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[PATCH 2/3] Support clauses of the form Var op Var
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[nested] [flat]

* [PATCH 2/3] Support clauses of the form Var op Var
@ 2019-11-11 00:34  Tomas Vondra <tv@fuzzy.cz>
  0 siblings, 0 replies; 6+ messages in thread

From: Tomas Vondra @ 2019-11-11 00:34 UTC (permalink / raw)

---
 src/backend/statistics/extended_stats.c       | 63 ++++++++++++----
 src/backend/statistics/mcv.c                  | 75 ++++++++++++++++++-
 .../statistics/extended_stats_internal.h      |  2 +-
 src/test/regress/expected/stats_ext.out       | 72 ++++++++++++++++++
 src/test/regress/sql/stats_ext.sql            | 22 ++++++
 5 files changed, 217 insertions(+), 17 deletions(-)

diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index 24ece6f99c..1872cd4529 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -986,14 +986,18 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 	{
 		RangeTblEntry *rte = root->simple_rte_array[relid];
 		OpExpr	   *expr = (OpExpr *) clause;
-		Var		   *var;
+		Var		   *var,
+				   *var2;
 
 		/* Only expressions with two arguments are considered compatible. */
 		if (list_length(expr->args) != 2)
 			return false;
 
-		/* Check if the expression the right shape (one Var, one Const) */
-		if (!examine_opclause_expression(expr, &var, NULL, NULL))
+		/*
+		 * Check if the expression the right shape (one Var and one Const,
+		 * or two Vars).
+		 */
+		if (!examine_opclause_expression(expr, &var, &var2, NULL, NULL))
 			return false;
 
 		/*
@@ -1033,7 +1037,20 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 			!get_func_leakproof(get_opcode(expr->opno)))
 			return false;
 
-		return statext_is_compatible_clause_internal(root, (Node *) var,
+		/*
+		 * Check compatibility of the first Var - we get this one for both
+		 * types of supported expressions (Var op Const) and (Var op Var).
+		 */
+		if (!statext_is_compatible_clause_internal(root, (Node *) var,
+												   relid, attnums))
+			return false;
+
+		/* For (Var op Const) we don't get the second Var, and we're done. */
+		if (!var2)
+			return true;
+
+		/* For (Var op Var) check compatibility of the second Var. */
+		return statext_is_compatible_clause_internal(root, (Node *) var2,
 													 relid, attnums);
 	}
 
@@ -1419,19 +1436,21 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
  * examine_opclause_expression
  *		Split expression into Var and Const parts.
  *
- * Attempts to match the arguments to either (Var op Const) or (Const op Var),
- * possibly with a RelabelType on top. When the expression matches this form,
- * returns true, otherwise returns false.
+ * Attempts to match the arguments to either (Var op Const) or (Const op Var)
+ * or (Var op Var), possibly with a RelabelType on top. When the expression
+ * matches this form, returns true, otherwise returns false.
  *
  * Optionally returns pointers to the extracted Var/Const nodes, when passed
  * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies
  * on which side of the operator we found the Var node.
  */
 bool
-examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
+examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
+							Const **cstp, bool *varonleftp)
 {
-	Var	   *var;
-	Const  *cst;
+	Var	   *var1 = NULL;
+	Var	   *var2 = NULL;
+	Const  *cst = NULL;
 	bool	varonleft;
 	Node   *leftop,
 		   *rightop;
@@ -1451,22 +1470,38 @@ examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonl
 
 	if (IsA(leftop, Var) && IsA(rightop, Const))
 	{
-		var = (Var *) leftop;
+		var1 = (Var *) leftop;
 		cst = (Const *) rightop;
 		varonleft = true;
 	}
 	else if (IsA(leftop, Const) && IsA(rightop, Var))
 	{
-		var = (Var *) rightop;
+		var1 = (Var *) rightop;
 		cst = (Const *) leftop;
 		varonleft = false;
 	}
+	else if (IsA(leftop, Var) && IsA(rightop, Var))
+	{
+		var1 = (Var *) leftop;
+		var2 = (Var *) rightop;
+		varonleft = false;
+
+		/*
+		 * Both variables have to be for the same relation (otherwise it's
+		 * a join clause, and we don't deal with those yet.
+		 */
+		if (var1->varno != var2->varno)
+			return false;
+	}
 	else
 		return false;
 
 	/* return pointers to the extracted parts if requested */
-	if (varp)
-		*varp = var;
+	if (var1p)
+		*var1p = var1;
+
+	if (var2p)
+		*var2p = var2;
 
 	if (cstp)
 		*cstp = cst;
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index 3f42713aa2..97d3083451 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1581,16 +1581,25 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 
 			/* valid only after examine_opclause_expression returns true */
 			Var		   *var;
+			Var		   *var2;
 			Const	   *cst;
 			bool		varonleft;
 
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
-			/* extract the var and const from the expression */
-			if (examine_opclause_expression(expr, &var, &cst, &varonleft))
+			/* extract the vars and const from the expression */
+			if (!examine_opclause_expression(expr, &var, &var2, &cst, &varonleft))
+				continue;	/* XXX Can this actually happen? */
+
+			/* We should always get at least one Var. */
+			Assert(var);
+
+			if (cst)
 			{
 				int			idx;
 
+				Assert(!var2);
+
 				/* match the attribute to a dimension of the statistic */
 				idx = bms_member_index(keys, var->varattno);
 
@@ -1651,6 +1660,68 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					matches[i] = RESULT_MERGE(matches[i], is_or, match);
 				}
 			}
+			else
+			{
+				int			idx;
+				int			idx2;
+
+				Assert(var2);
+
+				/* match the attribute to a dimension of the statistic */
+				idx = bms_member_index(keys, var->varattno);
+				idx2 = bms_member_index(keys, var2->varattno);
+
+				/*
+				 * Walk through the MCV items and evaluate the current clause.
+				 * We can skip items that were already ruled out, and
+				 * terminate if there are no remaining MCV items that might
+				 * possibly match.
+				 */
+				for (i = 0; i < mcvlist->nitems; i++)
+				{
+					bool		match = true;
+					MCVItem    *item = &mcvlist->items[i];
+
+					/*
+					 * When either of the MCV items is NULL we can treat this
+					 * as a mismatch. We must not call the operator because
+					 * of strictness.
+					 */
+					if (item->isnull[idx] || item->isnull[idx2])
+					{
+						matches[i] = RESULT_MERGE(matches[i], is_or, false);
+						continue;
+					}
+
+					/*
+					 * Skip MCV items that can't change result in the bitmap.
+					 * Once the value gets false for AND-lists, or true for
+					 * OR-lists, we don't need to look at more clauses.
+					 */
+					if (RESULT_IS_FINAL(matches[i], is_or))
+						continue;
+
+					/*
+					 * First check whether the constant is below the lower
+					 * boundary (in that case we can skip the bucket, because
+					 * there's no overlap).
+					 *
+					 * We don't store collations used to build the statistics,
+					 * but we can use the collation for the attribute itself,
+					 * as stored in varcollid. We do reset the statistics after
+					 * a type change (including collation change), so this is
+					 * OK. We may need to relax this after allowing extended
+					 * statistics on expressions.
+					 */
+					match = DatumGetBool(FunctionCall2Coll(&opproc,
+														   var->varcollid,
+														   item->values[idx],
+														   item->values[idx2]));
+
+					/* update the match bitmap with the result */
+					matches[i] = RESULT_MERGE(matches[i], is_or, match);
+				}
+			}
 		}
 		else if (IsA(clause, NullTest))
 		{
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index 5171895bba..804089bc57 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -96,7 +96,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
 									TupleDesc tdesc, MultiSortSupport mss,
 									int numattrs, AttrNumber *attnums);
 
