Support NOT VALID / VALIDATE constraint options for named NOT NULL constraints

From 0c4d83efa4b2693db0b7c9125252f6bba95f30f5 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 15:39:16 +0530
Subject: [PATCH 1/3] Convert pg_attribut.attnotnull to char type.

This commit change the pg_attribut.attnotnull to char type. Now
attnotnull holds three values, where attnotnull can be either
TRUE, FALSE and INVALID.  INVALID is when name not null constrint
is NOT VALIDATED.
---
 src/backend/access/common/tupdesc.c        | 12 +++++-----
 src/backend/bootstrap/bootstrap.c          | 13 ++++++-----
 src/backend/catalog/heap.c                 | 16 +++++++-------
 src/backend/catalog/index.c                |  2 +-
 src/backend/catalog/indexing.c             |  3 ++-
 src/backend/catalog/information_schema.sql |  4 ++--
 src/backend/commands/tablecmds.c           | 35 +++++++++++++++++-------------
 src/backend/executor/execMain.c            |  3 ++-
 src/backend/jit/llvm/llvmjit_deform.c      | 10 +++++----
 src/backend/optimizer/util/plancat.c       |  5 +++--
 src/include/access/tupdesc.h               |  2 +-
 src/include/catalog/pg_attribute.h         |  5 ++++-
 12 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f..5869881 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -251,7 +251,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -297,7 +297,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -417,7 +417,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 	{
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -463,7 +463,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	dstAtt->attnum = dstAttno;
 
 	/* since we're not copying constraints or defaults, clear these */
-	dstAtt->attnotnull = false;
+	dstAtt->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -840,7 +840,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -903,7 +903,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 359f58a..8b952d8 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,14 +582,17 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	/* set default to false */
+	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
+
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
-		attrtypes[attnum]->attnotnull = true;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 	}
 	else if (nullness == BOOTCOL_NULL_FORCE_NULL)
 	{
-		attrtypes[attnum]->attnotnull = false;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	}
 	else
 	{
@@ -608,11 +611,11 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 			for (i = 0; i < attnum; i++)
 			{
 				if (attrtypes[i]->attlen <= 0 ||
-					!attrtypes[i]->attnotnull)
+					attrtypes[i]->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					break;
 			}
 			if (i == attnum)
-				attrtypes[attnum]->attnotnull = true;
+				attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		}
 	}
 }
@@ -696,7 +699,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 956f196..6dc94e3 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -149,7 +149,7 @@ static const FormData_pg_attribute a1 = {
 	.attbyval = false,
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -162,7 +162,7 @@ static const FormData_pg_attribute a2 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -175,7 +175,7 @@ static const FormData_pg_attribute a3 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -188,7 +188,7 @@ static const FormData_pg_attribute a4 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -201,7 +201,7 @@ static const FormData_pg_attribute a5 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -220,7 +220,7 @@ static const FormData_pg_attribute a6 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -751,7 +751,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attalign - 1] = CharGetDatum(attrs->attalign);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
-		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = CharGetDatum(attrs->attnotnull);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1710,7 +1710,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 	attStruct->atttypid = InvalidOid;
 
 	/* Remove any not-null constraint the column may have */
-	attStruct->attnotnull = false;
+	attStruct->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index cdabf78..4417704 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -261,7 +261,7 @@ index_check_primary_key(Relation heapRel,
 				 attnum, RelationGetRelid(heapRel));
 		attform = (Form_pg_attribute) GETSTRUCT(atttuple);
 
-		if (!attform->attnotnull)
+		if (attform->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("primary key column \"%s\" is not marked NOT NULL",
diff --git a/src/backend/catalog/indexing.c b/src/backend/catalog/indexing.c
index 25c4b6b..a2211d7 100644
--- a/src/backend/catalog/indexing.c
+++ b/src/backend/catalog/indexing.c
@@ -207,7 +207,8 @@ CatalogTupleCheckConstraints(Relation heapRel, HeapTuple tup)
 		{
 			Form_pg_attribute thisatt = TupleDescAttr(tupdesc, attnum);
 
-			Assert(!(thisatt->attnotnull && att_isnull(attnum, bp)));
+			Assert(!(thisatt->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					 att_isnull(attnum, bp)));
 		}
 	}
 }
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index a7bffca..4f59bc4 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -292,7 +292,7 @@ CREATE VIEW attributes AS
            CAST(a.attname AS sql_identifier) AS attribute_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(pg_get_expr(ad.adbin, ad.adrelid) AS character_data) AS attribute_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't' OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable, -- This column was apparently removed between SQL:2003 and SQL:2008.
 
@@ -671,7 +671,7 @@ CREATE VIEW columns AS
            CAST(a.attname AS sql_identifier) AS column_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(CASE WHEN a.attgenerated = '' THEN pg_get_expr(ad.adbin, ad.adrelid) END AS character_data) AS column_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't'  OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable,
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 5823fce..8fa71ed 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1401,7 +1401,10 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		if (entry->is_not_null)
+			att->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		else
+			att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -6186,7 +6189,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
 		if (notnull_attrs)
@@ -7636,7 +7640,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 						RelationGetRelid(rel), attnum);
 
 	/* If the column is already nullable there's nothing to do. */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		table_close(attr_rel, RowExclusiveLock);
 		return InvalidObjectAddress;
@@ -7666,7 +7670,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 		AttrNumber	parent_attnum;
 
 		parent_attnum = get_attnum(parentId, colName);
-		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull)
+		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("column \"%s\" is marked NOT NULL in parent table",
@@ -7720,7 +7724,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7733,8 +7737,8 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
-		attr->attnotnull = true;
+		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
+		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -8140,7 +8144,7 @@ ATExecAddIdentity(Relation rel, const char *colName,
 	 * to an existing column that is not NOT NULL would create a state that
 	 * cannot be reproduced without contortions.
 	 */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" must be declared NOT NULL before identity can be added",
@@ -9342,7 +9346,7 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 					elog(ERROR, "cache lookup failed for attribute %s of relation %u",
 						 attname, childrelid);
 				attrForm = (Form_pg_attribute) GETSTRUCT(tup);
-				if (!attrForm->attnotnull)
+				if (attrForm->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					ereport(ERROR,
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
 								   attname, get_rel_name(childrelid)));
@@ -13274,9 +13278,9 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull)
+		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		{
-			attForm->attnotnull = false;
+			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16603,7 +16607,8 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			 *
 			 * Other constraints are checked elsewhere.
 			 */
-			if (parent_att->attnotnull && !child_att->attnotnull)
+			if (parent_att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				child_att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			{
 				HeapTuple	contup;
 
@@ -17646,7 +17651,7 @@ ATExecReplicaIdentity(Relation rel, ReplicaIdentityStmt *stmt, LOCKMODE lockmode
 							RelationGetRelationName(indexRel), attno)));
 
 		attr = TupleDescAttr(rel->rd_att, attno - 1);
-		if (!attr->attnotnull)
+		if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 					 errmsg("index \"%s\" cannot be used as replica identity because column \"%s\" is nullable",
@@ -19124,7 +19129,7 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
@@ -20956,7 +20961,7 @@ verifyPartitionIndexNotNull(IndexInfo *iinfo, Relation partition)
 		Form_pg_attribute att = TupleDescAttr(RelationGetDescr(partition),
 											  iinfo->ii_IndexAttrNumbers[i] - 1);
 
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					errmsg("invalid primary key definition"),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 39d80cc..06688ff 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1966,7 +1966,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull && slot_attisnull(slot, attrChk))
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
 				Relation	orig_rel = rel;
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7..e6444bc 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 71abb01..e322098 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1355,7 +1355,8 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					!att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7..1eba67c 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -76,7 +76,7 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnotnull;		/* as FormData_pg_attribute.attnotnull */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515..b51a267 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -118,7 +118,7 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	char		attcompression BKI_DEFAULT('\0');
 
 	/* This flag represents the "NOT NULL" constraint */
-	bool		attnotnull;
+	char		attnotnull;
 
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
@@ -227,6 +227,9 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_GENERATED_STORED	's'
 #define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
+#define		  ATTRIBUTE_NOTNULL_TRUE		't'
+#define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
 #endif							/* PG_ATTRIBUTE_H */
-- 
1.8.3.1

From eb8c8197743a30c558cb208d40d82b66f9c8fc58 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 16:22:30 +0530
Subject: [PATCH 2/3] Support NOT VALID and VALIDATE CONSTRAINT for named NOT
 NULL constraints.

---
 src/backend/commands/tablecmds.c          | 209 ++++++++++++++++++++++++++++--
 src/backend/executor/execMain.c           |   3 +-
 src/backend/parser/gram.y                 |   4 +-
 src/bin/psql/describe.c                   |  10 +-
 src/include/catalog/pg_attribute.h        |   1 +
 src/test/regress/expected/constraints.out | 110 ++++++++++++++++
 src/test/regress/sql/constraints.sql      |  59 +++++++++
 7 files changed, 380 insertions(+), 16 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8fa71ed..a889b6b 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -408,6 +408,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										char *constrName, HeapTuple contuple,
+										bool recurse, bool recursing, LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -471,7 +474,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool skip_validation, LOCKMODE lockmode);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -700,6 +703,8 @@ static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, const char *compression);
 static char GetAttributeStorage(Oid atttypid, const char *storagemode);
+static bool check_for_invalid_notnull(Oid relid, const char *attname);
+static char *getNNConnameForAttnum(Oid relid, AttrNumber  attnum);
 
 
 /* ----------------------------------------------------------------
@@ -1317,7 +1322,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, false, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -6189,7 +6194,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 attr->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
@@ -7710,7 +7716,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool skip_validation, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
@@ -7738,14 +7744,19 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
 		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
-		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+
+		if (skip_validation)
+			attr->attnotnull = ATTRIBUTE_NOTNULL_INVALID;
+		else
+			attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (!skip_validation &&
+			wqueue && !NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7914,7 +7925,7 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 							  RelationGetRelid(rel), attnum);
 
 	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	set_attnotnull(wqueue, rel, attnum, constraint->skip_validation, lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9360,6 +9371,16 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		String *colname = lfirst(lc);
+
+		/*
+		 * Throw an error if relation key column has invalid not null
+		 * constraint.
+		 */
+		if (check_for_invalid_notnull(RelationGetRelid(rel), colname->sval))
+			ereport(ERROR,
+					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constrint",
+						   colname->sval, RelationGetRelationName(rel)));
 
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
@@ -9373,6 +9394,30 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 }
 
 /*
+ * This function checks for any invalid NOT NULL constraint on the given
+ * relation and attribute name. It returns true if found, false otherwise.
+ */
+static bool
+check_for_invalid_notnull(Oid relid, const char *attname)
+{
+	HeapTuple	tuple;
+	bool		retval = false;
+
+	tuple = SearchSysCache2(ATTNAME,
+							ObjectIdGetDatum(relid),
+							CStringGetDatum(attname));
+	if (!HeapTupleIsValid(tuple))
+		return false;
+	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attisdropped &&
+		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull == ATTRIBUTE_NOTNULL_INVALID)
+		retval = true;
+
+	ReleaseSysCache(tuple);
+
+	return retval;
+}
+
+/*
  * ALTER TABLE ADD INDEX
  *
  * There is no such command in the grammar, but parse_utilcmd.c converts
@@ -9739,7 +9784,7 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * phase 3 to verify existing rows, if needed.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum, ccon->skip_validation, lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12169,7 +12214,8 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
@@ -12191,6 +12237,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel, constrName,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12408,6 +12459,146 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 }
 
 /*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given notnull constraint in Phase 3
+ * and update the convalidated field in the pg_constraint catalog for the
+ * specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+						  char *constrName, HeapTuple contuple,
+						  bool recurse, bool recursing, LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+
+	List	   *children = NIL;
+	ListCell   *child;
+	AttrNumber  attnum;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, the parent has already done this, so skip it. Also,
+	 * if the constraint is a NO INHERIT constraint, we shouldn't try to look
+	 * for it in the children.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel),
+									   lockmode, NULL);
+
+	/*
+	 * For CHECK constraints, we must ensure that we only mark the constraint
+	 * as validated on the parent if it's already validated on the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	foreach(child, children)
+	{
+		Oid			childoid = lfirst_oid(child);
+		Relation	childrel;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("constraint must be validated on child tables too")));
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = getNNConnameForAttnum(childoid, attnum);
+		if (conname == NULL)
+			continue;
+
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalog, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
+/*
+ * Function returns the invalid not null constrint name for the given
+ * relation and attnumber.
+ */
+static char *
+getNNConnameForAttnum(Oid relid, AttrNumber  attnum)
+{
+	Relation	constrRel;
+	HeapTuple	htup;
+	SysScanDesc conscan;
+	ScanKeyData skey;
+	char	   *conname = NULL;
+
+	constrRel = table_open(ConstraintRelationId, AccessShareLock);
+	ScanKeyInit(&skey,
+				Anum_pg_constraint_conrelid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(relid));
+	conscan = systable_beginscan(constrRel, ConstraintRelidTypidNameIndexId, true,
+								 NULL, 1, &skey);
+
+	while (HeapTupleIsValid(htup = systable_getnext(conscan)))
+	{
+		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(htup);
+		AttrNumber	colnum;
+
+		if (conForm->contype != CONSTRAINT_NOTNULL)
+			continue;
+		if (conForm->convalidated == true)
+			continue;
+
+		colnum = extractNotNullColumn(htup);
+
+		if (colnum != attnum)
+			continue;
+
+		conname = pstrdup(NameStr(conForm->conname));
+		break;
+	}
+
+	systable_endscan(conscan);
+	table_close(constrRel, AccessShareLock);
+
+	return conname;
+}
+
+/*
  * transformColumnNameList - transform list of column names
  *
  * Lookup each name and return its attnum and, optionally, type and collation
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 06688ff..d2cf422 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1966,7 +1966,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((att->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 att->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index d388762..bfbf752 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4196,9 +4196,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 3b7ba66..583b5ac 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2107,7 +2107,7 @@ describeOneTableDetails(const char *schemaname,
 			printTableAddCell(&cont, PQgetvalue(res, i, attcoll_col), false, false);
 
 			printTableAddCell(&cont,
-							  strcmp(PQgetvalue(res, i, attnotnull_col), "t") == 0 ? "not null" : "",
+							  strcmp(PQgetvalue(res, i, attnotnull_col), "f") == 0 ? "" : "not null",
 							  false, false);
 
 			identity = PQgetvalue(res, i, attidentity_col);
@@ -3114,7 +3114,7 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0, c.convalidated \n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3138,13 +3138,15 @@ describeOneTableDetails(const char *schemaname,
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  PQgetvalue(result, i, 5)[0] == 'f' ?
+								  " NOT VALID " : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index b51a267..a01a0fa 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -229,6 +229,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 
 #define		  ATTRIBUTE_NOTNULL_TRUE		't'
 #define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+#define		  ATTRIBUTE_NOTNULL_INVALID		'i'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 692a69f..a16422b 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -897,6 +897,116 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID 
+
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+ a | b 
+---+---
+   | 1
+   | 2
+(2 rows)
+
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+  a  | b 
+-----+---
+ 300 | 3
+ 100 | 1
+(2 rows)
+
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constrint
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+ conname | convalidated 
+---------+--------------
+ nn      | t
+(1 row)
+
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a"
+
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constrint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constrint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+  conname  | convalidated 
+-----------+--------------
+ nn_parent | t
+ nn_child  | t
+(2 rows)
+
+DROP TABLE notnull_tbl1 CASCADE;
+NOTICE:  drop cascades to table notnull_chld
+--Create table with NOT NULL INVALID constrint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be market as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+    conrelid    |   conname   | convalidated 
+----------------+-------------+--------------
+ notnull_tbl1   | notnull_con | f
+ notnull_tbl1_1 | notnull_con | t
+ notnull_tbl1_2 | notnull_con | t
+(3 rows)
+
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index d6742f8..b62d8c6 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -641,6 +641,65 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constrint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constrint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+DROP TABLE notnull_tbl1 CASCADE;
+--Create table with NOT NULL INVALID constrint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be market as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
1.8.3.1

From 9c458320cba13e3b7f70222c684a555f1adac315 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 22:41:45 +0530
Subject: [PATCH 3/3] Support pg_dump to dump NOT VALID named NOT NULL
 constraints.

Dump the INVALID NOT NULL constraint as separate from table schema,
just like CHECK constraints.
---
 src/bin/pg_dump/pg_dump.c        | 168 ++++++++++++++++++++++++++++++++++++---
 src/bin/pg_dump/pg_dump.h        |   1 +
 src/bin/pg_dump/t/002_pg_dump.pl |  17 ++++
 3 files changed, 173 insertions(+), 13 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 520e133..a96c69b 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8745,6 +8745,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8761,6 +8762,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_attlen;
 	int			i_attalign;
 	int			i_attislocal;
+	int			i_notnull_valid;
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
@@ -8857,11 +8859,13 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 */
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
+							 "CASE WHEN a.attnotnull = 'i' THEN 'f' ELSE 't' END AS notnull_valid,\n"
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
+							 "'t' AS notnull_valid,\n"
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
@@ -8936,6 +8940,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attlen = PQfnumber(res, "attlen");
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
+	i_notnull_valid = PQfnumber(res, "notnull_valid");
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
@@ -8955,6 +8960,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9003,6 +9009,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attcompression = (char *) pg_malloc(numatts * sizeof(char));
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_valid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
@@ -9029,12 +9036,28 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_valid[j] = (PQgetvalue(res, r, i_notnull_valid)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			/*
+			 * Dump the invalid NOT NULL constrint like the Check constraints
+			 */
+			if (tbinfo->notnull_valid[j])
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			else if(!PQgetisnull(res, r, i_notnull_name))
+			{
+				/*
+				 * Add the entry into invalidnotnull list so NOT NULL constraint get
+				 * dump as separate constrints.
+				 */
+				if (invalidnotnulloids->len > 1) /* do we have more than the '{'? */
+					appendPQExpBufferChar(invalidnotnulloids, ',');
+				appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9056,6 +9079,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	}
 
 	PQclear(res);
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	/*
 	 * Now get info about column defaults.  This is skipped for a data-only
@@ -9319,6 +9343,128 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table INVALID NOT NULL constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+		int			i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND convalidated = 'f'"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool		validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * An unvalidated constraint needs to be dumped separately, so
+				 * that potentially-violating existing data is loaded before
+				 * the constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+
+				/*
+				 * Mark the constraint as needing to appear before the table
+				 * --- this is so that any other dependencies of the
+				 * constraint will be emitted before we try to create the
+				 * table.  If the constraint is to be dumped separately, it
+				 * will be dumped after data is loaded anyway, so don't do it.
+				 * (There's an automatic dependency in the opposite direction
+				 * anyway, so don't need to add one manually here.)
+				 */
+				if (!constrs[j].separate)
+					addObjectDependency(&tbinfo->dobj,
+										constrs[j].dobj.dumpId);
+
+				/*
+				 * We will detect later whether the constraint must be split
+				 * out from the table definition.
+				 */
+			}
+		}
+		PQclear(res);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(tbloids);
 	destroyPQExpBuffer(checkoids);
@@ -16136,7 +16282,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 					 * defined, or if binary upgrade.  (In the latter case, we
 					 * reset conislocal below.)
 					 */
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
+					print_notnull = (tbinfo->notnull_valid[j] &&
+									 tbinfo->notnull_constrs[j] != NULL &&
 									 (tbinfo->notnull_islocal[j] ||
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
@@ -16198,11 +16345,6 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
-									 (tbinfo->notnull_islocal[j] ||
-									  dopt->binary_upgrade ||
-									  tbinfo->ispartition));
-
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -17524,9 +17666,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK/INVALID_NOTNULL constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 7139c88..c4e05bd 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -356,6 +356,7 @@ typedef struct _tableInfo
 	char	   *attcompression; /* per-attribute compression method */
 	char	  **attfdwoptions;	/* per-attribute fdw options */
 	char	  **attmissingval;	/* per attribute missing value */
+	bool       *notnull_valid;  /* NOT NULL status */
 	char	  **notnull_constrs;	/* NOT NULL constraint names. If null,
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index bc5d922..a25fa9c 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1069,6 +1069,23 @@ my %tests = (
 		},
 	},
 
+    'CONSTRAINT NOT NULL / INVALID' => {
+        create_sql => 'CREATE TABLE dump_test.test_table_nn (
+                            col1 int);
+                            ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+        regexp => qr/^
+            \QALTER TABLE dump_test.test_table_nn\E \n^\s+
+            \QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+            /xm,
+        like => {
+            %full_runs, %dump_test_schema_runs, section_post_data => 1,
+        },
+        unlike => {
+            exclude_dump_test_schema => 1,
+            only_dump_measurement => 1,
+        },
+    },
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
-- 
1.8.3.1

From 488d040fca4796b712f8ef9b4a0c61f679a486b6 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Wed, 12 Feb 2025 16:43:37 +0530
Subject: [PATCH 4/4] Documentation and tab-complete for the NOT NULL NOT
 VALID.

