found we add a new
+ *		EquivalenceFilter to the eclass containing the filter details.
+ */
+void
+distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
+{
+	ListCell *l;
+
+	/* fast path for when no eclasses have been generated */
+	if (root->eq_classes == NIL)
+		return;
+
+	/*
+	 * For each qual in quallist try and find an eclass which contains the
+	 * non-Const part of the OpExpr. We'll tag any matches that we find onto
+	 * the correct eclass.
+	 */
+	foreach(l, quallist)
+	{
+		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
+		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		Const	   *constexpr;
+		Expr	   *varexpr;
+		Relids		exprrels;
+		int			relid;
+		bool		const_isleft;
+		ListCell *l2;
+
+		/*
+		 * Determine if the the OpExpr is in the form "expr op const" or
+		 * "const op expr".
+		 */
+		if (IsA(leftexpr, Const))
+		{
+			constexpr = (Const *) leftexpr;
+			varexpr = rightexpr;
+			const_isleft = true;
+		}
+		else
+		{
+			constexpr = (Const *) rightexpr;
+			varexpr = leftexpr;
+			const_isleft = false;
+		}
+
+		exprrels = pull_varnos(root, (Node *) varexpr);
+
+		/* should be filtered out, but we need to determine relid anyway */
+		if (!bms_get_singleton_member(exprrels, &relid))
+			continue;
+
+		/* search for a matching eclass member in all eclasses */
+		foreach(l2, root->eq_classes)
+		{
+			EquivalenceClass *ec = (EquivalenceClass *) lfirst(l2);
+			ListCell *l3;
+
+			if (ec->ec_broken || ec->ec_has_volatile)
+				continue;
+
+			/*
+			 * if the eclass has a const then that const will serve as the
+			 * filter, we needn't add any others.
+			 */
+			if (ec->ec_has_const)
+				continue;
+
+			/* skip this eclass no members exist which belong to this relid */
+			if (!bms_is_member(relid, ec->ec_relids))
+				continue;
+
+			foreach(l3, ec->ec_members)
+			{
+				EquivalenceMember *em = (EquivalenceMember *) lfirst(l3);
+
+				if (!bms_is_member(relid, em->em_relids))
+					continue;
+
+				if (equal(em->em_expr, varexpr))
+				{
+					EquivalenceFilter *efilter;
+					efilter = makeNode(EquivalenceFilter);
+					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const_is_left = const_isleft;
+					efilter->ef_opno = opexpr->opno;
+					efilter->ef_source_rel = relid;
+
+					ec->ec_filters = lappend(ec->ec_filters, efilter);
+					break;		/* Onto the next eclass */
+				}
+			}
+		}
+	}
+}
 
 /*
  * reconsider_outer_join_clauses
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index d61419f61a5..7e355c94362 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -53,7 +53,7 @@ static void extract_lateral_references(PlannerInfo *root, RelOptInfo *brel,
 static List *deconstruct_recurse(PlannerInfo *root, Node *jtnode,
 								 bool below_outer_join,
 								 Relids *qualscope, Relids *inner_join_rels,
-								 List **postponed_qual_list);
+								 List **postponed_qual_list, List **filter_qual_list);
 static void process_security_barrier_quals(PlannerInfo *root,
 										   int rti, Relids qualscope,
 										   bool below_outer_join);
@@ -70,7 +70,8 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 									Relids qualscope,
 									Relids ojscope,
 									Relids outerjoin_nonnullable,
-									List **postponed_qual_list);
+									List **postponed_qual_list,
+									List **filter_qual_list);
 static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 								  Relids *nullable_relids_p, bool is_pushed_down);
 static bool check_equivalence_delay(PlannerInfo *root,
@@ -650,6 +651,43 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
+/*
+ * is_simple_filter_qual
+ *             Analyzes an OpExpr to determine if it may be useful as an
+ *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
+ *             false if it should not be used.
+ */
+static bool
+is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+{
+	Expr *leftexpr;
+	Expr *rightexpr;
+
+	if (!IsA(expr, OpExpr))
+			return false;
+
+	if (list_length(expr->args) != 2)
+			return false;
+
+	leftexpr = (Expr *) linitial(expr->args);
+	rightexpr = (Expr *) lsecond(expr->args);
+
+	/* XXX should we restrict these to simple Var op Const expressions? */
+	if (IsA(leftexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) rightexpr))
+			return true;
+	}
+	else if (IsA(rightexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) leftexpr))
+			return true;
+	}
+
+	return false;
+}
 
 /*****************************************************************************
  *
@@ -690,6 +728,7 @@ deconstruct_jointree(PlannerInfo *root)
 	Relids		qualscope;
 	Relids		inner_join_rels;
 	List	   *postponed_qual_list = NIL;
+	List	   *filter_qual_list = NIL;
 
 	/* Start recursion at top of jointree */
 	Assert(root->parse->jointree != NULL &&
@@ -700,11 +739,14 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list);
+								 &postponed_qual_list, &filter_qual_list);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
 
+	/* try and match each filter_qual_list item up with an eclass. */
+	distribute_filter_quals_to_eclass(root, filter_qual_list);
+
 	return result;
 }
 
@@ -725,6 +767,8 @@ deconstruct_jointree(PlannerInfo *root)
  *		or free this, either)
  *	*postponed_qual_list is a list of PostponedQual structs, which we can
  *		add quals to if they turn out to belong to a higher join level
+ *	*filter_qual_list is appended to with a list of quals which may be useful
+ *		include as EquivalenceFilters.
  *	Return value is the appropriate joinlist for this jointree node
  *
  * In addition, entries will be added to root->join_info_list for outer joins.
@@ -732,7 +776,7 @@ deconstruct_jointree(PlannerInfo *root)
 static List *
 deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 					Relids *qualscope, Relids *inner_join_rels,
-					List **postponed_qual_list)
+					List **postponed_qual_list, List **filter_qual_list)
 {
 	List	   *joinlist;
 
@@ -785,7 +829,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 											   below_outer_join,
 											   &sub_qualscope,
 											   inner_join_rels,
-											   &child_postponed_quals);
+											   &child_postponed_quals,
+											   filter_qual_list);
 			*qualscope = bms_add_members(*qualscope, sub_qualscope);
 			sub_members = list_length(sub_joinlist);
 			remaining--;
@@ -819,7 +864,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 										below_outer_join, JOIN_INNER,
 										root->qual_security_level,
 										*qualscope, NULL, NULL,
-										NULL);
+										NULL,
+										filter_qual_list);
 			else
 				*postponed_qual_list = lappend(*postponed_qual_list, pq);
 		}
@@ -835,7 +881,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									below_outer_join, JOIN_INNER,
 									root->qual_security_level,
 									*qualscope, NULL, NULL,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 	}
 	else if (IsA(jtnode, JoinExpr))
@@ -873,11 +920,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = *qualscope;
 				/* Inner join adds no restrictions for quals */
@@ -890,11 +939,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				nonnullable_rels = leftids;
@@ -904,11 +955,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* Semi join adds no restrictions for quals */
@@ -925,11 +978,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   true,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* each side is both outer and inner */
@@ -1013,7 +1068,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									root->qual_security_level,
 									*qualscope,
 									ojscope, nonnullable_rels,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 
 		/* Now we can add the SpecialJoinInfo to join_info_list */
@@ -1117,6 +1173,7 @@ process_security_barrier_quals(PlannerInfo *root,
 									qualscope,
 									qualscope,
 									NULL,
+									NULL,
 									NULL);
 		}
 		security_level++;
@@ -1610,7 +1667,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 						Relids qualscope,
 						Relids ojscope,
 						Relids outerjoin_nonnullable,
-						List **postponed_qual_list)
+						List **postponed_qual_list,
+						List **filter_qual_list)
 {
 	Relids		relids;
 	bool		is_pushed_down;
@@ -1967,6 +2025,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* No EC special case applies, so push it into the clause lists */
 	distribute_restrictinfo_to_rels(root, restrictinfo);
+
+	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
 /*
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 92c34ed8a49..6e03d40384c 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -341,6 +341,34 @@ get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
 	return result;
 }
 
+/*
+ * get_opfamilies
+ *		Returns a list of Oids of each opfamily which 'opno' belonging to
+ *		'method' access method.
+ */
+List *
+get_opfamilies(Oid opno, Oid method)
+{
+	List	   *result = NIL;
+	CatCList   *catlist;
+	int			i;
+
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == method)
+			result = lappend_oid(result, aform->amopfamily);
+	}
+
+	ReleaseSysCacheList(catlist);
+
+	return result;
+}
+
 /*
  * get_mergejoin_opfamilies
  *		Given a putatively mergejoinable operator, return a list of the OIDs
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 5d075f0c346..7349afe1640 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -265,6 +265,7 @@ typedef enum NodeTag
 	/* these aren't subclasses of Path: */
 	T_EquivalenceClass,
 	T_EquivalenceMember,
+	T_EquivalenceFilter,
 	T_PathKey,
 	T_PathTarget,
 	T_RestrictInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 3b95e4a8eae..dcae69635ce 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -990,6 +990,7 @@ typedef struct EquivalenceClass
 	List	   *ec_members;		/* list of EquivalenceMembers */
 	List	   *ec_sources;		/* list of generating RestrictInfos */
 	List	   *ec_derives;		/* list of derived RestrictInfos */
+	List	   *ec_filters;
 	Relids		ec_relids;		/* all relids appearing in ec_members, except
 								 * for child members (see below) */
 	bool		ec_has_const;	/* any pseudoconstants in ec_members? */
@@ -1002,6 +1003,42 @@ typedef struct EquivalenceClass
 	struct EquivalenceClass *ec_merged; /* set if merged into another EC */
 } EquivalenceClass;
 
+/*
+ * EquivalenceFilter - List of filters on Consts which belong to the
+ * EquivalenceClass.
+ *
+ * When building the equivalence classes we also collected a list of quals in
+ * the form of; "Expr op Const" and "Const op Expr". These are collected in the
+ * hope that we'll later generate an equivalence class which contains the
+ * "Expr" part. For example, if we parse a query such as;
+ *
+ *		SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id WHERE t1.id < 10;
+ *
+ * then since we'll end up with an equivalence class containing {t1.id,t2.id},
+ * we'll tag the "< 10" filter onto the eclass. We are able to do this because
+ * the eclass proves equality between each class member, therefore all members
+ * must be below 10.
+ *
+ * EquivalenceFilters store the details required to allow us to push these
+ * filter clauses down into other relations which share an equivalence class
+ * containing a member which matches the expression of this EquivalenceFilter.
+ *
+ * ef_const is the Const value which this filter should filter against.
+ * ef_opno is the operator to filter on.
+ * ef_const_is_left marks if the OpExpr was in the form "Const op Expr" or
+ * "Expr op Const".
+ * ef_source_rel is the relation id of where this qual originated from.
+ */
+typedef struct EquivalenceFilter
+{
+	NodeTag		type;
+
+	Const	   *ef_const;		/* the constant expression to filter on */
+	Oid			ef_opno;		/* Operator Oid of filter operator */
+	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
+	Index		ef_source_rel;	/* relid of originating relation. */
+} EquivalenceFilter;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 0c3a0b90c85..ce2aac7d3aa 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -126,6 +126,7 @@ extern bool process_equivalence(PlannerInfo *root,
 extern Expr *canonicalize_ec_expression(Expr *expr,
 										Oid req_type, Oid req_collation);
 extern void reconsider_outer_join_clauses(PlannerInfo *root);
+extern void distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist);
 extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
 												  Expr *expr,
 												  Relids nullable_relids,
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 5b5fac0397c..e0ed28f330b 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -78,6 +78,7 @@ extern bool get_ordering_op_properties(Oid opno,
 									   Oid *opfamily, Oid *opcintype, int16 *strategy);
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
+extern List *get_opfamilies(Oid opno, Oid method);
 extern List *get_mergejoin_opfamilies(Oid opno);
 extern void get_btree_opfamilies(Oid opno, List **mergeable_opfamilies, List **unmergeable_btree_opfamilies);
 extern bool get_compatible_hash_operators(Oid opno,
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 126f7047fed..92fcec1158b 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                 QUERY PLAN                  
----------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: (f1 < '5'::int8alias1)
+         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
 (6 rows)
 
 reset session authorization;
@@ -451,3 +451,42 @@ explain (costs off)  -- this should not require a sort
    Filter: (f1 = 'foo'::name)
 (2 rows)
 
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 19caebabd01..6a548903eec 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3337,7 +3337,7 @@ where t1.unique2 < 42 and t1.stringu1 > t2.stringu2;
    Join Filter: (t1.stringu1 > t2.stringu2)
    ->  Nested Loop
          ->  Seq Scan on int4_tbl i1
-               Filter: (f1 = 0)
+               Filter: ((f1 = 0) AND (11 < 42))
          ->  Index Scan using tenk1_unique2 on tenk1 t1
                Index Cond: ((unique2 = (11)) AND (unique2 < 42))
    ->  Index Scan using tenk1_unique1 on tenk1 t2
@@ -6550,23 +6550,22 @@ where exists (select 1 from tenk1 t3
 ---------------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
-   ->  Hash Join
+   ->  Nested Loop
          Output: t1.unique1, t3.tenthous
-         Hash Cond: (t3.thousand = t1.unique1)
+         Join Filter: (t1.unique1 = t3.thousand)
+         ->  Index Only Scan using onek_unique1 on public.onek t1
+               Output: t1.unique1
+               Index Cond: (t1.unique1 < 1)
          ->  HashAggregate
                Output: t3.thousand, t3.tenthous
                Group Key: t3.thousand, t3.tenthous
                ->  Index Only Scan using tenk1_thous_tenthous on public.tenk1 t3
                      Output: t3.thousand, t3.tenthous
-         ->  Hash
-               Output: t1.unique1
-               ->  Index Only Scan using onek_unique1 on public.onek t1
-                     Output: t1.unique1
-                     Index Cond: (t1.unique1 < 1)
+                     Index Cond: (t3.thousand < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = t3.tenthous)
-(18 rows)
+(17 rows)
 
 -- ... unless it actually is unique
 create table j3 as select unique1, tenthous from onek;
@@ -6584,15 +6583,16 @@ where exists (select 1 from j3
    Output: t1.unique1, t2.hundred
    ->  Nested Loop
          Output: t1.unique1, j3.tenthous
+         Join Filter: (t1.unique1 = j3.unique1)
          ->  Index Only Scan using onek_unique1 on public.onek t1
                Output: t1.unique1
                Index Cond: (t1.unique1 < 1)
          ->  Index Only Scan using j3_unique1_tenthous_idx on public.j3
                Output: j3.unique1, j3.tenthous
-               Index Cond: (j3.unique1 = t1.unique1)
+               Index Cond: (j3.unique1 < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = j3.tenthous)
-(13 rows)
+(14 rows)
 
 drop table j3;
diff --git a/src/test/regress/expected/partition_join.out b/src/test/regress/expected/partition_join.out
index bb5b7c47a45..5a2923bac6c 100644
--- a/src/test/regress/expected/partition_join.out
+++ b/src/test/regress/expected/partition_join.out
@@ -186,17 +186,17 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM (SELECT 50 phv, * FROM prt1 WHERE prt1.b = 0)
 -- Join with pruned partitions from joining relations
 EXPLAIN (COSTS OFF)
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
-                     QUERY PLAN                      
------------------------------------------------------
+                            QUERY PLAN                             
+-------------------------------------------------------------------
  Sort
    Sort Key: t1.a
    ->  Hash Join
          Hash Cond: (t2.b = t1.a)
          ->  Seq Scan on prt2_p2 t2
-               Filter: (b > 250)
+               Filter: ((b > 250) AND (b < 450))
          ->  Hash
                ->  Seq Scan on prt1_p2 t1
-                     Filter: ((a < 450) AND (b = 0))
+                     Filter: ((a < 450) AND (a > 250) AND (b = 0))
 (9 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
@@ -3100,16 +3100,18 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a < 300) AND (b = 0))
          ->  Hash Join
                Hash Cond: (t2_2.b = t1_2.a)
                ->  Seq Scan on prt2_adv_p2 t2_2
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a < 300) AND (b = 0))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -3139,16 +3141,19 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: ((b >= 100) AND (b < 300))
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-         ->  Hash Join
-               Hash Cond: (t2_2.b = t1_2.a)
-               ->  Seq Scan on prt2_adv_p2 t2_2
-               ->  Hash
+         ->  Merge Join
+               Merge Cond: (t2_2.b = t1_2.a)
+               ->  Index Scan using prt2_adv_p2_b_idx on prt2_adv_p2 t2_2
+                     Index Cond: ((b >= 100) AND (b < 300))
+               ->  Sort
+                     Sort Key: t1_2.a
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-(15 rows)
+(18 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a >= 100 AND t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -4692,27 +4697,32 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
                      Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Seq Scan on beta_neg_p1 t2_1
+                           Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.b = t1_2.b))
-               ->  Seq Scan on beta_neg_p2 t2_2
+               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b))
+               ->  Seq Scan on alpha_neg_p2 t1_2
+                     Filter: ((b >= 125) AND (b < 225))
                ->  Hash
-                     ->  Seq Scan on alpha_neg_p2 t1_2
+                     ->  Seq Scan on beta_neg_p2 t2_2
                            Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_4.a = t1_4.a) AND (t2_4.b = t1_4.b))
+               Hash Cond: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b))
                ->  Append
-                     ->  Seq Scan on beta_pos_p1 t2_4
-                     ->  Seq Scan on beta_pos_p2 t2_5
-                     ->  Seq Scan on beta_pos_p3 t2_6
+                     ->  Seq Scan on alpha_pos_p1 t1_4
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p2 t1_5
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p3 t1_6
+                           Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Append
-                           ->  Seq Scan on alpha_pos_p1 t1_4
+                           ->  Seq Scan on beta_pos_p1 t2_4
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p2 t1_5
+                           ->  Seq Scan on beta_pos_p2 t2_5
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p3 t1_6
+                           ->  Seq Scan on beta_pos_p3 t2_6
                                  Filter: ((b >= 125) AND (b < 225))
-(29 rows)
+(34 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b) WHERE t1.b >= 125 AND t1.b < 225 ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
diff --git a/src/test/regress/sql/equivclass.sql b/src/test/regress/sql/equivclass.sql
index 247b0a31055..dae83c41965 100644
--- a/src/test/regress/sql/equivclass.sql
+++ b/src/test/regress/sql/equivclass.sql
@@ -269,3 +269,15 @@ create temp view overview as
   select f1::information_schema.sql_identifier as sqli, f2 from undername;
 explain (costs off)  -- this should not require a sort
   select * from overview where sqli = 'foo' order by sqli;
+
+
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
-- 
2.21.0

From d6c0ebc19307af9863bc9b25321ff1106cc6ea76 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Tue, 8 Mar 2022 17:25:04 +0800
Subject: [PATCH v3 5/5] CorrectiveQuals is as simple as a List of
 RestrictInfo, a). only one

restrictinfo on this group should be counted for any joinrel estimation. b). at
least 1 restrictinfo in this group should be executed during execution. In this
commit, only rows estimation issue is addressed.

PlannerInfo.correlative_quals is added to manage all the CorrectiveQuals at
subquery level. RelOptInfo.cqual_indexes is a List * to indicate a which
CorrectiveQuals this relation related to. This is designed for easy to check if
the both sides of joinrel correlated to the same CorrectiveQuals. Why isn't the
type a Bitmapset * will be explained later.

The overall design of handing the joinrel size estimation is:
a). At the base relation level, we just count everything with the correlative
quals. b). During the any level joinrel size estimation, we just keep 1 side's
cqual (short for corrective qual) selectivity by eliminated the other one. so
the size estimation for a mergeable join selectivity becomes to:

rows = R1.rows X r2.rows X 1 / Max (ndistval_of_colA,  ndistinval_of_colB) X 1 /
Selectivity(R1's CorrectiveQual).

r1.rows X 1 / Selectivity(R1's CorrectiveQual) eliminated the impact of
CorrectiveQual on R1. After this,  the JoinRel of (R1, R2) still be impacted by
this CorrectiveQual but just one in this level.  Later if JoinRel(R1, R2) needs
to join with R3,  and R3 is impacted by this CorectiveQuals as well. This we
need to keep one and eliminating the other one as above again.

The algorithm for which Selectivity should be eliminated and which one should be
kept is:

When we join 2 inner_rel and outer_rel with a mergeable join restrictinfo, if
both sides is impacted with the same CorrectiveQual, we first choose which "side"
to eliminating based on which side of the restrictinfo has a higher distinct
value. The reason for this is more or less because we used "Max"(ndistinctValT1,
ndistinctValT2). After decide which "side" to eliminating, the real eliminating
selecitity is the side of RelOptInfo->cqual_selectivity[n]

Selectivity *RelOptInfo->cqual_selectivity:

 The number of elements in cqual_selecitity equals
 the length of cqual_indexes. The semantics is which
 selectivity in the corresponding CorectiveQuals's qual
 list is taking effect. At only time, only 1 Qual
 Selectivity is counted for any-level of joinrel.

and the other side's RelOptInfo->cqual_selectivty is used to set the upper
joinrel->cqual_selecivity.

In reality, it is possible for to have many CorrectiveQuals, but for design
discussion, the current implementation only take care of the 1 CorrectiveQuals.
this would be helpful for PoC/review/discussion.

Some flow for the key data:

1. root->corrective_quals is initialized at
generate_base_implied_equalities_no_const stage. we create a CorrectiveQual in
this list for each ec_filter and fill the RestrictInfo part for this cqual. At
the same time, we note which RelOptInfo (cqual_indexes) has related to this cqual.

2. RelOptInfo->cqual_selecitity for baserel is set at the end of set_rel_size,
at this time, the selectivity for every RestrictInfo is calcuated, we can just
fetch the cached value.  As for joinrel, it is maintained in
calc_join_cqual_selectivity, this function would return the Selectivity to
eliminate and set the above value.