-extern bool examine_opclause_expression(OpExpr *expr, Var **varp,
+extern bool examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
 										Const **cstp, bool *varonleftp);
 
 extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 5344b70cf4..4c078ae61f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -603,6 +603,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        343 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      1667 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+      1667 |      0
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -654,6 +666,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        200 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      3750 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+         1 |      0
+(1 row)
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 SELECT d.stxdmcv IS NOT NULL
@@ -749,6 +773,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       3750 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+        25 |   2500
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -758,6 +788,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       2500 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -808,6 +844,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
       1094 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      9950 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+        50 |   2500
+(1 row)
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 ANALYZE mcv_lists_bool;
@@ -835,6 +883,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
          1 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -869,6 +929,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
          4 |    142
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+         1 |   5000
+(1 row)
+
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
@@ -891,6 +957,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
        143 |    142
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+      5000 |   5000
+(1 row)
+
 DROP TABLE mcv_lists_multi;
 -- Permission tests. Users should not be able to see specific data values in
 -- the extended statistics, if they lack permission to see those values in
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index fa989fccb0..b7519b275b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -381,6 +381,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
@@ -402,6 +406,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 
@@ -473,6 +481,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 
@@ -480,6 +490,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -521,6 +533,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
@@ -534,6 +550,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -556,6 +576,7 @@ ANALYZE mcv_lists_multi;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
@@ -566,6 +587,7 @@ ANALYZE mcv_lists_multi;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 DROP TABLE mcv_lists_multi;
 
-- 
2.21.1


--n6bnrzck2js7zcqs--





^ permalink  raw  reply  [nested|flat] 6+ messages in thread

* [PATCH 2/3] Support clauses of the form Var op Var
@ 2019-11-11 00:34  Tomas Vondra <tv@fuzzy.cz>
  0 siblings, 0 replies; 6+ messages in thread

From: Tomas Vondra @ 2019-11-11 00:34 UTC (permalink / raw)

---
 src/backend/statistics/extended_stats.c       | 63 ++++++++++++----
 src/backend/statistics/mcv.c                  | 75 ++++++++++++++++++-
 .../statistics/extended_stats_internal.h      |  2 +-
 src/test/regress/expected/stats_ext.out       | 72 ++++++++++++++++++
 src/test/regress/sql/stats_ext.sql            | 22 ++++++
 5 files changed, 217 insertions(+), 17 deletions(-)

diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index 24ece6f99c..1872cd4529 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -986,14 +986,18 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 	{
 		RangeTblEntry *rte = root->simple_rte_array[relid];
 		OpExpr	   *expr = (OpExpr *) clause;
-		Var		   *var;
+		Var		   *var,
+				   *var2;
 
 		/* Only expressions with two arguments are considered compatible. */
 		if (list_length(expr->args) != 2)
 			return false;
 
-		/* Check if the expression the right shape (one Var, one Const) */
-		if (!examine_opclause_expression(expr, &var, NULL, NULL))
+		/*
+		 * Check if the expression the right shape (one Var and one Const,
+		 * or two Vars).
+		 */
+		if (!examine_opclause_expression(expr, &var, &var2, NULL, NULL))
 			return false;
 
 		/*
@@ -1033,7 +1037,20 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 			!get_func_leakproof(get_opcode(expr->opno)))
 			return false;
 
-		return statext_is_compatible_clause_internal(root, (Node *) var,
+		/*
+		 * Check compatibility of the first Var - we get this one for both
+		 * types of supported expressions (Var op Const) and (Var op Var).
+		 */
+		if (!statext_is_compatible_clause_internal(root, (Node *) var,
+												   relid, attnums))
+			return false;
+
+		/* For (Var op Const) we don't get the second Var, and we're done. */
+		if (!var2)
+			return true;
+
+		/* For (Var op Var) check compatibility of the second Var. */
+		return statext_is_compatible_clause_internal(root, (Node *) var2,
 													 relid, attnums);
 	}
 
@@ -1419,19 +1436,21 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
  * examine_opclause_expression
  *		Split expression into Var and Const parts.
  *
- * Attempts to match the arguments to either (Var op Const) or (Const op Var),
- * possibly with a RelabelType on top. When the expression matches this form,
- * returns true, otherwise returns false.
+ * Attempts to match the arguments to either (Var op Const) or (Const op Var)
+ * or (Var op Var), possibly with a RelabelType on top. When the expression
+ * matches this form, returns true, otherwise returns false.
  *
  * Optionally returns pointers to the extracted Var/Const nodes, when passed
  * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies
  * on which side of the operator we found the Var node.
  */
 bool
-examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
+examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
+							Const **cstp, bool *varonleftp)
 {
-	Var	   *var;
-	Const  *cst;
+	Var	   *var1 = NULL;
+	Var	   *var2 = NULL;
+	Const  *cst = NULL;
 	bool	varonleft;
 	Node   *leftop,
 		   *rightop;
@@ -1451,22 +1470,38 @@ examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonl
 
 	if (IsA(leftop, Var) && IsA(rightop, Const))
 	{
-		var = (Var *) leftop;
+		var1 = (Var *) leftop;
 		cst = (Const *) rightop;
 		varonleft = true;
 	}
 	else if (IsA(leftop, Const) && IsA(rightop, Var))
 	{
-		var = (Var *) rightop;
+		var1 = (Var *) rightop;
 		cst = (Const *) leftop;
 		varonleft = false;
 	}
+	else if (IsA(leftop, Var) && IsA(rightop, Var))
+	{
+		var1 = (Var *) leftop;
+		var2 = (Var *) rightop;
+		varonleft = false;
+
+		/*
+		 * Both variables have to be for the same relation (otherwise it's
+		 * a join clause, and we don't deal with those yet.
+		 */
+		if (var1->varno != var2->varno)
+			return false;
+	}
 	else
 		return false;
 
 	/* return pointers to the extracted parts if requested */
-	if (varp)
-		*varp = var;
+	if (var1p)
+		*var1p = var1;
+
+	if (var2p)
+		*var2p = var2;
 
 	if (cstp)
 		*cstp = cst;
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index 3f42713aa2..97d3083451 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1581,16 +1581,25 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 
 			/* valid only after examine_opclause_expression returns true */
 			Var		   *var;
+			Var		   *var2;
 			Const	   *cst;
 			bool		varonleft;
 