---
 doc/src/sgml/catalogs.sgml        | 6 ++++--
 doc/src/sgml/ref/alter_table.sgml | 2 +-
 src/bin/psql/tab-complete.in.c    | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index ee59a7e..c835d21 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1257,10 +1257,12 @@
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>attnotnull</structfield> <type>bool</type>
+       <structfield>attnotnull</structfield> <type>char</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       <literal>t</literal> = not null true,
+       <literal>f</literal> = not null false,
+       <literal>i</literal> = not null invalid,
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 8e56b8e..bb85cd7 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -98,7 +98,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
 <phrase>and <replaceable class="parameter">column_constraint</replaceable> is:</phrase>
 
 [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
-{ NOT NULL [ NO INHERIT ] |
+{ NOT NULL [ NOT VALID ] [ NO INHERIT ] |
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index 5f6897c..c2ba0d5 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -2701,7 +2701,7 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_datatypes);
 	/* ALTER TABLE xxx ADD CONSTRAINT yyy */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "CONSTRAINT", MatchAny))
-		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY");
+		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY", "NOT NULL");
 	/* ALTER TABLE xxx ADD [CONSTRAINT yyy] (PRIMARY KEY|UNIQUE) */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "PRIMARY", "KEY") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ADD", "UNIQUE") ||
-- 
1.8.3.1

From ac8e690c64d354faad421a48f5adf0e26a15202b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Thu, 20 Feb 2025 13:05:35 +0100
Subject: [PATCH] fixup

---
 src/backend/bootstrap/bootstrap.c         |   4 +-
 src/backend/catalog/pg_constraint.c       |  17 +-
 src/backend/commands/tablecmds.c          | 229 ++++++++++------------
 src/bin/pg_dump/pg_dump.c                 |  15 +-
 src/bin/pg_dump/pg_dump.h                 |   2 +-
 src/test/regress/expected/constraints.out |  10 +-
 src/test/regress/sql/constraints.sql      |   8 +-
 7 files changed, 131 insertions(+), 154 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 1e95dc32f46..919972dc409 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,10 +582,8 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
-	/* set default to false */
 	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
-
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
 		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
@@ -699,7 +697,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..f856f387502 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,7 +574,7 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
+ * not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,9 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return the pg_constraint tuple that implements a
+ * not-null constraint for the given column of the given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -743,6 +741,9 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 		pg_constraint = table_open(ConstraintRelationId, RowExclusiveLock);
 		conform = (Form_pg_constraint) GETSTRUCT(tup);
 
+		if (!conform->convalidated)
+			elog(WARNING, "got an unvalidated constraint");
+
 		/*
 		 * If the NO INHERIT flag we're asked for doesn't match what the
 		 * existing constraint has, throw an error.
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1edda86fafd..793b81fc6c8 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -406,7 +406,7 @@ static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relat
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
 static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
-										char *constrName, HeapTuple contuple,
+										HeapTuple contuple,
 										bool recurse, bool recursing, LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
@@ -471,7 +471,8 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   bool skip_validation, LOCKMODE lockmode);
+						   char newvalue, bool queue_validation,
+						   LOCKMODE lockmode);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -701,7 +702,6 @@ static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, const char *compression);
 static char GetAttributeStorage(Oid atttypid, const char *storagemode);
 static bool check_for_invalid_notnull(Oid relid, const char *attname);
-static char *getNNConnameForAttnum(Oid relid, AttrNumber  attnum);
 
 
 /* ----------------------------------------------------------------
@@ -1319,7 +1319,8 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, false, NoLock);
+		set_attnotnull(NULL, rel, attrnum, ATTRIBUTE_NOTNULL_TRUE,
+					   false, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -7717,10 +7718,13 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   bool skip_validation, LOCKMODE lockmode)
+			   char newvalue, bool queue_validation, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
+
+	Assert(!queue_validation || wqueue != NULL);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7731,7 +7735,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
+	if (attr->attnotnull != newvalue)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7744,20 +7748,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
+		attr->attnotnull = newvalue;
 
-		if (skip_validation)
-			attr->attnotnull = ATTRIBUTE_NOTNULL_INVALID;
-		else
-			attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
-		 * If the nullness isn't already proven by validated constraints, have
-		 * ALTER TABLE phase 3 test for it.
+		 * Queue later validation of this constraint, if necessary and
+		 * requested by caller.
 		 */
-		if (!skip_validation &&
-			wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation &&
+			newvalue == ATTRIBUTE_NOTNULL_TRUE &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7844,6 +7845,9 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 						   NameStr(conForm->conname),
 						   RelationGetRelationName(rel)));
 
+		if (!conForm->convalidated)
+			elog(WARNING, "trying to add a constraint where an invalid one already exists");
+
 		/*
 		 * If we find an appropriate constraint, we're almost done, but just
 		 * need to change some properties on it: if we're recursing, increment
@@ -7925,8 +7929,12 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, constraint->skip_validation, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and request validation */
+	set_attnotnull(wqueue, rel, attnum,
+				   constraint->skip_validation ?
+				   ATTRIBUTE_NOTNULL_INVALID :
+				   ATTRIBUTE_NOTNULL_TRUE,
+				   !constraint->skip_validation, lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9368,22 +9376,19 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 
 	/* Insert not-null constraints in the queue for the PK columns */
-	foreach(lc, pkconstr->keys)
+	foreach_node(String, colname, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
-		String *colname = lfirst(lc);
 
-		/*
-		 * Throw an error if relation key column has invalid not null
-		 * constraint.
-		 */
-		if (check_for_invalid_notnull(RelationGetRelid(rel), colname->sval))
+		/* Verify that the not-null constraint has been validated */
+		if (check_for_invalid_notnull(RelationGetRelid(rel), strVal(colname)))
 			ereport(ERROR,
-					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constrint",
-						   colname->sval, RelationGetRelationName(rel)));
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+						   strVal(colname), RelationGetRelationName(rel)));
 
-		nnconstr = makeNotNullConstraint(lfirst(lc));
+		nnconstr = makeNotNullConstraint(colname);
 
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
@@ -9785,7 +9790,12 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * phase 3 to verify existing rows, if needed.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, ccon->skip_validation, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   ccon->skip_validation ?
+						   ATTRIBUTE_NOTNULL_INVALID :
+						   ATTRIBUTE_NOTNULL_TRUE,
+						   !ccon->skip_validation,
+						   lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12203,7 +12213,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, not-null, or check constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12224,7 +12234,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 		}
 		else if (con->contype == CONSTRAINT_NOTNULL)
 		{
-			QueueNNConstraintValidation(wqueue, conrel, rel, constrName,
+			QueueNNConstraintValidation(wqueue, conrel, rel,
 										tuple, recurse, recursing, lockmode);
 		}
 
@@ -12356,9 +12366,7 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	AlteredTableInfo *tab;
 	HeapTuple	copyTuple;
 	Form_pg_constraint copy_con;
-
 	List	   *children = NIL;
-	ListCell   *child;
 	NewConstraint *newcon;
 	Datum		val;
 	char	   *conbin;
@@ -12367,24 +12375,19 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	Assert(con->contype == CONSTRAINT_CHECK);
 
 	/*
-	 * If we're recursing, the parent has already done this, so skip it. Also,
-	 * if the constraint is a NO INHERIT constraint, we shouldn't try to look
-	 * for it in the children.
-	 */
-	if (!recursing && !con->connoinherit)
-		children = find_all_inheritors(RelationGetRelid(rel),
-									   lockmode, NULL);
-
-	/*
-	 * For CHECK constraints, we must ensure that we only mark the constraint
-	 * as validated on the parent if it's already validated on the children.
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
 	 *
 	 * We recurse before validating on the parent, to reduce risk of
 	 * deadlocks.
 	 */
-	foreach(child, children)
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+	foreach_oid(childoid, children)
 	{
-		Oid			childoid = lfirst_oid(child);
 		Relation	childrel;
 
 		if (childoid == RelationGetRelid(rel))
@@ -12446,23 +12449,22 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 /*
  * QueueNNConstraintValidation
  *
- * Add an entry to the wqueue to validate the given notnull constraint in Phase 3
- * and update the convalidated field in the pg_constraint catalog for the
- * specified relation and all its inheriting children.
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
  */
 static void
 QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
-						  char *constrName, HeapTuple contuple,
-						  bool recurse, bool recursing, LOCKMODE lockmode)
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
 {
 	Form_pg_constraint con;
 	AlteredTableInfo *tab;
 	HeapTuple	copyTuple;
 	Form_pg_constraint copy_con;
-
 	List	   *children = NIL;
-	ListCell   *child;
-	AttrNumber  attnum;
+	AttrNumber	attnum;
+	char	   *colname;
 
 	con = (Form_pg_constraint) GETSTRUCT(contuple);
 	Assert(con->contype == CONSTRAINT_NOTNULL);
@@ -12470,25 +12472,24 @@ QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	attnum = extractNotNullColumn(contuple);
 
 	/*
-	 * If we're recursing, the parent has already done this, so skip it. Also,
-	 * if the constraint is a NO INHERIT constraint, we shouldn't try to look
-	 * for it in the children.
-	 */
-	if (!recursing && !con->connoinherit)
-		children = find_all_inheritors(RelationGetRelid(rel),
-									   lockmode, NULL);
-
-	/*
-	 * For CHECK constraints, we must ensure that we only mark the constraint
-	 * as validated on the parent if it's already validated on the children.
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
 	 *
 	 * We recurse before validating on the parent, to reduce risk of
 	 * deadlocks.
 	 */
-	foreach(child, children)
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
 	{
-		Oid			childoid = lfirst_oid(child);
 		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
 		char	   *conname;
 
 		if (childoid == RelationGetRelid(rel))
@@ -12501,21 +12502,31 @@ QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 		 */
 		if (!recurse)
 			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
-					 errmsg("constraint must be validated on child tables too")));
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
 
 		/* find_all_inheritors already got lock */
 		childrel = table_open(childoid, NoLock);
-		conname = getNNConnameForAttnum(childoid, attnum);
-		if (conname == NULL)
-			continue;
+		conname = pstrdup(NameStr(childcon->conname));
 
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
 		ATExecValidateConstraint(wqueue, childrel, conname,
 								 false, true, lockmode);
 		table_close(childrel, NoLock);
 	}
 
-
 	tab = ATGetQueueEntry(wqueue, rel);
 	tab->verify_new_notnull = true;
 
@@ -12525,64 +12536,22 @@ QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	CacheInvalidateRelcache(rel);
 
 	/*
-	 * Now update the catalog, while we have the door open.
+	 * Now update the catalogs, while we have the door open.
 	 */
 	copyTuple = heap_copytuple(contuple);
 	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
 	copy_con->convalidated = true;
 	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
 
+	/* Also flip attnotnull */
+	set_attnotnull(wqueue, rel, attnum, ATTRIBUTE_NOTNULL_TRUE, false,
+				   lockmode);
+
 	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
 
 	heap_freetuple(copyTuple);
 }
 
-/*
- * Function returns the invalid not null constrint name for the given
- * relation and attnumber.
- */
-static char *
-getNNConnameForAttnum(Oid relid, AttrNumber  attnum)
-{
-	Relation	constrRel;
-	HeapTuple	htup;
-	SysScanDesc conscan;
-	ScanKeyData skey;
-	char	   *conname = NULL;
-
-	constrRel = table_open(ConstraintRelationId, AccessShareLock);
-	ScanKeyInit(&skey,
-				Anum_pg_constraint_conrelid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(relid));
-	conscan = systable_beginscan(constrRel, ConstraintRelidTypidNameIndexId, true,
-								 NULL, 1, &skey);
-
-	while (HeapTupleIsValid(htup = systable_getnext(conscan)))
-	{
-		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(htup);
-		AttrNumber	colnum;
-
-		if (conForm->contype != CONSTRAINT_NOTNULL)
-			continue;
-		if (conForm->convalidated == true)
-			continue;
-
-		colnum = extractNotNullColumn(htup);
-
-		if (colnum != attnum)
-			continue;
-
-		conname = pstrdup(NameStr(conForm->conname));
-		break;
-	}
-
-	systable_endscan(conscan);
-	table_close(constrRel, AccessShareLock);
-
-	return conname;
-}
-
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13454,7 +13423,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+		if (attForm->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		{
 			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
@@ -16790,12 +16759,20 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
 													 parent_att->attnum);
-				if (HeapTupleIsValid(contup) &&
-					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
-					ereport(ERROR,
-							errcode(ERRCODE_DATATYPE_MISMATCH),
-							errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
-								   parent_attname, RelationGetRelationName(child_rel)));
+				if (HeapTupleIsValid(contup))
+				{
+					Form_pg_constraint	childcon;
+
+					childcon = (Form_pg_constraint) GETSTRUCT(contup);
+					if (!childcon->connoinherit)
+						ereport(ERROR,
+								errcode(ERRCODE_DATATYPE_MISMATCH),
+								errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
+									   parent_attname, RelationGetRelationName(child_rel)));
+
+					if (!childcon->convalidated)
+						elog(WARNING, "found an invalid constraint");
+				}
 			}
 
 			/*
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index c63b4504cee..7f0c39db88d 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -9124,7 +9124,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->notnull_valid[j] = (PQgetvalue(res, r, i_notnull_valid)[0] == 't');
 
 			/*
-			 * Dump the invalid NOT NULL constrint like the Check constraints
+			 * Dump the invalid NOT NULL constraint like the Check constraints
 			 */
 			if (tbinfo->notnull_valid[j])
 				/* Handle not-null constraint name and flags */
@@ -9132,13 +9132,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 									  tbinfo, j,
 									  i_notnull_name, i_notnull_noinherit,
 									  i_notnull_islocal);
-			else if(!PQgetisnull(res, r, i_notnull_name))
+			else if (!PQgetisnull(res, r, i_notnull_name))
 			{
 				/*
-				 * Add the entry into invalidnotnull list so NOT NULL constraint get
-				 * dump as separate constrints.
+				 * Add the entry into invalidnotnull list so NOT NULL
+				 * constraint get dump as separate constraints.
 				 */
-				if (invalidnotnulloids->len > 1) /* do we have more than the '{'? */
+				if (invalidnotnulloids->len > 1)	/* do we have more than
+													 * the '{'? */
 					appendPQExpBufferChar(invalidnotnulloids, ',');
 				appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
 
@@ -9429,8 +9430,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	}
 
 	/*
-	 * Get info about table INVALID NOT NULL constraints.  This is skipped for a
-	 * data-only dump, as it is only needed for table schemas.
+	 * Get info about table INVALID NOT NULL constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
 	 */
 	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
 	{
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 25d65b357a4..a393d993330 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -361,7 +361,7 @@ typedef struct _tableInfo
 	char	   *attcompression; /* per-attribute compression method */
 	char	  **attfdwoptions;	/* per-attribute fdw options */
 	char	  **attmissingval;	/* per attribute missing value */
-	bool       *notnull_valid;  /* NOT NULL status */
+	bool	   *notnull_valid;	/* NOT NULL status */
 	char	  **notnull_constrs;	/* NOT NULL constraint names. If null,
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index a16422b681b..341956f1cea 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -941,7 +941,7 @@ SELECT * FROM notnull_tbl1;
 -- Try to add primary key on table column marked as NOT VALID NOT NULL
 -- constraint. This should throw an error.
 ALTER TABLE notnull_tbl1 add primary key (a);
-ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constrint
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
 -- INHERITS table having NOT VALID NOT NULL constraints.
 CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
 NOTICE:  merging column "a" with inherited definition
@@ -965,13 +965,13 @@ Not-null constraints:
     "nn" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
--- Test the different Not null constrint name for parent and child table
+-- Test the different Not null constraint name for parent and child table
 CREATE TABLE notnull_tbl1 (a int);
 ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
 CREATE TABLE notnull_chld (a int);
 ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
 ALTER TABLE notnull_chld INHERIT notnull_tbl1;
--- This statement should validate not null constrint for parent as well as
+-- This statement should validate not null constraint for parent as well as
 -- child.
 ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
 SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
@@ -984,7 +984,7 @@ in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
 
 DROP TABLE notnull_tbl1 CASCADE;
 NOTICE:  drop cascades to table notnull_chld
---Create table with NOT NULL INVALID constrint, for pg_upgrade.
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
 CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
 INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
 INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
@@ -995,7 +995,7 @@ CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
 ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
 CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
 CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
--- Parent table NOT NULL constraints will be market as validated false, where
+-- Parent table NOT NULL constraints will be marked as validated false, where
 -- for child table it will be true
 SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
 conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index b62d8c69ff4..6dd7e4c79c7 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -670,19 +670,19 @@ DROP TABLE notnull_tbl1_child;
 ALTER TABLE notnull_tbl1 validate constraint nn;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
--- Test the different Not null constrint name for parent and child table
+-- Test the different Not null constraint name for parent and child table
 CREATE TABLE notnull_tbl1 (a int);
 ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
 CREATE TABLE notnull_chld (a int);
 ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
 ALTER TABLE notnull_chld INHERIT notnull_tbl1;
--- This statement should validate not null constrint for parent as well as
+-- This statement should validate not null constraint for parent as well as
 -- child.
 ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
 SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
 in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
 DROP TABLE notnull_tbl1 CASCADE;
---Create table with NOT NULL INVALID constrint, for pg_upgrade.
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
 CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
 INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
 INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
@@ -694,7 +694,7 @@ CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
 ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
 CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
 CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
--- Parent table NOT NULL constraints will be market as validated false, where
+-- Parent table NOT NULL constraints will be marked as validated false, where
 -- for child table it will be true
 SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
 conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
-- 
2.39.5

From c51ba611a16177f8950a9c7ed999bec12c02080b Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 15:39:16 +0530
Subject: [PATCH 1/3] Convert pg_attribut.attnotnull to char type.

This commit change the pg_attribut.attnotnull to char type. Now
attnotnull holds three values, where attnotnull can be either
TRUE, FALSE and INVALID.  INVALID is when name not null constrint
is NOT VALIDATED.
---
 src/backend/access/common/tupdesc.c        | 12 ++++----
 src/backend/bootstrap/bootstrap.c          | 13 ++++----
 src/backend/catalog/heap.c                 | 16 +++++-----
 src/backend/catalog/index.c                |  2 +-
 src/backend/catalog/indexing.c             |  3 +-
 src/backend/catalog/information_schema.sql |  4 +--
 src/backend/commands/tablecmds.c           | 35 ++++++++++++----------
 src/backend/executor/execMain.c            |  3 +-
 src/backend/jit/llvm/llvmjit_deform.c      | 10 ++++---
 src/backend/optimizer/util/plancat.c       |  5 ++--
 src/include/access/tupdesc.h               |  2 +-
 src/include/catalog/pg_attribute.h         |  5 +++-
 12 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b..58698812c0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -251,7 +251,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -297,7 +297,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -417,7 +417,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 	{
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -463,7 +463,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	dstAtt->attnum = dstAttno;
 
 	/* since we're not copying constraints or defaults, clear these */
-	dstAtt->attnotnull = false;
+	dstAtt->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -840,7 +840,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -903,7 +903,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d..1e95dc32f4 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,14 +582,17 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	/* set default to false */
+	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
+
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
-		attrtypes[attnum]->attnotnull = true;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 	}
 	else if (nullness == BOOTCOL_NULL_FORCE_NULL)
 	{
-		attrtypes[attnum]->attnotnull = false;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	}
 	else
 	{
@@ -608,11 +611,11 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 			for (i = 0; i < attnum; i++)
 			{
 				if (attrtypes[i]->attlen <= 0 ||
-					!attrtypes[i]->attnotnull)
+					attrtypes[i]->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					break;
 			}
 			if (i == attnum)
-				attrtypes[attnum]->attnotnull = true;
+				attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		}
 	}
 }
@@ -696,7 +699,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 956f196fc9..6dc94e3693 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -149,7 +149,7 @@ static const FormData_pg_attribute a1 = {
 	.attbyval = false,
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -162,7 +162,7 @@ static const FormData_pg_attribute a2 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -175,7 +175,7 @@ static const FormData_pg_attribute a3 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -188,7 +188,7 @@ static const FormData_pg_attribute a4 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -201,7 +201,7 @@ static const FormData_pg_attribute a5 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -220,7 +220,7 @@ static const FormData_pg_attribute a6 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -751,7 +751,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attalign - 1] = CharGetDatum(attrs->attalign);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
-		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = CharGetDatum(attrs->attnotnull);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1710,7 +1710,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 	attStruct->atttypid = InvalidOid;
 
 	/* Remove any not-null constraint the column may have */
-	attStruct->attnotnull = false;
+	attStruct->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index cdabf78024..44177047eb 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -261,7 +261,7 @@ index_check_primary_key(Relation heapRel,
 				 attnum, RelationGetRelid(heapRel));
 		attform = (Form_pg_attribute) GETSTRUCT(atttuple);
 
-		if (!attform->attnotnull)
+		if (attform->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("primary key column \"%s\" is not marked NOT NULL",
diff --git a/src/backend/catalog/indexing.c b/src/backend/catalog/indexing.c
index 25c4b6bdc8..a2211d7556 100644
--- a/src/backend/catalog/indexing.c
+++ b/src/backend/catalog/indexing.c
@@ -207,7 +207,8 @@ CatalogTupleCheckConstraints(Relation heapRel, HeapTuple tup)
 		{
 			Form_pg_attribute thisatt = TupleDescAttr(tupdesc, attnum);
 
-			Assert(!(thisatt->attnotnull && att_isnull(attnum, bp)));
+			Assert(!(thisatt->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					 att_isnull(attnum, bp)));
 		}
 	}
 }
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index a7bffca93d..4f59bc46e7 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -292,7 +292,7 @@ CREATE VIEW attributes AS
            CAST(a.attname AS sql_identifier) AS attribute_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(pg_get_expr(ad.adbin, ad.adrelid) AS character_data) AS attribute_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't' OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable, -- This column was apparently removed between SQL:2003 and SQL:2008.
 
@@ -671,7 +671,7 @@ CREATE VIEW columns AS
            CAST(a.attname AS sql_identifier) AS column_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(CASE WHEN a.attgenerated = '' THEN pg_get_expr(ad.adbin, ad.adrelid) END AS character_data) AS column_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't'  OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable,
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 9d8754be7e..c47ac4d1d3 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1398,7 +1398,10 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		if (entry->is_not_null)
+			att->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		else
+			att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -6187,7 +6190,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
 		if (notnull_attrs)
@@ -7637,7 +7641,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 						RelationGetRelid(rel), attnum);
 
 	/* If the column is already nullable there's nothing to do. */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		table_close(attr_rel, RowExclusiveLock);
 		return InvalidObjectAddress;
@@ -7667,7 +7671,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 		AttrNumber	parent_attnum;
 
 		parent_attnum = get_attnum(parentId, colName);
-		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull)
+		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("column \"%s\" is marked NOT NULL in parent table",
@@ -7721,7 +7725,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7734,8 +7738,8 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
-		attr->attnotnull = true;
+		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
+		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -8141,7 +8145,7 @@ ATExecAddIdentity(Relation rel, const char *colName,
 	 * to an existing column that is not NOT NULL would create a state that
 	 * cannot be reproduced without contortions.
 	 */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" must be declared NOT NULL before identity can be added",
@@ -9343,7 +9347,7 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 					elog(ERROR, "cache lookup failed for attribute %s of relation %u",
 						 attname, childrelid);
 				attrForm = (Form_pg_attribute) GETSTRUCT(tup);
-				if (!attrForm->attnotnull)
+				if (attrForm->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					ereport(ERROR,
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
 								   attname, get_rel_name(childrelid)));
@@ -13259,9 +13263,9 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull)
+		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		{
-			attForm->attnotnull = false;
+			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16588,7 +16592,8 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			 *
 			 * Other constraints are checked elsewhere.
 			 */
-			if (parent_att->attnotnull && !child_att->attnotnull)
+			if (parent_att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				child_att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			{
 				HeapTuple	contup;
 
@@ -17631,7 +17636,7 @@ ATExecReplicaIdentity(Relation rel, ReplicaIdentityStmt *stmt, LOCKMODE lockmode
 							RelationGetRelationName(indexRel), attno)));
 
 		attr = TupleDescAttr(rel->rd_att, attno - 1);
-		if (!attr->attnotnull)
+		if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 					 errmsg("index \"%s\" cannot be used as replica identity because column \"%s\" is nullable",
@@ -19109,7 +19114,7 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
@@ -20941,7 +20946,7 @@ verifyPartitionIndexNotNull(IndexInfo *iinfo, Relation partition)
 		Form_pg_attribute att = TupleDescAttr(RelationGetDescr(partition),
 											  iinfo->ii_IndexAttrNumbers[i] - 1);
 
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					errmsg("invalid primary key definition"),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 0493b7d536..d582231ab6 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,7 +2070,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull && slot_attisnull(slot, attrChk))
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
 				Relation	orig_rel = rel;
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40..e6444bc2c9 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 71abb01f65..e322098cfb 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1355,7 +1355,8 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					!att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0b..1eba67ca8e 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -76,7 +76,7 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnotnull;		/* as FormData_pg_attribute.attnotnull */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe5..b51a267095 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -118,7 +118,7 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	char		attcompression BKI_DEFAULT('\0');
 
 	/* This flag represents the "NOT NULL" constraint */
-	bool		attnotnull;
+	char		attnotnull;
 
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
@@ -227,6 +227,9 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_GENERATED_STORED	's'
 #define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
+#define		  ATTRIBUTE_NOTNULL_TRUE		't'
+#define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
 #endif							/* PG_ATTRIBUTE_H */
-- 
2.43.0

From 8348e55717086f08fb12cefd4fa0156a541867ab Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 16:22:30 +0530
Subject: [PATCH 2/3] Support NOT VALID and VALIDATE CONSTRAINT for named NOT
 NULL constraints.