Limitation in this PoC:
1. Only support 1 CorrectiveQual in root->correlative_quals
2. Only tested with INNER_JOIN.
3. Inherited table is not supported.
---
 src/backend/nodes/outfuncs.c              |   1 +
 src/backend/optimizer/path/allpaths.c     |  27 ++++
 src/backend/optimizer/path/costsize.c     | 182 ++++++++++++++++++++++
 src/backend/optimizer/path/equivclass.c   |  48 ++++--
 src/backend/optimizer/plan/planner.c      |   1 +
 src/backend/optimizer/prep/prepjointree.c |   1 +
 src/include/nodes/nodes.h                 |   1 +
 src/include/nodes/pathnodes.h             |  36 ++++-
 8 files changed, 280 insertions(+), 17 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index d29b64eb918..00989fedacb 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2515,6 +2515,7 @@ _outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
 	WRITE_UINT_FIELD(ef_source_rel);
 	WRITE_OID_FIELD(opfamily);
 	WRITE_INT_FIELD(amstrategy);
+	WRITE_NODE_FIELD(rinfo);
 }
 
 static void
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 169b1d53fc8..311a5e3837a 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -461,6 +461,33 @@ set_rel_size(PlannerInfo *root, RelOptInfo *rel,
 	 * We insist that all non-dummy rels have a nonzero rowcount estimate.
 	 */
 	Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
+
+	/* Now calculating the selectivity impacted by Corrective Qual */
+	if (!rte->inh)  /* not supported in this PoC */
+	{
+		ListCell *l;
+		int i = 0;
+		rel->cqual_selecitiy = palloc(sizeof(Selectivity) * list_length(rel->cqual_indexes));
+
+		foreach(l, rel->cqual_indexes)
+		{
+			int cq_index = lfirst_int(l);
+			CorrelativeQuals *cquals = list_nth_node(CorrelativeQuals, root->correlative_quals, cq_index);
+			ListCell *l2;
+			bool found = false;
+			foreach(l2, cquals->corr_restrictinfo)
+			{
+				RestrictInfo *rinfo = lfirst_node(RestrictInfo, l2);
+				if (bms_equal(rinfo->clause_relids, rel->relids))
+				{
+					found = true;
+					rel->cqual_selecitiy[i] = rinfo->norm_selec > 0 ? rinfo->norm_selec : rinfo->outer_selec;
+					Assert(rel->cqual_selecitiy[i] > 0);
+				}
+			}
+			Assert(found);
+		}
+	}
 }
 
 /*
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 8dc7dd4ca26..b4ad4297826 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -5062,6 +5062,138 @@ get_parameterized_joinrel_size(PlannerInfo *root, RelOptInfo *rel,
 	return nrows;
 }
 
+
+/*
+ * Given a mergeable RestrictInfo, find out which relid should be used for
+ * eliminating Corrective Qual Selectivity.
+ */
+static int
+find_relid_to_eliminate(PlannerInfo *root, RestrictInfo *rinfo)
+{
+	int left_relid,  right_relid;
+	RelOptInfo *lrel, *rrel;
+	bool res;
+
+	res = bms_get_singleton_member(rinfo->left_relids, &left_relid);
+	Assert(res);
+	res = bms_get_singleton_member(rinfo->left_relids, &right_relid);
+	Assert(res);
+
+	lrel = root->simple_rel_array[left_relid];
+	rrel = root->simple_rel_array[right_relid];
+
+	/* XXX: Assumed only one CorrectiveQual exists */
+
+	if (lrel->cqual_selecitiy[0] > rrel->cqual_selecitiy[0])
+		return left_relid;
+
+	return right_relid;
+}
+
+/*
+ * calc_join_cqual_selectivity
+ *
+ *	When join two relations, if both sides are impacted by the same CorrectiveQuals,
+ * we need to eliminate one of them and note the other one for future eliminating when join
+ * another corrective relation. or else just note the joinrel still being impacted by the
+ * single sides's CorrectiveQuals.
+ *
+ * Return value is the Selectivity we need to eliminate for estimating the current
+ * joinrel.
+ */
+static double
+calc_join_cqual_selectivity(PlannerInfo *root,
+							RelOptInfo *joinrel,
+							RelOptInfo *outer_rel,
+							RelOptInfo *inner_rel,
+							RestrictInfo *rinfo)
+{
+	double res = 1;
+	ListCell *lc1, *lc2;
+	Selectivity left_sel;  /* The cqual selectivity still impacted on this joinrel. */
+
+	/*
+	 * Find how many CorrectiveQual for this joinrel and allocate space for each left Selectivity
+	 * for each CorrectiveQual here.
+	 */
+	List	*final_cq_list = list_union_int(outer_rel->cqual_indexes, inner_rel->cqual_indexes);
+
+	joinrel->cqual_selecitiy = palloc(sizeof(Selectivity) * list_length(final_cq_list));
+
+	foreach(lc1, outer_rel->cqual_indexes)
+	{
+		int outer_cq_index = lfirst_int(lc1);
+		int inner_cq_pos = -1;
+		int outer_idx = foreach_current_index(lc1);
+		int curr_sel_len;
+
+		/*
+		 * Check if the same corrective quals applied in both sides,
+		 * if yes, we need to decide which one to eliminate and which one
+		 * to keep. or else, we just keep the selectivity for feature use.
+		 */
+		foreach(lc2, inner_rel->cqual_indexes)
+		{
+			if (outer_cq_index == lfirst_int(lc2))
+				inner_cq_pos = foreach_current_index(lc2);
+		}
+
+		if (inner_cq_pos >= 0)
+		{
+			/* Find the CorrectiveQual which impacts both side. */
+			int relid = find_relid_to_eliminate(root, rinfo);
+			if (bms_is_member(relid, outer_rel->relids))
+			{
+				/* XXXX: we assume only 1 CorrectiveQual exist, so [0] directly. */
+				res *= outer_rel->cqual_selecitiy[0];
+				left_sel = inner_rel->cqual_selecitiy[0];
+			}
+			else
+			{
+				/* XXXX: we assume only 1 CorrectiveQual exist */
+				res *= inner_rel->cqual_selecitiy[0];
+				left_sel = outer_rel->cqual_selecitiy[0];
+			}
+		}
+		else
+		{
+			/* Only shown in outer side. */
+			left_sel = outer_rel->cqual_selecitiy[outer_idx];
+		}
+
+		/*
+		 * If any side of join relation is impacted by a cqual, it is impacted for the joinrel
+		 * for sure.
+		 */
+		curr_sel_len = list_length(joinrel->cqual_indexes);
+		joinrel->cqual_indexes = lappend_int(joinrel->cqual_indexes, outer_idx);
+
+		joinrel->cqual_selecitiy[curr_sel_len] = left_sel;
+		// elog(INFO, "left_sel %f", left_sel);
+	}
+
+	/* Push any cqual information which exists in inner_rel only to join rel. */
+	foreach(lc1, inner_rel->cqual_indexes)
+	{
+		int inner_cq_index = lfirst_int(lc1);
+		int curr_sel_len;
+
+		if (list_member_int(outer_rel->cqual_indexes, inner_cq_index))
+			/* have been handled in the previous loop */
+			continue;
+
+		curr_sel_len = list_length(joinrel->cqual_indexes);
+		joinrel->cqual_selecitiy[curr_sel_len] = inner_rel->cqual_selecitiy[foreach_current_index(lc1)];
+	}
+
+	pfree(final_cq_list);
+
+	// elog(INFO, "Final adjust sel (%s): %f", bmsToString(joinrel->relids), res);
+
+	return res;
+}
+
+
 /*
  * calc_joinrel_size_estimate
  *		Workhorse for set_joinrel_size_estimates and
@@ -5205,6 +5337,56 @@ calc_joinrel_size_estimate(PlannerInfo *root,
 			break;
 	}
 
+	{
+		Selectivity m1 = 1;
+		bool should_eliminate = false;
+		RestrictInfo *rinfo;
+
+		// XXX: For hack only, the aim is the "only one" restrictinfo is the one impacted by "the only one"
+		// CorrectiveQuals. for example:
+		// SELECT * FROM t1, t2, t3 WHERE t1.a = t2.a and t2.a = t3.a and t3.a > 2;
+
+		if (list_length(root->correlative_quals) == 1 &&
+			list_length(restrictlist) == 1 &&
+			jointype == JOIN_INNER)
+		{
+			int left_relid, right_relid;
+			rinfo = linitial_node(RestrictInfo, restrictlist);
+			if (rinfo->mergeopfamilies != NIL &&
+				bms_get_singleton_member(rinfo->left_relids, &left_relid) &&
+				bms_get_singleton_member(rinfo->right_relids, &right_relid))
+			{
+				List *interset_cq_indexes = list_intersection_int(
+					root->simple_rel_array[left_relid]->cqual_indexes,
+					root->simple_rel_array[right_relid]->cqual_indexes);
+
+				if (interset_cq_indexes != NIL &&
+					!root->simple_rte_array[left_relid]->inh &&
+					!root->simple_rte_array[right_relid]->inh)
+ 					should_eliminate = true;
+			}
+		}
+
+		// elog(INFO, "joinrel: %s, %d", bmsToString(joinrel->relids), should_eliminate);
+
+		if (should_eliminate)
+			m1 = calc_join_cqual_selectivity(root, joinrel, outer_rel, inner_rel, rinfo);
+
+		/* elog(INFO, */
+		/*	 "joinrelids: %s, outer_rel: %s, inner_rel: %s, join_clauselist: %s outer rows: %f, inner_rows: %f, join rows: %f, jselec: %f, m1 = %f, m2 = %f", */
+		/*	 bmsToString(joinrel->relids), */
+		/*	 bmsToString(outer_rel->relids), */
+		/*	 bmsToString(inner_rel->relids), */
+		/*	 bmsToString(join_list_relids), */
+		/*	 outer_rel->rows, */
+		/*	 inner_rel->rows, */
+		/*	 nrows, */
+		/*	 jselec, */
+		/*	 m1, */
+		/*	 m2); */
+		nrows /= m1;
+	}
+
 	return clamp_row_est(nrows);
 }
 
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 6b638d184aa..6cdff399d0a 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1290,6 +1290,8 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
 	ListCell   *lc2;
+	int	start_cq_index = list_length(root->correlative_quals);
+	int	ef_index = 0;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1356,9 +1358,11 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 
 	pfree(prev_ems);
 
+	if (ec->ec_broken)
+		goto ec_filter_done;
 
 	/*
-	 * Also push any EquivalenceFilter clauses down into all relations
+	 * Push any EquivalenceFilter clauses down into all relations
 	 * other than the one which the filter actually originated from.
 	 */
 	foreach(lc2, ec->ec_filters)
@@ -1368,19 +1372,25 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 		Expr *rightexpr;
 		Oid opno;
 		int relid;
-
-		if (ec->ec_broken)
-			break;
+		CorrelativeQuals *cquals = makeNode(CorrelativeQuals);
 
 		foreach(lc, ec->ec_members)
 		{
 			EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
+			RelOptInfo *rel;
+			RestrictInfo *rinfo;
 
 			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
 				continue;
 
+			rel = root->simple_rel_array[relid];
+
 			if (ef->ef_source_rel == relid)
+			{
+				rel->cqual_indexes = lappend_int(rel->cqual_indexes, start_cq_index + ef_index);
+				cquals->corr_restrictinfo = lappend(cquals->corr_restrictinfo, ef->rinfo);
 				continue;
+			}
 
 			if (ef->ef_const_is_left)
 			{
@@ -1401,19 +1411,28 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (opno == InvalidOid)
 				continue;
 
-
-			process_implied_equality(root, opno,
-									 ec->ec_collation,
-									 leftexpr,
-									 rightexpr,
-									 bms_copy(ec->ec_relids),
-									 bms_copy(cur_em->em_nullable_relids),
-									 ec->ec_min_security,
-									 ec->ec_below_outer_join,
-									 false);
+			rinfo = process_implied_equality(root, opno,
+											 ec->ec_collation,
+											 leftexpr,
+											 rightexpr,
+											 bms_copy(ec->ec_relids),
+											 bms_copy(cur_em->em_nullable_relids),
+											 ec->ec_min_security,
+											 ec->ec_below_outer_join,
+											 false);
+			cquals->corr_restrictinfo = lappend(cquals->corr_restrictinfo, rinfo);
+			rel->cqual_indexes = lappend_int(rel->cqual_indexes, start_cq_index + ef_index);
 		}
+
+		ef_index += 1;
+
+		root->correlative_quals = lappend(root->correlative_quals, cquals);
 	}
 
+ec_filter_done:
+	/*
+	 * XXX this label can be removed after moving ec_filter to the end of this function.
+	 */
 	/*
 	 * We also have to make sure that all the Vars used in the member clauses
 	 * will be available at any join node we might try to reference them at.
@@ -2091,6 +2110,7 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 					efilter->ef_source_rel = relid;
 					efilter->opfamily = opfamily;
 					efilter->amstrategy = amstrategy;
+					efilter->rinfo = rinfo;
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index bd09f85aea1..5c9f2833f83 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -619,6 +619,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
 	root->multiexpr_params = NIL;
 	root->eq_classes = NIL;
 	root->ec_merging_done = false;
+	root->correlative_quals = NIL;
 	root->all_result_relids =
 		parse->resultRelation ? bms_make_singleton(parse->resultRelation) : NULL;
 	root->leaf_result_relids = NULL;	/* we'll find out leaf-ness later */
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 282589dec81..51d146e5a71 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -919,6 +919,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	subroot->multiexpr_params = NIL;
 	subroot->eq_classes = NIL;
 	subroot->ec_merging_done = false;
+	subroot->correlative_quals = NIL;
 	subroot->all_result_relids = NULL;
 	subroot->leaf_result_relids = NULL;
 	subroot->append_rel_list = NIL;
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 7349afe1640..3bf83a4e405 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -266,6 +266,7 @@ typedef enum NodeTag
 	T_EquivalenceClass,
 	T_EquivalenceMember,
 	T_EquivalenceFilter,
+	T_CorrelativeQuals,
 	T_PathKey,
 	T_PathTarget,
 	T_RestrictInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index e7b04211839..ca871fbb07a 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -250,6 +250,8 @@ struct PlannerInfo
 
 	bool		ec_merging_done;	/* set true once ECs are canonical */
 
+	List		*correlative_quals;  /* list of CorrelativeQuals for this subquery */
+
 	List	   *canon_pathkeys; /* list of "canonical" PathKeys */
 
 	List	   *left_join_clauses;	/* list of RestrictInfos for mergejoinable
@@ -722,6 +724,18 @@ typedef struct RelOptInfo
 	double		allvisfrac;
 	Bitmapset  *eclass_indexes; /* Indexes in PlannerInfo's eq_classes list of
 								 * ECs that mention this rel */
+	List		*cqual_indexes; /* Indexes in PlannerInfo's correlative_quals list of
+								 * CorrelativeQuals that this rel has applied. It is valid
+								 * on both baserel and joinrel. Used to quick check is the
+								 * both sides contains the same CorrectiveQuals object.
+								 */
+	Selectivity	*cqual_selecitiy; /*
+								   * The number of elements in cqual_selecitity equals
+								   * the length of cqual_indexes. The semantics is which
+								   * selectivity in the corresponding CorectiveQuals's qual
+								   * list is taking effect. At only time, only 1 Qual
+								   * Selectivity is counted for any-level of joinrel.
+								   */
 	PlannerInfo *subroot;		/* if subquery */
 	List	   *subplan_params; /* if subquery */
 	int			rel_parallel_workers;	/* wanted number of parallel workers */
@@ -1039,8 +1053,24 @@ typedef struct EquivalenceFilter
 	Index		ef_source_rel;	/* relid of originating relation. */
 	Oid			opfamily;
 	int			amstrategy;
+	struct RestrictInfo	*rinfo;		/* source restrictInfo for this EquivalenceFilter */
 } EquivalenceFilter;
 
+
+/*
+ * Currently it is as simple as a List of RestrictInfo, it means a). For any joinrel size
+ * estimation, only one restrictinfo on this group should be counted. b). During execution,
+ * at least 1 restrictinfo in this group should be executed.
+ *
+ * Define it as a Node just for better extendability, we can stripe it to a List *
+ * if we are sure nothing else is needed.
+ */
+typedef struct CorrelativeQuals
+{
+	NodeTag	type;
+	List	*corr_restrictinfo;
+} CorrelativeQuals;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
@@ -2620,7 +2650,7 @@ typedef enum
  *
  * flags indicating what kinds of grouping are possible.
  * partial_costs_set is true if the agg_partial_costs and agg_final_costs
- * 		have been initialized.
+ *		have been initialized.
  * agg_partial_costs gives partial aggregation costs.
  * agg_final_costs gives finalization costs.
  * target_parallel_safe is true if target is parallel safe.
@@ -2650,8 +2680,8 @@ typedef struct
  * limit_tuples is an estimated bound on the number of output tuples,
  *		or -1 if no LIMIT or couldn't estimate.
  * count_est and offset_est are the estimated values of the LIMIT and OFFSET
- * 		expressions computed by preprocess_limit() (see comments for
- * 		preprocess_limit() for more information).
+ *		expressions computed by preprocess_limit() (see comments for
+ *		preprocess_limit() for more information).
  */
 typedef struct
 {
-- 
2.21.0

From 57e64920b4a2a75ce85822f917cd3f529e9ce57c Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Mon, 7 Mar 2022 20:17:42 +0800
Subject: [PATCH v4 4/6] Prepare the code for CorrectiveQual structure.

Just refactor the method for 2-level loop in
generate_base_implied_equalities_no_const, no other things is changed.
---
 src/backend/optimizer/path/equivclass.c | 61 +++++++++++++++----------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 915888a8486..6b638d184aa 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1351,17 +1351,33 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+		prev_ems[relid] = cur_em;
+	}
 
-		/*
-		 * Also push any EquivalenceFilter clauses down into all relations
-		 * other than the one which the filter actually originated from.
-		 */
-		foreach(lc2, ec->ec_filters)
+	pfree(prev_ems);
+
+
+	/*
+	 * Also push any EquivalenceFilter clauses down into all relations
+	 * other than the one which the filter actually originated from.
+	 */
+	foreach(lc2, ec->ec_filters)
+	{
+		EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+		Expr *leftexpr;
+		Expr *rightexpr;
+		Oid opno;
+		int relid;
+
+		if (ec->ec_broken)
+			break;
+
+		foreach(lc, ec->ec_members)
 		{
-			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
-			Expr *leftexpr;
-			Expr *rightexpr;
-			Oid opno;
+			EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
+
+			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
+				continue;
 
 			if (ef->ef_source_rel == relid)
 				continue;
@@ -1378,29 +1394,26 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			}
 
 			opno = get_opfamily_member(ef->opfamily,
-										exprType((Node *) leftexpr),
-										exprType((Node *) rightexpr),
-										ef->amstrategy);
+									   exprType((Node *) leftexpr),
+									   exprType((Node *) rightexpr),
+									   ef->amstrategy);
 
 			if (opno == InvalidOid)
 				continue;
 
+
 			process_implied_equality(root, opno,
-										ec->ec_collation,
-										leftexpr,
-										rightexpr,
-										bms_copy(ec->ec_relids),
-										bms_copy(cur_em->em_nullable_relids),
-										ec->ec_min_security,
-										ec->ec_below_outer_join,
-										false);
+									 ec->ec_collation,
+									 leftexpr,
+									 rightexpr,
+									 bms_copy(ec->ec_relids),
+									 bms_copy(cur_em->em_nullable_relids),
+									 ec->ec_min_security,
+									 ec->ec_below_outer_join,
+									 false);
 		}
-
-		prev_ems[relid] = cur_em;
 	}
 
-	pfree(prev_ems);
-
 	/*
 	 * We also have to make sure that all the Vars used in the member clauses
 	 * will be available at any join node we might try to reference them at.
-- 
2.21.0

From 360d2f88ac3736cfa271867bf374939cf6e07681 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Tue, 8 Mar 2022 17:25:04 +0800
Subject: [PATCH v4 5/6] CorrectiveQuals is as simple as a List of
 RestrictInfo, a). only one

restrictinfo on this group should be counted for any joinrel estimation. b). at
least 1 restrictinfo in this group should be executed during execution. In this
commit, only rows estimation issue is addressed.

PlannerInfo.correlative_quals is added to manage all the CorrectiveQuals at
subquery level. RelOptInfo.cqual_indexes is a List * to indicate a which
CorrectiveQuals this relation related to. This is designed for easy to check if
the both sides of joinrel correlated to the same CorrectiveQuals. Why isn't the
type a Bitmapset * will be explained later.

The overall design of handing the joinrel size estimation is:
a). At the base relation level, we just count everything with the correlative
quals. b). During the any level joinrel size estimation, we just keep 1 side's
cqual (short for corrective qual) selectivity by eliminated the other one. so
the size estimation for a mergeable join selectivity becomes to:

rows = R1.rows X r2.rows X 1 / Max (ndistval_of_colA,  ndistinval_of_colB) X 1 /
Selectivity(R1's CorrectiveQual).

r1.rows X 1 / Selectivity(R1's CorrectiveQual) eliminated the impact of
CorrectiveQual on R1. After this,  the JoinRel of (R1, R2) still be impacted by
this CorrectiveQual but just one in this level.  Later if JoinRel(R1, R2) needs
to join with R3,  and R3 is impacted by this CorectiveQuals as well. This we
need to keep one and eliminating the other one as above again.

The algorithm for which Selectivity should be eliminated and which one should be
kept is:

When we join 2 inner_rel and outer_rel with a mergeable join restrictinfo, if
both sides is impacted with the same CorrectiveQual, we first choose which "side"
to eliminating based on which side of the restrictinfo has a higher distinct
value. The reason for this is more or less because we used "Max"(ndistinctValT1,
ndistinctValT2). After decide which "side" to eliminating, the real eliminating
selecitity is the side of RelOptInfo->cqual_selectivity[n]

Selectivity *RelOptInfo->cqual_selectivity:

 The number of elements in cqual_selecitity equals
 the length of cqual_indexes. The semantics is which
 selectivity in the corresponding CorectiveQuals's qual
 list is taking effect. At only time, only 1 Qual
 Selectivity is counted for any-level of joinrel.

and the other side's RelOptInfo->cqual_selectivty is used to set the upper
joinrel->cqual_selecivity.

In reality, it is possible for to have many CorrectiveQuals, but for design
discussion, the current implementation only take care of the 1 CorrectiveQuals.
this would be helpful for PoC/review/discussion.

Some flow for the key data:

1. root->corrective_quals is initialized at
generate_base_implied_equalities_no_const stage. we create a CorrectiveQual in
this list for each ec_filter and fill the RestrictInfo part for this cqual. At
the same time, we note which RelOptInfo (cqual_indexes) has related to this cqual.

2. RelOptInfo->cqual_selecitity for baserel is set at the end of set_rel_size,
at this time, the selectivity for every RestrictInfo is calcuated, we can just
fetch the cached value.  As for joinrel, it is maintained in
calc_join_cqual_selectivity, this function would return the Selectivity to
eliminate and set the above value.

Limitation in this PoC:
1. Only support 1 CorrectiveQual in root->correlative_quals
2. Only tested with INNER_JOIN.
3. Inherited table is not supported.
---
 src/backend/nodes/outfuncs.c              |   1 +
 src/backend/optimizer/path/allpaths.c     |  27 ++++
 src/backend/optimizer/path/costsize.c     | 182 ++++++++++++++++++++++
 src/backend/optimizer/path/equivclass.c   |  48 ++++--
 src/backend/optimizer/plan/planner.c      |   1 +
 src/backend/optimizer/prep/prepjointree.c |   1 +
 src/include/nodes/nodes.h                 |   1 +
 src/include/nodes/pathnodes.h             |  36 ++++-
 8 files changed, 280 insertions(+), 17 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index d29b64eb918..00989fedacb 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2515,6 +2515,7 @@ _outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
 	WRITE_UINT_FIELD(ef_source_rel);
 	WRITE_OID_FIELD(opfamily);
 	WRITE_INT_FIELD(amstrategy);
+	WRITE_NODE_FIELD(rinfo);
 }
 
 static void
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 169b1d53fc8..311a5e3837a 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -461,6 +461,33 @@ set_rel_size(PlannerInfo *root, RelOptInfo *rel,
 	 * We insist that all non-dummy rels have a nonzero rowcount estimate.
 	 */
 	Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
+
+	/* Now calculating the selectivity impacted by Corrective Qual */
+	if (!rte->inh)  /* not supported in this PoC */
+	{
+		ListCell *l;
+		int i = 0;
+		rel->cqual_selecitiy = palloc(sizeof(Selectivity) * list_length(rel->cqual_indexes));
+
+		foreach(l, rel->cqual_indexes)
+		{
+			int cq_index = lfirst_int(l);
+			CorrelativeQuals *cquals = list_nth_node(CorrelativeQuals, root->correlative_quals, cq_index);
+			ListCell *l2;
+			bool found = false;
+			foreach(l2, cquals->corr_restrictinfo)
+			{
+				RestrictInfo *rinfo = lfirst_node(RestrictInfo, l2);
+				if (bms_equal(rinfo->clause_relids, rel->relids))
+				{
+					found = true;
+					rel->cqual_selecitiy[i] = rinfo->norm_selec > 0 ? rinfo->norm_selec : rinfo->outer_selec;
+					Assert(rel->cqual_selecitiy[i] > 0);
+				}
+			}
+			Assert(found);
+		}
+	}
 }
 
 /*
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 4d9f3b4bb6b..fe3bc097fe0 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -5068,6 +5068,138 @@ get_parameterized_joinrel_size(PlannerInfo *root, RelOptInfo *rel,
 	return nrows;
 }
 