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
-			/* extract the var and const from the expression */
-			if (examine_opclause_expression(expr, &var, &cst, &varonleft))
+			/* extract the vars and const from the expression */
+			if (!examine_opclause_expression(expr, &var, &var2, &cst, &varonleft))
+				continue;	/* XXX Can this actually happen? */
+
+			/* We should always get at least one Var. */
+			Assert(var);
+
+			if (cst)
 			{
 				int			idx;
 
+				Assert(!var2);
+
 				/* match the attribute to a dimension of the statistic */
 				idx = bms_member_index(keys, var->varattno);
 
@@ -1651,6 +1660,68 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					matches[i] = RESULT_MERGE(matches[i], is_or, match);
 				}
 			}
+			else
+			{
+				int			idx;
+				int			idx2;
+
+				Assert(var2);
+
+				/* match the attribute to a dimension of the statistic */
+				idx = bms_member_index(keys, var->varattno);
+				idx2 = bms_member_index(keys, var2->varattno);
+
+				/*
+				 * Walk through the MCV items and evaluate the current clause.
+				 * We can skip items that were already ruled out, and
+				 * terminate if there are no remaining MCV items that might
+				 * possibly match.
+				 */
+				for (i = 0; i < mcvlist->nitems; i++)
+				{
+					bool		match = true;
+					MCVItem    *item = &mcvlist->items[i];
+
+					/*
+					 * When either of the MCV items is NULL we can treat this
+					 * as a mismatch. We must not call the operator because
+					 * of strictness.
+					 */
+					if (item->isnull[idx] || item->isnull[idx2])
+					{
+						matches[i] = RESULT_MERGE(matches[i], is_or, false);
+						continue;
+					}
+
+					/*
+					 * Skip MCV items that can't change result in the bitmap.
+					 * Once the value gets false for AND-lists, or true for
+					 * OR-lists, we don't need to look at more clauses.
+					 */
+					if (RESULT_IS_FINAL(matches[i], is_or))
+						continue;
+
+					/*
+					 * First check whether the constant is below the lower
+					 * boundary (in that case we can skip the bucket, because
+					 * there's no overlap).
+					 *
+					 * We don't store collations used to build the statistics,
+					 * but we can use the collation for the attribute itself,
+					 * as stored in varcollid. We do reset the statistics after
+					 * a type change (including collation change), so this is
+					 * OK. We may need to relax this after allowing extended
+					 * statistics on expressions.
+					 */
+					match = DatumGetBool(FunctionCall2Coll(&opproc,
+														   var->varcollid,
+														   item->values[idx],
+														   item->values[idx2]));
+
+					/* update the match bitmap with the result */
+					matches[i] = RESULT_MERGE(matches[i], is_or, match);
+				}
+			}
 		}
 		else if (IsA(clause, NullTest))
 		{
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index 5171895bba..804089bc57 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -96,7 +96,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
 									TupleDesc tdesc, MultiSortSupport mss,
 									int numattrs, AttrNumber *attnums);
 
-extern bool examine_opclause_expression(OpExpr *expr, Var **varp,
+extern bool examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
 										Const **cstp, bool *varonleftp);
 
 extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 5344b70cf4..4c078ae61f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -603,6 +603,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        343 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      1667 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+      1667 |      0
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -654,6 +666,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        200 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      3750 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+         1 |      0
+(1 row)
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 SELECT d.stxdmcv IS NOT NULL
@@ -749,6 +773,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       3750 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+        25 |   2500
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -758,6 +788,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       2500 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -808,6 +844,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
       1094 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      9950 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+        50 |   2500
+(1 row)
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 ANALYZE mcv_lists_bool;
@@ -835,6 +883,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
          1 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -869,6 +929,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
          4 |    142
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+         1 |   5000
+(1 row)
+
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
@@ -891,6 +957,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
        143 |    142
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+      5000 |   5000
+(1 row)
+
 DROP TABLE mcv_lists_multi;
 -- Permission tests. Users should not be able to see specific data values in
 -- the extended statistics, if they lack permission to see those values in
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index fa989fccb0..b7519b275b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -381,6 +381,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
@@ -402,6 +406,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 
@@ -473,6 +481,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 
@@ -480,6 +490,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -521,6 +533,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
@@ -534,6 +550,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -556,6 +576,7 @@ ANALYZE mcv_lists_multi;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
@@ -566,6 +587,7 @@ ANALYZE mcv_lists_multi;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 DROP TABLE mcv_lists_multi;
 
-- 
2.21.1


--mxrkhfy6o2lpe2eo
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename="0003-Support-for-extended-statistics-on-expressi-20200306.patch"



^ permalink  raw  reply  [nested|flat] 6+ messages in thread

* [PATCH 2/3] Support clauses of the form Var op Var
@ 2019-11-11 00:34  Tomas Vondra <tv@fuzzy.cz>
  0 siblings, 0 replies; 6+ messages in thread

From: Tomas Vondra @ 2019-11-11 00:34 UTC (permalink / raw)

---
 src/backend/statistics/extended_stats.c       | 63 ++++++++++++----
 src/backend/statistics/mcv.c                  | 75 ++++++++++++++++++-
 .../statistics/extended_stats_internal.h      |  2 +-
 src/test/regress/expected/stats_ext.out       | 72 ++++++++++++++++++
 src/test/regress/sql/stats_ext.sql            | 22 ++++++
 5 files changed, 217 insertions(+), 17 deletions(-)

diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index 24ece6f99c..1872cd4529 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -986,14 +986,18 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 	{
 		RangeTblEntry *rte = root->simple_rte_array[relid];
 		OpExpr	   *expr = (OpExpr *) clause;
-		Var		   *var;
+		Var		   *var,
+				   *var2;
 
 		/* Only expressions with two arguments are considered compatible. */
 		if (list_length(expr->args) != 2)
 			return false;
 
-		/* Check if the expression the right shape (one Var, one Const) */
-		if (!examine_opclause_expression(expr, &var, NULL, NULL))
+		/*
+		 * Check if the expression the right shape (one Var and one Const,
+		 * or two Vars).
+		 */
+		if (!examine_opclause_expression(expr, &var, &var2, NULL, NULL))
 			return false;
 
 		/*
@@ -1033,7 +1037,20 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 			!get_func_leakproof(get_opcode(expr->opno)))
 			return false;
 
-		return statext_is_compatible_clause_internal(root, (Node *) var,
+		/*
+		 * Check compatibility of the first Var - we get this one for both
+		 * types of supported expressions (Var op Const) and (Var op Var).
+		 */
+		if (!statext_is_compatible_clause_internal(root, (Node *) var,
+												   relid, attnums))
+			return false;
+
+		/* For (Var op Const) we don't get the second Var, and we're done. */
+		if (!var2)
+			return true;
+
+		/* For (Var op Var) check compatibility of the second Var. */
+		return statext_is_compatible_clause_internal(root, (Node *) var2,
 													 relid, attnums);
 	}
 