Commit also add support for pg_dump to dump NOT VALID named NOT NULL
constraints.
---
 src/backend/bootstrap/bootstrap.c         |   4 +-
 src/backend/catalog/heap.c                |   2 +-
 src/backend/catalog/pg_constraint.c       |  31 ++-
 src/backend/commands/tablecmds.c          | 250 ++++++++++++++++++----
 src/backend/executor/execMain.c           |   3 +-
 src/backend/parser/gram.y                 |   4 +-
 src/bin/pg_dump/pg_dump.c                 | 169 +++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   1 +
 src/bin/pg_dump/t/002_pg_dump.pl          |  17 ++
 src/bin/psql/describe.c                   |  10 +-
 src/include/catalog/pg_attribute.h        |   1 +
 src/include/catalog/pg_constraint.h       |   3 +-
 src/test/regress/expected/constraints.out | 153 +++++++++++++
 src/test/regress/sql/constraints.sql      |  85 ++++++++
 14 files changed, 661 insertions(+), 72 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 1e95dc32f4..919972dc40 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,10 +582,8 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
-	/* set default to false */
 	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
-
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
 		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
@@ -699,7 +697,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 6dc94e3693..4337cf3e7e 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2575,7 +2575,7 @@ AddRelationNewConstraints(Relation rel,
 			 * to add another one; just adjust inheritance status as needed.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 cdef->conname, is_local, cdef->is_no_inherit))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf..e14041b34c 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,7 +574,7 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
+ * not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,9 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return the pg_constraint tuple that implements a
+ * not-null constraint for the given column of the given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -726,10 +724,13 @@ extractNotNullColumn(HeapTuple constrTup)
  * conislocal/coninhcount and return true.
  * In the latter case, if is_local is true we flip conislocal true, or do
  * nothing if it's already true; otherwise we increment coninhcount by 1.
+ *
+ * Function add a check for existing INVALID not-null constraint on
+ * the table column.
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 const char *conname, bool is_local, bool is_no_inherit)
 {
 	HeapTuple	tup;
 
@@ -753,6 +754,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if an invalid NOT NULL constraint exists on the
+		 * table column and an attempt is made to add another valid NOT NULL
+		 * constraint.
+		 */
+		if (is_local && !conform->convalidated && conname)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("Invalid NOT NULL constraint \"%s\" exist on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("Do VALIDATE CONSTRAINT"));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index c47ac4d1d3..7fff892aba 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -405,6 +405,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple,
+										bool recurse, bool recursing, LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -468,6 +471,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
+						   char newvalue, bool queue_validation,
 						   LOCKMODE lockmode);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
@@ -697,6 +701,7 @@ static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, const char *compression);
 static char GetAttributeStorage(Oid atttypid, const char *storagemode);
+static bool check_for_invalid_notnull(Oid relid, const char *attname);
 
 
 /* ----------------------------------------------------------------
@@ -1314,7 +1319,8 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, ATTRIBUTE_NOTNULL_TRUE,
+					   false, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -6190,7 +6196,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 attr->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
@@ -7711,10 +7718,13 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   char newvalue, bool queue_validation, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
+
+	Assert(!queue_validation || wqueue != NULL);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7725,7 +7735,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
+	if (attr->attnotnull != newvalue)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7738,15 +7748,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
-		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		attr->attnotnull = newvalue;
+
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
-		 * If the nullness isn't already proven by validated constraints, have
-		 * ALTER TABLE phase 3 test for it.
+		 * Queue later validation of this constraint, if necessary and
+		 * requested by caller.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation &&
+			newvalue == ATTRIBUTE_NOTNULL_TRUE &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7852,6 +7864,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, conForm->conname.data,
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7914,8 +7935,12 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and request validation */
+	set_attnotnull(wqueue, rel, attnum,
+				   constraint->skip_validation ?
+				   ATTRIBUTE_NOTNULL_INVALID :
+				   ATTRIBUTE_NOTNULL_TRUE,
+				   !constraint->skip_validation, lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9357,12 +9382,19 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 
 	/* Insert not-null constraints in the queue for the PK columns */
-	foreach(lc, pkconstr->keys)
+	foreach_node(String, colname, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
 
-		nnconstr = makeNotNullConstraint(lfirst(lc));
+		/* Verify that the not-null constraint has been validated */
+		if (check_for_invalid_notnull(RelationGetRelid(rel), strVal(colname)))
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+						   strVal(colname), RelationGetRelationName(rel)));
+
+		nnconstr = makeNotNullConstraint(colname);
 
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
@@ -9373,6 +9405,30 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 }
 
+/*
+ * This function checks for any invalid NOT NULL constraint on the given
+ * relation and attribute name. It returns true if found, false otherwise.
+ */
+static bool
+check_for_invalid_notnull(Oid relid, const char *attname)
+{
+	HeapTuple	tuple;
+	bool		retval = false;
+
+	tuple = SearchSysCache2(ATTNAME,
+							ObjectIdGetDatum(relid),
+							CStringGetDatum(attname));
+	if (!HeapTupleIsValid(tuple))
+		return false;
+	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attisdropped &&
+		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull == ATTRIBUTE_NOTNULL_INVALID)
+		retval = true;
+
+	ReleaseSysCache(tuple);
+
+	return retval;
+}
+
 /*
  * ALTER TABLE ADD INDEX
  *
@@ -9740,7 +9796,12 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * phase 3 to verify existing rows, if needed.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   ccon->skip_validation ?
+						   ATTRIBUTE_NOTNULL_INVALID :
+						   ATTRIBUTE_NOTNULL_TRUE,
+						   !ccon->skip_validation,
+						   lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12154,10 +12215,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, not-null, or check constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12176,6 +12238,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12305,9 +12372,7 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	AlteredTableInfo *tab;
 	HeapTuple	copyTuple;
 	Form_pg_constraint copy_con;
-
 	List	   *children = NIL;
-	ListCell   *child;
 	NewConstraint *newcon;
 	Datum		val;
 	char	   *conbin;
@@ -12316,24 +12381,19 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	Assert(con->contype == CONSTRAINT_CHECK);
 
 	/*
-	 * If we're recursing, the parent has already done this, so skip it. Also,
-	 * if the constraint is a NO INHERIT constraint, we shouldn't try to look
-	 * for it in the children.
-	 */
-	if (!recursing && !con->connoinherit)
-		children = find_all_inheritors(RelationGetRelid(rel),
-									   lockmode, NULL);
-
-	/*
-	 * For CHECK constraints, we must ensure that we only mark the constraint
-	 * as validated on the parent if it's already validated on the children.
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
 	 *
 	 * We recurse before validating on the parent, to reduce risk of
 	 * deadlocks.
 	 */
-	foreach(child, children)
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+	foreach_oid(childoid, children)
 	{
-		Oid			childoid = lfirst_oid(child);
 		Relation	childrel;
 
 		if (childoid == RelationGetRelid(rel))
@@ -12392,6 +12452,112 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	/* Also flip attnotnull */
+	set_attnotnull(wqueue, rel, attnum, ATTRIBUTE_NOTNULL_TRUE, false,
+				   lockmode);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13263,7 +13429,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+		if (attForm->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		{
 			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
@@ -16599,12 +16765,20 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
 													 parent_att->attnum);
-				if (HeapTupleIsValid(contup) &&
-					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
-					ereport(ERROR,
-							errcode(ERRCODE_DATATYPE_MISMATCH),
-							errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
-								   parent_attname, RelationGetRelationName(child_rel)));
+				if (HeapTupleIsValid(contup))
+				{
+					Form_pg_constraint	childcon;
+
+					childcon = (Form_pg_constraint) GETSTRUCT(contup);
+					if (!childcon->connoinherit)
+						ereport(ERROR,
+								errcode(ERRCODE_DATATYPE_MISMATCH),
+								errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
+									   parent_attname, RelationGetRelationName(child_rel)));
+
+					if (!childcon->convalidated)
+						elog(WARNING, "found an invalid constraint");
+				}
 			}
 
 			/*
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index d582231ab6..4b0446b00d 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,7 +2070,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((att->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 att->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 7d99c9355c..b3fd4183b2 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4196,9 +4196,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index afd7928717..7f0c39db88 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8830,6 +8830,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8846,6 +8847,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_attlen;
 	int			i_attalign;
 	int			i_attislocal;
+	int			i_notnull_valid;
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
@@ -8942,11 +8944,13 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 */
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
+							 "CASE WHEN a.attnotnull = 'i' THEN 'f' ELSE 't' END AS notnull_valid,\n"
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
+							 "'t' AS notnull_valid,\n"
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
@@ -9021,6 +9025,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attlen = PQfnumber(res, "attlen");
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
+	i_notnull_valid = PQfnumber(res, "notnull_valid");
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
@@ -9040,6 +9045,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9088,6 +9094,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attcompression = (char *) pg_malloc(numatts * sizeof(char));
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_valid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
@@ -9114,12 +9121,29 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_valid[j] = (PQgetvalue(res, r, i_notnull_valid)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			/*
+			 * Dump the invalid NOT NULL constraint like the Check constraints
+			 */
+			if (tbinfo->notnull_valid[j])
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			else if (!PQgetisnull(res, r, i_notnull_name))
+			{
+				/*
+				 * Add the entry into invalidnotnull list so NOT NULL
+				 * constraint get dump as separate constraints.
+				 */
+				if (invalidnotnulloids->len > 1)	/* do we have more than
+													 * the '{'? */
+					appendPQExpBufferChar(invalidnotnulloids, ',');
+				appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9141,6 +9165,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	}
 
 	PQclear(res);
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	/*
 	 * Now get info about column defaults.  This is skipped for a data-only
@@ -9404,6 +9429,128 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table INVALID NOT NULL constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+		int			i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND convalidated = 'f'"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool		validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * An unvalidated constraint needs to be dumped separately, so
+				 * that potentially-violating existing data is loaded before
+				 * the constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+
+				/*
+				 * Mark the constraint as needing to appear before the table
+				 * --- this is so that any other dependencies of the
+				 * constraint will be emitted before we try to create the
+				 * table.  If the constraint is to be dumped separately, it
+				 * will be dumped after data is loaded anyway, so don't do it.
+				 * (There's an automatic dependency in the opposite direction
+				 * anyway, so don't need to add one manually here.)
+				 */
+				if (!constrs[j].separate)
+					addObjectDependency(&tbinfo->dobj,
+										constrs[j].dobj.dumpId);
+
+				/*
+				 * We will detect later whether the constraint must be split
+				 * out from the table definition.
+				 */
+			}
+		}
+		PQclear(res);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(tbloids);
 	destroyPQExpBuffer(checkoids);
@@ -16515,7 +16662,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 					 * defined, or if binary upgrade.  (In the latter case, we
 					 * reset conislocal below.)
 					 */
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
+					print_notnull = (tbinfo->notnull_valid[j] &&
+									 tbinfo->notnull_constrs[j] != NULL &&
 									 (tbinfo->notnull_islocal[j] ||
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
@@ -16577,11 +16725,6 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
-									 (tbinfo->notnull_islocal[j] ||
-									  dopt->binary_upgrade ||
-									  tbinfo->ispartition));
-
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -17903,9 +18046,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK/INVALID_NOTNULL constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index f08f5905aa..a393d99333 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -361,6 +361,7 @@ typedef struct _tableInfo
 	char	   *attcompression; /* per-attribute compression method */
 	char	  **attfdwoptions;	/* per-attribute fdw options */
 	char	  **attmissingval;	/* per attribute missing value */
+	bool	   *notnull_valid;	/* NOT NULL status */
 	char	  **notnull_constrs;	/* NOT NULL constraint names. If null,
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 3945e4f0e2..ce88865532 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1099,6 +1099,23 @@ my %tests = (
 		},
 	},
 
+    'CONSTRAINT NOT NULL / INVALID' => {
+        create_sql => 'CREATE TABLE dump_test.test_table_nn (
+                            col1 int);
+                            ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+        regexp => qr/^
+            \QALTER TABLE dump_test.test_table_nn\E \n^\s+
+            \QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+            /xm,
+        like => {
+            %full_runs, %dump_test_schema_runs, section_post_data => 1,
+        },
+        unlike => {
+            exclude_dump_test_schema => 1,
+            only_dump_measurement => 1,
+        },
+    },
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9..f48b24ed38 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2107,7 +2107,7 @@ describeOneTableDetails(const char *schemaname,
 			printTableAddCell(&cont, PQgetvalue(res, i, attcoll_col), false, false);
 
 			printTableAddCell(&cont,
-							  strcmp(PQgetvalue(res, i, attnotnull_col), "t") == 0 ? "not null" : "",
+							  strcmp(PQgetvalue(res, i, attnotnull_col), "f") == 0 ? "" : "not null",
 							  false, false);
 
 			identity = PQgetvalue(res, i, attidentity_col);
@@ -3114,7 +3114,7 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0, c.convalidated \n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3138,13 +3138,15 @@ describeOneTableDetails(const char *schemaname,
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  PQgetvalue(result, i, 5)[0] == 'f' ?
+								  " NOT VALID " : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index b51a267095..a01a0fa96d 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -229,6 +229,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 
 #define		  ATTRIBUTE_NOTNULL_TRUE		't'
 #define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+#define		  ATTRIBUTE_NOTNULL_INVALID		'i'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4..0e01ff1bbb 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -264,7 +264,8 @@ extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 const char *conname, bool is_local,
+									 bool is_no_inherit);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 692a69fe45..e5f2d78686 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -897,6 +897,159 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID 
+
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+ a | b 
+---+---
+   | 1
+   | 2
+(2 rows)
+
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+  a  | b 
+-----+---
+ 300 | 3
+ 100 | 1
+(2 rows)
+
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+ conname | convalidated 
+---------+--------------
+ nn      | t
+(1 row)
+
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a"
+
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+  conname  | convalidated 
+-----------+--------------
+ nn_parent | t
+ nn_child  | t
+(2 rows)
+
+DROP TABLE notnull_tbl1 CASCADE;
+NOTICE:  drop cascades to table notnull_chld
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  Invalid NOT NULL constraint "nn1" exist on relation "notnull_tbl1"
+HINT:  Do VALIDATE CONSTRAINT
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+ conname | convalidated 
+---------+--------------
+ nn1     | t
+(1 row)
+
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+    conrelid    |   conname   | convalidated 
+----------------+-------------+--------------
+ notnull_tbl1   | notnull_con | f
+ notnull_tbl1_1 | notnull_con | t
+ notnull_tbl1_2 | notnull_con | t
+(3 rows)
+
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index d6742f83fb..2b95d08684 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -641,6 +641,91 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+DROP TABLE notnull_tbl1 CASCADE;
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
2.43.0

From 6b8b92db3d276973293c3c1086a1bc8977296744 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Thu, 27 Feb 2025 15:22:56 +0530
Subject: [PATCH 3/3] Documentation changes

---
 doc/src/sgml/catalogs.sgml        | 5 +++--
 doc/src/sgml/ref/alter_table.sgml | 4 ++--
 src/bin/psql/tab-complete.in.c    | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index ee59a7e15d..eef82a8fe8 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1257,10 +1257,11 @@
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>attnotnull</structfield> <type>bool</type>
+       <structfield>attnotnull</structfield> <type>char</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       The value 't' indicates that a not-null constraint exists for the
+       column, 'i' for an invalid constraint and 'f' for none.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 8e56b8e59b..ef698c0a9b 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -98,7 +98,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
 <phrase>and <replaceable class="parameter">column_constraint</replaceable> is:</phrase>
 
 [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
-{ NOT NULL [ NO INHERIT ] |
+{ NOT NULL [ NOT VALID ] [ NO INHERIT ] |
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
@@ -457,7 +457,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
+      VALID</literal>, which is currently only allowed for foreign key, NOT NULL constraints
       and CHECK constraints.
      </para>
 
diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index 8432be641a..1c3295d949 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -2728,7 +2728,7 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_datatypes);
 	/* ALTER TABLE xxx ADD CONSTRAINT yyy */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "CONSTRAINT", MatchAny))
-		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY");
+		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY", "NOT NULL");
 	/* ALTER TABLE xxx ADD [CONSTRAINT yyy] (PRIMARY KEY|UNIQUE) */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "PRIMARY", "KEY") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ADD", "UNIQUE") ||
-- 
2.43.0

From 0d8f3ff345d25d3d19ef1e3afb7374c45acef44b Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Mar 2025 16:40:02 +0530
Subject: [PATCH 4/4] Adjust set_attnotnull() API input parameters.

---
 src/backend/commands/tablecmds.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index ef9ec42e624..a1730abd318 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -471,8 +471,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   char newvalue, bool queue_validation,
-						   LOCKMODE lockmode);
+						   char newvalue, LOCKMODE lockmode);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1319,8 +1318,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, ATTRIBUTE_NOTNULL_TRUE,
-					   false, NoLock);
+		set_attnotnull(NULL, rel, attrnum, ATTRIBUTE_NOTNULL_TRUE, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -7718,13 +7716,11 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   char newvalue, bool queue_validation, LOCKMODE lockmode)
+			   char newvalue, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
 
-	Assert(!queue_validation || wqueue != NULL);
-
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7756,7 +7752,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 		 * Queue later validation of this constraint, if necessary and
 		 * requested by caller.
 		 */
-		if (queue_validation &&
+		if (wqueue &&
 			newvalue == ATTRIBUTE_NOTNULL_TRUE &&
 			!NotNullImpliedByRelConstraints(rel, attr))
 		{
@@ -7940,7 +7936,7 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				   constraint->skip_validation ?
 				   ATTRIBUTE_NOTNULL_INVALID :
 				   ATTRIBUTE_NOTNULL_TRUE,
-				   !constraint->skip_validation, lockmode);
+				   lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9800,7 +9796,6 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						   ccon->skip_validation ?
 						   ATTRIBUTE_NOTNULL_INVALID :
 						   ATTRIBUTE_NOTNULL_TRUE,
-						   !ccon->skip_validation,
 						   lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
@@ -12550,8 +12545,7 @@ QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
 
 	/* Also flip attnotnull */
-	set_attnotnull(wqueue, rel, attnum, ATTRIBUTE_NOTNULL_TRUE, false,
-				   lockmode);
+	set_attnotnull(NULL, rel, attnum, ATTRIBUTE_NOTNULL_TRUE, lockmode);
 
 	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
 
-- 
2.43.0

From aee75c8f0b5b7e1f5ccd83ab62a631611fab72f9 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 16:22:30 +0530
Subject: [PATCH 2/3] Support NOT VALID and VALIDATE CONSTRAINT for named NOT
 NULL constraints.

Commit also add support for pg_dump to dump NOT VALID named NOT NULL
constraints.
---
 src/backend/bootstrap/bootstrap.c         |   4 +-
 src/backend/catalog/heap.c                |   2 +-
 src/backend/catalog/pg_constraint.c       |  31 ++-
 src/backend/commands/tablecmds.c          | 249 ++++++++++++++++++----
 src/backend/executor/execMain.c           |   3 +-
 src/backend/parser/gram.y                 |   4 +-
 src/bin/pg_dump/pg_dump.c                 | 169 +++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   1 +
 src/bin/pg_dump/t/002_pg_dump.pl          |  17 ++
 src/bin/psql/describe.c                   |  10 +-
 src/include/catalog/pg_attribute.h        |   1 +
 src/include/catalog/pg_constraint.h       |   3 +-
 src/test/regress/expected/constraints.out | 153 +++++++++++++
 src/test/regress/sql/constraints.sql      |  85 ++++++++
 14 files changed, 659 insertions(+), 73 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 1e95dc32f46..919972dc409 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,10 +582,8 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
-	/* set default to false */
 	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
-
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
 		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
@@ -699,7 +697,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 8c2d2cdcdfe..6458f78c216 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2626,7 +2626,7 @@ AddRelationNewConstraints(Relation rel,
 			 * to add another one; just adjust inheritance status as needed.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 cdef->conname, is_local, cdef->is_no_inherit))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..e14041b34ca 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,7 +574,7 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
+ * not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,9 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return the pg_constraint tuple that implements a
+ * not-null constraint for the given column of the given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -726,10 +724,13 @@ extractNotNullColumn(HeapTuple constrTup)
  * conislocal/coninhcount and return true.
  * In the latter case, if is_local is true we flip conislocal true, or do
  * nothing if it's already true; otherwise we increment coninhcount by 1.
+ *
+ * Function add a check for existing INVALID not-null constraint on
+ * the table column.
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 const char *conname, bool is_local, bool is_no_inherit)
 {
 	HeapTuple	tup;
 
@@ -753,6 +754,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if an invalid NOT NULL constraint exists on the
+		 * table column and an attempt is made to add another valid NOT NULL
+		 * constraint.
+		 */
+		if (is_local && !conform->convalidated && conname)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("Invalid NOT NULL constraint \"%s\" exist on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("Do VALIDATE CONSTRAINT"));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3c81e48cac1..6a757c7c374 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -410,6 +410,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple,
+										bool recurse, bool recursing, LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -473,7 +476,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   char newvalue, LOCKMODE lockmode);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -710,6 +713,7 @@ static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, const char *compression);
 static char GetAttributeStorage(Oid atttypid, const char *storagemode);
+static bool check_for_invalid_notnull(Oid relid, const char *attname);
 
 
 /* ----------------------------------------------------------------
@@ -1315,7 +1319,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, ATTRIBUTE_NOTNULL_TRUE, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -6191,7 +6195,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 attr->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
@@ -7743,10 +7748,11 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   char newvalue, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7757,7 +7763,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
+	if (attr->attnotnull != newvalue)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7770,15 +7776,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
-		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		attr->attnotnull = newvalue;
+
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
-		 * If the nullness isn't already proven by validated constraints, have
-		 * ALTER TABLE phase 3 test for it.
+		 * Queue later validation of this constraint, if necessary and
+		 * requested by caller.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (wqueue &&
+			newvalue == ATTRIBUTE_NOTNULL_TRUE &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7884,6 +7892,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, conForm->conname.data,
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7946,8 +7963,12 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and request validation */
+	set_attnotnull(wqueue, rel, attnum,
+				   constraint->skip_validation ?
+				   ATTRIBUTE_NOTNULL_INVALID :
+				   ATTRIBUTE_NOTNULL_TRUE,
+				   lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9387,12 +9408,19 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 
 	/* Insert not-null constraints in the queue for the PK columns */
-	foreach(lc, pkconstr->keys)
+	foreach_node(String, colname, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
 
-		nnconstr = makeNotNullConstraint(lfirst(lc));
+		/* Verify that the not-null constraint has been validated */
+		if (check_for_invalid_notnull(RelationGetRelid(rel), strVal(colname)))
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+						   strVal(colname), RelationGetRelationName(rel)));
+
+		nnconstr = makeNotNullConstraint(colname);
 
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
@@ -9403,6 +9431,30 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 }
 
+/*
+ * This function checks for any invalid NOT NULL constraint on the given
+ * relation and attribute name. It returns true if found, false otherwise.
+ */
+static bool
+check_for_invalid_notnull(Oid relid, const char *attname)
+{
+	HeapTuple	tuple;
+	bool		retval = false;
+
+	tuple = SearchSysCache2(ATTNAME,
+							ObjectIdGetDatum(relid),
+							CStringGetDatum(attname));
+	if (!HeapTupleIsValid(tuple))
+		return false;
+	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attisdropped &&
+		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull == ATTRIBUTE_NOTNULL_INVALID)
+		retval = true;
+
+	ReleaseSysCache(tuple);
+
+	return retval;
+}
+
 /*
  * ALTER TABLE ADD INDEX
  *
@@ -9770,7 +9822,11 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * phase 3 to verify existing rows, if needed.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   ccon->skip_validation ?
+						   ATTRIBUTE_NOTNULL_INVALID :
+						   ATTRIBUTE_NOTNULL_TRUE,
+						   lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12371,10 +12427,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, not-null, or check constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12393,6 +12450,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12522,9 +12584,7 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	AlteredTableInfo *tab;
 	HeapTuple	copyTuple;
 	Form_pg_constraint copy_con;
-
 	List	   *children = NIL;
-	ListCell   *child;
 	NewConstraint *newcon;
 	Datum		val;
 	char	   *conbin;
@@ -12533,24 +12593,19 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	Assert(con->contype == CONSTRAINT_CHECK);
 
