Subject: [PATCH 3/8] Process all scan keys in existing BRIN opclasses

From: Tomas Vondra <[email-masked]>
Date: Fri, 5 Mar 2021 00:45:33 +0100

This modifies the existing BRIN opclasses (minmax, inclusion) although
those don't really benefit from this change. The primary purpose of this
is to allow more advanced opclases in the future.
---
 src/backend/access/brin/brin_inclusion.c | 140 ++++++++++++++++-------
 src/backend/access/brin/brin_minmax.c    |  92 ++++++++++++---
 src/include/catalog/pg_proc.dat          |   4 +-
 3 files changed, 177 insertions(+), 59 deletions(-)

diff --git a/src/backend/access/brin/brin_inclusion.c b/src/backend/access/brin/brin_inclusion.c
index 12e5bddd1f..a260074c91 100644
--- a/src/backend/access/brin/brin_inclusion.c
+++ b/src/backend/access/brin/brin_inclusion.c
@@ -85,6 +85,8 @@ static FmgrInfo *inclusion_get_procinfo(BrinDesc *bdesc, uint16 attno,
 										uint16 procnum);
 static FmgrInfo *inclusion_get_strategy_procinfo(BrinDesc *bdesc, uint16 attno,
 												 Oid subtype, uint16 strategynum);
+static bool inclusion_consistent_key(BrinDesc *bdesc, BrinValues *column,
+									 ScanKey key, Oid colloid);

 /*
@@ -251,6 +253,10 @@ brin_inclusion_add_value(PG_FUNCTION_ARGS)
 /*
  * BRIN inclusion consistent function
  *
+ * We inspect the IS NULL scan keys first, which allows us to make a decision
+ * without looking at the contents of the page range. Only when the page range
+ * matches all those keys, we check the regular scan keys.
+ *
  * All of the strategies are optional.
  */
 Datum
@@ -258,24 +264,31 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 {
 	BrinDesc   *bdesc = (BrinDesc *) PG_GETARG_POINTER(0);
 	BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1);
-	ScanKey		key = (ScanKey) PG_GETARG_POINTER(2);
-	Oid			colloid = PG_GET_COLLATION(),
-				subtype;
-	Datum		unionval;
-	AttrNumber	attno;
-	Datum		query;
-	FmgrInfo   *finfo;
-	Datum		result;
-
-	Assert(key->sk_attno == column->bv_attno);
+	ScanKey    *keys = (ScanKey *) PG_GETARG_POINTER(2);
+	int			nkeys = PG_GETARG_INT32(3);
+	Oid			colloid = PG_GET_COLLATION();
+	int			keyno;
+	bool		has_regular_keys = false;
 
-	/* Handle IS NULL/IS NOT NULL tests. */
-	if (key->sk_flags & SK_ISNULL)
+	/* Handle IS NULL/IS NOT NULL tests */
+	for (keyno = 0; keyno < nkeys; keyno++)
 	{
+		ScanKey		key = keys[keyno];
+
+		Assert(key->sk_attno == column->bv_attno);
+
+		/* Skip regular scan keys (and remember that we have some). */
+		if ((!key->sk_flags & SK_ISNULL))
+		{
+			has_regular_keys = true;
+			continue;
+		}
+
 		if (key->sk_flags & SK_SEARCHNULL)
 		{
 			if (column->bv_allnulls || column->bv_hasnulls)
-				PG_RETURN_BOOL(true);
+				continue;		/* this key is fine, continue */
+
 			PG_RETURN_BOOL(false);
 		}
 
@@ -284,7 +297,12 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 		 * only nulls.
 		 */
 		if (key->sk_flags & SK_SEARCHNOTNULL)
-			PG_RETURN_BOOL(!column->bv_allnulls);
+		{
+			if (column->bv_allnulls)
+				PG_RETURN_BOOL(false);
+
+			continue;
+		}
 