@@ -1419,19 +1436,21 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
  * examine_opclause_expression
  *		Split expression into Var and Const parts.
  *
- * Attempts to match the arguments to either (Var op Const) or (Const op Var),
- * possibly with a RelabelType on top. When the expression matches this form,
- * returns true, otherwise returns false.
+ * Attempts to match the arguments to either (Var op Const) or (Const op Var)
+ * or (Var op Var), possibly with a RelabelType on top. When the expression
+ * matches this form, returns true, otherwise returns false.
  *
  * Optionally returns pointers to the extracted Var/Const nodes, when passed
  * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies
  * on which side of the operator we found the Var node.
  */
 bool
-examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
+examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
+							Const **cstp, bool *varonleftp)
 {
-	Var	   *var;
-	Const  *cst;
+	Var	   *var1 = NULL;
+	Var	   *var2 = NULL;
+	Const  *cst = NULL;
 	bool	varonleft;
 	Node   *leftop,
 		   *rightop;
@@ -1451,22 +1470,38 @@ examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonl
 
 	if (IsA(leftop, Var) && IsA(rightop, Const))
 	{
-		var = (Var *) leftop;
+		var1 = (Var *) leftop;
 		cst = (Const *) rightop;
 		varonleft = true;
 	}
 	else if (IsA(leftop, Const) && IsA(rightop, Var))
 	{
-		var = (Var *) rightop;
+		var1 = (Var *) rightop;
 		cst = (Const *) leftop;
 		varonleft = false;
 	}
+	else if (IsA(leftop, Var) && IsA(rightop, Var))
+	{
+		var1 = (Var *) leftop;
+		var2 = (Var *) rightop;
+		varonleft = false;
+
+		/*
+		 * Both variables have to be for the same relation (otherwise it's
+		 * a join clause, and we don't deal with those yet.
+		 */
+		if (var1->varno != var2->varno)
+			return false;
+	}
 	else
 		return false;
 
 	/* return pointers to the extracted parts if requested */
-	if (varp)
-		*varp = var;
+	if (var1p)
+		*var1p = var1;
+
+	if (var2p)
+		*var2p = var2;
 
 	if (cstp)
 		*cstp = cst;
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index 3f42713aa2..97d3083451 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1581,16 +1581,25 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 
 			/* valid only after examine_opclause_expression returns true */
 			Var		   *var;
+			Var		   *var2;
 			Const	   *cst;
 			bool		varonleft;
 
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
-			/* extract the var and const from the expression */
-			if (examine_opclause_expression(expr, &var, &cst, &varonleft))
+			/* extract the vars and const from the expression */
+			if (!examine_opclause_expression(expr, &var, &var2, &cst, &varonleft))
+				continue;	/* XXX Can this actually happen? */
+
+			/* We should always get at least one Var. */
+			Assert(var);
+
+			if (cst)
 			{
 				int			idx;
 
+				Assert(!var2);
+
 				/* match the attribute to a dimension of the statistic */
 				idx = bms_member_index(keys, var->varattno);
 
@@ -1651,6 +1660,68 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					matches[i] = RESULT_MERGE(matches[i], is_or, match);
 				}
 			}
+			else
+			{
+				int			idx;
+				int			idx2;
+
+				Assert(var2);
+
+				/* match the attribute to a dimension of the statistic */
+				idx = bms_member_index(keys, var->varattno);
+				idx2 = bms_member_index(keys, var2->varattno);
+
+				/*
+				 * Walk through the MCV items and evaluate the current clause.
+				 * We can skip items that were already ruled out, and
+				 * terminate if there are no remaining MCV items that might
+				 * possibly match.
+				 */
+				for (i = 0; i < mcvlist->nitems; i++)
+				{
+					bool		match = true;
+					MCVItem    *item = &mcvlist->items[i];
+
+					/*
+					 * When either of the MCV items is NULL we can treat this
+					 * as a mismatch. We must not call the operator because
+					 * of strictness.
+					 */
+					if (item->isnull[idx] || item->isnull[idx2])
+					{
+						matches[i] = RESULT_MERGE(matches[i], is_or, false);
+						continue;
+					}
+
+					/*
+					 * Skip MCV items that can't change result in the bitmap.
+					 * Once the value gets false for AND-lists, or true for
+					 * OR-lists, we don't need to look at more clauses.
+					 */
+					if (RESULT_IS_FINAL(matches[i], is_or))
+						continue;
+
+					/*
+					 * First check whether the constant is below the lower
+					 * boundary (in that case we can skip the bucket, because
+					 * there's no overlap).
+					 *
+					 * We don't store collations used to build the statistics,
+					 * but we can use the collation for the attribute itself,
+					 * as stored in varcollid. We do reset the statistics after
+					 * a type change (including collation change), so this is
+					 * OK. We may need to relax this after allowing extended
+					 * statistics on expressions.
+					 */
+					match = DatumGetBool(FunctionCall2Coll(&opproc,
+														   var->varcollid,
+														   item->values[idx],
+														   item->values[idx2]));
+
+					/* update the match bitmap with the result */
+					matches[i] = RESULT_MERGE(matches[i], is_or, match);
+				}
+			}
 		}
 		else if (IsA(clause, NullTest))
 		{
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index 5171895bba..804089bc57 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -96,7 +96,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
 									TupleDesc tdesc, MultiSortSupport mss,
 									int numattrs, AttrNumber *attnums);
 
-extern bool examine_opclause_expression(OpExpr *expr, Var **varp,
+extern bool examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
 										Const **cstp, bool *varonleftp);
 
 extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 5344b70cf4..4c078ae61f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -603,6 +603,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        343 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      1667 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+      1667 |      0
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -654,6 +666,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        200 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      3750 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+         1 |      0
+(1 row)
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 SELECT d.stxdmcv IS NOT NULL
@@ -749,6 +773,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       3750 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+        25 |   2500
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -758,6 +788,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       2500 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -808,6 +844,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
       1094 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      9950 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+        50 |   2500
+(1 row)
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 ANALYZE mcv_lists_bool;
@@ -835,6 +883,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
          1 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -869,6 +929,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
          4 |    142
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+         1 |   5000
+(1 row)
+
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
@@ -891,6 +957,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
        143 |    142
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+      5000 |   5000
+(1 row)
+
 DROP TABLE mcv_lists_multi;
 -- Permission tests. Users should not be able to see specific data values in
 -- the extended statistics, if they lack permission to see those values in
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index fa989fccb0..b7519b275b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -381,6 +381,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
@@ -402,6 +406,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 
@@ -473,6 +481,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 
@@ -480,6 +490,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -521,6 +533,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
@@ -534,6 +550,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -556,6 +576,7 @@ ANALYZE mcv_lists_multi;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
@@ -566,6 +587,7 @@ ANALYZE mcv_lists_multi;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 DROP TABLE mcv_lists_multi;
 
-- 
2.21.1


--n6bnrzck2js7zcqs--





^ permalink  raw  reply  [nested|flat] 6+ messages in thread

* [PATCH 4/4] Support clauses of the form Var op Var
@ 2020-03-08 22:27  Tomas Vondra <tv@fuzzy.cz>
  0 siblings, 0 replies; 6+ messages in thread

From: Tomas Vondra @ 2020-03-08 22:27 UTC (permalink / raw)