 	/*
-	 * If we're recursing, the parent has already done this, so skip it. Also,
-	 * if the constraint is a NO INHERIT constraint, we shouldn't try to look
-	 * for it in the children.
-	 */
-	if (!recursing && !con->connoinherit)
-		children = find_all_inheritors(RelationGetRelid(rel),
-									   lockmode, NULL);
-
-	/*
-	 * For CHECK constraints, we must ensure that we only mark the constraint
-	 * as validated on the parent if it's already validated on the children.
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
 	 *
 	 * We recurse before validating on the parent, to reduce risk of
 	 * deadlocks.
 	 */
-	foreach(child, children)
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+	foreach_oid(childoid, children)
 	{
-		Oid			childoid = lfirst_oid(child);
 		Relation	childrel;
 
 		if (childoid == RelationGetRelid(rel))
@@ -12609,6 +12664,114 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	/*
+	 * Also flip attnotnull. call function with wqueue as NULL to
+	 * bypass validation, as it has already been performed.
+	 */
+	set_attnotnull(NULL, rel, attnum, ATTRIBUTE_NOTNULL_TRUE, lockmode);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13480,7 +13643,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+		if (attForm->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		{
 			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
@@ -16816,12 +16979,20 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
 													 parent_att->attnum);
-				if (HeapTupleIsValid(contup) &&
-					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
-					ereport(ERROR,
-							errcode(ERRCODE_DATATYPE_MISMATCH),
-							errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
-								   parent_attname, RelationGetRelationName(child_rel)));
+				if (HeapTupleIsValid(contup))
+				{
+					Form_pg_constraint	childcon;
+
+					childcon = (Form_pg_constraint) GETSTRUCT(contup);
+					if (!childcon->connoinherit)
+						ereport(ERROR,
+								errcode(ERRCODE_DATATYPE_MISMATCH),
+								errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
+									   parent_attname, RelationGetRelationName(child_rel)));
+
+					if (!childcon->convalidated)
+						elog(WARNING, "found an invalid constraint");
+				}
 			}
 
 			/*
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index d582231ab60..4b0446b00d8 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,7 +2070,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((att->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 att->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..715eb51300b 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4224,9 +4224,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index c371570501a..1a946461219 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8876,6 +8876,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8892,6 +8893,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_attlen;
 	int			i_attalign;
 	int			i_attislocal;
+	int			i_notnull_valid;
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
@@ -8988,11 +8990,13 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 */
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
+							 "CASE WHEN a.attnotnull = 'i' THEN 'f' ELSE 't' END AS notnull_valid,\n"
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
+							 "'t' AS notnull_valid,\n"
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
@@ -9067,6 +9071,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attlen = PQfnumber(res, "attlen");
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
+	i_notnull_valid = PQfnumber(res, "notnull_valid");
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
@@ -9086,6 +9091,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9134,6 +9140,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attcompression = (char *) pg_malloc(numatts * sizeof(char));
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_valid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
@@ -9160,12 +9167,29 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_valid[j] = (PQgetvalue(res, r, i_notnull_valid)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			/*
+			 * Dump the invalid NOT NULL constraint like the Check constraints
+			 */
+			if (tbinfo->notnull_valid[j])
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			else if (!PQgetisnull(res, r, i_notnull_name))
+			{
+				/*
+				 * Add the entry into invalidnotnull list so NOT NULL
+				 * constraint get dump as separate constraints.
+				 */
+				if (invalidnotnulloids->len > 1)	/* do we have more than
+													 * the '{'? */
+					appendPQExpBufferChar(invalidnotnulloids, ',');
+				appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9187,6 +9211,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	}
 
 	PQclear(res);
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	/*
 	 * Now get info about column defaults.  This is skipped for a data-only
@@ -9450,6 +9475,128 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table INVALID NOT NULL constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+		int			i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND convalidated = 'f'"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool		validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * An unvalidated constraint needs to be dumped separately, so
+				 * that potentially-violating existing data is loaded before
+				 * the constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+
+				/*
+				 * Mark the constraint as needing to appear before the table
+				 * --- this is so that any other dependencies of the
+				 * constraint will be emitted before we try to create the
+				 * table.  If the constraint is to be dumped separately, it
+				 * will be dumped after data is loaded anyway, so don't do it.
+				 * (There's an automatic dependency in the opposite direction
+				 * anyway, so don't need to add one manually here.)
+				 */
+				if (!constrs[j].separate)
+					addObjectDependency(&tbinfo->dobj,
+										constrs[j].dobj.dumpId);
+
+				/*
+				 * We will detect later whether the constraint must be split
+				 * out from the table definition.
+				 */
+			}
+		}
+		PQclear(res);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(tbloids);
 	destroyPQExpBuffer(checkoids);
@@ -16543,7 +16690,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 					 * defined, or if binary upgrade.  (In the latter case, we
 					 * reset conislocal below.)
 					 */
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
+					print_notnull = (tbinfo->notnull_valid[j] &&
+									 tbinfo->notnull_constrs[j] != NULL &&
 									 (tbinfo->notnull_islocal[j] ||
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
@@ -16605,11 +16753,6 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
-									 (tbinfo->notnull_islocal[j] ||
-									  dopt->binary_upgrade ||
-									  tbinfo->ispartition));
-
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -17931,9 +18074,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK/INVALID_NOTNULL constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index bbdb30b5f54..90335d2bb0b 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -361,6 +361,7 @@ typedef struct _tableInfo
 	char	   *attcompression; /* per-attribute compression method */
 	char	  **attfdwoptions;	/* per-attribute fdw options */
 	char	  **attmissingval;	/* per attribute missing value */
+	bool	   *notnull_valid;	/* NOT NULL status */
 	char	  **notnull_constrs;	/* NOT NULL constraint names. If null,
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index c7bffc1b045..5b5b756e512 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1099,6 +1099,23 @@ my %tests = (
 		},
 	},
 
+    'CONSTRAINT NOT NULL / INVALID' => {
+        create_sql => 'CREATE TABLE dump_test.test_table_nn (
+                            col1 int);
+                            ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+        regexp => qr/^
+            \QALTER TABLE dump_test.test_table_nn\E \n^\s+
+            \QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+            /xm,
+        like => {
+            %full_runs, %dump_test_schema_runs, section_post_data => 1,
+        },
+        unlike => {
+            exclude_dump_test_schema => 1,
+            only_dump_measurement => 1,
+        },
+    },
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9e..f48b24ed38c 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2107,7 +2107,7 @@ describeOneTableDetails(const char *schemaname,
 			printTableAddCell(&cont, PQgetvalue(res, i, attcoll_col), false, false);
 
 			printTableAddCell(&cont,
-							  strcmp(PQgetvalue(res, i, attnotnull_col), "t") == 0 ? "not null" : "",
+							  strcmp(PQgetvalue(res, i, attnotnull_col), "f") == 0 ? "" : "not null",
 							  false, false);
 
 			identity = PQgetvalue(res, i, attidentity_col);
@@ -3114,7 +3114,7 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0, c.convalidated \n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3138,13 +3138,15 @@ describeOneTableDetails(const char *schemaname,
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  PQgetvalue(result, i, 5)[0] == 'f' ?
+								  " NOT VALID " : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index b51a2670958..a01a0fa96d2 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -229,6 +229,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 
 #define		  ATTRIBUTE_NOTNULL_TRUE		't'
 #define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+#define		  ATTRIBUTE_NOTNULL_INVALID		'i'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..0e01ff1bbbd 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -264,7 +264,8 @@ extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 const char *conname, bool is_local,
+									 bool is_no_inherit);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..b52578bf8d3 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,159 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID 
+
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+ a | b 
+---+---
+   | 1
+   | 2
+(2 rows)
+
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+  a  | b 
+-----+---
+ 300 | 3
+ 100 | 1
+(2 rows)
+
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+ conname | convalidated 
+---------+--------------
+ nn      | t
+(1 row)
+
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a"
+
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+  conname  | convalidated 
+-----------+--------------
+ nn_parent | t
+ nn_child  | t
+(2 rows)
+
+DROP TABLE notnull_tbl1 CASCADE;
+NOTICE:  drop cascades to table notnull_chld
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  Invalid NOT NULL constraint "nn1" exist on relation "notnull_tbl1"
+HINT:  Do VALIDATE CONSTRAINT
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+ conname | convalidated 
+---------+--------------
+ nn1     | t
+(1 row)
+
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+    conrelid    |   conname   | convalidated 
+----------------+-------------+--------------
+ notnull_tbl1   | notnull_con | f
+ notnull_tbl1_1 | notnull_con | t
+ notnull_tbl1_2 | notnull_con | t
+(3 rows)
+
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..7aff17e6764 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,91 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+DROP TABLE notnull_tbl1 CASCADE;
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
2.43.0

From 8e909c049dabe9d6ed559e14f076714ad7a43d8f Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 15:39:16 +0530
Subject: [PATCH 1/3] Convert pg_attribut.attnotnull to char type.

This commit change the pg_attribut.attnotnull to char type. Now
attnotnull holds three values, where attnotnull can be either
TRUE, FALSE and INVALID.  INVALID is when name not null constrint
is NOT VALIDATED.
---
 src/backend/access/common/tupdesc.c        | 12 ++++----
 src/backend/bootstrap/bootstrap.c          | 13 ++++----
 src/backend/catalog/heap.c                 | 16 +++++-----
 src/backend/catalog/index.c                |  2 +-
 src/backend/catalog/indexing.c             |  3 +-
 src/backend/catalog/information_schema.sql |  4 +--
 src/backend/commands/tablecmds.c           | 35 ++++++++++++----------
 src/backend/executor/execMain.c            |  3 +-
 src/backend/jit/llvm/llvmjit_deform.c      | 10 ++++---
 src/backend/optimizer/util/plancat.c       |  5 ++--
 src/include/access/tupdesc.h               |  2 +-
 src/include/catalog/pg_attribute.h         |  5 +++-
 12 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..58698812c0b 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -251,7 +251,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -297,7 +297,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -417,7 +417,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 	{
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -463,7 +463,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	dstAtt->attnum = dstAttno;
 
 	/* since we're not copying constraints or defaults, clear these */
-	dstAtt->attnotnull = false;
+	dstAtt->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -840,7 +840,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -903,7 +903,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..1e95dc32f46 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,14 +582,17 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	/* set default to false */
+	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
+
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
-		attrtypes[attnum]->attnotnull = true;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 	}
 	else if (nullness == BOOTCOL_NULL_FORCE_NULL)
 	{
-		attrtypes[attnum]->attnotnull = false;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	}
 	else
 	{
@@ -608,11 +611,11 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 			for (i = 0; i < attnum; i++)
 			{
 				if (attrtypes[i]->attlen <= 0 ||
-					!attrtypes[i]->attnotnull)
+					attrtypes[i]->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					break;
 			}
 			if (i == attnum)
-				attrtypes[attnum]->attnotnull = true;
+				attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		}
 	}
 }
@@ -696,7 +699,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..8c2d2cdcdfe 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -150,7 +150,7 @@ static const FormData_pg_attribute a1 = {
 	.attbyval = false,
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -163,7 +163,7 @@ static const FormData_pg_attribute a2 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -176,7 +176,7 @@ static const FormData_pg_attribute a3 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -189,7 +189,7 @@ static const FormData_pg_attribute a4 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -202,7 +202,7 @@ static const FormData_pg_attribute a5 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -221,7 +221,7 @@ static const FormData_pg_attribute a6 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -752,7 +752,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attalign - 1] = CharGetDatum(attrs->attalign);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
-		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = CharGetDatum(attrs->attnotnull);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1713,7 +1713,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 	attStruct->atttypid = InvalidOid;
 
 	/* Remove any not-null constraint the column may have */
-	attStruct->attnotnull = false;
+	attStruct->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 739a92bdcc1..6b0c16bf59d 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -262,7 +262,7 @@ index_check_primary_key(Relation heapRel,
 				 attnum, RelationGetRelid(heapRel));
 		attform = (Form_pg_attribute) GETSTRUCT(atttuple);
 
-		if (!attform->attnotnull)
+		if (attform->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("primary key column \"%s\" is not marked NOT NULL",
diff --git a/src/backend/catalog/indexing.c b/src/backend/catalog/indexing.c
index 25c4b6bdc87..a2211d75566 100644
--- a/src/backend/catalog/indexing.c
+++ b/src/backend/catalog/indexing.c
@@ -207,7 +207,8 @@ CatalogTupleCheckConstraints(Relation heapRel, HeapTuple tup)
 		{
 			Form_pg_attribute thisatt = TupleDescAttr(tupdesc, attnum);
 
-			Assert(!(thisatt->attnotnull && att_isnull(attnum, bp)));
+			Assert(!(thisatt->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					 att_isnull(attnum, bp)));
 		}
 	}
 }
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index a7bffca93d1..4f59bc46e74 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -292,7 +292,7 @@ CREATE VIEW attributes AS
            CAST(a.attname AS sql_identifier) AS attribute_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(pg_get_expr(ad.adbin, ad.adrelid) AS character_data) AS attribute_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't' OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable, -- This column was apparently removed between SQL:2003 and SQL:2008.
 
@@ -671,7 +671,7 @@ CREATE VIEW columns AS
            CAST(a.attname AS sql_identifier) AS column_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(CASE WHEN a.attgenerated = '' THEN pg_get_expr(ad.adbin, ad.adrelid) END AS character_data) AS column_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't'  OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable,
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 18ff8956577..3c81e48cac1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1399,7 +1399,10 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		if (entry->is_not_null)
+			att->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		else
+			att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -6188,7 +6191,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
 		if (notnull_attrs)
@@ -7669,7 +7673,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 						RelationGetRelid(rel), attnum);
 
 	/* If the column is already nullable there's nothing to do. */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		table_close(attr_rel, RowExclusiveLock);
 		return InvalidObjectAddress;
@@ -7699,7 +7703,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 		AttrNumber	parent_attnum;
 
 		parent_attnum = get_attnum(parentId, colName);
-		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull)
+		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("column \"%s\" is marked NOT NULL in parent table",
@@ -7753,7 +7757,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7766,8 +7770,8 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
-		attr->attnotnull = true;
+		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
+		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -8172,7 +8176,7 @@ ATExecAddIdentity(Relation rel, const char *colName,
 	 * to an existing column that is not NOT NULL would create a state that
 	 * cannot be reproduced without contortions.
 	 */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" must be declared NOT NULL before identity can be added",
@@ -9373,7 +9377,7 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 					elog(ERROR, "cache lookup failed for attribute %s of relation %u",
 						 attname, childrelid);
 				attrForm = (Form_pg_attribute) GETSTRUCT(tup);
-				if (!attrForm->attnotnull)
+				if (attrForm->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					ereport(ERROR,
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
 								   attname, get_rel_name(childrelid)));
@@ -13476,9 +13480,9 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull)
+		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		{
-			attForm->attnotnull = false;
+			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16805,7 +16809,8 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			 *
 			 * Other constraints are checked elsewhere.
 			 */
-			if (parent_att->attnotnull && !child_att->attnotnull)
+			if (parent_att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				child_att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			{
 				HeapTuple	contup;
 
@@ -17848,7 +17853,7 @@ ATExecReplicaIdentity(Relation rel, ReplicaIdentityStmt *stmt, LOCKMODE lockmode
 							RelationGetRelationName(indexRel), attno)));
 
 		attr = TupleDescAttr(rel->rd_att, attno - 1);
-		if (!attr->attnotnull)
+		if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 					 errmsg("index \"%s\" cannot be used as replica identity because column \"%s\" is nullable",
@@ -19326,7 +19331,7 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
@@ -21158,7 +21163,7 @@ verifyPartitionIndexNotNull(IndexInfo *iinfo, Relation partition)
 		Form_pg_attribute att = TupleDescAttr(RelationGetDescr(partition),
 											  iinfo->ii_IndexAttrNumbers[i] - 1);
 
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					errmsg("invalid primary key definition"),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 0493b7d5365..d582231ab60 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,7 +2070,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull && slot_attisnull(slot, attrChk))
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
 				Relation	orig_rel = rel;
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..e6444bc2c91 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 71abb01f655..e322098cfb2 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1355,7 +1355,8 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					!att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..1eba67ca8e9 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -76,7 +76,7 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnotnull;		/* as FormData_pg_attribute.attnotnull */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..b51a2670958 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -118,7 +118,7 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	char		attcompression BKI_DEFAULT('\0');
 
 	/* This flag represents the "NOT NULL" constraint */
-	bool		attnotnull;
+	char		attnotnull;
 
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
@@ -227,6 +227,9 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_GENERATED_STORED	's'
 #define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
+#define		  ATTRIBUTE_NOTNULL_TRUE		't'
+#define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
 #endif							/* PG_ATTRIBUTE_H */
-- 
2.43.0

From b093a8a109fa7aec8caf792d9e3521fcebada86f Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Thu, 27 Feb 2025 15:22:56 +0530
Subject: [PATCH 3/3] Documentation changes

---
 doc/src/sgml/catalogs.sgml        | 5 +++--
 doc/src/sgml/ref/alter_table.sgml | 4 ++--
 src/bin/psql/tab-complete.in.c    | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..d6066d7dba1 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1257,10 +1257,11 @@
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>attnotnull</structfield> <type>bool</type>
+       <structfield>attnotnull</structfield> <type>char</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       The value 't' indicates that a not-null constraint exists for the
+       column, 'i' for an invalid constraint and 'f' for none.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index dceb7a7593c..288cd3339f8 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -99,7 +99,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
 <phrase>and <replaceable class="parameter">column_constraint</replaceable> is:</phrase>
 
 [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
-{ NOT NULL [ NO INHERIT ] |
+{ NOT NULL [ NOT VALID ] [ NO INHERIT ] |
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
@@ -458,7 +458,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
+      VALID</literal>, which is currently only allowed for foreign key, NOT NULL constraints
       and CHECK constraints.
      </para>
 
diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index 8432be641ac..1c3295d949a 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -2728,7 +2728,7 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_datatypes);
 	/* ALTER TABLE xxx ADD CONSTRAINT yyy */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "CONSTRAINT", MatchAny))
-		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY");
+		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY", "NOT NULL");
 	/* ALTER TABLE xxx ADD [CONSTRAINT yyy] (PRIMARY KEY|UNIQUE) */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "PRIMARY", "KEY") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ADD", "UNIQUE") ||
-- 
2.43.0

From 547d79773cd88a94810d7d4c2e005f63316d9601 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 15:39:16 +0530
Subject: [PATCH 1/3] Convert pg_attribut.attnotnull to char type.

This commit change the pg_attribut.attnotnull to char type. Now
attnotnull holds three values, where attnotnull can be either
TRUE, FALSE and INVALID.  INVALID is when name not null constrint
is NOT VALIDATED.
---
 src/backend/access/common/tupdesc.c        | 12 ++++----
 src/backend/bootstrap/bootstrap.c          | 13 ++++----
 src/backend/catalog/heap.c                 | 16 +++++-----
 src/backend/catalog/index.c                |  2 +-
 src/backend/catalog/indexing.c             |  3 +-
 src/backend/catalog/information_schema.sql |  4 +--
 src/backend/commands/tablecmds.c           | 35 ++++++++++++----------
 src/backend/executor/execMain.c            |  3 +-
 src/backend/jit/llvm/llvmjit_deform.c      | 10 ++++---
 src/backend/optimizer/util/plancat.c       |  5 ++--
 src/include/access/tupdesc.h               |  2 +-
 src/include/catalog/pg_attribute.h         |  5 +++-
 12 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..58698812c0b 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -251,7 +251,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -297,7 +297,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -417,7 +417,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 	{
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
-		att->attnotnull = false;
+		att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -463,7 +463,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	dstAtt->attnum = dstAttno;
 
 	/* since we're not copying constraints or defaults, clear these */
-	dstAtt->attnotnull = false;
+	dstAtt->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -840,7 +840,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -903,7 +903,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attnum = attributeNumber;
 	att->attndims = attdim;
 
-	att->attnotnull = false;
+	att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..1e95dc32f46 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,14 +582,17 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	/* set default to false */
+	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
+
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
-		attrtypes[attnum]->attnotnull = true;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 	}
 	else if (nullness == BOOTCOL_NULL_FORCE_NULL)
 	{
-		attrtypes[attnum]->attnotnull = false;
+		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 	}
 	else
 	{
@@ -608,11 +611,11 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 			for (i = 0; i < attnum; i++)
 			{
 				if (attrtypes[i]->attlen <= 0 ||
-					!attrtypes[i]->attnotnull)
+					attrtypes[i]->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					break;
 			}
 			if (i == attnum)
-				attrtypes[attnum]->attnotnull = true;
+				attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		}
 	}
 }
@@ -696,7 +699,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..8c2d2cdcdfe 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -150,7 +150,7 @@ static const FormData_pg_attribute a1 = {
 	.attbyval = false,
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -163,7 +163,7 @@ static const FormData_pg_attribute a2 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -176,7 +176,7 @@ static const FormData_pg_attribute a3 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -189,7 +189,7 @@ static const FormData_pg_attribute a4 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -202,7 +202,7 @@ static const FormData_pg_attribute a5 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -221,7 +221,7 @@ static const FormData_pg_attribute a6 = {
 	.attbyval = true,
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
-	.attnotnull = true,
+	.attnotnull = ATTRIBUTE_NOTNULL_TRUE,
 	.attislocal = true,
 };
 
@@ -752,7 +752,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attalign - 1] = CharGetDatum(attrs->attalign);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
-		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = CharGetDatum(attrs->attnotnull);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1713,7 +1713,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 	attStruct->atttypid = InvalidOid;
 
 	/* Remove any not-null constraint the column may have */
-	attStruct->attnotnull = false;
+	attStruct->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 739a92bdcc1..6b0c16bf59d 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -262,7 +262,7 @@ index_check_primary_key(Relation heapRel,
 				 attnum, RelationGetRelid(heapRel));
 		attform = (Form_pg_attribute) GETSTRUCT(atttuple);
 
-		if (!attform->attnotnull)
+		if (attform->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("primary key column \"%s\" is not marked NOT NULL",
diff --git a/src/backend/catalog/indexing.c b/src/backend/catalog/indexing.c
index 25c4b6bdc87..a2211d75566 100644
--- a/src/backend/catalog/indexing.c
+++ b/src/backend/catalog/indexing.c
@@ -207,7 +207,8 @@ CatalogTupleCheckConstraints(Relation heapRel, HeapTuple tup)
 		{
 			Form_pg_attribute thisatt = TupleDescAttr(tupdesc, attnum);
 
-			Assert(!(thisatt->attnotnull && att_isnull(attnum, bp)));
+			Assert(!(thisatt->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					 att_isnull(attnum, bp)));
 		}
 	}
 }
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index a7bffca93d1..4f59bc46e74 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -292,7 +292,7 @@ CREATE VIEW attributes AS
            CAST(a.attname AS sql_identifier) AS attribute_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(pg_get_expr(ad.adbin, ad.adrelid) AS character_data) AS attribute_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't' OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable, -- This column was apparently removed between SQL:2003 and SQL:2008.
 