 		/*
 		 * Neither IS NULL nor IS NOT NULL was used; assume all indexable
@@ -293,7 +311,14 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 		PG_RETURN_BOOL(false);
 	}
 
-	/* If it is all nulls, it cannot possibly be consistent. */
+	/* If there are no regular keys, the page range is considered consistent. */
+	if (!has_regular_keys)
+		PG_RETURN_BOOL(true);
+
+	/*
+	 * If is all nulls, it cannot possibly be consistent (at this point we
+	 * know there are at least some regular scan keys).
+	 */
 	if (column->bv_allnulls)
 		PG_RETURN_BOOL(false);
 
@@ -301,10 +326,45 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 	if (DatumGetBool(column->bv_values[INCLUSION_UNMERGEABLE]))
 		PG_RETURN_BOOL(true);
 
-	attno = key->sk_attno;
-	subtype = key->sk_subtype;
-	query = key->sk_argument;
-	unionval = column->bv_values[INCLUSION_UNION];
+	/* Check that the range is consistent with all regular scan keys. */
+	for (keyno = 0; keyno < nkeys; keyno++)
+	{
+		ScanKey		key = keys[keyno];
+
+		/* Skip IS NULL/IS NOT NULL keys (already handled above). */
+		if (key->sk_flags & SK_ISNULL)
+			continue;
+
+		/*
+		 * When there are multiple scan keys, failure to meet the criteria for
+		 * a single one of them is enough to discard the range as a whole, so
+		 * break out of the loop as soon as a false return value is obtained.
+		 */
+		if (!inclusion_consistent_key(bdesc, column, key, colloid))
+			PG_RETURN_BOOL(false);
+	}
+
+	PG_RETURN_BOOL(true);
+}
+
+/*
+ * inclusion_consistent_key
+ *		Determine if the range is consistent with a single scan key.
+ */
+static bool
+inclusion_consistent_key(BrinDesc *bdesc, BrinValues *column, ScanKey key,
+						 Oid colloid)
+{
+	FmgrInfo   *finfo;
+	AttrNumber	attno = key->sk_attno;
+	Oid			subtype = key->sk_subtype;
+	Datum		query = key->sk_argument;
+	Datum		unionval = column->bv_values[INCLUSION_UNION];
+	Datum		result;
+
+	/* This should be called only for regular keys, not for IS [NOT] NULL. */
+	Assert(!(key->sk_flags & SK_ISNULL));
+
 	switch (key->sk_strategy)
 	{
 			/*
@@ -324,49 +384,49 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTOverRightStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTOverLeftStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTRightStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTOverRightStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTLeftStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTRightStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTOverLeftStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTBelowStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTOverAboveStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTOverBelowStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTAboveStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTOverAboveStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTBelowStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		case RTAboveStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTOverBelowStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 			/*
 			 * Overlap and contains strategies
@@ -384,7 +444,7 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													key->sk_strategy);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_DATUM(result);
+			return DatumGetBool(result);
 
 			/*
 			 * Contained by strategies
@@ -404,9 +464,9 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 													RTOverlapStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
 			if (DatumGetBool(result))
-				PG_RETURN_BOOL(true);
+				return true;
 
-			PG_RETURN_DATUM(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
+			return DatumGetBool(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
 
 			/*
 			 * Adjacent strategy
@@ -423,12 +483,12 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 													RTOverlapStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
 			if (DatumGetBool(result))
-				PG_RETURN_BOOL(true);
+				return true;
 
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTAdjacentStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_DATUM(result);
+			return DatumGetBool(result);
 
 			/*
 			 * Basic comparison strategies
@@ -458,9 +518,9 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 													RTRightStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
 			if (!DatumGetBool(result))
-				PG_RETURN_BOOL(true);
+				return true;
 