---
 src/backend/statistics/extended_stats.c       | 63 ++++++++++++----
 src/backend/statistics/mcv.c                  | 75 ++++++++++++++++++-
 .../statistics/extended_stats_internal.h      |  2 +-
 src/test/regress/expected/stats_ext.out       | 72 ++++++++++++++++++
 src/test/regress/sql/stats_ext.sql            | 22 ++++++
 5 files changed, 217 insertions(+), 17 deletions(-)

diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index daf95ff437..ddcb5d2955 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -986,14 +986,18 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 	{
 		RangeTblEntry *rte = root->simple_rte_array[relid];
 		OpExpr	   *expr = (OpExpr *) clause;
-		Var		   *var;
+		Var		   *var,
+				   *var2;
 
 		/* Only expressions with two arguments are considered compatible. */
 		if (list_length(expr->args) != 2)
 			return false;
 
-		/* Check if the expression the right shape (one Var, one Const) */
-		if (!examine_opclause_expression(expr, &var, NULL, NULL))
+		/*
+		 * Check if the expression the right shape (one Var and one Const,
+		 * or two Vars).
+		 */
+		if (!examine_opclause_expression(expr, &var, &var2, NULL, NULL))
 			return false;
 
 		/*
@@ -1033,7 +1037,20 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 			!get_func_leakproof(get_opcode(expr->opno)))
 			return false;
 
-		return statext_is_compatible_clause_internal(root, (Node *) var,
+		/*
+		 * Check compatibility of the first Var - we get this one for both
+		 * types of supported expressions (Var op Const) and (Var op Var).
+		 */
+		if (!statext_is_compatible_clause_internal(root, (Node *) var,
+												   relid, attnums))
+			return false;
+
+		/* For (Var op Const) we don't get the second Var, and we're done. */
+		if (!var2)
+			return true;
+
+		/* For (Var op Var) check compatibility of the second Var. */
+		return statext_is_compatible_clause_internal(root, (Node *) var2,
 													 relid, attnums);
 	}
 
@@ -1422,19 +1439,21 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
  * examine_opclause_expression
  *		Split expression into Var and Const parts.
  *
- * Attempts to match the arguments to either (Var op Const) or (Const op Var),
- * possibly with a RelabelType on top. When the expression matches this form,
- * returns true, otherwise returns false.
+ * Attempts to match the arguments to either (Var op Const) or (Const op Var)
+ * or (Var op Var), possibly with a RelabelType on top. When the expression
+ * matches this form, returns true, otherwise returns false.
  *
  * Optionally returns pointers to the extracted Var/Const nodes, when passed
  * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies
  * on which side of the operator we found the Var node.
  */
 bool
-examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
+examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
+							Const **cstp, bool *varonleftp)
 {
-	Var	   *var;
-	Const  *cst;
+	Var	   *var1 = NULL;
+	Var	   *var2 = NULL;
+	Const  *cst = NULL;
 	bool	varonleft;
 	Node   *leftop,
 		   *rightop;
@@ -1454,22 +1473,38 @@ examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonl
 
 	if (IsA(leftop, Var) && IsA(rightop, Const))
 	{
-		var = (Var *) leftop;
+		var1 = (Var *) leftop;
 		cst = (Const *) rightop;
 		varonleft = true;
 	}
 	else if (IsA(leftop, Const) && IsA(rightop, Var))
 	{
-		var = (Var *) rightop;
+		var1 = (Var *) rightop;
 		cst = (Const *) leftop;
 		varonleft = false;
 	}
+	else if (IsA(leftop, Var) && IsA(rightop, Var))
+	{
+		var1 = (Var *) leftop;
+		var2 = (Var *) rightop;
+		varonleft = false;
+
+		/*
+		 * Both variables have to be for the same relation (otherwise it's
+		 * a join clause, and we don't deal with those yet.
+		 */
+		if (var1->varno != var2->varno)
+			return false;
+	}
 	else
 		return false;
 
 	/* return pointers to the extracted parts if requested */
-	if (varp)
-		*varp = var;
+	if (var1p)
+		*var1p = var1;
+
+	if (var2p)
+		*var2p = var2;
 
 	if (cstp)
 		*cstp = cst;
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index 3f42713aa2..97d3083451 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1581,16 +1581,25 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 
 			/* valid only after examine_opclause_expression returns true */
 			Var		   *var;
+			Var		   *var2;
 			Const	   *cst;
 			bool		varonleft;
 
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
-			/* extract the var and const from the expression */
-			if (examine_opclause_expression(expr, &var, &cst, &varonleft))
+			/* extract the vars and const from the expression */
+			if (!examine_opclause_expression(expr, &var, &var2, &cst, &varonleft))
+				continue;	/* XXX Can this actually happen? */
+
+			/* We should always get at least one Var. */
+			Assert(var);
+
+			if (cst)
 			{
 				int			idx;
 
+				Assert(!var2);
+
 				/* match the attribute to a dimension of the statistic */
 				idx = bms_member_index(keys, var->varattno);
 
@@ -1651,6 +1660,68 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					matches[i] = RESULT_MERGE(matches[i], is_or, match);
 				}
 			}
+			else
+			{
+				int			idx;
+				int			idx2;
+
+				Assert(var2);
+
+				/* match the attribute to a dimension of the statistic */
+				idx = bms_member_index(keys, var->varattno);
+				idx2 = bms_member_index(keys, var2->varattno);
+
+				/*
+				 * Walk through the MCV items and evaluate the current clause.
+				 * We can skip items that were already ruled out, and
+				 * terminate if there are no remaining MCV items that might
+				 * possibly match.
+				 */
+				for (i = 0; i < mcvlist->nitems; i++)
+				{
+					bool		match = true;
+					MCVItem    *item = &mcvlist->items[i];
+
+					/*
+					 * When either of the MCV items is NULL we can treat this
+					 * as a mismatch. We must not call the operator because
+					 * of strictness.
+					 */
+					if (item->isnull[idx] || item->isnull[idx2])
+					{
+						matches[i] = RESULT_MERGE(matches[i], is_or, false);
+						continue;
+					}
+
+					/*
+					 * Skip MCV items that can't change result in the bitmap.
+					 * Once the value gets false for AND-lists, or true for
+					 * OR-lists, we don't need to look at more clauses.
+					 */
+					if (RESULT_IS_FINAL(matches[i], is_or))
+						continue;
+
+					/*
+					 * First check whether the constant is below the lower
+					 * boundary (in that case we can skip the bucket, because
+					 * there's no overlap).
+					 *
+					 * We don't store collations used to build the statistics,
+					 * but we can use the collation for the attribute itself,
+					 * as stored in varcollid. We do reset the statistics after
+					 * a type change (including collation change), so this is
+					 * OK. We may need to relax this after allowing extended
+					 * statistics on expressions.
+					 */
+					match = DatumGetBool(FunctionCall2Coll(&opproc,
+														   var->varcollid,
+														   item->values[idx],
+														   item->values[idx2]));
+
+					/* update the match bitmap with the result */
+					matches[i] = RESULT_MERGE(matches[i], is_or, match);
+				}
+			}
 		}
 		else if (IsA(clause, NullTest))
 		{
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index 5171895bba..804089bc57 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -96,7 +96,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
 									TupleDesc tdesc, MultiSortSupport mss,
 									int numattrs, AttrNumber *attnums);
 