@@ -671,7 +671,7 @@ CREATE VIEW columns AS
            CAST(a.attname AS sql_identifier) AS column_name,
            CAST(a.attnum AS cardinal_number) AS ordinal_position,
            CAST(CASE WHEN a.attgenerated = '' THEN pg_get_expr(ad.adbin, ad.adrelid) END AS character_data) AS column_default,
-           CAST(CASE WHEN a.attnotnull OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
+           CAST(CASE WHEN a.attnotnull = 't'  OR (t.typtype = 'd' AND t.typnotnull) THEN 'NO' ELSE 'YES' END
              AS yes_or_no)
              AS is_nullable,
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 18ff8956577..3c81e48cac1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1399,7 +1399,10 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		if (entry->is_not_null)
+			att->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		else
+			att->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -6188,7 +6191,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
 		if (notnull_attrs)
@@ -7669,7 +7673,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 						RelationGetRelid(rel), attnum);
 
 	/* If the column is already nullable there's nothing to do. */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		table_close(attr_rel, RowExclusiveLock);
 		return InvalidObjectAddress;
@@ -7699,7 +7703,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 		AttrNumber	parent_attnum;
 
 		parent_attnum = get_attnum(parentId, colName);
-		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull)
+		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("column \"%s\" is marked NOT NULL in parent table",
@@ -7753,7 +7757,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7766,8 +7770,8 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
-		attr->attnotnull = true;
+		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
+		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -8172,7 +8176,7 @@ ATExecAddIdentity(Relation rel, const char *colName,
 	 * to an existing column that is not NOT NULL would create a state that
 	 * cannot be reproduced without contortions.
 	 */
-	if (!attTup->attnotnull)
+	if (attTup->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" must be declared NOT NULL before identity can be added",
@@ -9373,7 +9377,7 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 					elog(ERROR, "cache lookup failed for attribute %s of relation %u",
 						 attname, childrelid);
 				attrForm = (Form_pg_attribute) GETSTRUCT(tup);
-				if (!attrForm->attnotnull)
+				if (attrForm->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 					ereport(ERROR,
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
 								   attname, get_rel_name(childrelid)));
@@ -13476,9 +13480,9 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull)
+		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 		{
-			attForm->attnotnull = false;
+			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16805,7 +16809,8 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			 *
 			 * Other constraints are checked elsewhere.
 			 */
-			if (parent_att->attnotnull && !child_att->attnotnull)
+			if (parent_att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				child_att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			{
 				HeapTuple	contup;
 
@@ -17848,7 +17853,7 @@ ATExecReplicaIdentity(Relation rel, ReplicaIdentityStmt *stmt, LOCKMODE lockmode
 							RelationGetRelationName(indexRel), attno)));
 
 		attr = TupleDescAttr(rel->rd_att, attno - 1);
-		if (!attr->attnotnull)
+		if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 					 errmsg("index \"%s\" cannot be used as replica identity because column \"%s\" is nullable",
@@ -19326,7 +19331,7 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
@@ -21158,7 +21163,7 @@ verifyPartitionIndexNotNull(IndexInfo *iinfo, Relation partition)
 		Form_pg_attribute att = TupleDescAttr(RelationGetDescr(partition),
 											  iinfo->ii_IndexAttrNumbers[i] - 1);
 
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 			ereport(ERROR,
 					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					errmsg("invalid primary key definition"),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 0493b7d5365..d582231ab60 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,7 +2070,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull && slot_attisnull(slot, attrChk))
+			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
 				Relation	orig_rel = rel;
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..e6444bc2c91 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 71abb01f655..e322098cfb2 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1355,7 +1355,8 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+					!att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..1eba67ca8e9 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -76,7 +76,7 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnotnull;		/* as FormData_pg_attribute.attnotnull */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..b51a2670958 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -118,7 +118,7 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	char		attcompression BKI_DEFAULT('\0');
 
 	/* This flag represents the "NOT NULL" constraint */
-	bool		attnotnull;
+	char		attnotnull;
 
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
@@ -227,6 +227,9 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_GENERATED_STORED	's'
 #define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
+#define		  ATTRIBUTE_NOTNULL_TRUE		't'
+#define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
 #endif							/* PG_ATTRIBUTE_H */
-- 
2.43.0

From 4d790fef210116b15ad0ec028405f735501cc144 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 10 Feb 2025 16:22:30 +0530
Subject: [PATCH 2/3] Support NOT VALID and VALIDATE CONSTRAINT for named NOT
 NULL constraints.

Commit also add support for pg_dump to dump NOT VALID named NOT NULL
constraints.
---
 src/backend/bootstrap/bootstrap.c         |   4 +-
 src/backend/catalog/heap.c                |   2 +-
 src/backend/catalog/pg_constraint.c       |  31 ++-
 src/backend/commands/tablecmds.c          | 249 ++++++++++++++++++----
 src/backend/executor/execMain.c           |   3 +-
 src/backend/parser/gram.y                 |   4 +-
 src/bin/pg_dump/pg_dump.c                 | 172 +++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   1 +
 src/bin/pg_dump/t/002_pg_dump.pl          |  17 ++
 src/bin/psql/describe.c                   |  10 +-
 src/include/catalog/pg_attribute.h        |   1 +
 src/include/catalog/pg_constraint.h       |   3 +-
 src/test/regress/expected/constraints.out | 153 +++++++++++++
 src/test/regress/sql/constraints.sql      |  85 ++++++++
 14 files changed, 661 insertions(+), 74 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 1e95dc32f46..919972dc409 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,10 +582,8 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
-	/* set default to false */
 	attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 
-
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
 		attrtypes[attnum]->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
@@ -699,7 +697,7 @@ InsertOneNull(int i)
 {
 	elog(DEBUG4, "inserting column %d NULL", i);
 	Assert(i >= 0 && i < MAXATTR);
-	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+	if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		elog(ERROR,
 			 "NULL value specified for not-null column \"%s\" of relation \"%s\"",
 			 NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 8c2d2cdcdfe..6458f78c216 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2626,7 +2626,7 @@ AddRelationNewConstraints(Relation rel,
 			 * to add another one; just adjust inheritance status as needed.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 cdef->conname, is_local, cdef->is_no_inherit))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..e14041b34ca 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,7 +574,7 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
+ * not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,9 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return the pg_constraint tuple that implements a
+ * not-null constraint for the given column of the given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -726,10 +724,13 @@ extractNotNullColumn(HeapTuple constrTup)
  * conislocal/coninhcount and return true.
  * In the latter case, if is_local is true we flip conislocal true, or do
  * nothing if it's already true; otherwise we increment coninhcount by 1.
+ *
+ * Function add a check for existing INVALID not-null constraint on
+ * the table column.
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 const char *conname, bool is_local, bool is_no_inherit)
 {
 	HeapTuple	tup;
 
@@ -753,6 +754,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if an invalid NOT NULL constraint exists on the
+		 * table column and an attempt is made to add another valid NOT NULL
+		 * constraint.
+		 */
+		if (is_local && !conform->convalidated && conname)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("Invalid NOT NULL constraint \"%s\" exist on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("Do VALIDATE CONSTRAINT"));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3c81e48cac1..6a757c7c374 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -410,6 +410,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple,
+										bool recurse, bool recursing, LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -473,7 +476,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   char newvalue, LOCKMODE lockmode);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -710,6 +713,7 @@ static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, const char *compression);
 static char GetAttributeStorage(Oid atttypid, const char *storagemode);
+static bool check_for_invalid_notnull(Oid relid, const char *attname);
 
 
 /* ----------------------------------------------------------------
@@ -1315,7 +1319,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, ATTRIBUTE_NOTNULL_TRUE, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -6191,7 +6195,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((attr->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 attr->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, i);
 		}
@@ -7743,10 +7748,11 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   char newvalue, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7757,7 +7763,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE)
+	if (attr->attnotnull != newvalue)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7770,15 +7776,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(attr->attnotnull == ATTRIBUTE_NOTNULL_FALSE);
-		attr->attnotnull = ATTRIBUTE_NOTNULL_TRUE;
+		attr->attnotnull = newvalue;
+
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
-		 * If the nullness isn't already proven by validated constraints, have
-		 * ALTER TABLE phase 3 test for it.
+		 * Queue later validation of this constraint, if necessary and
+		 * requested by caller.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (wqueue &&
+			newvalue == ATTRIBUTE_NOTNULL_TRUE &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7884,6 +7892,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, conForm->conname.data,
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7946,8 +7963,12 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and request validation */
+	set_attnotnull(wqueue, rel, attnum,
+				   constraint->skip_validation ?
+				   ATTRIBUTE_NOTNULL_INVALID :
+				   ATTRIBUTE_NOTNULL_TRUE,
+				   lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9387,12 +9408,19 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 
 	/* Insert not-null constraints in the queue for the PK columns */
-	foreach(lc, pkconstr->keys)
+	foreach_node(String, colname, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
 
-		nnconstr = makeNotNullConstraint(lfirst(lc));
+		/* Verify that the not-null constraint has been validated */
+		if (check_for_invalid_notnull(RelationGetRelid(rel), strVal(colname)))
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+						   strVal(colname), RelationGetRelationName(rel)));
+
+		nnconstr = makeNotNullConstraint(colname);
 
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
@@ -9403,6 +9431,30 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 }
 
+/*
+ * This function checks for any invalid NOT NULL constraint on the given
+ * relation and attribute name. It returns true if found, false otherwise.
+ */
+static bool
+check_for_invalid_notnull(Oid relid, const char *attname)
+{
+	HeapTuple	tuple;
+	bool		retval = false;
+
+	tuple = SearchSysCache2(ATTNAME,
+							ObjectIdGetDatum(relid),
+							CStringGetDatum(attname));
+	if (!HeapTupleIsValid(tuple))
+		return false;
+	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attisdropped &&
+		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull == ATTRIBUTE_NOTNULL_INVALID)
+		retval = true;
+
+	ReleaseSysCache(tuple);
+
+	return retval;
+}
+
 /*
  * ALTER TABLE ADD INDEX
  *
@@ -9770,7 +9822,11 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * phase 3 to verify existing rows, if needed.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   ccon->skip_validation ?
+						   ATTRIBUTE_NOTNULL_INVALID :
+						   ATTRIBUTE_NOTNULL_TRUE,
+						   lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12371,10 +12427,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, not-null, or check constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12393,6 +12450,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12522,9 +12584,7 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	AlteredTableInfo *tab;
 	HeapTuple	copyTuple;
 	Form_pg_constraint copy_con;
-
 	List	   *children = NIL;
-	ListCell   *child;
 	NewConstraint *newcon;
 	Datum		val;
 	char	   *conbin;
@@ -12533,24 +12593,19 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	Assert(con->contype == CONSTRAINT_CHECK);
 
 	/*
-	 * If we're recursing, the parent has already done this, so skip it. Also,
-	 * if the constraint is a NO INHERIT constraint, we shouldn't try to look
-	 * for it in the children.
-	 */
-	if (!recursing && !con->connoinherit)
-		children = find_all_inheritors(RelationGetRelid(rel),
-									   lockmode, NULL);
-
-	/*
-	 * For CHECK constraints, we must ensure that we only mark the constraint
-	 * as validated on the parent if it's already validated on the children.
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
 	 *
 	 * We recurse before validating on the parent, to reduce risk of
 	 * deadlocks.
 	 */
-	foreach(child, children)
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+	foreach_oid(childoid, children)
 	{
-		Oid			childoid = lfirst_oid(child);
 		Relation	childrel;
 
 		if (childoid == RelationGetRelid(rel))
@@ -12609,6 +12664,114 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	/*
+	 * Also flip attnotnull. call function with wqueue as NULL to
+	 * bypass validation, as it has already been performed.
+	 */
+	set_attnotnull(NULL, rel, attnum, ATTRIBUTE_NOTNULL_TRUE, lockmode);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13480,7 +13643,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 						   RelationGetRelationName(rel)));
 
 		/* All good -- reset attnotnull if needed */
-		if (attForm->attnotnull == ATTRIBUTE_NOTNULL_TRUE)
+		if (attForm->attnotnull != ATTRIBUTE_NOTNULL_FALSE)
 		{
 			attForm->attnotnull = ATTRIBUTE_NOTNULL_FALSE;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
@@ -16816,12 +16979,20 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
 													 parent_att->attnum);
-				if (HeapTupleIsValid(contup) &&
-					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
-					ereport(ERROR,
-							errcode(ERRCODE_DATATYPE_MISMATCH),
-							errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
-								   parent_attname, RelationGetRelationName(child_rel)));
+				if (HeapTupleIsValid(contup))
+				{
+					Form_pg_constraint	childcon;
+
+					childcon = (Form_pg_constraint) GETSTRUCT(contup);
+					if (!childcon->connoinherit)
+						ereport(ERROR,
+								errcode(ERRCODE_DATATYPE_MISMATCH),
+								errmsg("column \"%s\" in child table \"%s\" must be marked NOT NULL",
+									   parent_attname, RelationGetRelationName(child_rel)));
+
+					if (!childcon->convalidated)
+						elog(WARNING, "found an invalid constraint");
+				}
 			}
 
 			/*
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index d582231ab60..4b0446b00d8 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,7 +2070,8 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-			if (att->attnotnull == ATTRIBUTE_NOTNULL_TRUE &&
+			if ((att->attnotnull == ATTRIBUTE_NOTNULL_TRUE ||
+				 att->attnotnull == ATTRIBUTE_NOTNULL_INVALID) &&
 				slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..715eb51300b 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4224,9 +4224,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index c371570501a..4a5299d7c5c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8876,6 +8876,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8892,6 +8893,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_attlen;
 	int			i_attalign;
 	int			i_attislocal;
+	int			i_notnull_valid;
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
@@ -8988,11 +8990,13 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 */
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
+							 "CASE WHEN a.attnotnull = 'i' THEN 'f' ELSE 't' END AS notnull_valid,\n"
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
+							 "'t' AS notnull_valid,\n"
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
@@ -9067,6 +9071,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attlen = PQfnumber(res, "attlen");
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
+	i_notnull_valid = PQfnumber(res, "notnull_valid");
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
@@ -9086,6 +9091,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9134,6 +9140,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attcompression = (char *) pg_malloc(numatts * sizeof(char));
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_valid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
@@ -9160,12 +9167,29 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_valid[j] = (PQgetvalue(res, r, i_notnull_valid)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			/*
+			 * Dump the invalid NOT NULL constraint like the Check constraints
+			 */
+			if (tbinfo->notnull_valid[j])
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			else if (!PQgetisnull(res, r, i_notnull_name))
+			{
+				/*
+				 * Add the entry into invalidnotnull list so NOT NULL
+				 * constraint get dump as separate constraints.
+				 */
+				if (invalidnotnulloids->len > 1)	/* do we have more than
+													 * the '{'? */
+					appendPQExpBufferChar(invalidnotnulloids, ',');
+				appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9187,6 +9211,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	}
 
 	PQclear(res);
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	/*
 	 * Now get info about column defaults.  This is skipped for a data-only
@@ -9450,6 +9475,128 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table INVALID NOT NULL constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+		int			i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND convalidated = 'f'"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool		validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * An unvalidated constraint needs to be dumped separately, so
+				 * that potentially-violating existing data is loaded before
+				 * the constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+
+				/*
+				 * Mark the constraint as needing to appear before the table
+				 * --- this is so that any other dependencies of the
+				 * constraint will be emitted before we try to create the
+				 * table.  If the constraint is to be dumped separately, it
+				 * will be dumped after data is loaded anyway, so don't do it.
+				 * (There's an automatic dependency in the opposite direction
+				 * anyway, so don't need to add one manually here.)
+				 */
+				if (!constrs[j].separate)
+					addObjectDependency(&tbinfo->dobj,
+										constrs[j].dobj.dumpId);
+
+				/*
+				 * We will detect later whether the constraint must be split
+				 * out from the table definition.
+				 */
+			}
+		}
+		PQclear(res);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(tbloids);
 	destroyPQExpBuffer(checkoids);
@@ -16543,7 +16690,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 					 * defined, or if binary upgrade.  (In the latter case, we
 					 * reset conislocal below.)
 					 */
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
+					print_notnull = (tbinfo->notnull_valid[j] &&
+									 tbinfo->notnull_constrs[j] != NULL &&
 									 (tbinfo->notnull_islocal[j] ||
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
@@ -16605,11 +16753,6 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
-									 (tbinfo->notnull_islocal[j] ||
-									  dopt->binary_upgrade ||
-									  tbinfo->ispartition));
-
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -16928,7 +17071,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 				 * because the latter is not available.  (We distinguish the
 				 * case because the constraint name is the empty string.)
 				 */
-				if (tbinfo->notnull_constrs[j] != NULL &&
+				if (tbinfo->notnull_valid[j] &&
+					tbinfo->notnull_constrs[j] != NULL &&
 					!tbinfo->notnull_islocal[j])
 				{
 					if (tbinfo->notnull_constrs[j][0] != '\0')
@@ -17931,9 +18075,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK/INVALID_NOTNULL constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index bbdb30b5f54..90335d2bb0b 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -361,6 +361,7 @@ typedef struct _tableInfo
 	char	   *attcompression; /* per-attribute compression method */
 	char	  **attfdwoptions;	/* per-attribute fdw options */
 	char	  **attmissingval;	/* per attribute missing value */
+	bool	   *notnull_valid;	/* NOT NULL status */
 	char	  **notnull_constrs;	/* NOT NULL constraint names. If null,
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index c7bffc1b045..5b5b756e512 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1099,6 +1099,23 @@ my %tests = (
 		},
 	},
 
+    'CONSTRAINT NOT NULL / INVALID' => {
+        create_sql => 'CREATE TABLE dump_test.test_table_nn (
+                            col1 int);
+                            ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+        regexp => qr/^
+            \QALTER TABLE dump_test.test_table_nn\E \n^\s+
+            \QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+            /xm,
+        like => {
+            %full_runs, %dump_test_schema_runs, section_post_data => 1,
+        },
+        unlike => {
+            exclude_dump_test_schema => 1,
+            only_dump_measurement => 1,
+        },
+    },
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9e..f48b24ed38c 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2107,7 +2107,7 @@ describeOneTableDetails(const char *schemaname,
 			printTableAddCell(&cont, PQgetvalue(res, i, attcoll_col), false, false);
 
 			printTableAddCell(&cont,
-							  strcmp(PQgetvalue(res, i, attnotnull_col), "t") == 0 ? "not null" : "",
+							  strcmp(PQgetvalue(res, i, attnotnull_col), "f") == 0 ? "" : "not null",
 							  false, false);
 
 			identity = PQgetvalue(res, i, attidentity_col);
@@ -3114,7 +3114,7 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0, c.convalidated \n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3138,13 +3138,15 @@ describeOneTableDetails(const char *schemaname,
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  PQgetvalue(result, i, 5)[0] == 'f' ?
+								  " NOT VALID " : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index b51a2670958..a01a0fa96d2 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -229,6 +229,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 
 #define		  ATTRIBUTE_NOTNULL_TRUE		't'
 #define		  ATTRIBUTE_NOTNULL_FALSE		'f'
+#define		  ATTRIBUTE_NOTNULL_INVALID		'i'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..0e01ff1bbbd 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -264,7 +264,8 @@ extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 const char *conname, bool is_local,
+									 bool is_no_inherit);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..b52578bf8d3 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,159 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID 
+
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+ a | b 
+---+---
+   | 1
+   | 2
+(2 rows)
+
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+  a  | b 
+-----+---
+ 300 | 3
+ 100 | 1
+(2 rows)
+
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+ conname | convalidated 
+---------+--------------
+ nn      | t
+(1 row)
+
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a"
+
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+  conname  | convalidated 
+-----------+--------------
+ nn_parent | t
+ nn_child  | t
+(2 rows)
+
+DROP TABLE notnull_tbl1 CASCADE;
+NOTICE:  drop cascades to table notnull_chld
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  Invalid NOT NULL constraint "nn1" exist on relation "notnull_tbl1"
+HINT:  Do VALIDATE CONSTRAINT
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+ conname | convalidated 
+---------+--------------
+ nn1     | t
+(1 row)
+
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+    conrelid    |   conname   | convalidated 
+----------------+-------------+--------------
+ notnull_tbl1   | notnull_con | f
+ notnull_tbl1_1 | notnull_con | t
+ notnull_tbl1_2 | notnull_con | t
+(3 rows)
+
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..7aff17e6764 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,91 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+DROP TABLE notnull_tbl1 CASCADE;
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
2.43.0

From d6fd85b2142a6ba30da03b85b93ef3563e92eec8 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Thu, 27 Feb 2025 15:22:56 +0530
Subject: [PATCH 3/3] Documentation changes

---
 doc/src/sgml/catalogs.sgml        | 5 +++--
 doc/src/sgml/ref/alter_table.sgml | 4 ++--
 src/bin/psql/tab-complete.in.c    | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..d6066d7dba1 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1257,10 +1257,11 @@
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>attnotnull</structfield> <type>bool</type>
+       <structfield>attnotnull</structfield> <type>char</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       The value 't' indicates that a not-null constraint exists for the
+       column, 'i' for an invalid constraint and 'f' for none.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index dceb7a7593c..288cd3339f8 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -99,7 +99,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
 <phrase>and <replaceable class="parameter">column_constraint</replaceable> is:</phrase>
 
 [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
-{ NOT NULL [ NO INHERIT ] |
+{ NOT NULL [ NOT VALID ] [ NO INHERIT ] |
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
@@ -458,7 +458,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
+      VALID</literal>, which is currently only allowed for foreign key, NOT NULL constraints
       and CHECK constraints.
      </para>
 
diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index 8432be641ac..1c3295d949a 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -2728,7 +2728,7 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_datatypes);
 	/* ALTER TABLE xxx ADD CONSTRAINT yyy */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "CONSTRAINT", MatchAny))
-		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY");
+		COMPLETE_WITH("CHECK", "UNIQUE", "PRIMARY KEY", "EXCLUDE", "FOREIGN KEY", "NOT NULL");
 	/* ALTER TABLE xxx ADD [CONSTRAINT yyy] (PRIMARY KEY|UNIQUE) */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ADD", "PRIMARY", "KEY") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ADD", "UNIQUE") ||
-- 
2.43.0

From 5a66a8da2a8c5fef88d7730e127900e5b83e0cde Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Sun, 16 Mar 2025 20:50:53 +0800
Subject: [PATCH v4 1/1] not null not valid implementation