+
+/*
+ * Given a mergeable RestrictInfo, find out which relid should be used for
+ * eliminating Corrective Qual Selectivity.
+ */
+static int
+find_relid_to_eliminate(PlannerInfo *root, RestrictInfo *rinfo)
+{
+	int left_relid,  right_relid;
+	RelOptInfo *lrel, *rrel;
+	bool res;
+
+	res = bms_get_singleton_member(rinfo->left_relids, &left_relid);
+	Assert(res);
+	res = bms_get_singleton_member(rinfo->left_relids, &right_relid);
+	Assert(res);
+
+	lrel = root->simple_rel_array[left_relid];
+	rrel = root->simple_rel_array[right_relid];
+
+	/* XXX: Assumed only one CorrectiveQual exists */
+
+	if (lrel->cqual_selecitiy[0] > rrel->cqual_selecitiy[0])
+		return left_relid;
+
+	return right_relid;
+}
+
+/*
+ * calc_join_cqual_selectivity
+ *
+ *	When join two relations, if both sides are impacted by the same CorrectiveQuals,
+ * we need to eliminate one of them and note the other one for future eliminating when join
+ * another corrective relation. or else just note the joinrel still being impacted by the
+ * single sides's CorrectiveQuals.
+ *
+ * Return value is the Selectivity we need to eliminate for estimating the current
+ * joinrel.
+ */
+static double
+calc_join_cqual_selectivity(PlannerInfo *root,
+							RelOptInfo *joinrel,
+							RelOptInfo *outer_rel,
+							RelOptInfo *inner_rel,
+							RestrictInfo *rinfo)
+{
+	double res = 1;
+	ListCell *lc1, *lc2;
+	Selectivity left_sel;  /* The cqual selectivity still impacted on this joinrel. */
+
+	/*
+	 * Find how many CorrectiveQual for this joinrel and allocate space for each left Selectivity
+	 * for each CorrectiveQual here.
+	 */
+	List	*final_cq_list = list_union_int(outer_rel->cqual_indexes, inner_rel->cqual_indexes);
+
+	joinrel->cqual_selecitiy = palloc(sizeof(Selectivity) * list_length(final_cq_list));
+
+	foreach(lc1, outer_rel->cqual_indexes)
+	{
+		int outer_cq_index = lfirst_int(lc1);
+		int inner_cq_pos = -1;
+		int outer_idx = foreach_current_index(lc1);
+		int curr_sel_len;
+
+		/*
+		 * Check if the same corrective quals applied in both sides,
+		 * if yes, we need to decide which one to eliminate and which one
+		 * to keep. or else, we just keep the selectivity for feature use.
+		 */
+		foreach(lc2, inner_rel->cqual_indexes)
+		{
+			if (outer_cq_index == lfirst_int(lc2))
+				inner_cq_pos = foreach_current_index(lc2);
+		}
+
+		if (inner_cq_pos >= 0)
+		{
+			/* Find the CorrectiveQual which impacts both side. */
+			int relid = find_relid_to_eliminate(root, rinfo);
+			if (bms_is_member(relid, outer_rel->relids))
+			{
+				/* XXXX: we assume only 1 CorrectiveQual exist, so [0] directly. */
+				res *= outer_rel->cqual_selecitiy[0];
+				left_sel = inner_rel->cqual_selecitiy[0];
+			}
+			else
+			{
+				/* XXXX: we assume only 1 CorrectiveQual exist */
+				res *= inner_rel->cqual_selecitiy[0];
+				left_sel = outer_rel->cqual_selecitiy[0];
+			}
+		}
+		else
+		{
+			/* Only shown in outer side. */
+			left_sel = outer_rel->cqual_selecitiy[outer_idx];
+		}
+
+		/*
+		 * If any side of join relation is impacted by a cqual, it is impacted for the joinrel
+		 * for sure.
+		 */
+		curr_sel_len = list_length(joinrel->cqual_indexes);
+		joinrel->cqual_indexes = lappend_int(joinrel->cqual_indexes, outer_idx);
+
+		joinrel->cqual_selecitiy[curr_sel_len] = left_sel;
+		// elog(INFO, "left_sel %f", left_sel);
+	}
+
+	/* Push any cqual information which exists in inner_rel only to join rel. */
+	foreach(lc1, inner_rel->cqual_indexes)
+	{
+		int inner_cq_index = lfirst_int(lc1);
+		int curr_sel_len;
+
+		if (list_member_int(outer_rel->cqual_indexes, inner_cq_index))
+			/* have been handled in the previous loop */
+			continue;
+
+		curr_sel_len = list_length(joinrel->cqual_indexes);
+		joinrel->cqual_selecitiy[curr_sel_len] = inner_rel->cqual_selecitiy[foreach_current_index(lc1)];
+	}
+
+	pfree(final_cq_list);
+
+	// elog(INFO, "Final adjust sel (%s): %f", bmsToString(joinrel->relids), res);
+
+	return res;
+}
+
+
 /*
  * calc_joinrel_size_estimate
  *		Workhorse for set_joinrel_size_estimates and
@@ -5211,6 +5343,56 @@ calc_joinrel_size_estimate(PlannerInfo *root,
 			break;
 	}
 
+	{
+		Selectivity m1 = 1;
+		bool should_eliminate = false;
+		RestrictInfo *rinfo;
+
+		// XXX: For hack only, the aim is the "only one" restrictinfo is the one impacted by "the only one"
+		// CorrectiveQuals. for example:
+		// SELECT * FROM t1, t2, t3 WHERE t1.a = t2.a and t2.a = t3.a and t3.a > 2;
+
+		if (list_length(root->correlative_quals) == 1 &&
+			list_length(restrictlist) == 1 &&
+			jointype == JOIN_INNER)
+		{
+			int left_relid, right_relid;
+			rinfo = linitial_node(RestrictInfo, restrictlist);
+			if (rinfo->mergeopfamilies != NIL &&
+				bms_get_singleton_member(rinfo->left_relids, &left_relid) &&
+				bms_get_singleton_member(rinfo->right_relids, &right_relid))
+			{
+				List *interset_cq_indexes = list_intersection_int(
+					root->simple_rel_array[left_relid]->cqual_indexes,
+					root->simple_rel_array[right_relid]->cqual_indexes);
+
+				if (interset_cq_indexes != NIL &&
+					!root->simple_rte_array[left_relid]->inh &&
+					!root->simple_rte_array[right_relid]->inh)
+ 					should_eliminate = true;
+			}
+		}
+
+		// elog(INFO, "joinrel: %s, %d", bmsToString(joinrel->relids), should_eliminate);
+
+		if (should_eliminate)
+			m1 = calc_join_cqual_selectivity(root, joinrel, outer_rel, inner_rel, rinfo);
+
+		/* elog(INFO, */
+		/*	 "joinrelids: %s, outer_rel: %s, inner_rel: %s, join_clauselist: %s outer rows: %f, inner_rows: %f, join rows: %f, jselec: %f, m1 = %f, m2 = %f", */
+		/*	 bmsToString(joinrel->relids), */
+		/*	 bmsToString(outer_rel->relids), */
+		/*	 bmsToString(inner_rel->relids), */
+		/*	 bmsToString(join_list_relids), */
+		/*	 outer_rel->rows, */
+		/*	 inner_rel->rows, */
+		/*	 nrows, */
+		/*	 jselec, */
+		/*	 m1, */
+		/*	 m2); */
+		nrows /= m1;
+	}
+
 	return clamp_row_est(nrows);
 }
 
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 6b638d184aa..6cdff399d0a 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1290,6 +1290,8 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
 	ListCell   *lc2;
+	int	start_cq_index = list_length(root->correlative_quals);
+	int	ef_index = 0;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1356,9 +1358,11 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 
 	pfree(prev_ems);
 
+	if (ec->ec_broken)
+		goto ec_filter_done;
 
 	/*
-	 * Also push any EquivalenceFilter clauses down into all relations
+	 * Push any EquivalenceFilter clauses down into all relations
 	 * other than the one which the filter actually originated from.
 	 */
 	foreach(lc2, ec->ec_filters)
@@ -1368,19 +1372,25 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 		Expr *rightexpr;
 		Oid opno;
 		int relid;
-
-		if (ec->ec_broken)
-			break;
+		CorrelativeQuals *cquals = makeNode(CorrelativeQuals);
 
 		foreach(lc, ec->ec_members)
 		{
 			EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
+			RelOptInfo *rel;
+			RestrictInfo *rinfo;
 
 			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
 				continue;
 
+			rel = root->simple_rel_array[relid];
+
 			if (ef->ef_source_rel == relid)
+			{
+				rel->cqual_indexes = lappend_int(rel->cqual_indexes, start_cq_index + ef_index);
+				cquals->corr_restrictinfo = lappend(cquals->corr_restrictinfo, ef->rinfo);
 				continue;
+			}
 
 			if (ef->ef_const_is_left)
 			{
@@ -1401,19 +1411,28 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (opno == InvalidOid)
 				continue;
 
-
-			process_implied_equality(root, opno,
-									 ec->ec_collation,
-									 leftexpr,
-									 rightexpr,
-									 bms_copy(ec->ec_relids),
-									 bms_copy(cur_em->em_nullable_relids),
-									 ec->ec_min_security,
-									 ec->ec_below_outer_join,
-									 false);
+			rinfo = process_implied_equality(root, opno,
+											 ec->ec_collation,
+											 leftexpr,
+											 rightexpr,
+											 bms_copy(ec->ec_relids),
+											 bms_copy(cur_em->em_nullable_relids),
+											 ec->ec_min_security,
+											 ec->ec_below_outer_join,
+											 false);
+			cquals->corr_restrictinfo = lappend(cquals->corr_restrictinfo, rinfo);
+			rel->cqual_indexes = lappend_int(rel->cqual_indexes, start_cq_index + ef_index);
 		}
+
+		ef_index += 1;
+
+		root->correlative_quals = lappend(root->correlative_quals, cquals);
 	}
 
+ec_filter_done:
+	/*
+	 * XXX this label can be removed after moving ec_filter to the end of this function.
+	 */
 	/*
 	 * We also have to make sure that all the Vars used in the member clauses
 	 * will be available at any join node we might try to reference them at.
@@ -2091,6 +2110,7 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 					efilter->ef_source_rel = relid;
 					efilter->opfamily = opfamily;
 					efilter->amstrategy = amstrategy;
+					efilter->rinfo = rinfo;
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index bd09f85aea1..5c9f2833f83 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -619,6 +619,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
 	root->multiexpr_params = NIL;
 	root->eq_classes = NIL;
 	root->ec_merging_done = false;
+	root->correlative_quals = NIL;
 	root->all_result_relids =
 		parse->resultRelation ? bms_make_singleton(parse->resultRelation) : NULL;
 	root->leaf_result_relids = NULL;	/* we'll find out leaf-ness later */
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 74823e8437a..6d3aceaadfe 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -919,6 +919,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	subroot->multiexpr_params = NIL;
 	subroot->eq_classes = NIL;
 	subroot->ec_merging_done = false;
+	subroot->correlative_quals = NIL;
 	subroot->all_result_relids = NULL;
 	subroot->leaf_result_relids = NULL;
 	subroot->append_rel_list = NIL;
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 7349afe1640..3bf83a4e405 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -266,6 +266,7 @@ typedef enum NodeTag
 	T_EquivalenceClass,
 	T_EquivalenceMember,
 	T_EquivalenceFilter,
+	T_CorrelativeQuals,
 	T_PathKey,
 	T_PathTarget,
 	T_RestrictInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index e7b04211839..ca871fbb07a 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -250,6 +250,8 @@ struct PlannerInfo
 
 	bool		ec_merging_done;	/* set true once ECs are canonical */
 
+	List		*correlative_quals;  /* list of CorrelativeQuals for this subquery */
+
 	List	   *canon_pathkeys; /* list of "canonical" PathKeys */
 
 	List	   *left_join_clauses;	/* list of RestrictInfos for mergejoinable
@@ -722,6 +724,18 @@ typedef struct RelOptInfo
 	double		allvisfrac;
 	Bitmapset  *eclass_indexes; /* Indexes in PlannerInfo's eq_classes list of
 								 * ECs that mention this rel */
+	List		*cqual_indexes; /* Indexes in PlannerInfo's correlative_quals list of
+								 * CorrelativeQuals that this rel has applied. It is valid
+								 * on both baserel and joinrel. Used to quick check is the
+								 * both sides contains the same CorrectiveQuals object.
+								 */
+	Selectivity	*cqual_selecitiy; /*
+								   * The number of elements in cqual_selecitity equals
+								   * the length of cqual_indexes. The semantics is which
+								   * selectivity in the corresponding CorectiveQuals's qual
+								   * list is taking effect. At only time, only 1 Qual
+								   * Selectivity is counted for any-level of joinrel.
+								   */
 	PlannerInfo *subroot;		/* if subquery */
 	List	   *subplan_params; /* if subquery */
 	int			rel_parallel_workers;	/* wanted number of parallel workers */
@@ -1039,8 +1053,24 @@ typedef struct EquivalenceFilter
 	Index		ef_source_rel;	/* relid of originating relation. */
 	Oid			opfamily;
 	int			amstrategy;
+	struct RestrictInfo	*rinfo;		/* source restrictInfo for this EquivalenceFilter */
 } EquivalenceFilter;
 
+
+/*
+ * Currently it is as simple as a List of RestrictInfo, it means a). For any joinrel size
+ * estimation, only one restrictinfo on this group should be counted. b). During execution,
+ * at least 1 restrictinfo in this group should be executed.
+ *
+ * Define it as a Node just for better extendability, we can stripe it to a List *
+ * if we are sure nothing else is needed.
+ */
+typedef struct CorrelativeQuals
+{
+	NodeTag	type;
+	List	*corr_restrictinfo;
+} CorrelativeQuals;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
@@ -2620,7 +2650,7 @@ typedef enum
  *
  * flags indicating what kinds of grouping are possible.
  * partial_costs_set is true if the agg_partial_costs and agg_final_costs
- * 		have been initialized.
+ *		have been initialized.
  * agg_partial_costs gives partial aggregation costs.
  * agg_final_costs gives finalization costs.
  * target_parallel_safe is true if target is parallel safe.
@@ -2650,8 +2680,8 @@ typedef struct
  * limit_tuples is an estimated bound on the number of output tuples,
  *		or -1 if no LIMIT or couldn't estimate.
  * count_est and offset_est are the estimated values of the LIMIT and OFFSET
- * 		expressions computed by preprocess_limit() (see comments for
- * 		preprocess_limit() for more information).
+ *		expressions computed by preprocess_limit() (see comments for
+ *		preprocess_limit() for more information).
  */
 typedef struct
 {
-- 
2.21.0

From 42260ffcfac54f11abbdb57522a4feaa523d0f51 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Sun, 6 Mar 2022 14:20:55 +0800
Subject: [PATCH v4 3/6] Reduce some planning cost for deriving qual for EC
 filter feature.

Mainly changes includes:
1. Check if the qual is simple enough by checking rinfo->right_relids and
info->right_relids, save the pull_varnos of rinfo->clause calls.
2. check contain_volatile_functions against RestrictInfo, so that
the result can be shared with following calls.
3. By employing the RestictInfo->btreeineqfamility which is calculating.
with same round of calculating  RestrictInfo->mergeopfamilies. In this
way we save the some calls for syscache.
4. Calculating the opfamility and amstrategy at
distribute_filter_quals_to_eclass and cache the results in EquivalenceFilter.
if no suitable opfamility and amstrategy are found, bypass the qual immediately
and at last using the cached value generate_base_implied_equalities_no_const.

After this change, there is an testcase changed unexpectedly in equivclass.out
(compared with David's expectation file.)

create user regress_user_ectest;
grant select on ec0 to regress_user_ectest;
grant select on ec1 to regress_user_ectest;

set session authorization regress_user_ectest;

-- with RLS active, the non-leakproof a.ff = 43 clause is not treated
-- as a suitable source for an EquivalenceClass; currently, this is true
-- even though the RLS clause has nothing to do directly with the EC
explain (costs off)
regression->   select * from ec0 a, ec1 b
regression->   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;

The b.ff = 43 is disappeared from ec1 b. But since it even didn't shown
before the EC filter, so I'm not sure my changes here make something wrong,
maybe fix a issue by accidental?
---
 src/backend/nodes/outfuncs.c             |  2 +
 src/backend/optimizer/path/equivclass.c  | 59 +++++++++++++-----------
 src/backend/optimizer/plan/initsplan.c   | 50 ++++----------------
 src/include/nodes/pathnodes.h            |  2 +
 src/test/regress/expected/equivclass.out |  6 +--
 5 files changed, 48 insertions(+), 71 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 4c384511c39..d29b64eb918 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2513,6 +2513,8 @@ _outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
 	WRITE_OID_FIELD(ef_opno);
 	WRITE_BOOL_FIELD(ef_const_is_left);
 	WRITE_UINT_FIELD(ef_source_rel);
+	WRITE_OID_FIELD(opfamily);
+	WRITE_INT_FIELD(amstrategy);
 }
 
 static void
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index f9ae2785d60..915888a8486 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1252,19 +1252,17 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 }
 
 /*
- * finds the opfamily and strategy number for the specified 'opno' and 'method'
- * access method. Returns True if one is found and sets 'family' and
- * 'amstrategy', or returns False if none are found.
+ * finds the operator id for the specified 'opno' and 'method' and 'opfamilies'
+ * Returns True if one is found and sets 'opfamily_p' and 'amstrategy_p' or returns
+ * False if none are found.
  */
 static bool
-find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+find_am_family_and_stategy(Oid opno, Oid method, List *opfamilies,
+						   Oid *opfamily_p, int *amstrategy_p)
 {
-	List *opfamilies;
 	ListCell *l;
 	int strategy;
 
-	opfamilies = get_opfamilies(opno, method);
-
 	foreach(l, opfamilies)
 	{
 		Oid opfamily = lfirst_oid(l);
@@ -1273,8 +1271,8 @@ find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
 
 		if (strategy)
 		{
-			*amstrategy = strategy;
-			*family = opfamily;
+			*opfamily_p = opfamily;
+			*amstrategy_p = strategy;
 			return true;
 		}
 	}
@@ -1363,17 +1361,11 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
 			Expr *leftexpr;
 			Expr *rightexpr;
-			int strategy;
 			Oid opno;
-			Oid family;
 
 			if (ef->ef_source_rel == relid)
 				continue;
 
-			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
-				&family, &strategy))
-				continue;
-
 			if (ef->ef_const_is_left)
 			{
 				leftexpr = (Expr *) ef->ef_const;
@@ -1385,10 +1377,10 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rightexpr = (Expr *) ef->ef_const;
 			}
 
-			opno = get_opfamily_member(family,
+			opno = get_opfamily_member(ef->opfamily,
 										exprType((Node *) leftexpr),
 										exprType((Node *) rightexpr),
-										strategy);
+										ef->amstrategy);
 
 			if (opno == InvalidOid)
 				continue;
@@ -1399,7 +1391,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 										rightexpr,
 										bms_copy(ec->ec_relids),
 										bms_copy(cur_em->em_nullable_relids),
-									 	ec->ec_min_security,
+										ec->ec_min_security,
 										ec->ec_below_outer_join,
 										false);
 		}
@@ -2007,9 +1999,12 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 	 */
 	foreach(l, quallist)
 	{
-		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
-		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
-		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
+		OpExpr *opexpr = (OpExpr *)(rinfo->clause);
+
+		Oid opfamily;
+		int amstrategy;
+
 		Const	   *constexpr;
 		Expr	   *varexpr;
 		Relids		exprrels;
@@ -2021,25 +2016,31 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 		 * Determine if the the OpExpr is in the form "expr op const" or
 		 * "const op expr".
 		 */
-		if (IsA(leftexpr, Const))
+		if (bms_is_empty(rinfo->left_relids))
 		{
-			constexpr = (Const *) leftexpr;
-			varexpr = rightexpr;
+			constexpr = (Const *) get_leftop(rinfo->clause);
+			varexpr = (Expr *) get_rightop(rinfo->clause);
 			const_isleft = true;
+			exprrels = rinfo->right_relids;
 		}
 		else
 		{
-			constexpr = (Const *) rightexpr;
-			varexpr = leftexpr;
+			constexpr = (Const *) get_rightop(rinfo->clause);
+			varexpr = (Expr *) get_leftop(rinfo->clause);
 			const_isleft = false;
+			exprrels = rinfo->left_relids;
 		}
 
-		exprrels = pull_varnos(root, (Node *) varexpr);
-
 		/* should be filtered out, but we need to determine relid anyway */
 		if (!bms_get_singleton_member(exprrels, &relid))
 			continue;
 
+		if (!find_am_family_and_stategy(opexpr->opno, BTREE_AM_OID,
+										rinfo->btreeineqopfamilies,
+										&opfamily,
+										&amstrategy))
+			continue;
+
 		/* search for a matching eclass member in all eclasses */
 		foreach(l2, root->eq_classes)
 		{
@@ -2075,6 +2076,8 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 					efilter->ef_const_is_left = const_isleft;
 					efilter->ef_opno = opexpr->opno;
 					efilter->ef_source_rel = relid;
+					efilter->opfamily = opfamily;
+					efilter->amstrategy = amstrategy;
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 7e355c94362..5a32c3987a0 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -651,44 +651,6 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
-/*
- * is_simple_filter_qual
- *             Analyzes an OpExpr to determine if it may be useful as an
- *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
- *             false if it should not be used.
- */
-static bool
-is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
-{
-	Expr *leftexpr;
-	Expr *rightexpr;
-
-	if (!IsA(expr, OpExpr))
-			return false;
-
-	if (list_length(expr->args) != 2)
-			return false;
-
-	leftexpr = (Expr *) linitial(expr->args);
-	rightexpr = (Expr *) lsecond(expr->args);
-
-	/* XXX should we restrict these to simple Var op Const expressions? */
-	if (IsA(leftexpr, Const))
-	{
-		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) rightexpr))
-			return true;
-	}
-	else if (IsA(rightexpr, Const))
-	{
-		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) leftexpr))
-			return true;
-	}
-
-	return false;
-}
-
 /*****************************************************************************
  *
  *	  JOIN TREE PROCESSING
@@ -1678,6 +1640,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	bool		maybe_outer_join;
 	Relids		nullable_relids;
 	RestrictInfo *restrictinfo;
+	int	relid;
 
 	/*
 	 * Retrieve all relids mentioned within the clause.
@@ -2027,8 +1990,15 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	distribute_restrictinfo_to_rels(root, restrictinfo);
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
-	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
-		*filter_qual_list = lappend(*filter_qual_list, clause);
+	if (filter_qual_list != NULL &&
+		is_opclause(restrictinfo->clause) &&
+		!contain_volatile_functions((Node *)restrictinfo) && // Cachable
+		restrictinfo->btreeineqopfamilies != NIL &&  /* ineq expression */
+		/* simple & common enough filter, one side references one relation and the other one is a constant */
+		((bms_is_empty(restrictinfo->left_relids) && bms_get_singleton_member(restrictinfo->right_relids, &relid)) ||
+		 (bms_is_empty(restrictinfo->right_relids) && bms_get_singleton_member(restrictinfo->left_relids, &relid)))
+		)
+		*filter_qual_list = lappend(*filter_qual_list, restrictinfo);
 }
 
 /*
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index dcae69635ce..e7b04211839 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1037,6 +1037,8 @@ typedef struct EquivalenceFilter
 	Oid			ef_opno;		/* Operator Oid of filter operator */
 	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
 	Index		ef_source_rel;	/* relid of originating relation. */
+	Oid			opfamily;
+	int			amstrategy;
 } EquivalenceFilter;
 
 /*
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 92fcec1158b..980bd3817d3 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                              QUERY PLAN                              
-----------------------------------------------------------------------
+                 QUERY PLAN                  
+---------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
+         Filter: (f1 < '5'::int8alias1)
 (6 rows)
 
 reset session authorization;
-- 
2.21.0

From fbe7ad0a8111245d676b2104e4982665044a3982 Mon Sep 17 00:00:00 2001
From: David Rowley <dgrowleyml@gmail.com>
Date: Tue, 1 Feb 2022 20:56:40 +0800
Subject: [PATCH v4 2/6] Introudce ec_filters in EquivalenceClass struct, the
 semantics is the quals can

be applied to any EquivalenceMember in this EC. Later this information is used
to generate new RestrictInfo and was distributed to related RelOptInfo very
soon.  There are 3 major steps here:

a). In distribute_qual_to_rels to gather the ineq quallist.
b). After deconstruct_jointree, distribute_filter_quals_to_eclass distribute
these ineq-quallist to the related EC's ef_filters.
c). generate_base_implied_equalities_no_const scan the ec_filters and distriubte
the restrictinfo to related RelOptInfo.