-extern bool examine_opclause_expression(OpExpr *expr, Var **varp,
+extern bool examine_opclause_expression(OpExpr *expr, Var **var1p, Var **var2p,
 										Const **cstp, bool *varonleftp);
 
 extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 383465e8cb..3eb1804cf3 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -603,6 +603,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        343 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      1667 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+      1667 |      0
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -654,6 +666,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        200 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      3750 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+         1 |      0
+(1 row)
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 SELECT d.stxdmcv IS NOT NULL
@@ -749,6 +773,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       3750 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+        25 |   2500
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -758,6 +788,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d
       2500 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -808,6 +844,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
       1094 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      9950 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+        50 |   2500
+(1 row)
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 ANALYZE mcv_lists_bool;
@@ -835,6 +883,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
          1 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -893,6 +953,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
       2649 |   1572
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+         1 |   5000
+(1 row)
+
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
@@ -939,6 +1005,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
       1571 |   1572
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+      5000 |   5000
+(1 row)
+
 DROP TABLE mcv_lists_multi;
 -- Permission tests. Users should not be able to see specific data values in
 -- the extended statistics, if they lack permission to see those values in
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 6fd8b016bd..42b67f7cde 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -381,6 +381,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
@@ -402,6 +406,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 -- check change of unrelated column type does not reset the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
 
@@ -473,6 +481,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
 
@@ -480,6 +490,8 @@ ANALYZE mcv_lists;
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- mcv with arrays
 CREATE TABLE mcv_lists_arrays (
     a TEXT[],
@@ -521,6 +533,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
@@ -534,6 +550,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -560,6 +580,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
@@ -574,6 +595,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 DROP TABLE mcv_lists_multi;
 
-- 
2.21.1


--vcvacfll7i2xqkl4--





^ permalink  raw  reply  [nested|flat] 6+ messages in thread

* [PATCH 2/2] Support clauses of the form Var op Var
@ 2020-03-17 01:57  Tomas Vondra <tv@fuzzy.cz>
  0 siblings, 0 replies; 6+ messages in thread

From: Tomas Vondra @ 2020-03-17 01:57 UTC (permalink / raw)

---
 src/backend/statistics/extended_stats.c       | 67 ++++++++++++-----
 src/backend/statistics/mcv.c                  | 71 +++++++++++++++++-
 .../statistics/extended_stats_internal.h      |  2 +-
 src/test/regress/expected/stats_ext.out       | 72 +++++++++++++++++++
 src/test/regress/sql/stats_ext.sql            | 22 ++++++
 5 files changed, 215 insertions(+), 19 deletions(-)

diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index 93d67791c5..f8947d9097 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -987,14 +987,18 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 	{
 		RangeTblEntry *rte = root->simple_rte_array[relid];
 		OpExpr	   *expr = (OpExpr *) clause;
-		Var		   *var;
+		Var		   *var,
+				   *var2;
 
 		/* Only expressions with two arguments are considered compatible. */
 		if (list_length(expr->args) != 2)
 			return false;
 
-		/* Check if the expression has the right shape (one Var, one Const) */
-		if (!examine_clause_args(expr->args, &var, NULL, NULL))
+		/*
+		 * Check if the expression has the right shape (one Var and one Const,
+		 * or two Vars).
+		 */
+		if (!examine_clause_args(expr->args, &var, &var2, NULL, NULL))
 			return false;
 
 		/*
@@ -1034,7 +1038,20 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 			!get_func_leakproof(get_opcode(expr->opno)))
 			return false;
 
-		return statext_is_compatible_clause_internal(root, (Node *) var,
+		/*
+		 * Check compatibility of the first Var - we get this one for both
+		 * types of supported expressions (Var op Const) and (Var op Var).
+		 */
+		if (!statext_is_compatible_clause_internal(root, (Node *) var,
+												   relid, attnums))
+			return false;
+
+		/* For (Var op Const) we don't get the second Var, and we're done. */
+		if (!var2)
+			return true;
+
+		/* For (Var op Var) check compatibility of the second Var. */
+		return statext_is_compatible_clause_internal(root, (Node *) var2,
 													 relid, attnums);
 	}
 
@@ -1050,7 +1067,7 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
 			return false;
 
 		/* Check if the expression has the right shape (one Var, one Const) */
-		if (!examine_clause_args(expr->args, &var, NULL, NULL))
+		if (!examine_clause_args(expr->args, &var, NULL, NULL, NULL))
 			return false;
 
 		/*
@@ -1456,22 +1473,24 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
 }
 
 /*
- * examine_opclause_expression
+ * examine_clause_args
  *		Split expression into Var and Const parts.
  *
- * Attempts to match the arguments to either (Var op Const) or (Const op Var),
- * possibly with a RelabelType on top. When the expression matches this form,
- * returns true, otherwise returns false.
+ * Attempts to match the arguments to either (Var op Const) or (Const op Var)
+ * or (Var op Var), possibly with a RelabelType on top. When the expression
+ * matches this form, returns true, otherwise returns false.
  *
  * Optionally returns pointers to the extracted Var/Const nodes, when passed
  * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies
  * on which side of the operator we found the Var node.
  */
 bool
-examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp)
+examine_clause_args(List *args, Var **var1p, Var **var2p, Const **cstp,
+					bool *varonleftp)
 {
-	Var	   *var;
-	Const  *cst;
+	Var	   *var1 = NULL;
+	Var	   *var2 = NULL;
+	Const  *cst = NULL;
 	bool	varonleft;
 	Node   *leftop,
 		   *rightop;
@@ -1491,22 +1510,38 @@ examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp)
 
 	if (IsA(leftop, Var) && IsA(rightop, Const))
 	{
-		var = (Var *) leftop;
+		var1 = (Var *) leftop;
 		cst = (Const *) rightop;
 		varonleft = true;
 	}
 	else if (IsA(leftop, Const) && IsA(rightop, Var))
 	{
-		var = (Var *) rightop;
+		var1 = (Var *) rightop;
 		cst = (Const *) leftop;
 		varonleft = false;
 	}
+	else if (IsA(leftop, Var) && IsA(rightop, Var))
+	{
+		var1 = (Var *) leftop;
+		var2 = (Var *) rightop;
+		varonleft = false;
+
+		/*
+		 * Both variables have to be for the same relation (otherwise it's
+		 * a join clause, and we don't deal with those yet.
+		 */
+		if (var1->varno != var2->varno)
+			return false;
+	}
 	else
 		return false;
 
 	/* return pointers to the extracted parts if requested */
-	if (varp)
-		*varp = var;
+	if (var1p)
+		*var1p = var1;
+
+	if (var2p)
+		*var2p = var2;
 
 	if (cstp)
 		*cstp = cst;
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index 343011178b..3e58d36d68 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1581,13 +1581,17 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 
 			/* valid only after examine_clause_args returns true */
 			Var		   *var;
+			Var		   *var2;
 			Const	   *cst;
 			bool		varonleft;
 