---
 src/backend/catalog/heap.c                |  14 +-
 src/backend/catalog/index.c               |   1 +
 src/backend/catalog/pg_constraint.c       |   3 +
 src/backend/commands/tablecmds.c          | 168 +++++++++++++++++++++-
 src/backend/commands/trigger.c            |   1 +
 src/backend/commands/typecmds.c           |   2 +
 src/backend/parser/gram.y                 |   5 +-
 src/backend/parser/parse_utilcmd.c        |  63 +++++++-
 src/include/catalog/heap.h                |   1 +
 src/include/catalog/pg_constraint.h       |   3 +
 src/include/nodes/parsenodes.h            |   1 +
 src/test/regress/expected/constraints.out |  63 ++++++++
 src/test/regress/sql/constraints.sql      |  41 ++++++
 13 files changed, 355 insertions(+), 11 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..6dc0267bd5a 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -104,7 +104,7 @@ static ObjectAddress AddNewRelationType(const char *typeName,
 static void RelationRemoveInheritance(Oid relid);
 static Oid	StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 						  bool is_enforced, bool is_validated, bool is_local,
-						  int16 inhcount, bool is_no_inherit, bool is_internal);
+						  int16 inhcount, bool is_no_inherit, char coninternaltype, bool is_internal);
 static void StoreConstraints(Relation rel, List *cooked_constraints,
 							 bool is_internal);
 static bool MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
@@ -2136,7 +2136,7 @@ SetAttrMissing(Oid relid, char *attname, char *value)
 static Oid
 StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 			  bool is_enforced, bool is_validated, bool is_local,
-			  int16 inhcount, bool is_no_inherit, bool is_internal)
+			  int16 inhcount, bool is_no_inherit, char coninternaltype, bool is_internal)
 {
 	char	   *ccbin;
 	List	   *varList;
@@ -2228,6 +2228,7 @@ StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 							  inhcount, /* coninhcount */
 							  is_no_inherit,	/* connoinherit */
 							  false,	/* conperiod */
+							  coninternaltype,	/* coninternaltype */
 							  is_internal); /* internally constructed? */
 
 	pfree(ccbin);
@@ -2282,6 +2283,7 @@ StoreRelNotNull(Relation rel, const char *nnname, AttrNumber attnum,
 							  inhcount,
 							  is_no_inherit,
 							  false,
+							  '\0',		/* coninternaltype */
 							  false);
 	return constrOid;
 }
@@ -2327,7 +2329,9 @@ StoreConstraints(Relation rel, List *cooked_constraints, bool is_internal)
 					StoreRelCheck(rel, con->name, con->expr,
 								  con->is_enforced, !con->skip_validation,
 								  con->is_local, con->inhcount,
-								  con->is_no_inherit, is_internal);
+								  con->is_no_inherit,
+								  con->coninternaltype,
+								  is_internal);
 				numchecks++;
 				break;
 
@@ -2460,6 +2464,7 @@ AddRelationNewConstraints(Relation rel,
 		cooked->is_local = is_local;
 		cooked->inhcount = is_local ? 0 : 1;
 		cooked->is_no_inherit = false;
+		cooked->coninternaltype = '\0';
 		cookedConstraints = lappend(cookedConstraints, cooked);
 	}
 
@@ -2579,6 +2584,7 @@ AddRelationNewConstraints(Relation rel,
 				StoreRelCheck(rel, ccname, expr, cdef->is_enforced,
 							  cdef->initially_valid, is_local,
 							  is_local ? 0 : 1, cdef->is_no_inherit,
+							  cdef->contype_internal,
 							  is_internal);
 
 			numchecks++;
@@ -2594,6 +2600,7 @@ AddRelationNewConstraints(Relation rel,
 			cooked->is_local = is_local;
 			cooked->inhcount = is_local ? 0 : 1;
 			cooked->is_no_inherit = cdef->is_no_inherit;
+			cooked->coninternaltype = cdef->contype_internal;
 			cookedConstraints = lappend(cookedConstraints, cooked);
 		}
 		else if (cdef->contype == CONSTR_NOTNULL)
@@ -2670,6 +2677,7 @@ AddRelationNewConstraints(Relation rel,
 			nncooked->is_local = is_local;
 			nncooked->inhcount = inhcount;
 			nncooked->is_no_inherit = cdef->is_no_inherit;
+			nncooked->coninternaltype = '\0';
 
 			cookedConstraints = lappend(cookedConstraints, nncooked);
 		}
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 739a92bdcc1..e5bc679a850 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1986,6 +1986,7 @@ index_constraint_create(Relation heapRelation,
 								   inhcount,
 								   noinherit,
 								   is_without_overlaps,
+								   '\0',	/* coninternaltype */
 								   is_internal);
 
 	/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..3f3a276e3aa 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -80,6 +80,7 @@ CreateConstraintEntry(const char *constraintName,
 					  int16 conInhCount,
 					  bool conNoInherit,
 					  bool conPeriod,
+					  char coninternaltype,
 					  bool is_internal)
 {
 	Relation	conDesc;
@@ -202,6 +203,7 @@ CreateConstraintEntry(const char *constraintName,
 	values[Anum_pg_constraint_coninhcount - 1] = Int16GetDatum(conInhCount);
 	values[Anum_pg_constraint_connoinherit - 1] = BoolGetDatum(conNoInherit);
 	values[Anum_pg_constraint_conperiod - 1] = BoolGetDatum(conPeriod);
+	values[Anum_pg_constraint_coninternaltype - 1] = CharGetDatum(coninternaltype);
 
 	if (conkeyArray)
 		values[Anum_pg_constraint_conkey - 1] = PointerGetDatum(conkeyArray);
@@ -834,6 +836,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
+			cooked->coninternaltype = '\0';
 
 			notnulls = lappend(notnulls, cooked);
 		}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 129c97fdf28..b3df5b913a5 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -604,6 +604,9 @@ static void GetForeignKeyCheckTriggers(Relation trigrel,
 static void ATExecDropConstraint(Relation rel, const char *constrName,
 								 DropBehavior behavior, bool recurse,
 								 bool missing_ok, LOCKMODE lockmode);
+static void DropConstraintByOid(Relation rel, Oid constroid,
+								DropBehavior behavior, bool recurse,
+								bool missing_ok, LOCKMODE lockmode);
 static ObjectAddress dropconstraint_internal(Relation rel,
 											 HeapTuple constraintTup, DropBehavior behavior,
 											 bool recurse, bool recursing,
@@ -991,6 +994,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 			cooked->is_local = true;	/* not used for defaults */
 			cooked->inhcount = 0;	/* ditto */
 			cooked->is_no_inherit = false;
+			cooked->coninternaltype = '\0';
 			cookedDefaults = lappend(cookedDefaults, cooked);
 		}
 	}
@@ -10581,6 +10585,7 @@ addFkConstraint(addFkConstraintSides fkside,
 									  coninhcount,	/* inhcount */
 									  connoinherit, /* conNoInherit */
 									  with_period,	/* conPeriod */
+									  '\0',			/* coninternaltype */
 									  is_internal); /* is_internal */
 
 	ObjectAddressSet(address, ConstraintRelationId, constrOid);
@@ -12337,6 +12342,9 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 	HeapTuple	tuple;
 	Form_pg_constraint con;
 	ObjectAddress address;
+	Oid				constroid = InvalidOid;
+	AttrNumber		attnum	= -1;
+	char			*conname = NULL;
 
 	conrel = table_open(ConstraintRelationId, RowExclusiveLock);
 
@@ -12367,7 +12375,8 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
@@ -12383,14 +12392,30 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 		if (con->contype == CONSTRAINT_FOREIGN)
 		{
 			QueueFKConstraintValidation(wqueue, conrel, rel, tuple, lockmode);
+			ObjectAddressSet(address, ConstraintRelationId, con->oid);
 		}
-		else if (con->contype == CONSTRAINT_CHECK)
+		else if (con->contype == CONSTRAINT_CHECK && con->coninternaltype == '\0')
 		{
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
+			ObjectAddressSet(address, ConstraintRelationId, con->oid);
+		}
+		else if (con->contype == CONSTRAINT_CHECK && con->coninternaltype == CONSTRAINT_NOTNULL)
+		{
+			Datum		adatum;
+			ArrayType  *arr;
+			adatum = SysCacheGetAttrNotNull(CONSTROID, tuple,
+											Anum_pg_constraint_conkey);
+			arr = DatumGetArrayTypeP(adatum);	/* ensure not toasted */
+			if (ARR_NDIM(arr) != 1 ||
+				ARR_DIMS(arr)[0] != 1 ||
+				ARR_HASNULL(arr) ||
+				ARR_ELEMTYPE(arr) != INT2OID)
+				elog(ERROR, "confkey is not a 1-D smallint array");
+			memcpy(&attnum, ARR_DATA_PTR(arr), 1 * sizeof(int16));
+			constroid = con->oid;
+			conname =  pstrdup(NameStr(con->conname));
 		}
-
-		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
 	else
 		address = InvalidObjectAddress; /* already validated */
@@ -12399,6 +12424,80 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	table_close(conrel, RowExclusiveLock);
 
+	if (OidIsValid(constroid))
+	{
+		AlteredTableInfo *tab;
+		Constraint *n;
+		String	   *val;
+		List	   *children;
+
+		if (rel->rd_rel->relispartition)
+		{
+			char	   *relname;
+			List *ancestors = NIL;
+			Oid	rootrelid = InvalidOid;
+
+			ancestors = get_partition_ancestors(RelationGetRelid(rel));
+			Assert(ancestors != NIL);
+
+			rootrelid = llast_oid(ancestors);
+			list_free(ancestors);
+
+			relname = get_rel_name(rootrelid);
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("cannot validate not-null constraint from partition \"%s\"",
+							RelationGetRelationName(rel)),
+					errhint("You might need validate not-null constraint through root partition \"%s\"", relname));
+		}
+		else if (has_superclass(RelationGetRelid(rel)))
+		{
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("cannot validate not-null constraint on inheritance children \"%s\"",
+							RelationGetRelationName(rel)));
+		}
+
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+		DropConstraintByOid(rel, constroid,
+							DROP_CASCADE, true,
+							false, lockmode);
+
+		tab = ATGetQueueEntry(wqueue, rel);
+		n = makeNode(Constraint);
+		n->contype = CONSTR_NOTNULL;
+		n->conname = conname;
+		n->location = -1;
+		n->is_no_inherit = false;
+		n->raw_expr = NULL;
+		n->is_enforced = true;
+		n->initially_valid = true;
+		n->skip_validation = false;
+		val = makeString(get_attname(RelationGetRelid(rel), attnum,
+									 false));
+		n->keys = list_make1(val);
+		ATAddCheckNNConstraint(wqueue, tab, rel, n,
+							   recurse, recursing, false, lockmode);
+
+		/*
+		 * DropConstraintByOid will call RemoveConstraintById.
+		 * Inside RemoveConstraintById, the relation to which this constraint belongs
+		 * will be locked in AccessExclusiveLock mode.
+		 *
+		 * ATAddCheckNNConstraint will install not-null constraint for rel and it's children.
+		 * ALTER TABLE VALIDATE CONSTRAINT generally take ShareUpdateExclusiveLock lock.
+		 * removing the logical equivalent CHECK constraint will not impact the data integrity.
+		 * thus here release the AccessExclusiveLock on rel and its children.
+		*/
+		foreach_oid(childrelid, children)
+			UnlockRelationOid(childrelid, AccessExclusiveLock);
+
+		if (CheckRelationLockedByMe(rel, AccessExclusiveLock, true))
+			elog(ERROR, "relation \"%s\" was lock in AccessExclusiveLock", RelationGetRelationName(rel));
+
+		address = InvalidObjectAddress;
+	}
+
 	return address;
 }
 
@@ -13298,6 +13397,67 @@ createForeignKeyCheckTriggers(Oid myRelOid, Oid refRelOid,
 										  parentUpdTrigger, false);
 }
 
+
+
+/*
+ * DROP CONSTRAINT by Oid
+ *
+ * Like DROP COLUMN, we can't use the normal ALTER TABLE recursion mechanism.
+ * The constroid is the OID of the constraint to be dropped. If the constraint
+ * has any inherited child constraints, it will recursively drop them too.
+ */
+static void
+DropConstraintByOid(Relation rel, Oid constroid,
+					DropBehavior behavior, bool recurse,
+					bool missing_ok, LOCKMODE lockmode)
+{
+	Relation	conrel;
+	SysScanDesc scan;
+	ScanKeyData skey[1];
+	HeapTuple	tuple;
+	bool		found = false;
+	char	   *constrName = NULL;
+	Form_pg_constraint con;
+
+	conrel = table_open(ConstraintRelationId, RowExclusiveLock);
+	/*
+	 * Find and drop the target constraint
+	 */
+	ScanKeyInit(&skey[0],
+				Anum_pg_constraint_oid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(constroid));
+	scan = systable_beginscan(conrel, ConstraintOidIndexId,
+							  true, NULL, 1, skey);
+
+	/* There can be at most one matching row */
+	if (HeapTupleIsValid(tuple = systable_getnext(scan)))
+	{
+		con = (Form_pg_constraint) GETSTRUCT(tuple);
+		constrName = pstrdup(NameStr(con->conname));
+		dropconstraint_internal(rel, tuple, behavior, recurse, false,
+								missing_ok, lockmode);
+		found = true;
+	}
+
+	systable_endscan(scan);
+
+	if (!found)
+	{
+		if (!missing_ok)
+			ereport(ERROR,
+					errcode(ERRCODE_UNDEFINED_OBJECT),
+					errmsg("constraint \"%s\" of relation \"%s\" does not exist",
+						   constrName, RelationGetRelationName(rel)));
+		else
+			ereport(NOTICE,
+					errmsg("constraint \"%s\" of relation \"%s\" does not exist, skipping",
+						   constrName, RelationGetRelationName(rel)));
+	}
+
+	table_close(conrel, RowExclusiveLock);
+}
+
 /*
  * ALTER TABLE DROP CONSTRAINT
  *
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index c9f61130c69..e99b91d3840 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -839,6 +839,7 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 											  0,	/* inhcount */
 											  true, /* noinherit */
 											  false,	/* conperiod */
+											  '\0',		/* coninternaltype */
 											  isInternal);	/* is_internal */
 	}
 
diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 3cb3ca1cca1..457d47b7ba4 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -3606,6 +3606,7 @@ domainAddCheckConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 							  0,	/* inhcount */
 							  false,	/* connoinherit */
 							  false,	/* conperiod */
+							  '\0',		/* coninternaltype */
 							  false);	/* is_internal */
 	if (constrAddr)
 		ObjectAddressSet(*constrAddr, ConstraintRelationId, ccoid);
@@ -3714,6 +3715,7 @@ domainAddNotNullConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 							  0,	/* inhcount */
 							  false,	/* connoinherit */
 							  false,	/* conperiod */
+							  '\0',		/* coninternaltype */
 							  false);	/* is_internal */
 
 	if (constrAddr)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..0af53b6fbf3 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4222,11 +4222,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index abbe1bb45a3..d5fb9b70c9b 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -1090,7 +1090,68 @@ transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("not-null constraints on partitioned tables cannot be NO INHERIT"));
 
-			cxt->nnconstraints = lappend(cxt->nnconstraints, constraint);
+			if (constraint->skip_validation && (strcmp(cxt->stmtType, "ALTER TABLE") == 0))
+			{
+				Constraint *constr;
+				NullTest   *nnulltest;
+				AttrNumber	colnum;
+				TupleDesc	tupdesc;
+				Form_pg_attribute attr;
+
+				constr = makeNode(Constraint);
+				constr->contype = CONSTR_CHECK;
+				if (constraint->conname)
+					constr->conname = pstrdup(constraint->conname);
+				constr->deferrable = false;
+				constr->initdeferred = false;
+				constr->is_enforced = true;
+				constr->skip_validation = true;
+				constr->initially_valid = false;
+				constr->is_no_inherit = false;
+				constr->nulls_not_distinct = false;
+				constr->location = constraint->location;
+				constr->contype_internal = CONSTRAINT_NOTNULL;
+
+				colnum = get_attnum(RelationGetRelid(cxt->rel), strVal(linitial(constraint->keys)));
+				if (colnum == InvalidAttrNumber)
+					ereport(ERROR,
+							errcode(ERRCODE_UNDEFINED_COLUMN),
+							errmsg("column \"%s\" of relation \"%s\" does not exist",
+								   strVal(linitial(constraint->keys)), RelationGetRelationName(cxt->rel)));
+				if (colnum < InvalidAttrNumber)
+					ereport(ERROR,
+							errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							errmsg("cannot add not-null constraint on system column \"%s\"",
+									strVal(linitial(constraint->keys))));
+
+				tupdesc = RelationGetDescr(cxt->rel);
+				attr = TupleDescAttr(tupdesc, colnum - 1);
+
+				nnulltest = makeNode(NullTest);
+				nnulltest->arg = (Expr *) makeVar(1,
+												  attr->attnum,
+												  attr->atttypid,
+												  attr->atttypmod,
+												  attr->attcollation,
+												  0);
+
+				nnulltest->nulltesttype = IS_NOT_NULL;
+				nnulltest->argisrow = false;
+				nnulltest->location = constraint->location;
+				constr->cooked_expr = nodeToString(nnulltest);
+
+				cxt->ckconstraints = lappend(cxt->ckconstraints, constr);
+			}
+			else if (constraint->skip_validation && (strcmp(cxt->stmtType, "CREATE TABLE") == 0))
+			{
+				constraint->skip_validation = false;
+				constraint->initially_valid = true;
+				ereport(WARNING,
+						errmsg("CREATE TABLE NOT NULL NOT VALID CONSTRAINT WILL SET TO VALID"));
+				cxt->nnconstraints = lappend(cxt->nnconstraints, constraint);
+			}
+			else
+				cxt->nnconstraints = lappend(cxt->nnconstraints, constraint);
 			break;
 
 		case CONSTR_FOREIGN:
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index dbd339e9df4..70b61b12464 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -42,6 +42,7 @@ typedef struct CookedConstraint
 	Node	   *expr;			/* transformed default or check expr */
 	bool		is_enforced;	/* is enforced? (only for CHECK) */
 	bool		skip_validation;	/* skip validation? (only for CHECK) */
+	char		coninternaltype;	/* (only for NOT NULL) */
 	bool		is_local;		/* constraint has local (non-inherited) def */
 	int16		inhcount;		/* number of times constraint is inherited */
 	bool		is_no_inherit;	/* constraint has local def and cannot be
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..5740a277d8f 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -114,6 +114,8 @@ CATALOG(pg_constraint,2606,ConstraintRelationId)
 	 */
 	bool		conperiod;
 
+	char		coninternaltype; /* constraint internal type; see codes below */
+
 #ifdef CATALOG_VARLEN			/* variable-length fields start here */
 
 	/*
@@ -250,6 +252,7 @@ extern Oid	CreateConstraintEntry(const char *constraintName,
 								  int16 conInhCount,
 								  bool conNoInherit,
 								  bool conPeriod,
+								  char coninternaltype,
 								  bool is_internal);
 
 extern bool ConstraintNameIsUsed(ConstraintCategory conCat, Oid objId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 23c9e3c5abf..01a72589084 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2824,6 +2824,7 @@ typedef struct Constraint
 								 * untransformed parse tree */
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
+	char		contype_internal; /**/
 	char		generated_when; /* ALWAYS or BY DEFAULT */
 	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..cdba544bb8e 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1392,3 +1392,66 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+-- test cases for not null not valid and validate it.
+create table t0_ok(a int, constraint nn not null a not valid);
+WARNING:  CREATE TABLE NOT NULL NOT VALID CONSTRAINT WILL SET TO VALID
+create table t_notnull_notvalid(a int);
+insert into t_notnull_notvalid values(null);
+alter table t_notnull_notvalid add constraint nc1 not null a not valid;
+\d t_notnull_notvalid
+         Table "public.t_notnull_notvalid"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Check constraints:
+    "nc1" CHECK (a IS NOT NULL) NOT VALID
+
+alter table t_notnull_notvalid validate constraint nc1; --fail.
+ERROR:  column "a" of relation "t_notnull_notvalid" contains null values
+truncate t_notnull_notvalid;
+insert into t_notnull_notvalid values(1);
+alter table t_notnull_notvalid validate constraint nc1; --ok
+\d+ t_notnull_notvalid
+                            Table "public.t_notnull_notvalid"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+Not-null constraints:
+    "nc1" NOT NULL "a"
+
+create table lp (a int) partition by list (a);
+create table lp_default partition of lp default;
+create table lp_ef partition of lp for values in (1,2,3,4);
+create table lp_g partition of lp for values in (5,6,7,8);
+create table lp_null partition of lp for values in (null);
+alter table lp add constraint nc1 not null a not valid;
+insert into lp select g from generate_Series(2, 9) g;
+insert into lp_null select NULL; --fail
+ERROR:  new row for relation "lp_null" violates check constraint "nc1"
+DETAIL:  Failing row contains (null).
+alter table lp_default validate constraint nc1; --fail
+ERROR:  cannot validate not-null constraint from partition "lp_default"
+HINT:  You might need validate not-null constraint through root partition "lp"
+alter table lp_g validate constraint nc1; --fail
+ERROR:  cannot validate not-null constraint from partition "lp_g"
+HINT:  You might need validate not-null constraint through root partition "lp"
+alter table lp validate constraint nc1; --ok.
+alter table lp validate constraint nc1; --ok.
+\d lp
+           Partitioned table "public.lp"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+Partition key: LIST (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
+\d lp_default
+             Table "public.lp_default"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+Partition of: lp DEFAULT
+
+drop table t0_ok;
+drop table lp;
+drop table t_notnull_notvalid;
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..06c3895e745 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -836,3 +836,44 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+
+-- test cases for not null not valid and validate it.
+create table t0_ok(a int, constraint nn not null a not valid);
+
+create table t_notnull_notvalid(a int);
+insert into t_notnull_notvalid values(null);
+alter table t_notnull_notvalid add constraint nc1 not null a not valid;
+\d t_notnull_notvalid
+alter table t_notnull_notvalid validate constraint nc1; --fail.
+
+truncate t_notnull_notvalid;
+insert into t_notnull_notvalid values(1);
+alter table t_notnull_notvalid validate constraint nc1; --ok
+\d+ t_notnull_notvalid
+
+
+create table lp (a int) partition by list (a);
+create table lp_default partition of lp default;
+create table lp_ef partition of lp for values in (1,2,3,4);
+create table lp_g partition of lp for values in (5,6,7,8);
+create table lp_null partition of lp for values in (null);
+alter table lp add constraint nc1 not null a not valid;
+insert into lp select g from generate_Series(2, 9) g;
+
+insert into lp_null select NULL; --fail
+alter table lp_default validate constraint nc1; --fail
+alter table lp_g validate constraint nc1; --fail
+
+alter table lp validate constraint nc1; --ok.
+alter table lp validate constraint nc1; --ok.
+
+\d lp
+\d lp_default
+
+
+
+drop table t0_ok;
+drop table lp;
+drop table t_notnull_notvalid;
+
-- 
2.34.1

From 4eb5f71595753d035d5267aca93c8b2cca93b4a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Tue, 14 Jan 2025 18:43:47 +0100
Subject: [PATCH] Throw warning if NOT VALID is given during CREATE TABLE

Discussion: https://postgr.es/m/CACJufxEQcHNhN6M18JY1mQcgQq9Gn9ofMeop47SdFDE5B8wbug@mail.gmail.com
---
 src/backend/catalog/heap.c                | 8 ++++++++
 src/backend/commands/tablecmds.c          | 7 +++++++
 src/backend/parser/gram.y                 | 2 ++
 src/include/nodes/parsenodes.h            | 1 +
 src/test/regress/expected/alter_table.out | 1 +
 src/test/regress/expected/foreign_key.out | 3 ++-
 src/test/regress/sql/foreign_key.sql      | 2 +-
 7 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..0eb19f3c5cf 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2572,6 +2572,12 @@ AddRelationNewConstraints(Relation rel,
 				checknames = lappend(checknames, ccname);
 			}
 
+			/* XXX improve error report */
+			if (cdef->was_not_valid && cdef->initially_valid && cdef->is_enforced)
+				ereport(WARNING,
+						errcode(ERRCODE_WARNING),
+						errmsg("NOT VALID flag for constraint \"%s\" ignored", ccname));
+
 			/*
 			 * OK, store it.
 			 */
@@ -3039,6 +3045,8 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 										   nnnames);
 		nnnames = lappend(nnnames, conname);
 