Author: David Rowley at 2015-12 [1]
Andy Fan rebases this patch to current latest code.

https://www.postgresql.org/message-id/CAKJS1f9FK_X_5HKcPcSeimy16Owe3EmPmmGsGWLcKkj_rW9s6A%40mail.gmail.com
---
 .../postgres_fdw/expected/postgres_fdw.out    |  36 ++--
 src/backend/nodes/outfuncs.c                  |  14 ++
 src/backend/optimizer/path/equivclass.c       | 182 ++++++++++++++++++
 src/backend/optimizer/plan/initsplan.c        |  96 +++++++--
 src/backend/utils/cache/lsyscache.c           |  28 +++
 src/include/nodes/nodes.h                     |   1 +
 src/include/nodes/pathnodes.h                 |  37 ++++
 src/include/optimizer/paths.h                 |   1 +
 src/include/utils/lsyscache.h                 |   1 +
 src/test/regress/expected/equivclass.out      |  45 ++++-
 src/test/regress/expected/join.out            |  22 +--
 src/test/regress/expected/partition_join.out  |  52 +++--
 src/test/regress/sql/equivclass.sql           |  12 ++
 13 files changed, 457 insertions(+), 70 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f210f911880..ce102abe5d5 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1545,12 +1545,12 @@ SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNE
 -- full outer join + inner join
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
-                                                                                                                                                 QUERY PLAN                                                                                                                                                 
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: t1.c1, t2.c1, t3.c1
    Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
-   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND (((r2.c1 + 1) >= 50)) AND (((r2.c1 + 1) <= 60)) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
 (4 rows)
 
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
@@ -2335,12 +2335,12 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                QUERY PLAN                                                                                                                                 
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                    QUERY PLAN                                                                                                                                                     
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
    Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
 (4 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
@@ -2362,8 +2362,8 @@ SET enable_hashjoin TO false;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
     AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
-                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                      QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  LockRows
    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
    ->  Merge Join
@@ -2373,7 +2373,7 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
          ->  Foreign Scan
                Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
-               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
                ->  Merge Join
                      Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                      Merge Cond: (ft1.c2 = ft5.c1)
@@ -2391,12 +2391,12 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
                                              Sort Key: ft1.c1
                                              ->  Foreign Scan on public.ft1
                                                    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) FOR UPDATE
                                        ->  Materialize
                                              Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
                                              ->  Foreign Scan on public.ft2
                                                    Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
                            ->  Sort
                                  Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
                                  Sort Key: ft4.c1
@@ -5685,25 +5685,25 @@ UPDATE ft2 AS target SET (c2) = (
 EXPLAIN (VERBOSE, COSTS OFF)
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
   FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
-                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Update on public.ft2 d
    Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
    ->  Foreign Scan
          Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
          Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
-         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
-         ->  Hash Join
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" > 1000)) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Merge Join
                Output: d.c2, d.ctid, d.*, t.*
-               Hash Cond: (d.c1 = t.c1)
+               Merge Cond: (d.c1 = t.c1)
                ->  Foreign Scan on public.ft2 d
                      Output: d.c2, d.ctid, d.*, d.c1
                      Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
-               ->  Hash
+               ->  Materialize
                      Output: t.*, t.c1
                      ->  Foreign Scan on public.ft2 t
                            Output: t.*, t.c1
-                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST
 (17 rows)
 
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 6bdad462c78..4c384511c39 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2504,6 +2504,17 @@ _outEquivalenceMember(StringInfo str, const EquivalenceMember *node)
 	WRITE_OID_FIELD(em_datatype);
 }
 
+static void
+_outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
+{
+	WRITE_NODE_TYPE("EQUIVALENCEFILTER");
+
+	WRITE_NODE_FIELD(ef_const);
+	WRITE_OID_FIELD(ef_opno);
+	WRITE_BOOL_FIELD(ef_const_is_left);
+	WRITE_UINT_FIELD(ef_source_rel);
+}
+
 static void
 _outPathKey(StringInfo str, const PathKey *node)
 {
@@ -4306,6 +4317,9 @@ outNode(StringInfo str, const void *obj)
 			case T_EquivalenceMember:
 				_outEquivalenceMember(str, obj);
 				break;
+			case T_EquivalenceFilter:
+				_outEquivalenceFilter(str, obj);
+				break;
 			case T_PathKey:
 				_outPathKey(str, obj);
 				break;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 8c6770de972..f9ae2785d60 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -19,6 +19,7 @@
 #include <limits.h>
 
 #include "access/stratnum.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
@@ -1250,6 +1251,37 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 	}
 }
 
+/*
+ * finds the opfamily and strategy number for the specified 'opno' and 'method'
+ * access method. Returns True if one is found and sets 'family' and
+ * 'amstrategy', or returns False if none are found.
+ */
+static bool
+find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+{
+	List *opfamilies;
+	ListCell *l;
+	int strategy;
+
+	opfamilies = get_opfamilies(opno, method);
+
+	foreach(l, opfamilies)
+	{
+		Oid opfamily = lfirst_oid(l);
+
+		strategy = get_op_opfamily_strategy(opno, opfamily);
+
+		if (strategy)
+		{
+			*amstrategy = strategy;
+			*family = opfamily;
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /*
  * generate_base_implied_equalities when EC contains no pseudoconstants
  */
@@ -1259,6 +1291,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 {
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
+	ListCell   *lc2;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1320,6 +1353,57 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+
+		/*
+		 * Also push any EquivalenceFilter clauses down into all relations
+		 * other than the one which the filter actually originated from.
+		 */
+		foreach(lc2, ec->ec_filters)
+		{
+			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+			Expr *leftexpr;
+			Expr *rightexpr;
+			int strategy;
+			Oid opno;
+			Oid family;
+
+			if (ef->ef_source_rel == relid)
+				continue;
+
+			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
+				&family, &strategy))
+				continue;
+
+			if (ef->ef_const_is_left)
+			{
+				leftexpr = (Expr *) ef->ef_const;
+				rightexpr = cur_em->em_expr;
+			}
+			else
+			{
+				leftexpr = cur_em->em_expr;
+				rightexpr = (Expr *) ef->ef_const;
+			}
+
+			opno = get_opfamily_member(family,
+										exprType((Node *) leftexpr),
+										exprType((Node *) rightexpr),
+										strategy);
+
+			if (opno == InvalidOid)
+				continue;
+
+			process_implied_equality(root, opno,
+										ec->ec_collation,
+										leftexpr,
+										rightexpr,
+										bms_copy(ec->ec_relids),
+										bms_copy(cur_em->em_nullable_relids),
+									 	ec->ec_min_security,
+										ec->ec_below_outer_join,
+										false);
+		}
+
 		prev_ems[relid] = cur_em;
 	}
 
@@ -1901,6 +1985,104 @@ create_join_clause(PlannerInfo *root,
 	return rinfo;
 }
 
+/*
+ * distribute_filter_quals_to_eclass
+ *		For each OpExpr in quallist look for an eclass which has an Expr
+ *		matching the Expr in the OpExpr. If a match is found we add a new
+ *		EquivalenceFilter to the eclass containing the filter details.
+ */
+void
+distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
+{
+	ListCell *l;
+
+	/* fast path for when no eclasses have been generated */
+	if (root->eq_classes == NIL)
+		return;
+
+	/*
+	 * For each qual in quallist try and find an eclass which contains the
+	 * non-Const part of the OpExpr. We'll tag any matches that we find onto
+	 * the correct eclass.
+	 */
+	foreach(l, quallist)
+	{
+		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
+		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		Const	   *constexpr;
+		Expr	   *varexpr;
+		Relids		exprrels;
+		int			relid;
+		bool		const_isleft;
+		ListCell *l2;
+
+		/*
+		 * Determine if the the OpExpr is in the form "expr op const" or
+		 * "const op expr".
+		 */
+		if (IsA(leftexpr, Const))
+		{
+			constexpr = (Const *) leftexpr;
+			varexpr = rightexpr;
+			const_isleft = true;
+		}
+		else
+		{
+			constexpr = (Const *) rightexpr;
+			varexpr = leftexpr;
+			const_isleft = false;
+		}
+
+		exprrels = pull_varnos(root, (Node *) varexpr);
+
+		/* should be filtered out, but we need to determine relid anyway */
+		if (!bms_get_singleton_member(exprrels, &relid))
+			continue;
+
+		/* search for a matching eclass member in all eclasses */
+		foreach(l2, root->eq_classes)
+		{
+			EquivalenceClass *ec = (EquivalenceClass *) lfirst(l2);
+			ListCell *l3;
+
+			if (ec->ec_broken || ec->ec_has_volatile)
+				continue;
+
+			/*
+			 * if the eclass has a const then that const will serve as the
+			 * filter, we needn't add any others.
+			 */
+			if (ec->ec_has_const)
+				continue;
+
+			/* skip this eclass no members exist which belong to this relid */
+			if (!bms_is_member(relid, ec->ec_relids))
+				continue;
+
+			foreach(l3, ec->ec_members)
+			{
+				EquivalenceMember *em = (EquivalenceMember *) lfirst(l3);
+
+				if (!bms_is_member(relid, em->em_relids))
+					continue;
+
+				if (equal(em->em_expr, varexpr))
+				{
+					EquivalenceFilter *efilter;
+					efilter = makeNode(EquivalenceFilter);
+					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const_is_left = const_isleft;
+					efilter->ef_opno = opexpr->opno;
+					efilter->ef_source_rel = relid;
+
+					ec->ec_filters = lappend(ec->ec_filters, efilter);
+					break;		/* Onto the next eclass */
+				}
+			}
+		}
+	}
+}
 
 /*
  * reconsider_outer_join_clauses
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index d61419f61a5..7e355c94362 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -53,7 +53,7 @@ static void extract_lateral_references(PlannerInfo *root, RelOptInfo *brel,
 static List *deconstruct_recurse(PlannerInfo *root, Node *jtnode,
 								 bool below_outer_join,
 								 Relids *qualscope, Relids *inner_join_rels,
-								 List **postponed_qual_list);
+								 List **postponed_qual_list, List **filter_qual_list);
 static void process_security_barrier_quals(PlannerInfo *root,
 										   int rti, Relids qualscope,
 										   bool below_outer_join);
@@ -70,7 +70,8 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 									Relids qualscope,
 									Relids ojscope,
 									Relids outerjoin_nonnullable,
-									List **postponed_qual_list);
+									List **postponed_qual_list,
+									List **filter_qual_list);
 static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 								  Relids *nullable_relids_p, bool is_pushed_down);
 static bool check_equivalence_delay(PlannerInfo *root,
@@ -650,6 +651,43 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
+/*
+ * is_simple_filter_qual
+ *             Analyzes an OpExpr to determine if it may be useful as an
+ *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
+ *             false if it should not be used.
+ */
+static bool
+is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+{
+	Expr *leftexpr;
+	Expr *rightexpr;
+
+	if (!IsA(expr, OpExpr))
+			return false;
+
+	if (list_length(expr->args) != 2)
+			return false;
+
+	leftexpr = (Expr *) linitial(expr->args);
+	rightexpr = (Expr *) lsecond(expr->args);
+
+	/* XXX should we restrict these to simple Var op Const expressions? */
+	if (IsA(leftexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) rightexpr))
+			return true;
+	}
+	else if (IsA(rightexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) leftexpr))
+			return true;
+	}
+
+	return false;
+}
 
 /*****************************************************************************
  *
@@ -690,6 +728,7 @@ deconstruct_jointree(PlannerInfo *root)
 	Relids		qualscope;
 	Relids		inner_join_rels;
 	List	   *postponed_qual_list = NIL;
+	List	   *filter_qual_list = NIL;
 
 	/* Start recursion at top of jointree */
 	Assert(root->parse->jointree != NULL &&
@@ -700,11 +739,14 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list);
+								 &postponed_qual_list, &filter_qual_list);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
 
+	/* try and match each filter_qual_list item up with an eclass. */
+	distribute_filter_quals_to_eclass(root, filter_qual_list);
+
 	return result;
 }
 
@@ -725,6 +767,8 @@ deconstruct_jointree(PlannerInfo *root)
  *		or free this, either)
  *	*postponed_qual_list is a list of PostponedQual structs, which we can
  *		add quals to if they turn out to belong to a higher join level
+ *	*filter_qual_list is appended to with a list of quals which may be useful
+ *		include as EquivalenceFilters.
  *	Return value is the appropriate joinlist for this jointree node
  *
  * In addition, entries will be added to root->join_info_list for outer joins.
@@ -732,7 +776,7 @@ deconstruct_jointree(PlannerInfo *root)
 static List *
 deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 					Relids *qualscope, Relids *inner_join_rels,
-					List **postponed_qual_list)
+					List **postponed_qual_list, List **filter_qual_list)
 {
 	List	   *joinlist;
 
@@ -785,7 +829,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 											   below_outer_join,
 											   &sub_qualscope,
 											   inner_join_rels,
-											   &child_postponed_quals);
+											   &child_postponed_quals,
+											   filter_qual_list);
 			*qualscope = bms_add_members(*qualscope, sub_qualscope);
 			sub_members = list_length(sub_joinlist);
 			remaining--;
@@ -819,7 +864,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 										below_outer_join, JOIN_INNER,
 										root->qual_security_level,
 										*qualscope, NULL, NULL,
-										NULL);
+										NULL,
+										filter_qual_list);
 			else
 				*postponed_qual_list = lappend(*postponed_qual_list, pq);
 		}
@@ -835,7 +881,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									below_outer_join, JOIN_INNER,
 									root->qual_security_level,
 									*qualscope, NULL, NULL,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 	}
 	else if (IsA(jtnode, JoinExpr))
@@ -873,11 +920,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = *qualscope;
 				/* Inner join adds no restrictions for quals */
@@ -890,11 +939,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				nonnullable_rels = leftids;
@@ -904,11 +955,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* Semi join adds no restrictions for quals */
@@ -925,11 +978,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   true,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* each side is both outer and inner */
@@ -1013,7 +1068,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									root->qual_security_level,
 									*qualscope,
 									ojscope, nonnullable_rels,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 
 		/* Now we can add the SpecialJoinInfo to join_info_list */
@@ -1117,6 +1173,7 @@ process_security_barrier_quals(PlannerInfo *root,
 									qualscope,
 									qualscope,
 									NULL,
+									NULL,
 									NULL);
 		}
 		security_level++;
@@ -1610,7 +1667,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 						Relids qualscope,
 						Relids ojscope,
 						Relids outerjoin_nonnullable,
-						List **postponed_qual_list)
+						List **postponed_qual_list,
+						List **filter_qual_list)
 {
 	Relids		relids;
 	bool		is_pushed_down;
@@ -1967,6 +2025,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* No EC special case applies, so push it into the clause lists */
 	distribute_restrictinfo_to_rels(root, restrictinfo);
+
+	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
 /*
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 91cd813ce8f..b0243925e43 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -341,6 +341,34 @@ get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
 	return result;
 }
 
+/*
+ * get_opfamilies
+ *		Returns a list of Oids of each opfamily which 'opno' belonging to
+ *		'method' access method.
+ */
+List *
+get_opfamilies(Oid opno, Oid method)
+{
+	List	   *result = NIL;
+	CatCList   *catlist;
+	int			i;
+
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == method)
+			result = lappend_oid(result, aform->amopfamily);
+	}
+
+	ReleaseSysCacheList(catlist);
+
+	return result;
+}
+
 /*
  * get_mergejoin_opfamilies
  *		Given a putatively mergejoinable operator, return a list of the OIDs
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 5d075f0c346..7349afe1640 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -265,6 +265,7 @@ typedef enum NodeTag
 	/* these aren't subclasses of Path: */
 	T_EquivalenceClass,
 	T_EquivalenceMember,
+	T_EquivalenceFilter,
 	T_PathKey,
 	T_PathTarget,
 	T_RestrictInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 3b95e4a8eae..dcae69635ce 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -990,6 +990,7 @@ typedef struct EquivalenceClass
 	List	   *ec_members;		/* list of EquivalenceMembers */
 	List	   *ec_sources;		/* list of generating RestrictInfos */
 	List	   *ec_derives;		/* list of derived RestrictInfos */
+	List	   *ec_filters;
 	Relids		ec_relids;		/* all relids appearing in ec_members, except
 								 * for child members (see below) */
 	bool		ec_has_const;	/* any pseudoconstants in ec_members? */
@@ -1002,6 +1003,42 @@ typedef struct EquivalenceClass
 	struct EquivalenceClass *ec_merged; /* set if merged into another EC */
 } EquivalenceClass;
 
+/*
+ * EquivalenceFilter - List of filters on Consts which belong to the
+ * EquivalenceClass.
+ *
+ * When building the equivalence classes we also collected a list of quals in
+ * the form of; "Expr op Const" and "Const op Expr". These are collected in the
+ * hope that we'll later generate an equivalence class which contains the
+ * "Expr" part. For example, if we parse a query such as;
+ *
+ *		SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id WHERE t1.id < 10;
+ *
+ * then since we'll end up with an equivalence class containing {t1.id,t2.id},
+ * we'll tag the "< 10" filter onto the eclass. We are able to do this because
+ * the eclass proves equality between each class member, therefore all members
+ * must be below 10.
+ *
+ * EquivalenceFilters store the details required to allow us to push these
+ * filter clauses down into other relations which share an equivalence class
+ * containing a member which matches the expression of this EquivalenceFilter.
+ *
+ * ef_const is the Const value which this filter should filter against.
+ * ef_opno is the operator to filter on.
+ * ef_const_is_left marks if the OpExpr was in the form "Const op Expr" or
+ * "Expr op Const".
+ * ef_source_rel is the relation id of where this qual originated from.
+ */
+typedef struct EquivalenceFilter
+{
+	NodeTag		type;
+
+	Const	   *ef_const;		/* the constant expression to filter on */
+	Oid			ef_opno;		/* Operator Oid of filter operator */
+	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
+	Index		ef_source_rel;	/* relid of originating relation. */
+} EquivalenceFilter;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 0c3a0b90c85..ce2aac7d3aa 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -126,6 +126,7 @@ extern bool process_equivalence(PlannerInfo *root,
 extern Expr *canonicalize_ec_expression(Expr *expr,
 										Oid req_type, Oid req_collation);
 extern void reconsider_outer_join_clauses(PlannerInfo *root);
+extern void distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist);
 extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
 												  Expr *expr,
 												  Relids nullable_relids,
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 5b5fac0397c..e0ed28f330b 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -78,6 +78,7 @@ extern bool get_ordering_op_properties(Oid opno,
 									   Oid *opfamily, Oid *opcintype, int16 *strategy);
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
+extern List *get_opfamilies(Oid opno, Oid method);
 extern List *get_mergejoin_opfamilies(Oid opno);
 extern void get_btree_opfamilies(Oid opno, List **mergeable_opfamilies, List **unmergeable_btree_opfamilies);
 extern bool get_compatible_hash_operators(Oid opno,
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 126f7047fed..92fcec1158b 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                 QUERY PLAN                  
----------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: (f1 < '5'::int8alias1)
+         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
 (6 rows)
 
 reset session authorization;
@@ -451,3 +451,42 @@ explain (costs off)  -- this should not require a sort
    Filter: (f1 = 'foo'::name)
 (2 rows)
 
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 19caebabd01..6a548903eec 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3337,7 +3337,7 @@ where t1.unique2 < 42 and t1.stringu1 > t2.stringu2;
    Join Filter: (t1.stringu1 > t2.stringu2)
    ->  Nested Loop
          ->  Seq Scan on int4_tbl i1
-               Filter: (f1 = 0)
+               Filter: ((f1 = 0) AND (11 < 42))
          ->  Index Scan using tenk1_unique2 on tenk1 t1
                Index Cond: ((unique2 = (11)) AND (unique2 < 42))
    ->  Index Scan using tenk1_unique1 on tenk1 t2
@@ -6550,23 +6550,22 @@ where exists (select 1 from tenk1 t3
 ---------------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
-   ->  Hash Join
+   ->  Nested Loop
          Output: t1.unique1, t3.tenthous
-         Hash Cond: (t3.thousand = t1.unique1)
+         Join Filter: (t1.unique1 = t3.thousand)
+         ->  Index Only Scan using onek_unique1 on public.onek t1
+               Output: t1.unique1
+               Index Cond: (t1.unique1 < 1)
          ->  HashAggregate
                Output: t3.thousand, t3.tenthous
                Group Key: t3.thousand, t3.tenthous
                ->  Index Only Scan using tenk1_thous_tenthous on public.tenk1 t3
                      Output: t3.thousand, t3.tenthous
-         ->  Hash
-               Output: t1.unique1
-               ->  Index Only Scan using onek_unique1 on public.onek t1
-                     Output: t1.unique1
-                     Index Cond: (t1.unique1 < 1)
+                     Index Cond: (t3.thousand < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = t3.tenthous)
-(18 rows)
+(17 rows)
 
 -- ... unless it actually is unique
 create table j3 as select unique1, tenthous from onek;
@@ -6584,15 +6583,16 @@ where exists (select 1 from j3
    Output: t1.unique1, t2.hundred
    ->  Nested Loop
          Output: t1.unique1, j3.tenthous
+         Join Filter: (t1.unique1 = j3.unique1)
          ->  Index Only Scan using onek_unique1 on public.onek t1
                Output: t1.unique1
                Index Cond: (t1.unique1 < 1)
          ->  Index Only Scan using j3_unique1_tenthous_idx on public.j3
                Output: j3.unique1, j3.tenthous
-               Index Cond: (j3.unique1 = t1.unique1)
+               Index Cond: (j3.unique1 < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = j3.tenthous)
-(13 rows)
+(14 rows)
 
 drop table j3;
diff --git a/src/test/regress/expected/partition_join.out b/src/test/regress/expected/partition_join.out
index bb5b7c47a45..5a2923bac6c 100644
--- a/src/test/regress/expected/partition_join.out
+++ b/src/test/regress/expected/partition_join.out
@@ -186,17 +186,17 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM (SELECT 50 phv, * FROM prt1 WHERE prt1.b = 0)
 -- Join with pruned partitions from joining relations
 EXPLAIN (COSTS OFF)
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
-                     QUERY PLAN                      
------------------------------------------------------
+                            QUERY PLAN                             
+-------------------------------------------------------------------
  Sort
    Sort Key: t1.a
    ->  Hash Join
          Hash Cond: (t2.b = t1.a)
          ->  Seq Scan on prt2_p2 t2
-               Filter: (b > 250)
+               Filter: ((b > 250) AND (b < 450))
          ->  Hash
                ->  Seq Scan on prt1_p2 t1
-                     Filter: ((a < 450) AND (b = 0))
+                     Filter: ((a < 450) AND (a > 250) AND (b = 0))
 (9 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
@@ -3100,16 +3100,18 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a < 300) AND (b = 0))
          ->  Hash Join
                Hash Cond: (t2_2.b = t1_2.a)
                ->  Seq Scan on prt2_adv_p2 t2_2
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a < 300) AND (b = 0))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -3139,16 +3141,19 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: ((b >= 100) AND (b < 300))
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-         ->  Hash Join
-               Hash Cond: (t2_2.b = t1_2.a)
-               ->  Seq Scan on prt2_adv_p2 t2_2
-               ->  Hash
+         ->  Merge Join
+               Merge Cond: (t2_2.b = t1_2.a)
+               ->  Index Scan using prt2_adv_p2_b_idx on prt2_adv_p2 t2_2
+                     Index Cond: ((b >= 100) AND (b < 300))
+               ->  Sort
+                     Sort Key: t1_2.a
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-(15 rows)
+(18 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a >= 100 AND t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -4692,27 +4697,32 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
                      Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Seq Scan on beta_neg_p1 t2_1
+                           Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.b = t1_2.b))
-               ->  Seq Scan on beta_neg_p2 t2_2
+               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b))
+               ->  Seq Scan on alpha_neg_p2 t1_2
+                     Filter: ((b >= 125) AND (b < 225))
                ->  Hash
-                     ->  Seq Scan on alpha_neg_p2 t1_2
+                     ->  Seq Scan on beta_neg_p2 t2_2
                            Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_4.a = t1_4.a) AND (t2_4.b = t1_4.b))
+               Hash Cond: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b))
                ->  Append
-                     ->  Seq Scan on beta_pos_p1 t2_4
-                     ->  Seq Scan on beta_pos_p2 t2_5
-                     ->  Seq Scan on beta_pos_p3 t2_6
+                     ->  Seq Scan on alpha_pos_p1 t1_4
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p2 t1_5
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p3 t1_6
+                           Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Append
-                           ->  Seq Scan on alpha_pos_p1 t1_4
+                           ->  Seq Scan on beta_pos_p1 t2_4
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p2 t1_5
+                           ->  Seq Scan on beta_pos_p2 t2_5
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p3 t1_6
+                           ->  Seq Scan on beta_pos_p3 t2_6
                                  Filter: ((b >= 125) AND (b < 225))
-(29 rows)
+(34 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b) WHERE t1.b >= 125 AND t1.b < 225 ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
diff --git a/src/test/regress/sql/equivclass.sql b/src/test/regress/sql/equivclass.sql
index 247b0a31055..dae83c41965 100644
--- a/src/test/regress/sql/equivclass.sql
+++ b/src/test/regress/sql/equivclass.sql
@@ -269,3 +269,15 @@ create temp view overview as
   select f1::information_schema.sql_identifier as sqli, f2 from undername;
 explain (costs off)  -- this should not require a sort
   select * from overview where sqli = 'foo' order by sqli;
+
+
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
-- 
2.21.0

From 0efd829e3c411b6733aa308d9e1267e592873005 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Mon, 7 Mar 2022 10:07:44 +0800
Subject: [PATCH v4 1/6] expand the duties of check_mergejoinable to check
 non-equal btree

operator as well to support the EC Filter function.  A new filed
named btreeineqopfamilies is added in RestictInfo and it is set
with the same round syscache search for check_mergejoinable. because
of this, check_mergejoinable is renamed to check_btreeable.