-			PG_RETURN_DATUM(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
+			return DatumGetBool(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
 
 		case RTSameStrategyNumber:
 		case RTEqualStrategyNumber:
@@ -468,30 +528,30 @@ brin_inclusion_consistent(PG_FUNCTION_ARGS)
 													RTContainsStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
 			if (DatumGetBool(result))
-				PG_RETURN_BOOL(true);
+				return true;
 
-			PG_RETURN_DATUM(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
+			return DatumGetBool(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
 
 		case RTGreaterEqualStrategyNumber:
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTLeftStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
 			if (!DatumGetBool(result))
-				PG_RETURN_BOOL(true);
+				return true;
 
-			PG_RETURN_DATUM(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
+			return DatumGetBool(column->bv_values[INCLUSION_CONTAINS_EMPTY]);
 
 		case RTGreaterStrategyNumber:
 			/* no need to check for empty elements */
 			finfo = inclusion_get_strategy_procinfo(bdesc, attno, subtype,
 													RTLeftStrategyNumber);
 			result = FunctionCall2Coll(finfo, colloid, unionval, query);
-			PG_RETURN_BOOL(!DatumGetBool(result));
+			return !DatumGetBool(result);
 
 		default:
 			/* shouldn't happen */
 			elog(ERROR, "invalid strategy number %d", key->sk_strategy);
-			PG_RETURN_BOOL(false);
+			return false;
 	}
 }
 
diff --git a/src/backend/access/brin/brin_minmax.c b/src/backend/access/brin/brin_minmax.c
index 2ffbd9bf0d..e116084a02 100644
--- a/src/backend/access/brin/brin_minmax.c
+++ b/src/backend/access/brin/brin_minmax.c
@@ -30,6 +30,8 @@ typedef struct MinmaxOpaque
 
 static FmgrInfo *minmax_get_strategy_procinfo(BrinDesc *bdesc, uint16 attno,
 											  Oid subtype, uint16 strategynum);
+static bool minmax_consistent_key(BrinDesc *bdesc, BrinValues *column,
+								  ScanKey key, Oid colloid);

 Datum
@@ -140,29 +142,41 @@ brin_minmax_add_value(PG_FUNCTION_ARGS)
  * Given an index tuple corresponding to a certain page range and a scan key,
  * return whether the scan key is consistent with the index tuple's min/max
  * values.  Return true if so, false otherwise.
+ *
+ * We inspect the IS NULL scan keys first, which allows us to make a decision
+ * without looking at the contents of the page range. Only when the page range
+ * matches all those keys, we check the regular scan keys.
  */
 Datum
 brin_minmax_consistent(PG_FUNCTION_ARGS)
 {
 	BrinDesc   *bdesc = (BrinDesc *) PG_GETARG_POINTER(0);
 	BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1);
-	ScanKey		key = (ScanKey) PG_GETARG_POINTER(2);
-	Oid			colloid = PG_GET_COLLATION(),
-				subtype;
-	AttrNumber	attno;
-	Datum		value;
-	Datum		matches;
-	FmgrInfo   *finfo;
-
-	Assert(key->sk_attno == column->bv_attno);
+	ScanKey    *keys = (ScanKey *) PG_GETARG_POINTER(2);
+	int			nkeys = PG_GETARG_INT32(3);
+	Oid			colloid = PG_GET_COLLATION();
+	int			keyno;
+	bool		has_regular_keys = false;
 
 	/* handle IS NULL/IS NOT NULL tests */
-	if (key->sk_flags & SK_ISNULL)
+	for (keyno = 0; keyno < nkeys; keyno++)
 	{
+		ScanKey		key = keys[keyno];
+
+		Assert(key->sk_attno == column->bv_attno);
+
+		/* Skip regular scan keys (and remember that we have some). */
+		if ((!key->sk_flags & SK_ISNULL))
+		{
+			has_regular_keys = true;
+			continue;
+		}
+
 		if (key->sk_flags & SK_SEARCHNULL)
 		{
 			if (column->bv_allnulls || column->bv_hasnulls)
-				PG_RETURN_BOOL(true);
+				continue;		/* this key is fine, continue */
+
 			PG_RETURN_BOOL(false);
 		}
 