+		/* XXX if NOT VALID is given during CREATE TABLE, throw warning */
+
 		StoreRelNotNull(rel, conname,
 						attnum, true, true,
 						inhcount, constr->is_no_inherit);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 129c97fdf28..b59f25b79eb 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -10546,6 +10546,13 @@ addFkConstraint(addFkConstraintSides fkside,
 		connoinherit = rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE;
 	}
 
+	/* XXX improve error report */
+	if (fkconstraint->was_not_valid && fkconstraint->initially_valid)
+		ereport(WARNING,
+				errcode(ERRCODE_WARNING),
+				errmsg("NOT VALID flag for constraint \"%s\" ignored",
+					   fkconstraint->conname));
+
 	/*
 	 * Record the FK constraint in pg_constraint.
 	 */
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..29b12a2ff46 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4213,6 +4213,7 @@ ConstraintElem:
 								   NULL, NULL, &n->is_enforced, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
 					n->initially_valid = !n->skip_validation;
+					n->was_not_valid = n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| NOT NULL_P ColId ConstraintAttributeSpec
@@ -4347,6 +4348,7 @@ ConstraintElem:
 								   NULL, &n->skip_validation, NULL,
 								   yyscanner);
 					n->initially_valid = !n->skip_validation;
+					n->was_not_valid = n->skip_validation;
 					$$ = (Node *) n;
 				}
 		;
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 23c9e3c5abf..a1878e565ff 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2819,6 +2819,7 @@ typedef struct Constraint
 	bool		is_enforced;	/* enforced constraint? */
 	bool		skip_validation;	/* skip validation of existing rows? */
 	bool		initially_valid;	/* mark the new constraint as valid? */
+	bool		was_not_valid;	/* did the user request NOT VALID? */
 	bool		is_no_inherit;	/* is constraint non-inheritable? */
 	Node	   *raw_expr;		/* CHECK or DEFAULT expression, as
 								 * untransformed parse tree */
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..59736648ce4 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -574,6 +574,7 @@ DROP TABLE attmp2;
 -- exclusion until validated
 set constraint_exclusion TO 'partition';
 create table nv_parent (d date, check (false) no inherit not valid);
+WARNING:  NOT VALID flag for constraint "nv_parent_check" ignored
 -- not valid constraint added at creation time should automatically become valid
 \d nv_parent
             Table "public.nv_parent"
diff --git a/src/test/regress/expected/foreign_key.out b/src/test/regress/expected/foreign_key.out
index 6a3374d5152..b1e94a3d42b 100644
--- a/src/test/regress/expected/foreign_key.out
+++ b/src/test/regress/expected/foreign_key.out
@@ -61,7 +61,8 @@ DROP TABLE PKTABLE;
 --
 CREATE TABLE PKTABLE ( ptest1 int, ptest2 int, ptest3 text, PRIMARY KEY(ptest1, ptest2) );
 CREATE TABLE FKTABLE ( ftest1 int, ftest2 int, ftest3 int, CONSTRAINT constrname FOREIGN KEY(ftest1, ftest2)
-                       REFERENCES PKTABLE MATCH FULL ON DELETE SET NULL ON UPDATE SET NULL);
+                       REFERENCES PKTABLE MATCH FULL ON DELETE SET NULL ON UPDATE SET NULL NOT VALID);
+WARNING:  NOT VALID flag for constraint "constrname" ignored
 -- Test comments
 COMMENT ON CONSTRAINT constrname_wrong ON FKTABLE IS 'fk constraint comment';
 ERROR:  constraint "constrname_wrong" for table "fktable" does not exist
diff --git a/src/test/regress/sql/foreign_key.sql b/src/test/regress/sql/foreign_key.sql
index 44945b0453a..83f1733253c 100644
--- a/src/test/regress/sql/foreign_key.sql
+++ b/src/test/regress/sql/foreign_key.sql
@@ -48,7 +48,7 @@ DROP TABLE PKTABLE;
 --
 CREATE TABLE PKTABLE ( ptest1 int, ptest2 int, ptest3 text, PRIMARY KEY(ptest1, ptest2) );
 CREATE TABLE FKTABLE ( ftest1 int, ftest2 int, ftest3 int, CONSTRAINT constrname FOREIGN KEY(ftest1, ftest2)
-                       REFERENCES PKTABLE MATCH FULL ON DELETE SET NULL ON UPDATE SET NULL);
+                       REFERENCES PKTABLE MATCH FULL ON DELETE SET NULL ON UPDATE SET NULL NOT VALID);
 
 -- Test comments
 COMMENT ON CONSTRAINT constrname_wrong ON FKTABLE IS 'fk constraint comment';
-- 
2.39.5

From 110b2f60bdd53d3b4eb31dc71c9ffb83afac59ea Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Thu, 20 Mar 2025 11:39:56 +0530
Subject: [PATCH 2/2] Support for pg_dump.

---
 src/bin/pg_dump/pg_dump.c | 167 ++++++++++++++++++++++++++++++++++++--
 src/bin/pg_dump/pg_dump.h |   1 +
 2 files changed, 159 insertions(+), 9 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index c371570501a..96b7d181f91 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8876,6 +8876,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8892,6 +8893,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_attlen;
 	int			i_attalign;
 	int			i_attislocal;
+	int			i_notnull_validated;
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
@@ -8988,11 +8990,13 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 */
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
+							 "co.convalidated as notnull_validated,\n"
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
+							 "false as notnull_validated,\n"
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
@@ -9067,6 +9071,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attlen = PQfnumber(res, "attlen");
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
+	i_notnull_validated = PQfnumber(res, "notnull_validated");
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
@@ -9086,6 +9091,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9135,6 +9141,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_validated = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9160,6 +9167,28 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_validated[j] = (PQgetvalue(res, r, i_notnull_validated)[0] == 't');
+
+			/*
+			 * Dump the invalid NOT NULL constraint like the Check constraints
+			 */
+			if (tbinfo->notnull_validated[j])
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			else if (!PQgetisnull(res, r, i_notnull_name))
+			{
+				/*
+				 * Add the entry into invalidnotnull list so NOT NULL
+				 * constraint get dump as separate constraints.
+				 */
+				if (invalidnotnulloids->len > 1)    /* do we have more than
+													 * the '{'? */
+					appendPQExpBufferChar(invalidnotnulloids, ',');
+				appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+			}
 
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
@@ -9187,6 +9216,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	}
 
 	PQclear(res);
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	/*
 	 * Now get info about column defaults.  This is skipped for a data-only
@@ -9450,6 +9480,128 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table INVALID NOT NULL constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int         numConstrs;
+		int         i_tableoid;
+		int         i_oid;
+		int         i_conrelid;
+		int         i_conname;
+		int         i_consrc;
+		int         i_conislocal;
+		int         i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND convalidated = 'f'"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid         conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int         numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool        validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * An unvalidated constraint needs to be dumped separately, so
+				 * that potentially-violating existing data is loaded before
+				 * the constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+
+				/*
+				 * Mark the constraint as needing to appear before the table
+				 * --- this is so that any other dependencies of the
+				 * constraint will be emitted before we try to create the
+				 * table.  If the constraint is to be dumped separately, it
+				 * will be dumped after data is loaded anyway, so don't do it.
+				 * (There's an automatic dependency in the opposite direction
+				 * anyway, so don't need to add one manually here.)
+				 */
+				if (!constrs[j].separate)
+					addObjectDependency(&tbinfo->dobj,
+										constrs[j].dobj.dumpId);
+
+				/*
+				 * We will detect later whether the constraint must be split
+				 * out from the table definition.
+				 */
+			}
+		}
+		PQclear(res);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(tbloids);
 	destroyPQExpBuffer(checkoids);
@@ -16543,7 +16695,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 					 * defined, or if binary upgrade.  (In the latter case, we
 					 * reset conislocal below.)
 					 */
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
+					print_notnull = (tbinfo->notnull_validated[j] &&
+									 tbinfo->notnull_constrs[j] != NULL &&
 									 (tbinfo->notnull_islocal[j] ||
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
@@ -16605,11 +16758,6 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
-					print_notnull = (tbinfo->notnull_constrs[j] != NULL &&
-									 (tbinfo->notnull_islocal[j] ||
-									  dopt->binary_upgrade ||
-									  tbinfo->ispartition));
-
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -16928,7 +17076,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 				 * because the latter is not available.  (We distinguish the
 				 * case because the constraint name is the empty string.)
 				 */
-				if (tbinfo->notnull_constrs[j] != NULL &&
+				if (tbinfo->notnull_validated[j] &&
+					tbinfo->notnull_constrs[j] != NULL &&
 					!tbinfo->notnull_islocal[j])
 				{
 					if (tbinfo->notnull_constrs[j][0] != '\0')
@@ -17931,9 +18080,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK/INVALID_NOTNULL constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index bbdb30b5f54..676bf2c53c1 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,6 +365,7 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_validated;	/* NOT NULL is VALIDATED */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-- 
2.43.0

From 02a3fbe6fedadde45374fc9cbb73c32b7dd3fce3 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Thu, 20 Mar 2025 11:22:46 +0530
Subject: [PATCH 1/2] Support NOT VALID and VALIDATE CONSTRAINT for named NOT
 NULL constraints.

Commit also add support for pg_dump to dump NOT VALID named NOT NULL
constraints.
---
 src/backend/access/common/tupdesc.c       |   6 +
 src/backend/bootstrap/bootstrap.c         |   1 +
 src/backend/catalog/heap.c                |   3 +-
 src/backend/catalog/pg_constraint.c       |  17 +-
 src/backend/commands/tablecmds.c          | 216 +++++++++++++++++++++-
 src/backend/optimizer/util/plancat.c      |   3 +-
 src/backend/parser/gram.y                 |   4 +-
 src/bin/psql/describe.c                   |   7 +-
 src/include/access/tupdesc.h              |   2 +
 src/include/catalog/pg_attribute.h        |   3 +
 src/include/catalog/pg_constraint.h       |   3 +-
 src/test/regress/expected/constraints.out | 153 +++++++++++++++
 src/test/regress/sql/constraints.sql      |  85 +++++++++
 13 files changed, 484 insertions(+), 19 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..ed269d26090 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -75,6 +75,7 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
 	dst->attnotnull = src->attnotnull;
+	dst->attinvalidnotnull = src->attinvalidnotnull;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attinvalidnotnull = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -841,6 +846,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attinvalidnotnull = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..9077ed46d33 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,6 +582,7 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	attrtypes[attnum]->attinvalidnotnull = false;
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..3a258ab4e69 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -753,6 +753,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attinvalidnotnull - 1] = BoolGetDatum(attrs->attinvalidnotnull);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -2626,7 +2627,7 @@ AddRelationNewConstraints(Relation rel,
 			 * to add another one; just adjust inheritance status as needed.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 cdef->conname, is_local, cdef->is_no_inherit))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..a1200ac8abb 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -609,8 +609,6 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -729,7 +727,8 @@ extractNotNullColumn(HeapTuple constrTup)
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 const char *conname, bool is_local,
+						 bool is_no_inherit)
 {
 	HeapTuple	tup;
 
@@ -753,6 +752,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if an invalid NOT NULL constraint exists on the
+		 * table column and an attempt is made to add another valid NOT NULL
+		 * constraint.
+		 */
+		if (is_local && !conform->convalidated && conname)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("Invalid NOT NULL constraint \"%s\" exist on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("Do VALIDATE CONSTRAINT"));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 18ff8956577..5f9d02ebe84 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -410,6 +410,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -473,7 +476,9 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool skip_validation, LOCKMODE lockmode);
+static void set_attinvalidnotnull(Relation rel, AttrNumber attnum,
+								  bool attinvalidnotnull);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -710,6 +715,7 @@ static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, const char *compression);
 static char GetAttributeStorage(Oid atttypid, const char *storagemode);
+static bool check_for_invalid_notnull(Oid relid, const char *attname);
 
 
 /* ----------------------------------------------------------------
@@ -1315,7 +1321,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, false, NoLock);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -7729,6 +7735,45 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	return address;
 }
 
+static void
+set_attinvalidnotnull(Relation rel, AttrNumber attnum,
+					  bool attinvalidnotnull)
+{
+	Form_pg_attribute attr;
+
+	CheckAlterTableIsSafe(rel);
+
+	/*
+	 * Exit quickly by testing attnotnull from the tupledesc's copy of the
+	 * attribute.
+	 */
+	attr = TupleDescAttr(RelationGetDescr(rel), attnum - 1);
+	if (attr->attisdropped)
+		return;
+
+	if (attr->attinvalidnotnull != attinvalidnotnull)
+	{
+		Relation	attr_rel;
+		HeapTuple	tuple;
+
+		attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum);
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup failed for attribute %d of relation %u",
+				 attnum, RelationGetRelid(rel));
+
+		attr = (Form_pg_attribute) GETSTRUCT(tuple);
+		attr->attinvalidnotnull = attinvalidnotnull;
+
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+		CommandCounterIncrement();
+
+		table_close(attr_rel, RowExclusiveLock);
+		heap_freetuple(tuple);
+	}
+}
+
 /*
  * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
  * to verify it.
@@ -7739,7 +7784,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool skip_validation, LOCKMODE lockmode)
 {
 	Form_pg_attribute attr;
 
@@ -7768,20 +7813,23 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
 		Assert(!attr->attnotnull);
 		attr->attnotnull = true;
-		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (!skip_validation &&
+			wqueue && !NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
 			tab = ATGetQueueEntry(wqueue, rel);
 			tab->verify_new_notnull = true;
 		}
+		else
+			attr->attinvalidnotnull = true;
 
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 		CommandCounterIncrement();
 
 		table_close(attr_rel, RowExclusiveLock);
@@ -7880,6 +7928,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, conForm->conname.data,
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7943,7 +8000,7 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 							  RelationGetRelid(rel), attnum);
 
 	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	set_attnotnull(wqueue, rel, attnum, constraint->skip_validation, lockmode);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9388,6 +9445,13 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
 
+		/* Verify that the not-null constraint has been validated */
+		if (check_for_invalid_notnull(RelationGetRelid(rel), strVal(lfirst(lc))))
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+						   strVal(lfirst(lc)), RelationGetRelationName(rel)));
+
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
 		newcmd = makeNode(AlterTableCmd);
@@ -9399,6 +9463,28 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	}
 }
 
+/*
+ * This function checks for any invalid NOT NULL constraint on the given
+ * relation and attribute name. It returns true if found, false otherwise.
+ */
+static bool
+check_for_invalid_notnull(Oid relid, const char *attname)
+{
+	HeapTuple	tuple;
+	bool		retval = false;
+
+	tuple = findNotNullConstraint(relid, attname);
+	if (!HeapTupleIsValid(tuple))
+		return false;
+
+	if (((Form_pg_constraint) GETSTRUCT(tuple))->convalidated == false)
+		retval = true;
+
+	heap_freetuple(tuple);
+
+	return retval;
+}
+
 /*
  * ALTER TABLE ADD INDEX
  *
@@ -9766,7 +9852,7 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * phase 3 to verify existing rows, if needed.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum, ccon->skip_validation, lockmode);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12367,7 +12453,8 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
@@ -12389,6 +12476,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12605,6 +12697,114 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	/*
+	 * Also flip attnotnull. call function with wqueue as NULL to
+	 * bypass validation, as it has already been performed.
+	 */
+	set_attinvalidnotnull(rel, attnum, false);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 71abb01f655..5cc6980eced 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -28,6 +28,7 @@
 #include "catalog/catalog.h"
 #include "catalog/heap.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_constraint.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_statistic_ext.h"
 #include "catalog/pg_statistic_ext_data.h"
@@ -177,7 +178,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnotnull && !attr->attinvalidnotnull)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..715eb51300b 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4224,9 +4224,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9e..b7e444f7489 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,7 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0, c.convalidated \n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3138,13 +3138,14 @@ describeOneTableDetails(const char *schemaname,
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  PQgetvalue(result, i, 5)[0] == 'f' ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..fcea828e713 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -45,6 +45,7 @@ typedef struct TupleConstr
 	bool		has_not_null;
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
+	bool        has_invalid_not_null;
 } TupleConstr;
 
 /*
@@ -77,6 +78,7 @@ typedef struct CompactAttribute
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
 	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	bool		attinvalidnotnull; /* as FormData_pg_attribute.attinvalidnotnull */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..bac4267d21d 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -120,6 +120,9 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	/* This flag represents the "NOT NULL" constraint */
 	bool		attnotnull;
 
+	/* This flag represents the "INVALID NOT NULL" constraint */
+	bool		attinvalidnotnull BKI_DEFAULT(f);
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..0e01ff1bbbd 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -264,7 +264,8 @@ extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 const char *conname, bool is_local,
+									 bool is_no_inherit);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..8e22a492c7d 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,159 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+ a | b 
+---+---
+   | 1
+   | 2
+(2 rows)
+
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+  a  | b 
+-----+---
+ 300 | 3
+ 100 | 1
+(2 rows)
+
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+ conname | convalidated 
+---------+--------------
+ nn      | t
+(1 row)
+
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a"
+
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+  conname  | convalidated 
+-----------+--------------
+ nn_parent | t
+ nn_child  | t
+(2 rows)
+
+DROP TABLE notnull_tbl1 CASCADE;
+NOTICE:  drop cascades to table notnull_chld
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  Invalid NOT NULL constraint "nn1" exist on relation "notnull_tbl1"
+HINT:  Do VALIDATE CONSTRAINT
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+ conname | convalidated 
+---------+--------------
+ nn1     | t
+(1 row)
+
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+    conrelid    |   conname   | convalidated 
+----------------+-------------+--------------
+ notnull_tbl1   | notnull_con | f
+ notnull_tbl1_1 | notnull_con | t
+ notnull_tbl1_2 | notnull_con | t
+(3 rows)
+
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..7aff17e6764 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,91 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- verify NOT NULL VALID/NOT VALID
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1);
+INSERT INTO notnull_tbl1 VALUES (NULL, 2);
+INSERT INTO notnull_tbl1 VALUES (300, 3);
+-- Below statement should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
+\d+ notnull_tbl1
+-- Try to insert new record with NULL, should throw an error
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+-- SELECT NULL values for COLUMN a, should return 2 records.
+SELECT * FROM notnull_tbl1 WHERE a is NULL;
+-- UPDATE the one of the NULL values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+-- DELETE the record (NULL, 2)
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1;
+-- Try to add primary key on table column marked as NOT VALID NOT NULL
+-- constraint. This should throw an error.
+ALTER TABLE notnull_tbl1 add primary key (a);
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+-- Child table NOT NULL constraints should be valid.
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid = 'notnull_tbl1_child'::regclass;
+DROP TABLE notnull_tbl1_child;
+ALTER TABLE notnull_tbl1 validate constraint nn;
+\d+ notnull_tbl1
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent not null a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child not null a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+-- This statement should validate not null constraint for parent as well as
+-- child.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass, 'notnull_chld'::regclass);
+DROP TABLE notnull_tbl1 CASCADE;
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+-- Should throw an error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+-- This should throw an error while validating the NOT NULL
+-- constraint.
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+-- After deleting null values, SET NOT NULL should work
+DELETE FROM notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+SELECT conname, convalidated FROM pg_catalog.pg_constraint WHERE conrelid
+in ('notnull_tbl1'::regclass);
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL;
+SELECT conrelid::regclass, conname, convalidated, coninhcount FROM pg_catalog.pg_constraint WHERE conrelid
+in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_grandchild'::regclass) ORDER BY 1;
+drop table inh_parent, inh_child, inh_grandchild;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 2);
+INSERT INTO notnull_tbl1_upg VALUES (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID;
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES FROM (0) TO (10);
+CREATE TABLE notnull_tbl1_2 PARTITION OF notnull_tbl1 FOR VALUES FROM (20) TO (30);
+-- Parent table NOT NULL constraints will be marked as validated false, where
+-- for child table it will be true
+SELECT conrelid::regclass, conname, convalidated FROM pg_catalog.pg_constraint WHERE
+conrelid IN ('notnull_tbl1'::regclass, 'notnull_tbl1_1'::regclass, 'notnull_tbl1_2'::regclass);
+DROP TABLE notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2;
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
2.43.0

From 0106f2ded55a699324369412de859ab93f374960 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 20 Mar 2025 22:43:08 +0800
Subject: [PATCH v3 1/1] NOT NULL NOT VALID
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* it will logically be equivalent to CHECK(x IS NOT NULL) NOT VALID.
* it can only be added using ALTER TABLE, not with CREATE TABLE (a warning will issued)
* if attnotnull is true, then attinvalidnotnull should be false.
  Conversely, if attinvalidnotnull is true, then attnotnull should be false.
* an invalid not-null cannot be used while adding a primary key.
* if attinvalidnotnull is true, this column can not accept NULL values,
  but the existing column value may contain NULLs, we need to
  VALIDATE the not-null constraint to check if this column exists NULL values or not.
* TODO: currently, partitioned table can not mark as NO VALID. maybe it's doable.
  partition with not valid not-null will error out while attach to the partitioned table.
---
 doc/src/sgml/catalogs.sgml                |  10 +
 src/backend/access/common/tupdesc.c       |  11 ++
 src/backend/bootstrap/bootstrap.c         |   1 +
 src/backend/catalog/heap.c                |   8 +-
 src/backend/catalog/pg_constraint.c       |  45 ++++-
 src/backend/commands/tablecmds.c          | 211 +++++++++++++++++++++-
 src/backend/executor/execMain.c           | 130 ++++++++-----
 src/backend/parser/gram.y                 |   4 +-
 src/backend/parser/parse_utilcmd.c        |   7 +-
 src/backend/utils/cache/relcache.c        |   3 +
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   1 +
 src/include/catalog/pg_attribute.h        |   3 +
 src/include/catalog/pg_constraint.h       |   8 +-
 src/test/regress/expected/constraints.out | 128 +++++++++++++
 src/test/regress/sql/constraints.sql      |  92 ++++++++++
 16 files changed, 593 insertions(+), 78 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..299d2a46f4e 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1264,6 +1264,16 @@
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attinvalidnotnull</structfield> <type>bool</type>
+      </para>
+      <para>
+       This column has a attinvalidnotnull not-null constraint.
+       If <structfield>attnotnull</structfield> is true, this has to be false.
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>atthasdef</structfield> <type>bool</type>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..634cfddff23 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -252,6 +252,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +299,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -341,6 +343,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 		TupleConstr *cpy = (TupleConstr *) palloc0(sizeof(TupleConstr));
 
 		cpy->has_not_null = constr->has_not_null;
+		cpy->has_invalid_not_null = constr->has_invalid_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
 		cpy->has_generated_virtual = constr->has_generated_virtual;
 
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attinvalidnotnull = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attinvalidnotnull != attr2->attinvalidnotnull)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -639,6 +646,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_not_null != constr2->has_not_null)
 			return false;
+		if (constr1->has_invalid_not_null != constr2->has_invalid_not_null)
+			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
 		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
@@ -841,6 +850,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attinvalidnotnull = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +914,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attinvalidnotnull = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..9077ed46d33 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,6 +582,7 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	attrtypes[attnum]->attinvalidnotnull = false;
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..e3ae6993c95 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -753,6 +753,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attinvalidnotnull - 1] = BoolGetDatum(attrs->attinvalidnotnull);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -2621,12 +2622,17 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("not-null constraints are not supported on virtual generated columns"));
 