The bad part of this is it only works for opclause so far.
---
 src/backend/optimizer/plan/initsplan.c    | 33 ++++++++++-----------
 src/backend/optimizer/util/restrictinfo.c |  1 +
 src/backend/utils/cache/lsyscache.c       | 35 +++++++++++++++++++++++
 src/include/nodes/pathnodes.h             |  1 +
 src/include/utils/lsyscache.h             |  1 +
 5 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 023efbaf092..d61419f61a5 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -76,7 +76,7 @@ static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 static bool check_equivalence_delay(PlannerInfo *root,
 									RestrictInfo *restrictinfo);
 static bool check_redundant_nullability_qual(PlannerInfo *root, Node *clause);
-static void check_mergejoinable(RestrictInfo *restrictinfo);
+static void check_btreeable(RestrictInfo *restrictinfo);
 static void check_hashjoinable(RestrictInfo *restrictinfo);
 static void check_memoizable(RestrictInfo *restrictinfo);
 
@@ -1874,8 +1874,11 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	 * We check "mergejoinability" of every clause, not only join clauses,
 	 * because we want to know about equivalences between vars of the same
 	 * relation, or between vars and consts.
+	 *
+	 * We also checked the btree-able properity at the same round of checking
+	 * mergejoinability to support ec filter function.
 	 */
-	check_mergejoinable(restrictinfo);
+	check_btreeable(restrictinfo);
 
 	/*
 	 * If it is a true equivalence clause, send it to the EquivalenceClass
@@ -2389,7 +2392,7 @@ process_implied_equality(PlannerInfo *root,
 	 * from an EquivalenceClass; but we could have reduced the original clause
 	 * to a constant.
 	 */
-	check_mergejoinable(restrictinfo);
+	check_btreeable(restrictinfo);
 
 	/*
 	 * Note we don't do initialize_mergeclause_eclasses(); the caller can
@@ -2456,8 +2459,8 @@ build_implied_join_equality(PlannerInfo *root,
 									 NULL,	/* outer_relids */
 									 nullable_relids);	/* nullable_relids */
 
-	/* Set mergejoinability/hashjoinability flags */
-	check_mergejoinable(restrictinfo);
+	/* Set btreeability/hashjoinability flags */
+	check_btreeable(restrictinfo);
 	check_hashjoinable(restrictinfo);
 	check_memoizable(restrictinfo);
 
@@ -2641,16 +2644,13 @@ match_foreign_keys_to_quals(PlannerInfo *root)
  *****************************************************************************/
 
 /*
- * check_mergejoinable
- *	  If the restrictinfo's clause is mergejoinable, set the mergejoin
- *	  info fields in the restrictinfo.
- *
- *	  Currently, we support mergejoin for binary opclauses where
- *	  the operator is a mergejoinable operator.  The arguments can be
- *	  anything --- as long as there are no volatile functions in them.
+ * check_btreeable
+ *	  If the restrictinfo's clause is btreeable, set the mergejoin
+ *	  info field and btreeineq info field in the restrictinfo. btreeable
+ *	  now is a superset of mergeable.
  */
 static void
-check_mergejoinable(RestrictInfo *restrictinfo)
+check_btreeable(RestrictInfo *restrictinfo)
 {
 	Expr	   *clause = restrictinfo->clause;
 	Oid			opno;
@@ -2666,9 +2666,10 @@ check_mergejoinable(RestrictInfo *restrictinfo)
 	opno = ((OpExpr *) clause)->opno;
 	leftarg = linitial(((OpExpr *) clause)->args);
 
-	if (op_mergejoinable(opno, exprType(leftarg)) &&
-		!contain_volatile_functions((Node *) restrictinfo))
-		restrictinfo->mergeopfamilies = get_mergejoin_opfamilies(opno);
+	if (!contain_volatile_functions((Node *) restrictinfo))
+		get_btree_opfamilies(opno,
+							 &restrictinfo->mergeopfamilies,
+							 &restrictinfo->btreeineqopfamilies);
 
 	/*
 	 * Note: op_mergejoinable is just a hint; if we fail to find the operator
diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c
index ef8df3d098e..e09196d26f6 100644
--- a/src/backend/optimizer/util/restrictinfo.c
+++ b/src/backend/optimizer/util/restrictinfo.c
@@ -201,6 +201,7 @@ make_restrictinfo_internal(PlannerInfo *root,
 	restrictinfo->outer_selec = -1;
 
 	restrictinfo->mergeopfamilies = NIL;
+	restrictinfo->btreeineqopfamilies = NIL;
 
 	restrictinfo->left_ec = NULL;
 	restrictinfo->right_ec = NULL;
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1b7e11b93e0..91cd813ce8f 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -389,6 +389,41 @@ get_mergejoin_opfamilies(Oid opno)
 	return result;
 }
 
+/*
+ * TODO:  get_mergejoin_opfamilies shoud be replaced with this function.
+ */
+void
+get_btree_opfamilies(Oid opno,
+					 List **mergeable_opfamilies,
+					 List **unmergeable_btree_opfamilies)
+{
+	CatCList   *catlist;
+	int			i;
+
+	/*
+	 * Search pg_amop to see find out all the btree opfamilies.
+	 */
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == BTREE_AM_OID)
+		{
+			if (aform->amopstrategy == BTEqualStrategyNumber)
+				*mergeable_opfamilies = lappend_oid(*mergeable_opfamilies,
+													aform->amopfamily);
+			else
+				*unmergeable_btree_opfamilies = lappend_oid(*unmergeable_btree_opfamilies,
+															aform->amopfamily);
+		}
+	}
+
+	ReleaseSysCacheList(catlist);
+}
+
 /*
  * get_compatible_hash_operators
  *		Get the OID(s) of hash equality operator(s) compatible with the given
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 1f3845b3fec..3b95e4a8eae 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -2105,6 +2105,7 @@ typedef struct RestrictInfo
 
 	/* valid if clause is mergejoinable, else NIL */
 	List	   *mergeopfamilies;	/* opfamilies containing clause operator */
+	List		*btreeineqopfamilies; /* btree families except the mergeable ones */
 
 	/* cache space for mergeclause processing; NULL if not yet set */
 	EquivalenceClass *left_ec;	/* EquivalenceClass containing lefthand */
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index b8dd27d4a96..5b5fac0397c 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -79,6 +79,7 @@ extern bool get_ordering_op_properties(Oid opno,
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
 extern List *get_mergejoin_opfamilies(Oid opno);
+extern void get_btree_opfamilies(Oid opno, List **mergeable_opfamilies, List **unmergeable_btree_opfamilies);
 extern bool get_compatible_hash_operators(Oid opno,
 										  Oid *lhs_opno, Oid *rhs_opno);
 extern bool get_op_hash_functions(Oid opno,
-- 
2.21.0

From 9887557db64ce270f5179877852bf399cec057a3 Mon Sep 17 00:00:00 2001
From: Andy Fan <yizhi.fzh@alibaba-inc.com>
Date: Thu, 24 Mar 2022 10:11:57 +0800
Subject: [PATCH v4 6/6] Disable ec filter for foregin table for now.

we do need support EC filter against for foreign table, but when fixing
the cost model issue, we need to know the selecvitiy of the qual on foregin
table. However it is impossible for now to know that when use_remote_estimate = true.
see for postgresGetForeignRelSize. Since we currently only doing PoC for
this cost-model-fix algorithm, I just disable that for foregin table. At last,
we need improve the use_remote_estimate somehow to get the selectivity.
---
 .../postgres_fdw/expected/postgres_fdw.out    | 36 +++++++++----------
 src/backend/optimizer/path/allpaths.c         |  2 +-
 src/backend/optimizer/path/equivclass.c       | 14 ++++++++
 src/backend/optimizer/plan/initsplan.c        |  7 +++-
 4 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index ce102abe5d5..f210f911880 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1545,12 +1545,12 @@ SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNE
 -- full outer join + inner join
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
-                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                 QUERY PLAN                                                                                                                                                 
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: t1.c1, t2.c1, t3.c1
    Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
-   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND (((r2.c1 + 1) >= 50)) AND (((r2.c1 + 1) <= 60)) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
 (4 rows)
 
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
@@ -2335,12 +2335,12 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                                    QUERY PLAN                                                                                                                                                     
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                QUERY PLAN                                                                                                                                 
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
    Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
 (4 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
@@ -2362,8 +2362,8 @@ SET enable_hashjoin TO false;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
     AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
-                                                                                                                                                                                                                                                                                                                                                                                                                                                                      QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  LockRows
    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
    ->  Merge Join
@@ -2373,7 +2373,7 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
          ->  Foreign Scan
                Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
-               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
                ->  Merge Join
                      Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                      Merge Cond: (ft1.c2 = ft5.c1)
@@ -2391,12 +2391,12 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
                                              Sort Key: ft1.c1
                                              ->  Foreign Scan on public.ft1
                                                    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
                                        ->  Materialize
                                              Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
                                              ->  Foreign Scan on public.ft2
                                                    Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
                            ->  Sort
                                  Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
                                  Sort Key: ft4.c1
@@ -5685,25 +5685,25 @@ UPDATE ft2 AS target SET (c2) = (
 EXPLAIN (VERBOSE, COSTS OFF)
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
   FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
-                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                    
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Update on public.ft2 d
    Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
    ->  Foreign Scan
          Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
          Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
-         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" > 1000)) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
-         ->  Merge Join
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Hash Join
                Output: d.c2, d.ctid, d.*, t.*
-               Merge Cond: (d.c1 = t.c1)
+               Hash Cond: (d.c1 = t.c1)
                ->  Foreign Scan on public.ft2 d
                      Output: d.c2, d.ctid, d.*, d.c1
                      Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
-               ->  Materialize
+               ->  Hash
                      Output: t.*, t.c1
                      ->  Foreign Scan on public.ft2 t
                            Output: t.*, t.c1
-                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
 (17 rows)
 
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 311a5e3837a..d497639623a 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -463,7 +463,7 @@ set_rel_size(PlannerInfo *root, RelOptInfo *rel,
 	Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
 
 	/* Now calculating the selectivity impacted by Corrective Qual */
-	if (!rte->inh)  /* not supported in this PoC */
+	if (!rte->inh)  /* Inherited table is not supported in this PoC */
 	{
 		ListCell *l;
 		int i = 0;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 6cdff399d0a..7dd7f373926 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -21,6 +21,7 @@
 #include "access/stratnum.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
+#include "catalog/pg_class.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/appendinfo.h"
@@ -1383,6 +1384,19 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
 				continue;
 
+			if (root->simple_rte_array[relid]->relkind == RELKIND_FOREIGN_TABLE)
+			{
+				/*
+				 * We do need support EC filter against for foreign table, but when fixing
+				 * the cost model issue, we need to know the selecvitiy of the qual on foregin
+				 * table. However it is impossible for now to know that when use_remote_estimate = true.
+				 * see for postgresGetForeignRelSize. Since we currently only doing PoC for
+				 * this cost-model-fix algorithm, I just disable that for foregin table. At last,
+				 * we need improve the use_remote_estimate somehow to get the selectivity.
+				 */
+				continue;
+			}
+
 			rel = root->simple_rel_array[relid];
 
 			if (ef->ef_source_rel == relid)
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 5a32c3987a0..9707c35f5c8 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -1991,9 +1991,14 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
 	if (filter_qual_list != NULL &&
+
+		// Must be an OpExpr for now.
 		is_opclause(restrictinfo->clause) &&
-		!contain_volatile_functions((Node *)restrictinfo) && // Cachable
+		// Checking volatile against RestrictInfo so that the result can be cached.
+		!contain_volatile_functions((Node *)restrictinfo) && 
+
 		restrictinfo->btreeineqopfamilies != NIL &&  /* ineq expression */
+		
 		/* simple & common enough filter, one side references one relation and the other one is a constant */
 		((bms_is_empty(restrictinfo->left_relids) && bms_get_singleton_member(restrictinfo->right_relids, &relid)) ||
 		 (bms_is_empty(restrictinfo->right_relids) && bms_get_singleton_member(restrictinfo->left_relids, &relid)))
-- 
2.21.0

From 9bc8ce0021869cef0ce6029d8aaf2a363434e268 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Jul 2022 14:44:56 +0300
Subject: [PATCH 1/6] Expand the duties of check_mergejoinable to check
 non-equal btree operator as well to support the EC Filter function.  A new
 field named btreeineqopfamilies is added into RestictInfo and it is set with
 the same round syscache search for check_mergejoinable. because of this,
 check_mergejoinable is renamed to check_btreeable.

The bad part of this is it only works for opclause so far.
---
 src/backend/optimizer/plan/initsplan.c    | 35 +++++++++++------------
 src/backend/optimizer/util/restrictinfo.c |  1 +
 src/backend/utils/cache/lsyscache.c       | 35 +++++++++++++++++++++++
 src/include/nodes/pathnodes.h             |  1 +
 src/include/utils/lsyscache.h             |  1 +
 5 files changed, 55 insertions(+), 18 deletions(-)

diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 023efbaf09..fa2bfbfb72 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -76,7 +76,7 @@ static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 static bool check_equivalence_delay(PlannerInfo *root,
 									RestrictInfo *restrictinfo);
 static bool check_redundant_nullability_qual(PlannerInfo *root, Node *clause);
-static void check_mergejoinable(RestrictInfo *restrictinfo);
+static void check_btreeable(RestrictInfo *restrictinfo);
 static void check_hashjoinable(RestrictInfo *restrictinfo);
 static void check_memoizable(RestrictInfo *restrictinfo);
 
@@ -1874,8 +1874,11 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	 * We check "mergejoinability" of every clause, not only join clauses,
 	 * because we want to know about equivalences between vars of the same
 	 * relation, or between vars and consts.
+	 *
+	 * We also checked the btree-able properity at the same round of checking
+	 * mergejoinability to support ec filter function.
 	 */
-	check_mergejoinable(restrictinfo);
+	check_btreeable(restrictinfo);
 
 	/*
 	 * If it is a true equivalence clause, send it to the EquivalenceClass
@@ -2389,7 +2392,7 @@ process_implied_equality(PlannerInfo *root,
 	 * from an EquivalenceClass; but we could have reduced the original clause
 	 * to a constant.
 	 */
-	check_mergejoinable(restrictinfo);
+	check_btreeable(restrictinfo);
 
 	/*
 	 * Note we don't do initialize_mergeclause_eclasses(); the caller can
@@ -2456,8 +2459,8 @@ build_implied_join_equality(PlannerInfo *root,
 									 NULL,	/* outer_relids */
 									 nullable_relids);	/* nullable_relids */
 
-	/* Set mergejoinability/hashjoinability flags */
-	check_mergejoinable(restrictinfo);
+	/* Set btreeability/hashjoinability flags */
+	check_btreeable(restrictinfo);
 	check_hashjoinable(restrictinfo);
 	check_memoizable(restrictinfo);
 
@@ -2641,20 +2644,16 @@ match_foreign_keys_to_quals(PlannerInfo *root)
  *****************************************************************************/
 
 /*
- * check_mergejoinable
- *	  If the restrictinfo's clause is mergejoinable, set the mergejoin
- *	  info fields in the restrictinfo.
- *
- *	  Currently, we support mergejoin for binary opclauses where
- *	  the operator is a mergejoinable operator.  The arguments can be
- *	  anything --- as long as there are no volatile functions in them.
+ * check_btreeable
+ *	  If the restrictinfo's clause is btreeable, set the mergejoin
+ *	  info field and btreeineq info field in the restrictinfo. btreeable
+ *	  now is a superset of mergeable.
  */
 static void
-check_mergejoinable(RestrictInfo *restrictinfo)
+check_btreeable(RestrictInfo *restrictinfo)
 {
 	Expr	   *clause = restrictinfo->clause;
 	Oid			opno;
-	Node	   *leftarg;
 
 	if (restrictinfo->pseudoconstant)
 		return;
@@ -2664,11 +2663,11 @@ check_mergejoinable(RestrictInfo *restrictinfo)
 		return;
 
 	opno = ((OpExpr *) clause)->opno;
-	leftarg = linitial(((OpExpr *) clause)->args);
 
-	if (op_mergejoinable(opno, exprType(leftarg)) &&
-		!contain_volatile_functions((Node *) restrictinfo))
-		restrictinfo->mergeopfamilies = get_mergejoin_opfamilies(opno);
+	if (!contain_volatile_functions((Node *) restrictinfo))
+		get_btree_opfamilies(opno,
+							 &restrictinfo->mergeopfamilies,
+							 &restrictinfo->btreeineqopfamilies);
 
 	/*
 	 * Note: op_mergejoinable is just a hint; if we fail to find the operator
diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c
index ef8df3d098..e09196d26f 100644
--- a/src/backend/optimizer/util/restrictinfo.c
+++ b/src/backend/optimizer/util/restrictinfo.c
@@ -201,6 +201,7 @@ make_restrictinfo_internal(PlannerInfo *root,
 	restrictinfo->outer_selec = -1;
 
 	restrictinfo->mergeopfamilies = NIL;
+	restrictinfo->btreeineqopfamilies = NIL;
 
 	restrictinfo->left_ec = NULL;
 	restrictinfo->right_ec = NULL;
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1b7e11b93e..91cd813ce8 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -389,6 +389,41 @@ get_mergejoin_opfamilies(Oid opno)
 	return result;
 }
 
+/*
+ * TODO:  get_mergejoin_opfamilies shoud be replaced with this function.
+ */
+void
+get_btree_opfamilies(Oid opno,
+					 List **mergeable_opfamilies,
+					 List **unmergeable_btree_opfamilies)
+{
+	CatCList   *catlist;
+	int			i;
+
+	/*
+	 * Search pg_amop to see find out all the btree opfamilies.
+	 */
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == BTREE_AM_OID)
+		{
+			if (aform->amopstrategy == BTEqualStrategyNumber)
+				*mergeable_opfamilies = lappend_oid(*mergeable_opfamilies,
+													aform->amopfamily);
+			else
+				*unmergeable_btree_opfamilies = lappend_oid(*unmergeable_btree_opfamilies,
+															aform->amopfamily);
+		}
+	}
+
+	ReleaseSysCacheList(catlist);
+}
+
 /*
  * get_compatible_hash_operators
  *		Get the OID(s) of hash equality operator(s) compatible with the given
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index b88cfb8dc0..f407f1852d 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -2305,6 +2305,7 @@ typedef struct RestrictInfo
 	 * mergejoinable, else NIL
 	 */
 	List	   *mergeopfamilies;
+	List		*btreeineqopfamilies; /* btree families except the mergeable ones */
 
 	/*
 	 * cache space for mergeclause processing; NULL if not yet set
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index b8dd27d4a9..5b5fac0397 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -79,6 +79,7 @@ extern bool get_ordering_op_properties(Oid opno,
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
 extern List *get_mergejoin_opfamilies(Oid opno);
+extern void get_btree_opfamilies(Oid opno, List **mergeable_opfamilies, List **unmergeable_btree_opfamilies);
 extern bool get_compatible_hash_operators(Oid opno,
 										  Oid *lhs_opno, Oid *rhs_opno);
 extern bool get_op_hash_functions(Oid opno,
-- 
2.37.0

From e67d5767ae85606f99d696874d53388bac6543b7 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Jul 2022 15:36:19 +0300
Subject: [PATCH 2/6] Introudce ec_filters in EquivalenceClass struct, the
 semantics is the quals can be applied to any EquivalenceMember in this EC.
 Later this information is used to generate new RestrictInfo and was
 distributed to related RelOptInfo very soon.

There are 3 major steps here:
a). In distribute_qual_to_rels to gather the ineq quallist.
b). After deconstruct_jointree, distribute_filter_quals_to_eclass distribute
these ineq-quallist to the related EC's ef_filters.
c). generate_base_implied_equalities_no_const scan the ec_filters and distriubte
the restrictinfo to related RelOptInfo.

Author: David Rowley at 2015-12 [1]
Andy Fan rebases this patch to current latest code.
---
 .../postgres_fdw/expected/postgres_fdw.out    |  36 ++--
 src/backend/nodes/outfuncs.c                  |  14 ++
 src/backend/optimizer/path/equivclass.c       | 182 ++++++++++++++++++
 src/backend/optimizer/plan/initsplan.c        |  96 +++++++--
 src/backend/utils/cache/lsyscache.c           |  28 +++
 src/include/nodes/nodes.h                     |   1 +
 src/include/nodes/pathnodes.h                 |  37 ++++
 src/include/optimizer/paths.h                 |   1 +
 src/include/utils/lsyscache.h                 |   1 +
 src/test/regress/expected/equivclass.out      |  45 ++++-
 src/test/regress/expected/join.out            |  22 +--
 src/test/regress/expected/merge.out           |  16 +-
 src/test/regress/expected/partition_join.out  |  43 +++--
 src/test/regress/sql/equivclass.sql           |  12 ++
 14 files changed, 460 insertions(+), 74 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 44457f930c..2758049f5b 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1545,12 +1545,12 @@ SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNE
 -- full outer join + inner join
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
-                                                                                                                                                 QUERY PLAN                                                                                                                                                 
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: t1.c1, t2.c1, t3.c1
    Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
-   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND (((r2.c1 + 1) >= 50)) AND (((r2.c1 + 1) <= 60)) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
 (4 rows)
 
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
@@ -2335,12 +2335,12 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                QUERY PLAN                                                                                                                                 
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                    QUERY PLAN                                                                                                                                                     
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
    Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
 (4 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
@@ -2362,8 +2362,8 @@ SET enable_hashjoin TO false;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
     AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
-                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                      QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  LockRows
    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
    ->  Merge Join
@@ -2373,7 +2373,7 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
          ->  Foreign Scan
                Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
-               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
                ->  Merge Join
                      Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                      Merge Cond: (ft1.c2 = ft5.c1)
@@ -2391,12 +2391,12 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
                                              Sort Key: ft1.c1
                                              ->  Foreign Scan on public.ft1
                                                    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) FOR UPDATE
                                        ->  Materialize
                                              Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
                                              ->  Foreign Scan on public.ft2
                                                    Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
                            ->  Sort
                                  Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
                                  Sort Key: ft4.c1
@@ -5705,25 +5705,25 @@ UPDATE ft2 AS target SET (c2) = (
 EXPLAIN (VERBOSE, COSTS OFF)
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
   FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
-                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                    
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Update on public.ft2 d
    Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
    ->  Foreign Scan
          Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
          Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
-         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
-         ->  Hash Join
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" > 1000)) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Merge Join
                Output: d.c2, d.ctid, d.*, t.*
-               Hash Cond: (d.c1 = t.c1)
+               Merge Cond: (d.c1 = t.c1)
                ->  Foreign Scan on public.ft2 d
                      Output: d.c2, d.ctid, d.*, d.c1
                      Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
-               ->  Hash
+               ->  Materialize
                      Output: t.*, t.c1
                      ->  Foreign Scan on public.ft2 t
                            Output: t.*, t.c1
-                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST
 (17 rows)
 
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 05f27f044b..b19462c758 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2665,6 +2665,17 @@ _outEquivalenceMember(StringInfo str, const EquivalenceMember *node)
 	WRITE_OID_FIELD(em_datatype);
 }
 
+static void
+_outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
+{
+	WRITE_NODE_TYPE("EQUIVALENCEFILTER");
+
+	WRITE_NODE_FIELD(ef_const);
+	WRITE_OID_FIELD(ef_opno);
+	WRITE_BOOL_FIELD(ef_const_is_left);
+	WRITE_UINT_FIELD(ef_source_rel);
+}
+
 static void
 _outPathKey(StringInfo str, const PathKey *node)
 {
@@ -4496,6 +4507,9 @@ outNode(StringInfo str, const void *obj)
 			case T_EquivalenceMember:
 				_outEquivalenceMember(str, obj);
 				break;
+			case T_EquivalenceFilter:
+				_outEquivalenceFilter(str, obj);
+				break;
 			case T_PathKey:
 				_outPathKey(str, obj);
 				break;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 60c0e3f108..89c7f0dc39 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -19,6 +19,7 @@
 #include <limits.h>
 