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
 			/* extract the var and const from the expression */
-			if (examine_clause_args(expr->args, &var, &cst, &varonleft))
+			if (!examine_clause_args(expr->args, &var, &var2, &cst, &varonleft))
+				continue;
+
+			if (cst)	/* Var op Const */
 			{
 				int			idx;
 
@@ -1651,6 +1655,68 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					matches[i] = RESULT_MERGE(matches[i], is_or, match);
 				}
 			}
+			else	/* Var op Var */
+			{
+				int			idx;
+				int			idx2;
+
+				Assert(var2);
+
+				/* match the attribute to a dimension of the statistic */
+				idx = bms_member_index(keys, var->varattno);
+				idx2 = bms_member_index(keys, var2->varattno);
+
+				/*
+				 * Walk through the MCV items and evaluate the current clause.
+				 * We can skip items that were already ruled out, and
+				 * terminate if there are no remaining MCV items that might
+				 * possibly match.
+				 */
+				for (i = 0; i < mcvlist->nitems; i++)
+				{
+					bool		match = true;
+					MCVItem    *item = &mcvlist->items[i];
+
+					/*
+					 * When either of the MCV items is NULL we can treat this
+					 * as a mismatch. We must not call the operator because
+					 * of strictness.
+					 */
+					if (item->isnull[idx] || item->isnull[idx2])
+					{
+						matches[i] = RESULT_MERGE(matches[i], is_or, false);
+						continue;
+					}
+
+					/*
+					 * Skip MCV items that can't change result in the bitmap.
+					 * Once the value gets false for AND-lists, or true for
+					 * OR-lists, we don't need to look at more clauses.
+					 */
+					if (RESULT_IS_FINAL(matches[i], is_or))
+						continue;
+
+					/*
+					 * First check whether the constant is below the lower
+					 * boundary (in that case we can skip the bucket, because
+					 * there's no overlap).
+					 *
+					 * We don't store collations used to build the statistics,
+					 * but we can use the collation for the attribute itself,
+					 * as stored in varcollid. We do reset the statistics after
+					 * a type change (including collation change), so this is
+					 * OK. We may need to relax this after allowing extended
+					 * statistics on expressions.
+					 */
+					match = DatumGetBool(FunctionCall2Coll(&opproc,
+														   var->varcollid,
+														   item->values[idx],
+														   item->values[idx2]));
+
+					/* update the match bitmap with the result */
+					matches[i] = RESULT_MERGE(matches[i], is_or, match);
+				}
+			}
 		}
 		else if (IsA(clause, ScalarArrayOpExpr))
 		{
@@ -1665,7 +1731,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
 			/* extract the var and const from the expression */
-			if (examine_clause_args(expr->args, &var, &cst, &varonleft))
+			if (examine_clause_args(expr->args, &var, NULL, &cst, &varonleft))
 			{
 				int			idx;
 
@@ -1679,6 +1745,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 
 				/* ScalarArrayOpExpr has the Var always on the left */
 				Assert(varonleft);
+				Assert(cst);
 
 				if (!cst->constisnull)
 				{
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index 6c039a81c2..ee34a897c8 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -96,7 +96,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
 									TupleDesc tdesc, MultiSortSupport mss,
 									int numattrs, AttrNumber *attnums);
 
-extern bool examine_clause_args(List *args, Var **varp,
+extern bool examine_clause_args(List *args, Var **var1p, Var **var2p,
 								Const **cstp, bool *varonleftp);
 
 extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 3aba4a37c6..481be40141 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -940,6 +940,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        343 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      1667 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+      1667 |      0
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
  estimated | actual 
 -----------+--------
@@ -1081,6 +1093,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
        200 |    200
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+ estimated | actual 
+-----------+--------
+      3750 |   3750
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+ estimated | actual 
+-----------+--------
+         1 |      0
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
  estimated | actual 
 -----------+--------
@@ -1284,6 +1308,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND
       3750 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+        25 |   2500
+(1 row)
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, d FROM mcv_lists;
 ANALYZE mcv_lists;
@@ -1317,6 +1347,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND
       2500 |   2500
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- mcv with pass-by-ref fixlen types, e.g. uuid
 CREATE TABLE mcv_lists_uuid (
     a UUID,
@@ -1408,6 +1444,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
       1094 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      9950 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+        50 |   2500
+(1 row)
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 ANALYZE mcv_lists_bool;
@@ -1435,6 +1483,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
          1 |      0
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+ estimated | actual 
+-----------+--------
+      2500 |   2500
+(1 row)
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -1493,6 +1553,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
       2649 |   1572
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+         1 |   5000
+(1 row)
+
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
@@ -1539,6 +1605,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
       1571 |   1572
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
+ estimated | actual 
+-----------+--------
+      5000 |   5000
+(1 row)
+
 DROP TABLE mcv_lists_multi;
 -- Permission tests. Users should not be able to see specific data values in
 -- the extended statistics, if they lack permission to see those values in
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 54ceb1f4ee..f5e4468129 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -498,6 +498,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)');
@@ -549,6 +553,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c');
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)');
@@ -656,6 +664,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND (b = ''x'' OR d = ''x'')');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, d FROM mcv_lists;
 
@@ -674,6 +684,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND (b = ''x'' OR d = ''x'')');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d');
+
 -- mcv with pass-by-ref fixlen types, e.g. uuid
 CREATE TABLE mcv_lists_uuid (
     a UUID,
@@ -746,6 +758,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
@@ -759,6 +775,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
 
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c');
+
 -- check the ability to use multiple MCV lists
 CREATE TABLE mcv_lists_multi (
 	a INTEGER,
@@ -785,6 +805,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 -- create separate MCV statistics
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
@@ -799,6 +820,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d');
 
 DROP TABLE mcv_lists_multi;
 
-- 
2.21.1


--qmgrvggedyprimol--





^ permalink  raw  reply  [nested|flat] 6+ messages in thread

* [PATCH v20 4/8] Row pattern recognition patch (planner).
@ 2024-05-24 02:26  Tatsuo Ishii <ishii@postgresql.org>
  0 siblings, 0 replies; 6+ messages in thread

From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)

---
 src/backend/optimizer/plan/createplan.c   | 24 +++++++++++++++-----
 src/backend/optimizer/plan/planner.c      |  3 +++
 src/backend/optimizer/plan/setrefs.c      | 27 ++++++++++++++++++++++-
 src/backend/optimizer/prep/prepjointree.c |  9 ++++++++
 src/include/nodes/plannodes.h             | 19 ++++++++++++++++
 5 files changed, 76 insertions(+), 6 deletions(-)