@@ -171,7 +185,12 @@ brin_minmax_consistent(PG_FUNCTION_ARGS)
 		 * only nulls.
 		 */
 		if (key->sk_flags & SK_SEARCHNOTNULL)
-			PG_RETURN_BOOL(!column->bv_allnulls);
+		{
+			if (column->bv_allnulls)
+				PG_RETURN_BOOL(false);
+
+			continue;
+		}
 
 		/*
 		 * Neither IS NULL nor IS NOT NULL was used; assume all indexable
@@ -180,13 +199,52 @@ brin_minmax_consistent(PG_FUNCTION_ARGS)
 		PG_RETURN_BOOL(false);
 	}
 
-	/* if the range is all empty, it cannot possibly be consistent */
+	/* If there are no regular keys, the page range is considered consistent. */
+	if (!has_regular_keys)
+		PG_RETURN_BOOL(true);
+
+	/*
+	 * If is all nulls, it cannot possibly be consistent (at this point we
+	 * know there are at least some regular scan keys).
+	 */
 	if (column->bv_allnulls)
 		PG_RETURN_BOOL(false);
 
-	attno = key->sk_attno;
-	subtype = key->sk_subtype;
-	value = key->sk_argument;
+	/* Check that the range is consistent with all scan keys. */
+	for (keyno = 0; keyno < nkeys; keyno++)
+	{
+		ScanKey		key = keys[keyno];
+
+		/* ignore IS NULL/IS NOT NULL tests handled above */
+		if (key->sk_flags & SK_ISNULL)
+			continue;
+
+		/*
+		 * When there are multiple scan keys, failure to meet the criteria for
+		 * a single one of them is enough to discard the range as a whole, so
+		 * break out of the loop as soon as a false return value is obtained.
+		 */
+		if (!minmax_consistent_key(bdesc, column, key, colloid))
+			PG_RETURN_DATUM(false);;
+	}
+
+	PG_RETURN_DATUM(true);
+}
+
+/*
+ * minmax_consistent_key
+ *		Determine if the range is consistent with a single scan key.
+ */
+static bool
+minmax_consistent_key(BrinDesc *bdesc, BrinValues *column, ScanKey key,
+					  Oid colloid)
+{
+	FmgrInfo   *finfo;
+	AttrNumber	attno = key->sk_attno;
+	Oid			subtype = key->sk_subtype;
+	Datum		value = key->sk_argument;
+	Datum		matches;
+
 	switch (key->sk_strategy)
 	{
 		case BTLessStrategyNumber:
@@ -229,7 +287,7 @@ brin_minmax_consistent(PG_FUNCTION_ARGS)
 			break;
 	}
 
-	PG_RETURN_DATUM(matches);
+	return DatumGetBool(matches);
 }
 
 /*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 506689d8ac..ad11a2b66f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -8206,7 +8206,7 @@
   prosrc => 'brin_minmax_add_value' },
 { oid => '3385', descr => 'BRIN minmax support',
   proname => 'brin_minmax_consistent', prorettype => 'bool',
-  proargtypes => 'internal internal internal',
+  proargtypes => 'internal internal internal int4',
   prosrc => 'brin_minmax_consistent' },
 { oid => '3386', descr => 'BRIN minmax support',
   proname => 'brin_minmax_union', prorettype => 'bool',
@@ -8222,7 +8222,7 @@
   prosrc => 'brin_inclusion_add_value' },
 { oid => '4107', descr => 'BRIN inclusion support',
   proname => 'brin_inclusion_consistent', prorettype => 'bool',
-  proargtypes => 'internal internal internal',
+  proargtypes => 'internal internal internal int4',
   prosrc => 'brin_inclusion_consistent' },
 { oid => '4108', descr => 'BRIN inclusion support',
   proname => 'brin_inclusion_union', prorettype => 'bool',
-- 
2.26.2

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