 #include "access/stratnum.h"
+#include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
@@ -1232,6 +1233,37 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 	}
 }
 
+/*
+ * finds the opfamily and strategy number for the specified 'opno' and 'method'
+ * access method. Returns True if one is found and sets 'family' and
+ * 'amstrategy', or returns False if none are found.
+ */
+static bool
+find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+{
+	List *opfamilies;
+	ListCell *l;
+	int strategy;
+
+	opfamilies = get_opfamilies(opno, method);
+
+	foreach(l, opfamilies)
+	{
+		Oid opfamily = lfirst_oid(l);
+
+		strategy = get_op_opfamily_strategy(opno, opfamily);
+
+		if (strategy)
+		{
+			*amstrategy = strategy;
+			*family = opfamily;
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /*
  * generate_base_implied_equalities when EC contains no pseudoconstants
  */
@@ -1241,6 +1273,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 {
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
+	ListCell   *lc2;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1302,6 +1335,57 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+
+		/*
+		 * Also push any EquivalenceFilter clauses down into all relations
+		 * other than the one which the filter actually originated from.
+		 */
+		foreach(lc2, ec->ec_filters)
+		{
+			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+			Expr *leftexpr;
+			Expr *rightexpr;
+			int strategy;
+			Oid opno;
+			Oid family;
+
+			if (ef->ef_source_rel == relid)
+				continue;
+
+			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
+				&family, &strategy))
+				continue;
+
+			if (ef->ef_const_is_left)
+			{
+				leftexpr = (Expr *) ef->ef_const;
+				rightexpr = cur_em->em_expr;
+			}
+			else
+			{
+				leftexpr = cur_em->em_expr;
+				rightexpr = (Expr *) ef->ef_const;
+			}
+
+			opno = get_opfamily_member(family,
+										exprType((Node *) leftexpr),
+										exprType((Node *) rightexpr),
+										strategy);
+
+			if (opno == InvalidOid)
+				continue;
+
+			process_implied_equality(root, opno,
+										ec->ec_collation,
+										leftexpr,
+										rightexpr,
+										bms_copy(ec->ec_relids),
+										bms_copy(cur_em->em_nullable_relids),
+										ec->ec_min_security,
+										ec->ec_below_outer_join,
+										false);
+		}
+
 		prev_ems[relid] = cur_em;
 	}
 
@@ -1883,6 +1967,104 @@ create_join_clause(PlannerInfo *root,
 	return rinfo;
 }
 
+/*
+ * distribute_filter_quals_to_eclass
+ *		For each OpExpr in quallist look for an eclass which has an Expr
+ *		matching the Expr in the OpExpr. If a match is found we add a new
+ *		EquivalenceFilter to the eclass containing the filter details.
+ */
+void
+distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
+{
+	ListCell *l;
+
+	/* fast path for when no eclasses have been generated */
+	if (root->eq_classes == NIL)
+		return;
+
+	/*
+	 * For each qual in quallist try and find an eclass which contains the
+	 * non-Const part of the OpExpr. We'll tag any matches that we find onto
+	 * the correct eclass.
+	 */
+	foreach(l, quallist)
+	{
+		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
+		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
+		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		Const	   *constexpr;
+		Expr	   *varexpr;
+		Relids		exprrels;
+		int			relid;
+		bool		const_isleft;
+		ListCell *l2;
+
+		/*
+		 * Determine if the the OpExpr is in the form "expr op const" or
+		 * "const op expr".
+		 */
+		if (IsA(leftexpr, Const))
+		{
+			constexpr = (Const *) leftexpr;
+			varexpr = rightexpr;
+			const_isleft = true;
+		}
+		else
+		{
+			constexpr = (Const *) rightexpr;
+			varexpr = leftexpr;
+			const_isleft = false;
+		}
+
+		exprrels = pull_varnos(root, (Node *) varexpr);
+
+		/* should be filtered out, but we need to determine relid anyway */
+		if (!bms_get_singleton_member(exprrels, &relid))
+			continue;
+
+		/* search for a matching eclass member in all eclasses */
+		foreach(l2, root->eq_classes)
+		{
+			EquivalenceClass *ec = (EquivalenceClass *) lfirst(l2);
+			ListCell *l3;
+
+			if (ec->ec_broken || ec->ec_has_volatile)
+				continue;
+
+			/*
+			 * if the eclass has a const then that const will serve as the
+			 * filter, we needn't add any others.
+			 */
+			if (ec->ec_has_const)
+				continue;
+
+			/* skip this eclass no members exist which belong to this relid */
+			if (!bms_is_member(relid, ec->ec_relids))
+				continue;
+
+			foreach(l3, ec->ec_members)
+			{
+				EquivalenceMember *em = (EquivalenceMember *) lfirst(l3);
+
+				if (!bms_is_member(relid, em->em_relids))
+					continue;
+
+				if (equal(em->em_expr, varexpr))
+				{
+					EquivalenceFilter *efilter;
+					efilter = makeNode(EquivalenceFilter);
+					efilter->ef_const = (Const *) copyObject(constexpr);
+					efilter->ef_const_is_left = const_isleft;
+					efilter->ef_opno = opexpr->opno;
+					efilter->ef_source_rel = relid;
+
+					ec->ec_filters = lappend(ec->ec_filters, efilter);
+					break;		/* Onto the next eclass */
+				}
+			}
+		}
+	}
+}
 
 /*
  * reconsider_outer_join_clauses
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index fa2bfbfb72..f86276b667 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -53,7 +53,7 @@ static void extract_lateral_references(PlannerInfo *root, RelOptInfo *brel,
 static List *deconstruct_recurse(PlannerInfo *root, Node *jtnode,
 								 bool below_outer_join,
 								 Relids *qualscope, Relids *inner_join_rels,
-								 List **postponed_qual_list);
+								 List **postponed_qual_list, List **filter_qual_list);
 static void process_security_barrier_quals(PlannerInfo *root,
 										   int rti, Relids qualscope,
 										   bool below_outer_join);
@@ -70,7 +70,8 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 									Relids qualscope,
 									Relids ojscope,
 									Relids outerjoin_nonnullable,
-									List **postponed_qual_list);
+									List **postponed_qual_list,
+									List **filter_qual_list);
 static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
 								  Relids *nullable_relids_p, bool is_pushed_down);
 static bool check_equivalence_delay(PlannerInfo *root,
@@ -650,6 +651,43 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
+/*
+ * is_simple_filter_qual
+ *             Analyzes an OpExpr to determine if it may be useful as an
+ *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
+ *             false if it should not be used.
+ */
+static bool
+is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
+{
+	Expr *leftexpr;
+	Expr *rightexpr;
+
+	if (!IsA(expr, OpExpr))
+			return false;
+
+	if (list_length(expr->args) != 2)
+			return false;
+
+	leftexpr = (Expr *) linitial(expr->args);
+	rightexpr = (Expr *) lsecond(expr->args);
+
+	/* XXX should we restrict these to simple Var op Const expressions? */
+	if (IsA(leftexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) rightexpr))
+			return true;
+	}
+	else if (IsA(rightexpr, Const))
+	{
+		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
+			!contain_volatile_functions((Node *) leftexpr))
+			return true;
+	}
+
+	return false;
+}
 
 /*****************************************************************************
  *
@@ -690,6 +728,7 @@ deconstruct_jointree(PlannerInfo *root)
 	Relids		qualscope;
 	Relids		inner_join_rels;
 	List	   *postponed_qual_list = NIL;
+	List	   *filter_qual_list = NIL;
 
 	/* Start recursion at top of jointree */
 	Assert(root->parse->jointree != NULL &&
@@ -700,11 +739,14 @@ deconstruct_jointree(PlannerInfo *root)
 
 	result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
 								 &qualscope, &inner_join_rels,
-								 &postponed_qual_list);
+								 &postponed_qual_list, &filter_qual_list);
 
 	/* Shouldn't be any leftover quals */
 	Assert(postponed_qual_list == NIL);
 
+	/* try and match each filter_qual_list item up with an eclass. */
+	distribute_filter_quals_to_eclass(root, filter_qual_list);
+
 	return result;
 }
 
@@ -725,6 +767,8 @@ deconstruct_jointree(PlannerInfo *root)
  *		or free this, either)
  *	*postponed_qual_list is a list of PostponedQual structs, which we can
  *		add quals to if they turn out to belong to a higher join level
+ *	*filter_qual_list is appended to with a list of quals which may be useful
+ *		include as EquivalenceFilters.
  *	Return value is the appropriate joinlist for this jointree node
  *
  * In addition, entries will be added to root->join_info_list for outer joins.
@@ -732,7 +776,7 @@ deconstruct_jointree(PlannerInfo *root)
 static List *
 deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 					Relids *qualscope, Relids *inner_join_rels,
-					List **postponed_qual_list)
+					List **postponed_qual_list, List **filter_qual_list)
 {
 	List	   *joinlist;
 
@@ -785,7 +829,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 											   below_outer_join,
 											   &sub_qualscope,
 											   inner_join_rels,
-											   &child_postponed_quals);
+											   &child_postponed_quals,
+											   filter_qual_list);
 			*qualscope = bms_add_members(*qualscope, sub_qualscope);
 			sub_members = list_length(sub_joinlist);
 			remaining--;
@@ -819,7 +864,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 										below_outer_join, JOIN_INNER,
 										root->qual_security_level,
 										*qualscope, NULL, NULL,
-										NULL);
+										NULL,
+										filter_qual_list);
 			else
 				*postponed_qual_list = lappend(*postponed_qual_list, pq);
 		}
@@ -835,7 +881,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									below_outer_join, JOIN_INNER,
 									root->qual_security_level,
 									*qualscope, NULL, NULL,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 	}
 	else if (IsA(jtnode, JoinExpr))
@@ -873,11 +920,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = *qualscope;
 				/* Inner join adds no restrictions for quals */
@@ -890,11 +939,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				nonnullable_rels = leftids;
@@ -904,11 +955,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   below_outer_join,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													below_outer_join,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* Semi join adds no restrictions for quals */
@@ -925,11 +978,13 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 				leftjoinlist = deconstruct_recurse(root, j->larg,
 												   true,
 												   &leftids, &left_inners,
-												   &child_postponed_quals);
+												   &child_postponed_quals,
+												   filter_qual_list);
 				rightjoinlist = deconstruct_recurse(root, j->rarg,
 													true,
 													&rightids, &right_inners,
-													&child_postponed_quals);
+													&child_postponed_quals,
+													filter_qual_list);
 				*qualscope = bms_union(leftids, rightids);
 				*inner_join_rels = bms_union(left_inners, right_inners);
 				/* each side is both outer and inner */
@@ -1013,7 +1068,8 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
 									root->qual_security_level,
 									*qualscope,
 									ojscope, nonnullable_rels,
-									postponed_qual_list);
+									postponed_qual_list,
+									filter_qual_list);
 		}
 
 		/* Now we can add the SpecialJoinInfo to join_info_list */
@@ -1117,6 +1173,7 @@ process_security_barrier_quals(PlannerInfo *root,
 									qualscope,
 									qualscope,
 									NULL,
+									NULL,
 									NULL);
 		}
 		security_level++;
@@ -1610,7 +1667,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 						Relids qualscope,
 						Relids ojscope,
 						Relids outerjoin_nonnullable,
-						List **postponed_qual_list)
+						List **postponed_qual_list,
+						List **filter_qual_list)
 {
 	Relids		relids;
 	bool		is_pushed_down;
@@ -1967,6 +2025,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* No EC special case applies, so push it into the clause lists */
 	distribute_restrictinfo_to_rels(root, restrictinfo);
+
+	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
+	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
+		*filter_qual_list = lappend(*filter_qual_list, clause);
 }
 
 /*
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 91cd813ce8..b0243925e4 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -341,6 +341,34 @@ get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
 	return result;
 }
 
+/*
+ * get_opfamilies
+ *		Returns a list of Oids of each opfamily which 'opno' belonging to
+ *		'method' access method.
+ */
+List *
+get_opfamilies(Oid opno, Oid method)
+{
+	List	   *result = NIL;
+	CatCList   *catlist;
+	int			i;
+
+	catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+	for (i = 0; i < catlist->n_members; i++)
+	{
+		HeapTuple	tuple = &catlist->members[i]->tuple;
+		Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+		if (aform->amopmethod == method)
+			result = lappend_oid(result, aform->amopfamily);
+	}
+
+	ReleaseSysCacheList(catlist);
+
+	return result;
+}
+
 /*
  * get_mergejoin_opfamilies
  *		Given a putatively mergejoinable operator, return a list of the OIDs
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 7ce1fc4deb..ba879ab3e9 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -277,6 +277,7 @@ typedef enum NodeTag
 	T_LimitPath,
 	/* these aren't subclasses of Path: */
 	T_EquivalenceClass,
+	T_EquivalenceFilter,
 	T_EquivalenceMember,
 	T_PathKey,
 	T_PathKeyInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index f407f1852d..f80b47ae2c 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1132,6 +1132,7 @@ typedef struct EquivalenceClass
 	List	   *ec_members;		/* list of EquivalenceMembers */
 	List	   *ec_sources;		/* list of generating RestrictInfos */
 	List	   *ec_derives;		/* list of derived RestrictInfos */
+	List	   *ec_filters;
 	Relids		ec_relids;		/* all relids appearing in ec_members, except
 								 * for child members (see below) */
 	bool		ec_has_const;	/* any pseudoconstants in ec_members? */
@@ -1144,6 +1145,42 @@ typedef struct EquivalenceClass
 	struct EquivalenceClass *ec_merged; /* set if merged into another EC */
 } EquivalenceClass;
 
+/*
+ * EquivalenceFilter - List of filters on Consts which belong to the
+ * EquivalenceClass.
+ *
+ * When building the equivalence classes we also collected a list of quals in
+ * the form of; "Expr op Const" and "Const op Expr". These are collected in the
+ * hope that we'll later generate an equivalence class which contains the
+ * "Expr" part. For example, if we parse a query such as;
+ *
+ *		SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id WHERE t1.id < 10;
+ *
+ * then since we'll end up with an equivalence class containing {t1.id,t2.id},
+ * we'll tag the "< 10" filter onto the eclass. We are able to do this because
+ * the eclass proves equality between each class member, therefore all members
+ * must be below 10.
+ *
+ * EquivalenceFilters store the details required to allow us to push these
+ * filter clauses down into other relations which share an equivalence class
+ * containing a member which matches the expression of this EquivalenceFilter.
+ *
+ * ef_const is the Const value which this filter should filter against.
+ * ef_opno is the operator to filter on.
+ * ef_const_is_left marks if the OpExpr was in the form "Const op Expr" or
+ * "Expr op Const".
+ * ef_source_rel is the relation id of where this qual originated from.
+ */
+typedef struct EquivalenceFilter
+{
+	NodeTag		type;
+
+	Const	   *ef_const;		/* the constant expression to filter on */
+	Oid			ef_opno;		/* Operator Oid of filter operator */
+	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
+	Index		ef_source_rel;	/* relid of originating relation. */
+} EquivalenceFilter;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index b6e137cf83..79553778cd 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -127,6 +127,7 @@ extern bool process_equivalence(PlannerInfo *root,
 extern Expr *canonicalize_ec_expression(Expr *expr,
 										Oid req_type, Oid req_collation);
 extern void reconsider_outer_join_clauses(PlannerInfo *root);
+extern void distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist);
 extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
 												  Expr *expr,
 												  Relids nullable_relids,
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 5b5fac0397..e0ed28f330 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -78,6 +78,7 @@ extern bool get_ordering_op_properties(Oid opno,
 									   Oid *opfamily, Oid *opcintype, int16 *strategy);
 extern Oid	get_equality_op_for_ordering_op(Oid opno, bool *reverse);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
+extern List *get_opfamilies(Oid opno, Oid method);
 extern List *get_mergejoin_opfamilies(Oid opno);
 extern void get_btree_opfamilies(Oid opno, List **mergeable_opfamilies, List **unmergeable_btree_opfamilies);
 extern bool get_compatible_hash_operators(Oid opno,
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 126f7047fe..92fcec1158 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                 QUERY PLAN                  
----------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: (f1 < '5'::int8alias1)
+         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
 (6 rows)
 
 reset session authorization;
@@ -451,3 +451,42 @@ explain (costs off)  -- this should not require a sort
    Filter: (f1 = 'foo'::name)
 (2 rows)
 
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
+                         QUERY PLAN                         
+------------------------------------------------------------
+ Nested Loop
+   Join Filter: (ec0.ff = ec1.ff)
+   ->  Bitmap Heap Scan on ec0
+         Recheck Cond: ((ff >= 1) AND (ff <= 10))
+         ->  Bitmap Index Scan on ec0_pkey
+               Index Cond: ((ff >= 1) AND (ff <= 10))
+   ->  Materialize
+         ->  Bitmap Heap Scan on ec1
+               Recheck Cond: ((ff >= 1) AND (ff <= 10))
+               ->  Bitmap Index Scan on ec1_pkey
+                     Index Cond: ((ff >= 1) AND (ff <= 10))
+(11 rows)
+
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 2538bd6a79..f173074621 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3337,7 +3337,7 @@ where t1.unique2 < 42 and t1.stringu1 > t2.stringu2;
    Join Filter: (t1.stringu1 > t2.stringu2)
    ->  Nested Loop
          ->  Seq Scan on int4_tbl i1
-               Filter: (f1 = 0)
+               Filter: ((f1 = 0) AND (11 < 42))
          ->  Index Scan using tenk1_unique2 on tenk1 t1
                Index Cond: ((unique2 = (11)) AND (unique2 < 42))
    ->  Index Scan using tenk1_unique1 on tenk1 t2
@@ -6544,23 +6544,22 @@ where exists (select 1 from tenk1 t3
 ---------------------------------------------------------------------------------
  Nested Loop
    Output: t1.unique1, t2.hundred
-   ->  Hash Join
+   ->  Nested Loop
          Output: t1.unique1, t3.tenthous
-         Hash Cond: (t3.thousand = t1.unique1)
+         Join Filter: (t1.unique1 = t3.thousand)
+         ->  Index Only Scan using onek_unique1 on public.onek t1
+               Output: t1.unique1
+               Index Cond: (t1.unique1 < 1)
          ->  HashAggregate
                Output: t3.thousand, t3.tenthous
                Group Key: t3.thousand, t3.tenthous
                ->  Index Only Scan using tenk1_thous_tenthous on public.tenk1 t3
                      Output: t3.thousand, t3.tenthous
-         ->  Hash
-               Output: t1.unique1
-               ->  Index Only Scan using onek_unique1 on public.onek t1
-                     Output: t1.unique1
-                     Index Cond: (t1.unique1 < 1)
+                     Index Cond: (t3.thousand < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = t3.tenthous)
-(18 rows)
+(17 rows)
 
 -- ... unless it actually is unique
 create table j3 as select unique1, tenthous from onek;
@@ -6578,15 +6577,16 @@ where exists (select 1 from j3
    Output: t1.unique1, t2.hundred
    ->  Nested Loop
          Output: t1.unique1, j3.tenthous
+         Join Filter: (t1.unique1 = j3.unique1)
          ->  Index Only Scan using onek_unique1 on public.onek t1
                Output: t1.unique1
                Index Cond: (t1.unique1 < 1)
          ->  Index Only Scan using j3_unique1_tenthous_idx on public.j3
                Output: j3.unique1, j3.tenthous
-               Index Cond: (j3.unique1 = t1.unique1)
+               Index Cond: (j3.unique1 < 1)
    ->  Index Only Scan using tenk1_hundred on public.tenk1 t2
          Output: t2.hundred
          Index Cond: (t2.hundred = j3.tenthous)
-(13 rows)
+(14 rows)
 
 drop table j3;
diff --git a/src/test/regress/expected/merge.out b/src/test/regress/expected/merge.out
index af670e28e7..ab3a711d61 100644
--- a/src/test/regress/expected/merge.out
+++ b/src/test/regress/expected/merge.out
@@ -1437,17 +1437,17 @@ SELECT explain_merge('
 MERGE INTO ex_mtarget t USING ex_msource s ON t.a = s.a AND t.a < -1000
 WHEN MATCHED AND t.a < 10 THEN
 	DO NOTHING');
-                           explain_merge                            
---------------------------------------------------------------------
+                        explain_merge                         
+--------------------------------------------------------------
  Merge on ex_mtarget t (actual rows=0 loops=1)
    ->  Hash Join (actual rows=0 loops=1)
-         Hash Cond: (s.a = t.a)
-         ->  Seq Scan on ex_msource s (actual rows=1 loops=1)
-         ->  Hash (actual rows=0 loops=1)
-               Buckets: xxx  Batches: xxx  Memory Usage: xxx
-               ->  Seq Scan on ex_mtarget t (actual rows=0 loops=1)
+         Hash Cond: (t.a = s.a)
+         ->  Seq Scan on ex_mtarget t (actual rows=0 loops=1)
+               Filter: (a < '-1000'::integer)
+               Rows Removed by Filter: 54
+         ->  Hash (never executed)
+               ->  Seq Scan on ex_msource s (never executed)
                      Filter: (a < '-1000'::integer)
-                     Rows Removed by Filter: 54
 (9 rows)
 
 DROP TABLE ex_msource, ex_mtarget;
diff --git a/src/test/regress/expected/partition_join.out b/src/test/regress/expected/partition_join.out
index 03926a8413..3be9a2bed5 100644
--- a/src/test/regress/expected/partition_join.out
+++ b/src/test/regress/expected/partition_join.out
@@ -186,17 +186,17 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM (SELECT 50 phv, * FROM prt1 WHERE prt1.b = 0)
 -- Join with pruned partitions from joining relations
 EXPLAIN (COSTS OFF)
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
-                     QUERY PLAN                      
------------------------------------------------------
+                            QUERY PLAN                             
+-------------------------------------------------------------------
  Sort
    Sort Key: t1.a
    ->  Hash Join
          Hash Cond: (t2.b = t1.a)
          ->  Seq Scan on prt2_p2 t2
-               Filter: (b > 250)
+               Filter: ((b > 250) AND (b < 450))
          ->  Hash
                ->  Seq Scan on prt1_p2 t1
-                     Filter: ((a < 450) AND (b = 0))
+                     Filter: ((a < 450) AND (a > 250) AND (b = 0))
 (9 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1 t1, prt2 t2 WHERE t1.a = t2.b AND t1.a < 450 AND t2.b > 250 AND t1.b = 0 ORDER BY t1.a, t2.b;
@@ -3089,16 +3089,18 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a < 300) AND (b = 0))
          ->  Hash Join
                Hash Cond: (t2_2.b = t1_2.a)
                ->  Seq Scan on prt2_adv_p2 t2_2
+                     Filter: (b < 300)
                ->  Hash
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a < 300) AND (b = 0))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -3128,16 +3130,18 @@ SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a =
          ->  Hash Join
                Hash Cond: (t2_1.b = t1_1.a)
                ->  Seq Scan on prt2_adv_p1 t2_1
+                     Filter: ((b >= 100) AND (b < 300))
                ->  Hash
                      ->  Seq Scan on prt1_adv_p1 t1_1
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
          ->  Hash Join
                Hash Cond: (t2_2.b = t1_2.a)
                ->  Seq Scan on prt2_adv_p2 t2_2
+                     Filter: ((b >= 100) AND (b < 300))
                ->  Hash
                      ->  Seq Scan on prt1_adv_p2 t1_2
                            Filter: ((a >= 100) AND (a < 300) AND (b = 0))
-(15 rows)
+(17 rows)
 
 SELECT t1.a, t1.c, t2.b, t2.c FROM prt1_adv t1 INNER JOIN prt2_adv t2 ON (t1.a = t2.b) WHERE t1.a >= 100 AND t1.a < 300 AND t1.b = 0 ORDER BY t1.a, t2.b;
   a  |  c   |  b  |  c   
@@ -4681,27 +4685,32 @@ SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2
                      Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Seq Scan on beta_neg_p1 t2_1
+                           Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_2.a = t1_2.a) AND (t2_2.b = t1_2.b))
-               ->  Seq Scan on beta_neg_p2 t2_2
+               Hash Cond: ((t1_2.a = t2_2.a) AND (t1_2.b = t2_2.b))
+               ->  Seq Scan on alpha_neg_p2 t1_2
+                     Filter: ((b >= 125) AND (b < 225))
                ->  Hash
-                     ->  Seq Scan on alpha_neg_p2 t1_2
+                     ->  Seq Scan on beta_neg_p2 t2_2
                            Filter: ((b >= 125) AND (b < 225))
          ->  Hash Join
-               Hash Cond: ((t2_4.a = t1_4.a) AND (t2_4.b = t1_4.b))
+               Hash Cond: ((t1_4.a = t2_4.a) AND (t1_4.b = t2_4.b))
                ->  Append
-                     ->  Seq Scan on beta_pos_p1 t2_4
-                     ->  Seq Scan on beta_pos_p2 t2_5
-                     ->  Seq Scan on beta_pos_p3 t2_6
+                     ->  Seq Scan on alpha_pos_p1 t1_4
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p2 t1_5
+                           Filter: ((b >= 125) AND (b < 225))
+                     ->  Seq Scan on alpha_pos_p3 t1_6
+                           Filter: ((b >= 125) AND (b < 225))
                ->  Hash
                      ->  Append
-                           ->  Seq Scan on alpha_pos_p1 t1_4
+                           ->  Seq Scan on beta_pos_p1 t2_4
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p2 t1_5
+                           ->  Seq Scan on beta_pos_p2 t2_5
                                  Filter: ((b >= 125) AND (b < 225))
-                           ->  Seq Scan on alpha_pos_p3 t1_6
+                           ->  Seq Scan on beta_pos_p3 t2_6
                                  Filter: ((b >= 125) AND (b < 225))
-(29 rows)
+(34 rows)
 
 SELECT t1.*, t2.* FROM alpha t1 INNER JOIN beta t2 ON (t1.a = t2.a AND t1.b = t2.b) WHERE t1.b >= 125 AND t1.b < 225 ORDER BY t1.a, t1.b;
  a  |  b  |  c   | a  |  b  |  c   
diff --git a/src/test/regress/sql/equivclass.sql b/src/test/regress/sql/equivclass.sql
index 247b0a3105..dae83c4196 100644
--- a/src/test/regress/sql/equivclass.sql
+++ b/src/test/regress/sql/equivclass.sql
@@ -269,3 +269,15 @@ create temp view overview as
   select f1::information_schema.sql_identifier as sqli, f2 from undername;
 explain (costs off)  -- this should not require a sort
   select * from overview where sqli = 'foo' order by sqli;
+
+
+-- test equivalence filters
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec0.ff between 1 and 10;
+
+explain (costs off)
+  select * from ec0
+  inner join ec1 on ec0.ff = ec1.ff
+  where ec1.ff between 1 and 10;
-- 
2.37.0

From b19ec90394d5d933028355725754b4bb7a8c9094 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Jul 2022 15:47:30 +0300
Subject: [PATCH 3/6] Reduce some planning cost for deriving qual for EC filter
 feature.