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 6b64c4a362..ef2101e216 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -287,9 +287,11 @@ static WindowAgg *make_windowagg(List *tlist, Index winref,
 								 int ordNumCols, AttrNumber *ordColIdx, Oid *ordOperators, Oid *ordCollations,
 								 int frameOptions, Node *startOffset, Node *endOffset,
 								 Oid startInRangeFunc, Oid endInRangeFunc,
-								 Oid inRangeColl, bool inRangeAsc, bool inRangeNullsFirst,
-								 List *runCondition, List *qual, bool topWindow,
-								 Plan *lefttree);
+								 Oid inRangeColl, bool inRangeAsc, bool inRangeNullsFirst, List *runCondition,
+								 RPSkipTo rpSkipTo, List *patternVariable, List *patternRegexp,
+								 List *defineClause,
+								 List *defineInitial,
+								 List *qual, bool topWindow, Plan *lefttree);
 static Group *make_group(List *tlist, List *qual, int numGroupCols,
 						 AttrNumber *grpColIdx, Oid *grpOperators, Oid *grpCollations,
 						 Plan *lefttree);
@@ -2700,6 +2702,11 @@ create_windowagg_plan(PlannerInfo *root, WindowAggPath *best_path)
 						  wc->inRangeAsc,
 						  wc->inRangeNullsFirst,
 						  best_path->runCondition,
+						  wc->rpSkipTo,
+						  wc->patternVariable,
+						  wc->patternRegexp,
+						  wc->defineClause,
+						  wc->defineInitial,
 						  best_path->qual,
 						  best_path->topwindow,
 						  subplan);
@@ -6629,8 +6636,10 @@ make_windowagg(List *tlist, Index winref,
 			   int ordNumCols, AttrNumber *ordColIdx, Oid *ordOperators, Oid *ordCollations,
 			   int frameOptions, Node *startOffset, Node *endOffset,
 			   Oid startInRangeFunc, Oid endInRangeFunc,
-			   Oid inRangeColl, bool inRangeAsc, bool inRangeNullsFirst,
-			   List *runCondition, List *qual, bool topWindow, Plan *lefttree)
+			   Oid inRangeColl, bool inRangeAsc, bool inRangeNullsFirst, List *runCondition,
+			   RPSkipTo rpSkipTo, List *patternVariable, List *patternRegexp, List *defineClause,
+			   List *defineInitial,
+			   List *qual, bool topWindow, Plan *lefttree)
 {
 	WindowAgg  *node = makeNode(WindowAgg);
 	Plan	   *plan = &node->plan;
@@ -6656,6 +6665,11 @@ make_windowagg(List *tlist, Index winref,
 	node->inRangeAsc = inRangeAsc;
 	node->inRangeNullsFirst = inRangeNullsFirst;
 	node->topWindow = topWindow;
+	node->rpSkipTo = rpSkipTo,
+		node->patternVariable = patternVariable;
+	node->patternRegexp = patternRegexp;
+	node->defineClause = defineClause;
+	node->defineInitial = defineInitial;
 
 	plan->targetlist = tlist;
 	plan->lefttree = lefttree;
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 032818423f..a5d17e3fda 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -870,6 +870,9 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root,
 												EXPRKIND_LIMIT);
 		wc->endOffset = preprocess_expression(root, wc->endOffset,
 											  EXPRKIND_LIMIT);
+		wc->defineClause = (List *) preprocess_expression(root,
+														  (Node *) wc->defineClause,
+														  EXPRKIND_TARGET);
 	}
 
 	parse->limitOffset = preprocess_expression(root, parse->limitOffset,
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 37abcb4701..cd0e7c57d8 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -210,7 +210,6 @@ static List *set_windowagg_runcondition_references(PlannerInfo *root,
 												   List *runcondition,
 												   Plan *plan);
 
-
 /*****************************************************************************
  *
  *		SUBPLAN REFERENCES
@@ -2471,6 +2470,32 @@ set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset)
 					   NRM_EQUAL,
 					   NUM_EXEC_QUAL(plan));
 
+	/*
+	 * Modifies an expression tree in each DEFINE clause so that all Var
+	 * nodes's varno refers to OUTER_VAR.
+	 */
+	if (IsA(plan, WindowAgg))
+	{
+		WindowAgg  *wplan = (WindowAgg *) plan;
+
+		if (wplan->defineClause != NIL)
+		{
+			foreach(l, wplan->defineClause)
+			{
+				TargetEntry *tle = (TargetEntry *) lfirst(l);
+
+				tle->expr = (Expr *)
+					fix_upper_expr(root,
+								   (Node *) tle->expr,
+								   subplan_itlist,
+								   OUTER_VAR,
+								   rtoffset,
+								   NRM_EQUAL,
+								   NUM_EXEC_QUAL(plan));
+			}
+		}
+	}
+
 	pfree(subplan_itlist);
 }
 
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5482ab85a7..f54db3f044 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -2175,6 +2175,15 @@ perform_pullup_replace_vars(PlannerInfo *root,
 	parse->returningList = (List *)
 		pullup_replace_vars((Node *) parse->returningList, rvcontext);
 
+	foreach(lc, parse->windowClause)
+	{
+		WindowClause *wc = lfirst_node(WindowClause, lc);
+
+		if (wc->defineClause != NIL)
+			wc->defineClause = (List *)
+				pullup_replace_vars((Node *) wc->defineClause, rvcontext);
+	}
+
 	if (parse->onConflict)
 	{
 		parse->onConflict->onConflictSet = (List *)
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 1aeeaec95e..5b8d8a6dac 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -20,6 +20,7 @@
 #include "lib/stringinfo.h"
 #include "nodes/bitmapset.h"
 #include "nodes/lockoptions.h"
+#include "nodes/parsenodes.h"
 #include "nodes/primnodes.h"
 
 
@@ -1098,6 +1099,24 @@ typedef struct WindowAgg
 	/* nulls sort first for in_range tests? */
 	bool		inRangeNullsFirst;
 
+	/* Row Pattern Recognition AFTER MACH SKIP clause */
+	RPSkipTo	rpSkipTo;		/* Row Pattern Skip To type */
+
+	/* Row Pattern PATTERN variable name (list of String) */
+	List	   *patternVariable;
+
+	/*
+	 * Row Pattern RPATTERN regular expression quantifier ('+' or ''. list of
+	 * String)
+	 */
+	List	   *patternRegexp;
+
+	/* Row Pattern DEFINE clause (list of TargetEntry) */
+	List	   *defineClause;
+
+	/* Row Pattern DEFINE variable initial names (list of String) */
+	List	   *defineInitial;
+
 	/*
 	 * false for all apart from the WindowAgg that's closest to the root of
 	 * the plan
-- 
2.25.1


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2019-11-11 00:34 [PATCH 2/3] Support clauses of the form Var op Var Tomas Vondra <tv@fuzzy.cz>
2019-11-11 00:34 [PATCH 2/3] Support clauses of the form Var op Var Tomas Vondra <tv@fuzzy.cz>
2019-11-11 00:34 [PATCH 2/3] Support clauses of the form Var op Var Tomas Vondra <tv@fuzzy.cz>
2020-03-08 22:27 [PATCH 4/4] Support clauses of the form Var op Var Tomas Vondra <tv@fuzzy.cz>
2020-03-17 01:57 [PATCH 2/2] Support clauses of the form Var op Var Tomas Vondra <tv@fuzzy.cz>
2024-05-24 02:26 [PATCH v20 4/8] Row pattern recognition patch (planner). Tatsuo Ishii <ishii@postgresql.org>

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