Mainly changes includes:
1. Check if the qual is simple enough by checking rinfo->right_relids and
info->right_relids, save the pull_varnos of rinfo->clause calls.
2. check contain_volatile_functions against RestrictInfo, so that
the result can be shared with following calls.
3. By employing the RestictInfo->btreeineqfamility which is calculating.
with same round of calculating  RestrictInfo->mergeopfamilies. In this
way we save the some calls for syscache.
4. Calculating the opfamility and amstrategy at
distribute_filter_quals_to_eclass and cache the results in EquivalenceFilter.
if no suitable opfamility and amstrategy are found, bypass the qual immediately
and at last using the cached value generate_base_implied_equalities_no_const.

After this change, there is an testcase changed unexpectedly in equivclass.out
(compared with David's expectation file.)

create user regress_user_ectest;
grant select on ec0 to regress_user_ectest;
grant select on ec1 to regress_user_ectest;

set session authorization regress_user_ectest;

-- with RLS active, the non-leakproof a.ff = 43 clause is not treated
-- as a suitable source for an EquivalenceClass; currently, this is true
-- even though the RLS clause has nothing to do directly with the EC
explain (costs off)
regression->   select * from ec0 a, ec1 b
regression->   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;

The b.ff = 43 is disappeared from ec1 b. But since it even didn't shown
before the EC filter, so I'm not sure my changes here make something wrong,
maybe fix a issue by accidental?
---
 src/backend/nodes/outfuncs.c             |  2 +
 src/backend/optimizer/path/equivclass.c  | 57 +++++++++++++-----------
 src/backend/optimizer/plan/initsplan.c   | 50 +++++----------------
 src/include/nodes/pathnodes.h            |  2 +
 src/test/regress/expected/equivclass.out |  6 +--
 5 files changed, 47 insertions(+), 70 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index b19462c758..f31f1de983 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2674,6 +2674,8 @@ _outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
 	WRITE_OID_FIELD(ef_opno);
 	WRITE_BOOL_FIELD(ef_const_is_left);
 	WRITE_UINT_FIELD(ef_source_rel);
+	WRITE_OID_FIELD(opfamily);
+	WRITE_INT_FIELD(amstrategy);
 }
 
 static void
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 89c7f0dc39..38bbc325b0 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1234,19 +1234,17 @@ generate_base_implied_equalities_const(PlannerInfo *root,
 }
 
 /*
- * finds the opfamily and strategy number for the specified 'opno' and 'method'
- * access method. Returns True if one is found and sets 'family' and
- * 'amstrategy', or returns False if none are found.
+ * finds the operator id for the specified 'opno' and 'method' and 'opfamilies'
+ * Returns True if one is found and sets 'opfamily_p' and 'amstrategy_p' or returns
+ * False if none are found.
  */
 static bool
-find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
+find_am_family_and_stategy(Oid opno, Oid method, List *opfamilies,
+						   Oid *opfamily_p, int *amstrategy_p)
 {
-	List *opfamilies;
 	ListCell *l;
 	int strategy;
 
-	opfamilies = get_opfamilies(opno, method);
-
 	foreach(l, opfamilies)
 	{
 		Oid opfamily = lfirst_oid(l);
@@ -1255,8 +1253,8 @@ find_am_family_and_stategy(Oid opno, Oid method, Oid *family, int *amstrategy)
 
 		if (strategy)
 		{
-			*amstrategy = strategy;
-			*family = opfamily;
+			*opfamily_p = opfamily;
+			*amstrategy_p = strategy;
 			return true;
 		}
 	}
@@ -1345,17 +1343,11 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
 			Expr *leftexpr;
 			Expr *rightexpr;
-			int strategy;
 			Oid opno;
-			Oid family;
 
 			if (ef->ef_source_rel == relid)
 				continue;
 
-			if (!find_am_family_and_stategy(ef->ef_opno, BTREE_AM_OID,
-				&family, &strategy))
-				continue;
-
 			if (ef->ef_const_is_left)
 			{
 				leftexpr = (Expr *) ef->ef_const;
@@ -1367,10 +1359,10 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rightexpr = (Expr *) ef->ef_const;
 			}
 
-			opno = get_opfamily_member(family,
+			opno = get_opfamily_member(ef->opfamily,
 										exprType((Node *) leftexpr),
 										exprType((Node *) rightexpr),
-										strategy);
+										ef->amstrategy);
 
 			if (opno == InvalidOid)
 				continue;
@@ -1989,9 +1981,12 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 	 */
 	foreach(l, quallist)
 	{
-		OpExpr	   *opexpr = (OpExpr *) lfirst(l);
-		Expr	   *leftexpr = (Expr *) linitial(opexpr->args);
-		Expr	   *rightexpr = (Expr *) lsecond(opexpr->args);
+		RestrictInfo *rinfo = lfirst_node(RestrictInfo, l);
+		OpExpr *opexpr = (OpExpr *)(rinfo->clause);
+
+		Oid opfamily;
+		int amstrategy;
+
 		Const	   *constexpr;
 		Expr	   *varexpr;
 		Relids		exprrels;
@@ -2003,25 +1998,31 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 		 * Determine if the the OpExpr is in the form "expr op const" or
 		 * "const op expr".
 		 */
-		if (IsA(leftexpr, Const))
+		if (bms_is_empty(rinfo->left_relids))
 		{
-			constexpr = (Const *) leftexpr;
-			varexpr = rightexpr;
+			constexpr = (Const *) get_leftop(rinfo->clause);
+			varexpr = (Expr *) get_rightop(rinfo->clause);
 			const_isleft = true;
+			exprrels = rinfo->right_relids;
 		}
 		else
 		{
-			constexpr = (Const *) rightexpr;
-			varexpr = leftexpr;
+			constexpr = (Const *) get_rightop(rinfo->clause);
+			varexpr = (Expr *) get_leftop(rinfo->clause);
 			const_isleft = false;
+			exprrels = rinfo->left_relids;
 		}
 
-		exprrels = pull_varnos(root, (Node *) varexpr);
-
 		/* should be filtered out, but we need to determine relid anyway */
 		if (!bms_get_singleton_member(exprrels, &relid))
 			continue;
 
+		if (!find_am_family_and_stategy(opexpr->opno, BTREE_AM_OID,
+										rinfo->btreeineqopfamilies,
+										&opfamily,
+										&amstrategy))
+			continue;
+
 		/* search for a matching eclass member in all eclasses */
 		foreach(l2, root->eq_classes)
 		{
@@ -2057,6 +2058,8 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 					efilter->ef_const_is_left = const_isleft;
 					efilter->ef_opno = opexpr->opno;
 					efilter->ef_source_rel = relid;
+					efilter->opfamily = opfamily;
+					efilter->amstrategy = amstrategy;
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index f86276b667..d7a173b327 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -651,44 +651,6 @@ create_lateral_join_info(PlannerInfo *root)
 	}
 }
 
-/*
- * is_simple_filter_qual
- *             Analyzes an OpExpr to determine if it may be useful as an
- *             EquivalenceFilter. Returns true if the OpExpr may be of some use, or
- *             false if it should not be used.
- */
-static bool
-is_simple_filter_qual(PlannerInfo *root, OpExpr *expr)
-{
-	Expr *leftexpr;
-	Expr *rightexpr;
-
-	if (!IsA(expr, OpExpr))
-			return false;
-
-	if (list_length(expr->args) != 2)
-			return false;
-
-	leftexpr = (Expr *) linitial(expr->args);
-	rightexpr = (Expr *) lsecond(expr->args);
-
-	/* XXX should we restrict these to simple Var op Const expressions? */
-	if (IsA(leftexpr, Const))
-	{
-		if (bms_membership(pull_varnos(root, (Node *) rightexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) rightexpr))
-			return true;
-	}
-	else if (IsA(rightexpr, Const))
-	{
-		if (bms_membership(pull_varnos(root, (Node *) leftexpr)) == BMS_SINGLETON &&
-			!contain_volatile_functions((Node *) leftexpr))
-			return true;
-	}
-
-	return false;
-}
-
 /*****************************************************************************
  *
  *	  JOIN TREE PROCESSING
@@ -1678,6 +1640,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	bool		maybe_outer_join;
 	Relids		nullable_relids;
 	RestrictInfo *restrictinfo;
+	int	relid;
 
 	/*
 	 * Retrieve all relids mentioned within the clause.
@@ -2027,8 +1990,15 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	distribute_restrictinfo_to_rels(root, restrictinfo);
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
-	if (filter_qual_list != NULL && is_simple_filter_qual(root, (OpExpr *) clause))
-		*filter_qual_list = lappend(*filter_qual_list, clause);
+	if (filter_qual_list != NULL &&
+		is_opclause(restrictinfo->clause) &&
+		!contain_volatile_functions((Node *)restrictinfo) && // Cachable
+		restrictinfo->btreeineqopfamilies != NIL &&  /* ineq expression */
+		/* simple & common enough filter, one side references one relation and the other one is a constant */
+		((bms_is_empty(restrictinfo->left_relids) && bms_get_singleton_member(restrictinfo->right_relids, &relid)) ||
+		 (bms_is_empty(restrictinfo->right_relids) && bms_get_singleton_member(restrictinfo->left_relids, &relid)))
+		)
+		*filter_qual_list = lappend(*filter_qual_list, restrictinfo);
 }
 
 /*
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index f80b47ae2c..942a52fcac 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1179,6 +1179,8 @@ typedef struct EquivalenceFilter
 	Oid			ef_opno;		/* Operator Oid of filter operator */
 	bool		ef_const_is_left; /* Is the Const on the left of the OpExrp? */
 	Index		ef_source_rel;	/* relid of originating relation. */
+	Oid			opfamily;
+	int			amstrategy;
 } EquivalenceFilter;
 
 /*
diff --git a/src/test/regress/expected/equivclass.out b/src/test/regress/expected/equivclass.out
index 92fcec1158..980bd3817d 100644
--- a/src/test/regress/expected/equivclass.out
+++ b/src/test/regress/expected/equivclass.out
@@ -407,14 +407,14 @@ set session authorization regress_user_ectest;
 explain (costs off)
   select * from ec0 a, ec1 b
   where a.ff = b.ff and a.ff = 43::bigint::int8alias1;
-                              QUERY PLAN                              
-----------------------------------------------------------------------
+                 QUERY PLAN                  
+---------------------------------------------
  Nested Loop
    ->  Index Scan using ec0_pkey on ec0 a
          Index Cond: (ff = '43'::int8alias1)
    ->  Index Scan using ec1_pkey on ec1 b
          Index Cond: (ff = a.ff)
-         Filter: ((f1 < '5'::int8alias1) AND (ff = '43'::int8alias1))
+         Filter: (f1 < '5'::int8alias1)
 (6 rows)
 
 reset session authorization;
-- 
2.37.0

From e84fa416c5e55fcdb250bfbb0125fa2fc75013df Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Jul 2022 15:48:00 +0300
Subject: [PATCH 4/6] Prepare the code for CorrectiveQual structure. Just
 refactor the method for 2-level loop in
 generate_base_implied_equalities_no_const, no other things is changed.

---
 src/backend/optimizer/path/equivclass.c | 61 +++++++++++++++----------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 38bbc325b0..b3e5ebfbb1 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1333,17 +1333,33 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 				rinfo->right_em = cur_em;
 			}
 		}
+		prev_ems[relid] = cur_em;
+	}
 
-		/*
-		 * Also push any EquivalenceFilter clauses down into all relations
-		 * other than the one which the filter actually originated from.
-		 */
-		foreach(lc2, ec->ec_filters)
+	pfree(prev_ems);
+
+
+	/*
+	 * Also push any EquivalenceFilter clauses down into all relations
+	 * other than the one which the filter actually originated from.
+	 */
+	foreach(lc2, ec->ec_filters)
+	{
+		EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
+		Expr *leftexpr;
+		Expr *rightexpr;
+		Oid opno;
+		int relid;
+
+		if (ec->ec_broken)
+			break;
+
+		foreach(lc, ec->ec_members)
 		{
-			EquivalenceFilter *ef = (EquivalenceFilter *) lfirst(lc2);
-			Expr *leftexpr;
-			Expr *rightexpr;
-			Oid opno;
+			EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
+
+			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
+				continue;
 
 			if (ef->ef_source_rel == relid)
 				continue;
@@ -1360,29 +1376,26 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			}
 
 			opno = get_opfamily_member(ef->opfamily,
-										exprType((Node *) leftexpr),
-										exprType((Node *) rightexpr),
-										ef->amstrategy);
+									   exprType((Node *) leftexpr),
+									   exprType((Node *) rightexpr),
+									   ef->amstrategy);
 
 			if (opno == InvalidOid)
 				continue;
 
+
 			process_implied_equality(root, opno,
-										ec->ec_collation,
-										leftexpr,
-										rightexpr,
-										bms_copy(ec->ec_relids),
-										bms_copy(cur_em->em_nullable_relids),
-										ec->ec_min_security,
-										ec->ec_below_outer_join,
-										false);
+									 ec->ec_collation,
+									 leftexpr,
+									 rightexpr,
+									 bms_copy(ec->ec_relids),
+									 bms_copy(cur_em->em_nullable_relids),
+									 ec->ec_min_security,
+									 ec->ec_below_outer_join,
+									 false);
 		}
-
-		prev_ems[relid] = cur_em;
 	}
 
-	pfree(prev_ems);
-
 	/*
 	 * We also have to make sure that all the Vars used in the member clauses
 	 * will be available at any join node we might try to reference them at.
-- 
2.37.0

From 03e75cf5db6b607cd62d2fdcd1b44e56fccaf3cf Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Jul 2022 15:52:36 +0300
Subject: [PATCH 5/6] CorrectiveQuals is as simple as a List of RestrictInfo,
 a). only one restrictinfo on this group should be counted for any joinrel
 estimation. b). at least 1 restrictinfo in this group should be executed
 during execution. In this commit, only rows estimation issue is addressed.

PlannerInfo.correlative_quals is added to manage all the CorrectiveQuals at
subquery level. RelOptInfo.cqual_indexes is a List * to indicate a which
CorrectiveQuals this relation related to. This is designed for easy to check if
the both sides of joinrel correlated to the same CorrectiveQuals. Why isn't the
type a Bitmapset * will be explained later.

The overall design of handing the joinrel size estimation is:
a). At the base relation level, we just count everything with the correlative
quals. b). During the any level joinrel size estimation, we just keep 1 side's
cqual (short for corrective qual) selectivity by eliminated the other one. so
the size estimation for a mergeable join selectivity becomes to:

rows = R1.rows X r2.rows X 1 / Max (ndistval_of_colA,  ndistinval_of_colB) X 1 /
Selectivity(R1's CorrectiveQual).

r1.rows X 1 / Selectivity(R1's CorrectiveQual) eliminated the impact of
CorrectiveQual on R1. After this,  the JoinRel of (R1, R2) still be impacted by
this CorrectiveQual but just one in this level.  Later if JoinRel(R1, R2) needs
to join with R3,  and R3 is impacted by this CorectiveQuals as well. This we
need to keep one and eliminating the other one as above again.

The algorithm for which Selectivity should be eliminated and which one should be
kept is:

When we join 2 inner_rel and outer_rel with a mergeable join restrictinfo, if
both sides is impacted with the same CorrectiveQual, we first choose which "side"
to eliminating based on which side of the restrictinfo has a higher distinct
value. The reason for this is more or less because we used "Max"(ndistinctValT1,
ndistinctValT2). After decide which "side" to eliminating, the real eliminating
selecitity is the side of RelOptInfo->cqual_selectivity[n]

Selectivity *RelOptInfo->cqual_selectivity:

 The number of elements in cqual_selecitity equals
 the length of cqual_indexes. The semantics is which
 selectivity in the corresponding CorectiveQuals's qual
 list is taking effect. At only time, only 1 Qual
 Selectivity is counted for any-level of joinrel.

and the other side's RelOptInfo->cqual_selectivty is used to set the upper
joinrel->cqual_selecivity.

In reality, it is possible for to have many CorrectiveQuals, but for design
discussion, the current implementation only take care of the 1 CorrectiveQuals.
this would be helpful for PoC/review/discussion.

Some flow for the key data:

1. root->corrective_quals is initialized at
generate_base_implied_equalities_no_const stage. we create a CorrectiveQual in
this list for each ec_filter and fill the RestrictInfo part for this cqual. At
the same time, we note which RelOptInfo (cqual_indexes) has related to this cqual.

2. RelOptInfo->cqual_selecitity for baserel is set at the end of set_rel_size,
at this time, the selectivity for every RestrictInfo is calcuated, we can just
fetch the cached value.  As for joinrel, it is maintained in
calc_join_cqual_selectivity, this function would return the Selectivity to
eliminate and set the above value.

Limitation in this PoC:
1. Only support 1 CorrectiveQual in root->correlative_quals
2. Only tested with INNER_JOIN.
3. Inherited table is not supported.
---
 src/backend/nodes/outfuncs.c              |   1 +
 src/backend/optimizer/path/allpaths.c     |  27 ++++
 src/backend/optimizer/path/costsize.c     | 182 ++++++++++++++++++++++
 src/backend/optimizer/path/equivclass.c   |  48 ++++--
 src/backend/optimizer/plan/planner.c      |   1 +
 src/backend/optimizer/prep/prepjointree.c |   1 +
 src/include/nodes/nodes.h                 |   1 +
 src/include/nodes/pathnodes.h             |  36 ++++-
 8 files changed, 280 insertions(+), 17 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index f31f1de983..5e0434df1e 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2676,6 +2676,7 @@ _outEquivalenceFilter(StringInfo str, const EquivalenceFilter *node)
 	WRITE_UINT_FIELD(ef_source_rel);
 	WRITE_OID_FIELD(opfamily);
 	WRITE_INT_FIELD(amstrategy);
+	WRITE_NODE_FIELD(rinfo);
 }
 
 static void
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index e9342097e5..2ee28a94fc 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -463,6 +463,33 @@ set_rel_size(PlannerInfo *root, RelOptInfo *rel,
 	 * We insist that all non-dummy rels have a nonzero rowcount estimate.
 	 */
 	Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
+
+	/* Now calculating the selectivity impacted by Corrective Qual */
+	if (!rte->inh)  /* not supported in this PoC */
+	{
+		ListCell *l;
+		int i = 0;
+		rel->cqual_selectivity = palloc(sizeof(Selectivity) * list_length(rel->cqual_indexes));
+
+		foreach(l, rel->cqual_indexes)
+		{
+			int cq_index = lfirst_int(l);
+			CorrelativeQuals *cquals = list_nth_node(CorrelativeQuals, root->correlative_quals, cq_index);
+			ListCell *l2;
+			bool found = false;
+			foreach(l2, cquals->corr_restrictinfo)
+			{
+				RestrictInfo *rinfo = lfirst_node(RestrictInfo, l2);
+				if (bms_equal(rinfo->clause_relids, rel->relids))
+				{
+					found = true;
+					rel->cqual_selectivity[i] = rinfo->norm_selec > 0 ? rinfo->norm_selec : rinfo->outer_selec;
+					Assert(rel->cqual_selectivity[i] > 0);
+				}
+			}
+			Assert(found);
+		}
+	}
 }
 
 /*
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index fcc26b01a4..03b92a2a88 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -5428,6 +5428,138 @@ get_parameterized_joinrel_size(PlannerInfo *root, RelOptInfo *rel,
 	return nrows;
 }
 
+
+/*
+ * Given a mergeable RestrictInfo, find out which relid should be used for
+ * eliminating Corrective Qual Selectivity.
+ */
+static int
+find_relid_to_eliminate(PlannerInfo *root, RestrictInfo *rinfo)
+{
+	int left_relid,  right_relid;
+	RelOptInfo *lrel, *rrel;
+	bool res;
+
+	res = bms_get_singleton_member(rinfo->left_relids, &left_relid);
+	Assert(res);
+	res = bms_get_singleton_member(rinfo->left_relids, &right_relid);
+	Assert(res);
+
+	lrel = root->simple_rel_array[left_relid];
+	rrel = root->simple_rel_array[right_relid];
+
+	/* XXX: Assumed only one CorrectiveQual exists */
+
+	if (lrel->cqual_selectivity[0] > rrel->cqual_selectivity[0])
+		return left_relid;
+
+	return right_relid;
+}
+
+/*
+ * calc_join_cqual_selectivity
+ *
+ *	When join two relations, if both sides are impacted by the same CorrectiveQuals,
+ * we need to eliminate one of them and note the other one for future eliminating when join
+ * another corrective relation. or else just note the joinrel still being impacted by the
+ * single sides's CorrectiveQuals.
+ *
+ * Return value is the Selectivity we need to eliminate for estimating the current
+ * joinrel.
+ */
+static double
+calc_join_cqual_selectivity(PlannerInfo *root,
+							RelOptInfo *joinrel,
+							RelOptInfo *outer_rel,
+							RelOptInfo *inner_rel,
+							RestrictInfo *rinfo)
+{
+	double res = 1;
+	ListCell *lc1, *lc2;
+	Selectivity left_sel;  /* The cqual selectivity still impacted on this joinrel. */
+
+	/*
+	 * Find how many CorrectiveQual for this joinrel and allocate space for each left Selectivity
+	 * for each CorrectiveQual here.
+	 */
+	List	*final_cq_list = list_union_int(outer_rel->cqual_indexes, inner_rel->cqual_indexes);
+
+	joinrel->cqual_selectivity = palloc(sizeof(Selectivity) * list_length(final_cq_list));
+
+	foreach(lc1, outer_rel->cqual_indexes)
+	{
+		int outer_cq_index = lfirst_int(lc1);
+		int inner_cq_pos = -1;
+		int outer_idx = foreach_current_index(lc1);
+		int curr_sel_len;
+
+		/*
+		 * Check if the same corrective quals applied in both sides,
+		 * if yes, we need to decide which one to eliminate and which one
+		 * to keep. or else, we just keep the selectivity for feature use.
+		 */
+		foreach(lc2, inner_rel->cqual_indexes)
+		{
+			if (outer_cq_index == lfirst_int(lc2))
+				inner_cq_pos = foreach_current_index(lc2);
+		}
+
+		if (inner_cq_pos >= 0)
+		{
+			/* Find the CorrectiveQual which impacts both side. */
+			int relid = find_relid_to_eliminate(root, rinfo);
+			if (bms_is_member(relid, outer_rel->relids))
+			{
+				/* XXXX: we assume only 1 CorrectiveQual exist, so [0] directly. */
+				res *= outer_rel->cqual_selectivity[0];
+				left_sel = inner_rel->cqual_selectivity[0];
+			}
+			else
+			{
+				/* XXXX: we assume only 1 CorrectiveQual exist */
+				res *= inner_rel->cqual_selectivity[0];
+				left_sel = outer_rel->cqual_selectivity[0];
+			}
+		}
+		else
+		{
+			/* Only shown in outer side. */
+			left_sel = outer_rel->cqual_selectivity[outer_idx];
+		}
+
+		/*
+		 * If any side of join relation is impacted by a cqual, it is impacted for the joinrel
+		 * for sure.
+		 */
+		curr_sel_len = list_length(joinrel->cqual_indexes);
+		joinrel->cqual_indexes = lappend_int(joinrel->cqual_indexes, outer_idx);
+
+		joinrel->cqual_selectivity[curr_sel_len] = left_sel;
+		// elog(INFO, "left_sel %f", left_sel);
+	}
+
+	/* Push any cqual information which exists in inner_rel only to join rel. */
+	foreach(lc1, inner_rel->cqual_indexes)
+	{
+		int inner_cq_index = lfirst_int(lc1);
+		int curr_sel_len;
+
+		if (list_member_int(outer_rel->cqual_indexes, inner_cq_index))
+			/* have been handled in the previous loop */
+			continue;
+
+		curr_sel_len = list_length(joinrel->cqual_indexes);
+		joinrel->cqual_selectivity[curr_sel_len] = inner_rel->cqual_selectivity[foreach_current_index(lc1)];
+	}
+
+	pfree(final_cq_list);
+
+	// elog(INFO, "Final adjust sel (%s): %f", bmsToString(joinrel->relids), res);
+
+	return res;
+}
+
+
 /*
  * calc_joinrel_size_estimate
  *		Workhorse for set_joinrel_size_estimates and
@@ -5571,6 +5703,56 @@ calc_joinrel_size_estimate(PlannerInfo *root,
 			break;
 	}
 
+	{
+		Selectivity m1 = 1;
+		bool should_eliminate = false;
+		RestrictInfo *rinfo;
+
+		// XXX: For hack only, the aim is the "only one" restrictinfo is the one impacted by "the only one"
+		// CorrectiveQuals. for example:
+		// SELECT * FROM t1, t2, t3 WHERE t1.a = t2.a and t2.a = t3.a and t3.a > 2;
+
+		if (list_length(root->correlative_quals) == 1 &&
+			list_length(restrictlist) == 1 &&
+			jointype == JOIN_INNER)
+		{
+			int left_relid, right_relid;
+			rinfo = linitial_node(RestrictInfo, restrictlist);
+			if (rinfo->mergeopfamilies != NIL &&
+				bms_get_singleton_member(rinfo->left_relids, &left_relid) &&
+				bms_get_singleton_member(rinfo->right_relids, &right_relid))
+			{
+				List *interset_cq_indexes = list_intersection_int(
+					root->simple_rel_array[left_relid]->cqual_indexes,
+					root->simple_rel_array[right_relid]->cqual_indexes);
+
+				if (interset_cq_indexes != NIL &&
+					!root->simple_rte_array[left_relid]->inh &&
+					!root->simple_rte_array[right_relid]->inh)
+					should_eliminate = true;
+			}
+		}
+
+		// elog(INFO, "joinrel: %s, %d", bmsToString(joinrel->relids), should_eliminate);
+
+		if (should_eliminate)
+			m1 = calc_join_cqual_selectivity(root, joinrel, outer_rel, inner_rel, rinfo);
+
+		/* elog(INFO, */
+		/*	 "joinrelids: %s, outer_rel: %s, inner_rel: %s, join_clauselist: %s outer rows: %f, inner_rows: %f, join rows: %f, jselec: %f, m1 = %f, m2 = %f", */
+		/*	 bmsToString(joinrel->relids), */
+		/*	 bmsToString(outer_rel->relids), */
+		/*	 bmsToString(inner_rel->relids), */
+		/*	 bmsToString(join_list_relids), */
+		/*	 outer_rel->rows, */
+		/*	 inner_rel->rows, */
+		/*	 nrows, */
+		/*	 jselec, */
+		/*	 m1, */
+		/*	 m2); */
+		nrows /= m1;
+	}
+
 	return clamp_row_est(nrows);
 }
 
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index b3e5ebfbb1..3efeb1f333 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1272,6 +1272,8 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 	EquivalenceMember **prev_ems;
 	ListCell   *lc;
 	ListCell   *lc2;
+	int	start_cq_index = list_length(root->correlative_quals);
+	int	ef_index = 0;
 
 	/*
 	 * We scan the EC members once and track the last-seen member for each
@@ -1338,9 +1340,11 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 
 	pfree(prev_ems);
 
+	if (ec->ec_broken)
+		goto ec_filter_done;
 
 	/*
-	 * Also push any EquivalenceFilter clauses down into all relations
+	 * Push any EquivalenceFilter clauses down into all relations
 	 * other than the one which the filter actually originated from.
 	 */
 	foreach(lc2, ec->ec_filters)
@@ -1350,19 +1354,25 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 		Expr *rightexpr;
 		Oid opno;
 		int relid;
-
-		if (ec->ec_broken)
-			break;
+		CorrelativeQuals *cquals = makeNode(CorrelativeQuals);
 
 		foreach(lc, ec->ec_members)
 		{
 			EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc);
+			RelOptInfo *rel;
+			RestrictInfo *rinfo;
 
 			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
 				continue;
 
+			rel = root->simple_rel_array[relid];
+
 			if (ef->ef_source_rel == relid)
+			{
+				rel->cqual_indexes = lappend_int(rel->cqual_indexes, start_cq_index + ef_index);
+				cquals->corr_restrictinfo = lappend(cquals->corr_restrictinfo, ef->rinfo);
 				continue;
+			}
 
 			if (ef->ef_const_is_left)
 			{
@@ -1383,19 +1393,28 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (opno == InvalidOid)
 				continue;
 
-
-			process_implied_equality(root, opno,
-									 ec->ec_collation,
-									 leftexpr,
-									 rightexpr,
-									 bms_copy(ec->ec_relids),
-									 bms_copy(cur_em->em_nullable_relids),
-									 ec->ec_min_security,
-									 ec->ec_below_outer_join,
-									 false);
+			rinfo = process_implied_equality(root, opno,
+											 ec->ec_collation,
+											 leftexpr,
+											 rightexpr,
+											 bms_copy(ec->ec_relids),
+											 bms_copy(cur_em->em_nullable_relids),
+											 ec->ec_min_security,
+											 ec->ec_below_outer_join,
+											 false);
+			cquals->corr_restrictinfo = lappend(cquals->corr_restrictinfo, rinfo);
+			rel->cqual_indexes = lappend_int(rel->cqual_indexes, start_cq_index + ef_index);
 		}
+
+		ef_index += 1;
+
+		root->correlative_quals = lappend(root->correlative_quals, cquals);
 	}
 
+ec_filter_done:
+	/*
+	 * XXX this label can be removed after moving ec_filter to the end of this function.
+	 */
 	/*
 	 * We also have to make sure that all the Vars used in the member clauses
 	 * will be available at any join node we might try to reference them at.
@@ -2073,6 +2092,7 @@ distribute_filter_quals_to_eclass(PlannerInfo *root, List *quallist)
 					efilter->ef_source_rel = relid;
 					efilter->opfamily = opfamily;
 					efilter->amstrategy = amstrategy;
+					efilter->rinfo = rinfo;
 
 					ec->ec_filters = lappend(ec->ec_filters, efilter);
 					break;		/* Onto the next eclass */
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 06ad856eac..2be2429454 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -619,6 +619,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
 	root->multiexpr_params = NIL;
 	root->eq_classes = NIL;
 	root->ec_merging_done = false;
+	root->correlative_quals = NIL;
 	root->all_result_relids =
 		parse->resultRelation ? bms_make_singleton(parse->resultRelation) : NULL;
 	root->leaf_result_relids = NULL;	/* we'll find out leaf-ness later */
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 0bd99acf83..d427de6f85 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -999,6 +999,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	subroot->multiexpr_params = NIL;
 	subroot->eq_classes = NIL;
 	subroot->ec_merging_done = false;
+	subroot->correlative_quals = NIL;
 	subroot->all_result_relids = NULL;
 	subroot->leaf_result_relids = NULL;
 	subroot->append_rel_list = NIL;
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index ba879ab3e9..8800a05252 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -278,6 +278,7 @@ typedef enum NodeTag
 	/* these aren't subclasses of Path: */
 	T_EquivalenceClass,
 	T_EquivalenceFilter,
+	T_CorrelativeQuals,
 	T_EquivalenceMember,
 	T_PathKey,
 	T_PathKeyInfo,
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 942a52fcac..1e9bb39277 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -251,6 +251,8 @@ struct PlannerInfo
 
 	bool		ec_merging_done;	/* set true once ECs are canonical */
 
+	List		*correlative_quals;  /* list of CorrelativeQuals for this subquery */
+
 	List	   *canon_pathkeys; /* list of "canonical" PathKeys */
 
 	List	   *left_join_clauses;	/* list of RestrictInfos for mergejoinable
@@ -767,6 +769,18 @@ typedef struct RelOptInfo
 	 * Indexes in PlannerInfo's eq_classes list of ECs that mention this rel
 	 */
 	Bitmapset  *eclass_indexes;
+	List		*cqual_indexes; /* Indexes in PlannerInfo's correlative_quals list of
+								 * CorrelativeQuals that this rel has applied. It is valid
+								 * on both baserel and joinrel. Used to quick check is the
+								 * both sides contains the same CorrectiveQuals object.
+								 */
+	Selectivity	*cqual_selectivity; /*
+								   * The number of elements in cqual_selectivity equals
+								   * the length of cqual_indexes. The semantics is which
+								   * selectivity in the corresponding CorectiveQuals's qual
+								   * list is taking effect. At only time, only 1 Qual
+								   * Selectivity is counted for any-level of joinrel.
+								   */
 	PlannerInfo *subroot;		/* if subquery */
 	List	   *subplan_params; /* if subquery */
 	/* wanted number of parallel workers */
@@ -1181,8 +1195,24 @@ typedef struct EquivalenceFilter
 	Index		ef_source_rel;	/* relid of originating relation. */
 	Oid			opfamily;
 	int			amstrategy;
+	struct RestrictInfo	*rinfo;		/* source restrictInfo for this EquivalenceFilter */
 } EquivalenceFilter;
 
+
+/*
+ * Currently it is as simple as a List of RestrictInfo, it means a). For any joinrel size
+ * estimation, only one restrictinfo on this group should be counted. b). During execution,
+ * at least 1 restrictinfo in this group should be executed.
+ *
+ * Define it as a Node just for better extendability, we can stripe it to a List *
+ * if we are sure nothing else is needed.
+ */
+typedef struct CorrelativeQuals
+{
+	NodeTag	type;
+	List	*corr_restrictinfo;
+} CorrelativeQuals;
+
 /*
  * If an EC contains a const and isn't below-outer-join, any PathKey depending
  * on it must be redundant, since there's only one possible value of the key.
@@ -2872,7 +2902,7 @@ typedef enum
  *
  * flags indicating what kinds of grouping are possible.
  * partial_costs_set is true if the agg_partial_costs and agg_final_costs
- * 		have been initialized.
+ *		have been initialized.
  * agg_partial_costs gives partial aggregation costs.
  * agg_final_costs gives finalization costs.
  * target_parallel_safe is true if target is parallel safe.
@@ -2902,8 +2932,8 @@ typedef struct
  * limit_tuples is an estimated bound on the number of output tuples,
  *		or -1 if no LIMIT or couldn't estimate.
  * count_est and offset_est are the estimated values of the LIMIT and OFFSET
- * 		expressions computed by preprocess_limit() (see comments for
- * 		preprocess_limit() for more information).
+ *		expressions computed by preprocess_limit() (see comments for
+ *		preprocess_limit() for more information).
  */
 typedef struct
 {
-- 
2.37.0

From b05f3381a5cfde1d3e628b829fe2e7cff3649804 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Jul 2022 15:54:24 +0300
Subject: [PATCH 6/6] Disable ec filter for foregin table for now. We do need
 support EC filter against for foreign table, but when fixing the cost model
 issue, we need to know the selecvitiy of the qual on foregin table. However
 it is impossible for now to know that when use_remote_estimate = true. see
 for postgresGetForeignRelSize. Since we currently only doing PoC for this
 cost-model-fix algorithm, I just disable that for foregin table. At last, we
 need improve the use_remote_estimate somehow to get the selectivity.

---
 .../postgres_fdw/expected/postgres_fdw.out    | 36 +++++++++----------
 src/backend/optimizer/path/allpaths.c         |  2 +-
 src/backend/optimizer/path/equivclass.c       | 14 ++++++++
 src/backend/optimizer/plan/initsplan.c        |  9 +++--
 4 files changed, 40 insertions(+), 21 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 2758049f5b..44457f930c 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1545,12 +1545,12 @@ SELECT t1.c1, ss.a, ss.b FROM (SELECT c1 FROM "S 1"."T 3" WHERE c1 = 50) t1 INNE
 -- full outer join + inner join
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
-                                                                                                                                                                           QUERY PLAN                                                                                                                                                                           
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                 QUERY PLAN                                                                                                                                                 
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: t1.c1, t2.c1, t3.c1
    Relations: ((public.ft4 t1) INNER JOIN (public.ft5 t2)) FULL JOIN (public.ft4 t3)
-   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND (((r2.c1 + 1) >= 50)) AND (((r2.c1 + 1) <= 60)) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
+   Remote SQL: SELECT r1.c1, r2.c1, r4.c1 FROM (("S 1"."T 3" r1 INNER JOIN "S 1"."T 4" r2 ON (((r1.c1 = (r2.c1 + 1))) AND ((r1.c1 >= 50)) AND ((r1.c1 <= 60)))) FULL JOIN "S 1"."T 3" r4 ON (((r2.c1 = r4.c1)))) ORDER BY r1.c1 ASC NULLS LAST, r2.c1 ASC NULLS LAST, r4.c1 ASC NULLS LAST LIMIT 10::bigint
 (4 rows)
 
 SELECT t1.c1, t2.c1, t3.c1 FROM ft4 t1 INNER JOIN ft5 t2 ON (t1.c1 = t2.c1 + 1 and t1.c1 between 50 and 60) FULL JOIN ft4 t3 ON (t2.c1 = t3.c1) ORDER BY t1.c1, t2.c1, t3.c1 LIMIT 10;
@@ -2335,12 +2335,12 @@ SELECT ft4.c1, q.* FROM ft4 LEFT JOIN (SELECT 13, ft1.c1, ft2.c1 FROM ft1 RIGHT
 UPDATE ft5 SET c3 = null where c1 % 9 = 0;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
-                                                                                                                                                    QUERY PLAN                                                                                                                                                     
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                QUERY PLAN                                                                                                                                 
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: ft5.*, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2
    Relations: (public.ft5) INNER JOIN (public.ft4)
-   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)) AND ((r1.c1 >= 10)) AND ((r1.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
+   Remote SQL: SELECT CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1.c1, r1.c2, r1.c3) END, r1.c1, r1.c2, r1.c3, r2.c1, r2.c2 FROM ("S 1"."T 4" r1 INNER JOIN "S 1"."T 3" r2 ON (((r1.c1 = r2.c1)) AND ((r2.c1 >= 10)) AND ((r2.c1 <= 30)))) ORDER BY r1.c1 ASC NULLS LAST
 (4 rows)
 
 SELECT ft5, ft5.c1, ft5.c2, ft5.c3, ft4.c1, ft4.c2 FROM ft5 left join ft4 on ft5.c1 = ft4.c1 WHERE ft4.c1 BETWEEN 10 and 30 ORDER BY ft5.c1, ft4.c1;
@@ -2362,8 +2362,8 @@ SET enable_hashjoin TO false;
 EXPLAIN (VERBOSE, COSTS OFF)
 SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = ft4.c1
     AND ft1.c2 = ft5.c1 AND ft1.c2 = local_tbl.c1 AND ft1.c1 < 100 AND ft2.c1 < 100 FOR UPDATE;
-                                                                                                                                                                                                                                                                                                                                                                                                                                                                      QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                                                                                                                                                                                                                                               QUERY PLAN                                                                                                                                                                                                                                                                                                                                                                                                                                               
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  LockRows
    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft4.c1, ft4.c2, ft4.c3, ft5.c1, ft5.c2, ft5.c3, local_tbl.c1, local_tbl.c2, local_tbl.c3, ft1.*, ft2.*, ft4.*, ft5.*, local_tbl.ctid
    ->  Merge Join
@@ -2373,7 +2373,7 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
          ->  Foreign Scan
                Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                Relations: (((public.ft1) INNER JOIN (public.ft2)) INNER JOIN (public.ft4)) INNER JOIN (public.ft5)
-               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
+               Remote SQL: SELECT r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END, r3.c1, r3.c2, r3.c3, CASE WHEN (r3.*)::text IS NOT NULL THEN ROW(r3.c1, r3.c2, r3.c3) END, r4.c1, r4.c2, r4.c3, CASE WHEN (r4.*)::text IS NOT NULL THEN ROW(r4.c1, r4.c2, r4.c3) END FROM ((("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" < 100)) AND ((r1."C 1" < 100)))) INNER JOIN "S 1"."T 3" r3 ON (((r1.c2 = r3.c1)))) INNER JOIN "S 1"."T 4" r4 ON (((r1.c2 = r4.c1)))) ORDER BY r1.c2 ASC NULLS LAST FOR UPDATE OF r1 FOR UPDATE OF r2 FOR UPDATE OF r3 FOR UPDATE OF r4
                ->  Merge Join
                      Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*, ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*, ft4.c1, ft4.c2, ft4.c3, ft4.*, ft5.c1, ft5.c2, ft5.c3, ft5.*
                      Merge Cond: (ft1.c2 = ft5.c1)
@@ -2391,12 +2391,12 @@ SELECT * FROM ft1, ft2, ft4, ft5, local_tbl WHERE ft1.c1 = ft2.c1 AND ft1.c2 = f
                                              Sort Key: ft1.c1
                                              ->  Foreign Scan on public.ft1
                                                    Output: ft1.c1, ft1.c2, ft1.c3, ft1.c4, ft1.c5, ft1.c6, ft1.c7, ft1.c8, ft1.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) FOR UPDATE
                                        ->  Materialize
                                              Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
                                              ->  Foreign Scan on public.ft2
                                                    Output: ft2.c1, ft2.c2, ft2.c3, ft2.c4, ft2.c5, ft2.c6, ft2.c7, ft2.c8, ft2.*
-                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
+                                                   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" < 100)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
                            ->  Sort
                                  Output: ft4.c1, ft4.c2, ft4.c3, ft4.*
                                  Sort Key: ft4.c1
@@ -5705,25 +5705,25 @@ UPDATE ft2 AS target SET (c2) = (
 EXPLAIN (VERBOSE, COSTS OFF)
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
   FROM ft2 AS t WHERE d.c1 = t.c1 AND d.c1 > 1000;
-                                                                                                                                                                                                   QUERY PLAN                                                                                                                                                                                                    
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                       QUERY PLAN                                                                                                                                                                                        
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Update on public.ft2 d
    Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
    ->  Foreign Scan
          Output: CASE WHEN (random() >= '0'::double precision) THEN d.c2 ELSE 0 END, d.ctid, d.*, t.*
          Relations: (public.ft2 d) INNER JOIN (public.ft2 t)
-         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r2."C 1" > 1000)) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
-         ->  Merge Join
+         Remote SQL: SELECT r1.c2, r1.ctid, CASE WHEN (r1.*)::text IS NOT NULL THEN ROW(r1."C 1", r1.c2, r1.c3, r1.c4, r1.c5, r1.c6, r1.c7, r1.c8) END, CASE WHEN (r2.*)::text IS NOT NULL THEN ROW(r2."C 1", r2.c2, r2.c3, r2.c4, r2.c5, r2.c6, r2.c7, r2.c8) END FROM ("S 1"."T 1" r1 INNER JOIN "S 1"."T 1" r2 ON (((r1."C 1" = r2."C 1")) AND ((r1."C 1" > 1000)))) FOR UPDATE OF r1
+         ->  Hash Join
                Output: d.c2, d.ctid, d.*, t.*
-               Merge Cond: (d.c1 = t.c1)
+               Hash Cond: (d.c1 = t.c1)
                ->  Foreign Scan on public.ft2 d
                      Output: d.c2, d.ctid, d.*, d.c1
                      Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST FOR UPDATE
-               ->  Materialize
+               ->  Hash
                      Output: t.*, t.c1
                      ->  Foreign Scan on public.ft2 t
                            Output: t.*, t.c1
-                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" > 1000)) ORDER BY "C 1" ASC NULLS LAST
+                           Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
 (17 rows)
 
 UPDATE ft2 d SET c2 = CASE WHEN random() >= 0 THEN d.c2 ELSE 0 END
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 2ee28a94fc..eb4ecc8478 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -465,7 +465,7 @@ set_rel_size(PlannerInfo *root, RelOptInfo *rel,
 	Assert(rel->rows > 0 || IS_DUMMY_REL(rel));
 
 	/* Now calculating the selectivity impacted by Corrective Qual */
-	if (!rte->inh)  /* not supported in this PoC */
+	if (!rte->inh)  /* Inherited table is not supported in this PoC */
 	{
 		ListCell *l;
 		int i = 0;
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 3efeb1f333..7b8124e1f2 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -21,6 +21,7 @@
 #include "access/stratnum.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_type.h"
+#include "catalog/pg_class.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/appendinfo.h"
@@ -1365,6 +1366,19 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 			if (!bms_get_singleton_member(cur_em->em_relids, &relid))
 				continue;
 
+			if (root->simple_rte_array[relid]->relkind == RELKIND_FOREIGN_TABLE)
+			{
+				/*
+				 * We do need support EC filter against for foreign table, but when fixing
+				 * the cost model issue, we need to know the selecvitiy of the qual on foregin
+				 * table. However it is impossible for now to know that when use_remote_estimate = true.
+				 * see for postgresGetForeignRelSize. Since we currently only doing PoC for
+				 * this cost-model-fix algorithm, I just disable that for foregin table. At last,
+				 * we need improve the use_remote_estimate somehow to get the selectivity.
+				 */
+				continue;
+			}
+
 			rel = root->simple_rel_array[relid];
 
 			if (ef->ef_source_rel == relid)
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index d7a173b327..9153b8d296 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -1991,9 +1991,14 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 
 	/* Check if the qual looks useful to harvest as an EquivalenceFilter */
 	if (filter_qual_list != NULL &&
+
+		// Must be an OpExpr for now.
 		is_opclause(restrictinfo->clause) &&
-		!contain_volatile_functions((Node *)restrictinfo) && // Cachable
-		restrictinfo->btreeineqopfamilies != NIL &&  /* ineq expression */
+		// Checking volatile against RestrictInfo so that the result can be cached.
+		!contain_volatile_functions((Node *)restrictinfo) &&
+
+		restrictinfo->btreeineqopfamilies != NIL && /* ineq expression */
+
 		/* simple & common enough filter, one side references one relation and the other one is a constant */
 		((bms_is_empty(restrictinfo->left_relids) && bms_get_singleton_member(restrictinfo->right_relids, &relid)) ||
 		 (bms_is_empty(restrictinfo->right_relids) && bms_get_singleton_member(restrictinfo->left_relids, &relid)))
-- 
2.37.0