+			if (cdef->initially_valid)
+				Assert(!cdef->skip_validation);
+			else
+				Assert(cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
 			 * to add another one; just adjust inheritance status as needed.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 is_local, cdef->is_no_inherit, cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..64f2e04859a 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -576,13 +576,14 @@ ChooseConstraintName(const char *name1, const char *name2,
  * Find and return a copy of the pg_constraint tuple that implements a
  * validated not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
+ * if include_invalid is true, it may return an invalid not-null tuple.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
  * I'm not sure it's worth the catalog bloat and de-normalization, however.
  */
 HeapTuple
-findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
+findNotNullConstraintAttnum(Oid relid, AttrNumber attnum, bool include_invalid)
 {
 	Relation	pg_constraint;
 	HeapTuple	conTup,
@@ -609,7 +610,7 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
+		if (!con->convalidated && !include_invalid)
 			continue;
 
 		conkey = extractNotNullColumn(conTup);
@@ -631,9 +632,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
  * Find and return the pg_constraint tuple that implements a validated
  * not-null constraint for the given column of the given relation.  If
  * no such column or no such constraint exists, return NULL.
+ * if include_invalid is true, it may return an invalid not-null tuple.
  */
 HeapTuple
-findNotNullConstraint(Oid relid, const char *colname)
+findNotNullConstraint(Oid relid, const char *colname, bool include_invalid)
 {
 	AttrNumber	attnum;
 
@@ -641,7 +643,7 @@ findNotNullConstraint(Oid relid, const char *colname)
 	if (attnum <= InvalidAttrNumber)
 		return NULL;
 
-	return findNotNullConstraintAttnum(relid, attnum);
+	return findNotNullConstraintAttnum(relid, attnum, include_invalid);
 }
 
 /*
@@ -729,11 +731,11 @@ extractNotNullColumn(HeapTuple constrTup)
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(relid, attnum, true);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -753,6 +755,27 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if an invalid NOT NULL constraint exists on the
+		 * table column and an attempt is made to add another valid NOT NULL
+		 * constraint.
+		 */
+		if (is_notvalid && conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("cannot change VALID status of NOT NULL constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+							 NameStr(conform->conname)));
+
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("cannot change VALID status of NOT NULL constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+							 NameStr(conform->conname)));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
@@ -788,9 +811,10 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
  * This is seldom needed, so we just scan pg_constraint each time.
  *
  * 'include_noinh' determines whether to include NO INHERIT constraints or not.
+ * 'include_notvalid' determines whether to include NO VALID constraints or not.
  */
 List *
-RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
+RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh, bool include_notvalid)
 {
 	List	   *notnulls = NIL;
 	Relation	constrRel;
@@ -816,6 +840,9 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 		if (conForm->connoinherit && !include_noinh)
 			continue;
 
+		if (!conForm->convalidated && !include_notvalid)
+			continue;
+
 		colnum = extractNotNullColumn(htup);
 
 		if (cooked)
@@ -830,7 +857,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -850,7 +877,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 129c97fdf28..b1828ec0945 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -410,6 +410,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -2713,10 +2716,10 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT. but we will include NOT VALID
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
-												  true, false);
+												  true, false, true);
 		foreach_ptr(CookedConstraint, cc, nnconstrs)
 			nncols = bms_add_member(nncols, cc->attnum);
 
@@ -7711,7 +7714,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	 * Find the constraint that makes this column NOT NULL, and drop it.
 	 * dropconstraint_internal() resets attnotnull.
 	 */
-	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
+	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum, false);
 	if (conTup == NULL)
 		elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
 			 colName, RelationGetRelationName(rel));
@@ -7729,6 +7732,45 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	return address;
 }
 
+static void
+set_attinvalidnotnull(Relation rel, AttrNumber attnum,
+					  bool attinvalidnotnull)
+{
+	Form_pg_attribute attr;
+
+	CheckAlterTableIsSafe(rel);
+
+	/*
+	 * Exit quickly by testing attnotnull from the tupledesc's copy of the
+	 * attribute.
+	 */
+	attr = TupleDescAttr(RelationGetDescr(rel), attnum - 1);
+	if (attr->attisdropped)
+		return;
+
+	if (attr->attinvalidnotnull != attinvalidnotnull)
+	{
+		Relation	attr_rel;
+		HeapTuple	tuple;
+
+		attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum);
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup failed for attribute %d of relation %u",
+				 attnum, RelationGetRelid(rel));
+
+		attr = (Form_pg_attribute) GETSTRUCT(tuple);
+		attr->attinvalidnotnull = attinvalidnotnull;
+
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+		CommandCounterIncrement();
+
+		table_close(attr_rel, RowExclusiveLock);
+		heap_freetuple(tuple);
+	}
+}
+
 /*
  * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
  * to verify it.
@@ -7845,7 +7887,7 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 						   colName, RelationGetRelationName(rel))));
 
 	/* See if there's already a constraint */
-	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
+	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum, true);
 	if (HeapTupleIsValid(tuple))
 	{
 		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
@@ -7880,6 +7922,19 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+		   /*
+			* Don't let a NO VALID constraint be changed into VALID.
+			* Only way to validate a not-nul constraint is through ALTER TABLE VALIDATE CONSTRAINT
+		   */
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("cannot change VALID status of NOT NULL constraint \"%s\" on relation \"%s\"",
+						   NameStr(conForm->conname), get_rel_name(RelationGetRelid(rel))),
+					errhint("You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+							NameStr(conForm->conname)));
+		}
 
 		if (changed)
 		{
@@ -9387,6 +9442,21 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
+
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)), true);
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+							   strVal(lfirst(lc)), RelationGetRelationName(rel)),
+						errhint("You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+								NameStr(conForm->conname)));
+			heap_freetuple(tuple);
+		}
 
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
@@ -9765,9 +9835,12 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * If adding a not-null constraint, set the pg_attribute flag and tell
 		 * phase 3 to verify existing rows, if needed.
 		 */
-		if (constr->contype == CONSTR_NOTNULL)
+		if (constr->contype == CONSTR_NOTNULL && !constr->skip_validation)
 			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
 
+		if (constr->contype == CONSTR_NOTNULL && constr->skip_validation)
+			set_attinvalidnotnull(rel, ccon->attnum, lockmode);
+
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
 
@@ -12176,7 +12249,7 @@ ATExecAlterConstraintInternal(List **wqueue, ATAlterConstraint *cmdcon,
 				HeapTuple	childtup;
 				Form_pg_constraint childcon;
 
-				childtup = findNotNullConstraint(childoid, colName);
+				childtup = findNotNullConstraint(childoid, colName, false);
 				if (!childtup)
 					elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation %u",
 						 colName, childoid);
@@ -12367,10 +12440,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12389,6 +12463,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12605,6 +12684,117 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname, true);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	set_attnotnull(NULL, rel, attnum, lockmode);
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	/*
+	 * Also flip attnotnull. call function with wqueue as NULL to
+	 * bypass validation, as it has already been performed.
+	 */
+	set_attinvalidnotnull(rel, attnum, false);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13549,7 +13739,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 		 */
 		if (con->contype == CONSTRAINT_NOTNULL)
 		{
-			tuple = findNotNullConstraint(childrelid, colname);
+			tuple = findNotNullConstraint(childrelid, colname, false);
 			if (!HeapTupleIsValid(tuple))
 				elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation %u",
 					 colname, RelationGetRelid(childrel));
@@ -16813,8 +17003,9 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			{
 				HeapTuple	contup;
 
+				Assert(!parent_att->attinvalidnotnull);
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
-													 parent_att->attnum);
+													 parent_att->attnum, false);
 				if (HeapTupleIsValid(contup) &&
 					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
 					ereport(ERROR,
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index e9bd98c7738..06226150f94 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -93,6 +93,9 @@ static bool ExecCheckPermissionsModified(Oid relOid, Oid userid,
 static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt);
 static void EvalPlanQualStart(EPQState *epqstate, Plan *planTree);
 
+static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo,
+										TupleTableSlot *slot,
+										EState *estate, int attrChk);
 /* end of local decls */
 
 
@@ -2071,57 +2074,21 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
 			if (att->attnotnull && slot_attisnull(slot, attrChk))
-			{
-				char	   *val_desc;
-				Relation	orig_rel = rel;
-				TupleDesc	orig_tupdesc = RelationGetDescr(rel);
+				ReportNotNullViolationError(resultRelInfo, slot, estate, attrChk);
+		}
+	}
 
-				/*
-				 * If the tuple has been routed, it's been converted to the
-				 * partition's rowtype, which might differ from the root
-				 * table's.  We must convert it back to the root table's
-				 * rowtype so that val_desc shown error message matches the
-				 * input tuple.
-				 */
-				if (resultRelInfo->ri_RootResultRelInfo)
-				{
-					ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
-					AttrMap    *map;
+	if (constr->has_invalid_not_null)
+	{
+		int			natts = tupdesc->natts;
+		int			attrChk;
 
-					tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
-					/* a reverse map */
-					map = build_attrmap_by_name_if_req(orig_tupdesc,
-													   tupdesc,
-													   false);
+		for (attrChk = 1; attrChk <= natts; attrChk++)
+		{
+			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-					/*
-					 * Partition-specific slot's tupdesc can't be changed, so
-					 * allocate a new one.
-					 */
-					if (map != NULL)
-						slot = execute_attr_map_slot(map, slot,
-													 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
-					modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
-											 ExecGetUpdatedCols(rootrel, estate));
-					rel = rootrel->ri_RelationDesc;
-				}
-				else
-					modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
-											 ExecGetUpdatedCols(resultRelInfo, estate));
-				val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
-														 slot,
-														 tupdesc,
-														 modifiedCols,
-														 64);
-
-				ereport(ERROR,
-						(errcode(ERRCODE_NOT_NULL_VIOLATION),
-						 errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
-								NameStr(att->attname),
-								RelationGetRelationName(orig_rel)),
-						 val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
-						 errtablecol(orig_rel, attrChk)));
-			}
+			if (att->attinvalidnotnull && slot_attisnull(slot, attrChk))
+				ReportNotNullViolationError(resultRelInfo, slot, estate, attrChk);
 		}
 	}
 
@@ -2176,6 +2143,73 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	}
 }
 
+
+/*
+ * Report a violation of a not-null constraint that was already detected.
+ */
+static void
+ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
+							EState *estate, int attrChk)
+{
+	Bitmapset  *modifiedCols;
+	char	   *val_desc;
+
+	Relation	rel = resultRelInfo->ri_RelationDesc;
+	Relation	orig_rel = rel;
+
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+	TupleDesc	orig_tupdesc = RelationGetDescr(rel);
+	Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
+
+	Assert(attrChk > 0);
+
+	/*
+	 * If the tuple has been routed, it's been converted to the partition's
+	 * rowtype, which might differ from the root table's.  We must convert it
+	 * back to the root table's rowtype so that val_desc shown error message
+	 * matches the input tuple.
+	 */
+	if (resultRelInfo->ri_RootResultRelInfo)
+	{
+		ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
+		AttrMap    *map;
+
+		tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
+		/* a reverse map */
+		map = build_attrmap_by_name_if_req(orig_tupdesc,
+										   tupdesc,
+										   false);
+
+		/*
+		 * Partition-specific slot's tupdesc can't be changed, so allocate a
+		 * new one.
+		 */
+		if (map != NULL)
+			slot = execute_attr_map_slot(map, slot,
+										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
+		modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
+								 ExecGetUpdatedCols(rootrel, estate));
+		rel = rootrel->ri_RelationDesc;
+	}
+	else
+		modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
+								 ExecGetUpdatedCols(resultRelInfo, estate));
+
+	val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+											 slot,
+											 tupdesc,
+											 modifiedCols,
+											 64);
+	ereport(ERROR,
+			errcode(ERRCODE_NOT_NULL_VIOLATION),
+			errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
+				   NameStr(att->attname),
+				   RelationGetRelationName(orig_rel)),
+			val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
+			errtablecol(orig_rel, attrChk));
+}
+
+
 /*
  * ExecWithCheckOptions -- check that tuple satisfies any WITH CHECK OPTIONs
  * of the specified kind.
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..715eb51300b 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4224,9 +4224,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 896a7f2c59b..49fa91ea139 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -1089,6 +1089,11 @@ transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
 				ereport(ERROR,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("not-null constraints on partitioned tables cannot be NO INHERIT"));
+			/* XXX TODO, this can be done */
+			if (cxt->ispartitioned && constraint->skip_validation)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("not-null constraints on partitioned tables cannot be NO VALID"));
 
 			cxt->nnconstraints = lappend(cxt->nnconstraints, constraint);
 			break;
@@ -1291,7 +1296,7 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 		List	   *lst;
 
 		lst = RelationGetNotNullConstraints(RelationGetRelid(relation), false,
-											true);
+											true, false);
 		cxt->nnconstraints = list_concat(cxt->nnconstraints, lst);
 	}
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9f54a9e72b7..d5cd93e55c3 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -593,6 +593,8 @@ RelationBuildTupleDesc(Relation relation)
 		/* Update constraint/default info */
 		if (attp->attnotnull)
 			constr->has_not_null = true;
+		if (attp->attinvalidnotnull)
+			constr->has_invalid_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -678,6 +680,7 @@ RelationBuildTupleDesc(Relation relation)
 	 * Set up constraint/default info
 	 */
 	if (constr->has_not_null ||
+		constr->has_invalid_not_null ||
 		constr->has_generated_stored ||
 		constr->has_generated_virtual ||
 		ndef > 0 ||
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9e..09f8f92a59c 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3137,14 +3138,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NO VALID": "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..cc619477b63 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_defval;
 	uint16		num_check;
 	bool		has_not_null;
+	bool        has_invalid_not_null;
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9998b4abdef 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -120,6 +120,9 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	/* This flag represents the "NOT NULL" constraint */
 	bool		attnotnull;
 
+	/* This flag represents the "NOT NULL NOT VALID" constraint */
+	bool		attinvalidnotnull BKI_DEFAULT(f);
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..f00a8e25d5d 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -259,14 +259,14 @@ extern char *ChooseConstraintName(const char *name1, const char *name2,
 								  const char *label, Oid namespaceid,
 								  List *others);
 
-extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
-extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
+extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum, bool include_invalid);
+extern HeapTuple findNotNullConstraint(Oid relid, const char *colname, bool include_invalid);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
-										   bool include_noinh);
+										   bool include_noinh, bool include_notvalid);
 
 extern void RemoveConstraintById(Oid conId);
 extern void RenameConstraintById(Oid conId, const char *newname);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..c8363a44523 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,134 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-------tests for NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid  = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1),(NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; --ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           |          |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NO VALID
+
+INSERT INTO notnull_tbl1 VALUES (NULL, 4); --error
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1 ORDER BY a, b;
+  a  | b 
+-----+---
+ 100 | 1
+ 300 | 3
+(2 rows)
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+-- Child table NOT NULL constraints should be valid.
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+---now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1_child;
+DROP TABLE notnull_tbl1;
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_tbl1 CASCADE;
+NOTICE:  drop cascades to table notnull_chld
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid no inherit; --error
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn1" on relation "notnull_tbl1"
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error can't change not-null status
+ERROR:  cannot change VALID status of NOT NULL constraint "nn1" on relation "notnull_tbl1"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn1"
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL; --error can't change not-null status
+ERROR:  cannot change VALID status of NOT NULL constraint "nn1" on relation "notnull_tbl1"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn1"
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --error
+ERROR:  cannot change VALID status of NOT NULL constraint "nn" on relation "inh_parent"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  cannot change VALID status of NOT NULL constraint "nn" on relation "inh_child"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --error
+ERROR:  not-null constraints on partitioned tables cannot be NO VALID
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a; --ok
+CREATE TABLE notnull_tbl1_1(a int, b int);
+INSERT INTO notnull_tbl1_1 DEFAULT VALUES;
+ALTER TABLE notnull_tbl1_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_1 FOR VALUES FROM (0) TO (10); --error
+ERROR:  column "a" in child table "notnull_tbl1_1" must be marked NOT NULL
+TRUNCATE notnull_tbl1_1;
+ALTER TABLE notnull_tbl1_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_1 FOR VALUES FROM (0) TO (10); --ok
+DROP TABLE notnull_tbl1, notnull_tbl1_1;
+DEALLOCATE get_nnconstraint_info;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..b708dded7d6 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,98 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-------tests for NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid  = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1),(NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; --ok
+\d+ notnull_tbl1
+
+INSERT INTO notnull_tbl1 VALUES (NULL, 4); --error
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1 ORDER BY a, b;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+-- INHERITS table having NOT VALID NOT NULL constraints.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+-- Child table NOT NULL constraints should be valid.
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+---now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1_child;
+DROP TABLE notnull_tbl1;
+
+
+-- Test the different Not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_tbl1 CASCADE;
+
+
+-- test to throw an error when trying to add another NOT NULL
+-- on the table column with INVALID NOT NULL constraint.
+CREATE TABLE notnull_tbl1 (a INTEGER);
+INSERT INTO notnull_tbl1 VALUES ( NULL );
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid no inherit; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error can't change not-null status
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL; --error can't change not-null status
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY RANGE (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a; --ok
+
+CREATE TABLE notnull_tbl1_1(a int, b int);
+INSERT INTO notnull_tbl1_1 DEFAULT VALUES;
+ALTER TABLE notnull_tbl1_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_1 FOR VALUES FROM (0) TO (10); --error
+TRUNCATE notnull_tbl1_1;
+
+ALTER TABLE notnull_tbl1_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_1 FOR VALUES FROM (0) TO (10); --ok
+
+DROP TABLE notnull_tbl1, notnull_tbl1_1;
+
+DEALLOCATE get_nnconstraint_info;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
2.34.1

From 4c60297c019bebfd5cdcfbfdde3b4f57e168626c Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Fri, 21 Mar 2025 22:10:42 +0800
Subject: [PATCH v4 1/1] NOT NULL NOT VALID
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* it will logically be equivalent to CHECK(x IS NOT NULL) NOT VALID.
* it can only be added using ALTER TABLE. entry point is
 ATAddCheckNNConstraint. when we add a constraint, it will either valid or not valid.
``
    if (constr->contype == CONSTR_NOTNULL)
    {
        if (!constr->skip_validation)
            set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
        else
            set_attinvalidnotnull(rel, ccon->attnum, true);
    }
``
we will only change the state attinvalidnotnull in QueueNNConstraintValidation,
which we will validate the constraint, so attinvalidnotnull should be false.
when we insert a pg_attribute tuple, attinvalidnotnull will always false,
we can even add a assert in InsertPgAttributeTuples: Assert(!attrs->attinvalidnotnull);

* if attnotnull is true, then attinvalidnotnull should be false.
  Conversely, if attinvalidnotnull is true, then attnotnull should be false.
* an invalid not-null cannot be used while adding a primary key.
* if attinvalidnotnull is true, this column can not accept NULL values,
  but the existing column value may contain NULLs, we need to
  VALIDATE the not-null constraint to check if this column exists NULL values or not.
* if partitioned table have valid not-null, then can not attach a not valid to partition tree.
  if partitioned table have not valid not-null, we *can* attach a valid not-null to partition tree.
  (inheritance hierarchy behave the same).

  i tested loaclally, pg_dump will works fine with partitioned table, mainly by tweak
  AdjustNotNullInheritance.
  normal table not null not valid pg_dump also works fine.

discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
---
 doc/src/sgml/catalogs.sgml                |  10 +
 doc/src/sgml/ref/alter_table.sgml         |   2 +
 src/backend/access/common/tupdesc.c       |  11 ++
 src/backend/bootstrap/bootstrap.c         |   1 +
 src/backend/catalog/heap.c                |  11 +-
 src/backend/catalog/pg_constraint.c       |  57 +++++-
 src/backend/commands/tablecmds.c          | 214 ++++++++++++++++++++--
 src/backend/executor/execMain.c           | 130 ++++++++-----
 src/backend/parser/gram.y                 |   4 +-
 src/backend/parser/parse_utilcmd.c        |  14 +-
 src/backend/utils/cache/relcache.c        |   3 +
 src/bin/pg_dump/pg_dump.c                 | 155 +++++++++++++++-
 src/bin/pg_dump/pg_dump.h                 |   1 +
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   1 +
 src/include/catalog/pg_attribute.h        |   3 +
 src/include/catalog/pg_constraint.h       |  10 +-
 src/test/regress/expected/constraints.out | 169 +++++++++++++++++
 src/test/regress/sql/constraints.sql      | 114 ++++++++++++
 19 files changed, 827 insertions(+), 92 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..299d2a46f4e 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1264,6 +1264,16 @@
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attinvalidnotnull</structfield> <type>bool</type>
+      </para>
+      <para>
+       This column has a attinvalidnotnull not-null constraint.
+       If <structfield>attnotnull</structfield> is true, this has to be false.
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>atthasdef</structfield> <type>bool</type>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 4f15b89a98f..75d90654275 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column is marked as <literal>NOT NULL NOT VALID</literal>,
+      <literal>SET NOT NULL</literal> will change it to a validated <literal>NOT NULL</literal> constraint.
      </para>
 
      <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..634cfddff23 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -252,6 +252,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +299,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -341,6 +343,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 		TupleConstr *cpy = (TupleConstr *) palloc0(sizeof(TupleConstr));
 
 		cpy->has_not_null = constr->has_not_null;
+		cpy->has_invalid_not_null = constr->has_invalid_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
 		cpy->has_generated_virtual = constr->has_generated_virtual;
 
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attinvalidnotnull = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attinvalidnotnull = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attinvalidnotnull != attr2->attinvalidnotnull)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -639,6 +646,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_not_null != constr2->has_not_null)
 			return false;
+		if (constr1->has_invalid_not_null != constr2->has_invalid_not_null)
+			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
 		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
@@ -841,6 +850,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attinvalidnotnull = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +914,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attinvalidnotnull = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..9077ed46d33 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -582,6 +582,7 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
+	attrtypes[attnum]->attinvalidnotnull = false;
 
 	if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
 	{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..9b2315a27e7 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -753,6 +753,8 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attinvalidnotnull - 1] = BoolGetDatum(attrs->attinvalidnotnull);
+		Assert(!attrs->attinvalidnotnull); /*test demo only*/
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -2621,12 +2623,17 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("not-null constraints are not supported on virtual generated columns"));
 
+			if (cdef->initially_valid)
+				Assert(!cdef->skip_validation);
+			else
+				Assert(cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
 			 * to add another one; just adjust inheritance status as needed.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum,
+										 is_local, cdef->is_no_inherit, cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..9b4d0427877 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -576,13 +576,14 @@ ChooseConstraintName(const char *name1, const char *name2,
  * Find and return a copy of the pg_constraint tuple that implements a
  * validated not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
+ * if include_invalid is true, it may return an invalid not-null tuple.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
  * I'm not sure it's worth the catalog bloat and de-normalization, however.
  */
 HeapTuple
-findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
+findNotNullConstraintAttnum(Oid relid, AttrNumber attnum, bool include_invalid)
 {
 	Relation	pg_constraint;
 	HeapTuple	conTup,
@@ -609,7 +610,7 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
+		if (!con->convalidated && !include_invalid)
 			continue;
 
 		conkey = extractNotNullColumn(conTup);
@@ -631,9 +632,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
  * Find and return the pg_constraint tuple that implements a validated
  * not-null constraint for the given column of the given relation.  If
  * no such column or no such constraint exists, return NULL.
+ * if include_invalid is true, it may return an invalid not-null tuple.
  */
 HeapTuple
-findNotNullConstraint(Oid relid, const char *colname)
+findNotNullConstraint(Oid relid, const char *colname, bool include_invalid)
 {
 	AttrNumber	attnum;
 
@@ -641,7 +643,7 @@ findNotNullConstraint(Oid relid, const char *colname)
 	if (attnum <= InvalidAttrNumber)
 		return NULL;
 
-	return findNotNullConstraintAttnum(relid, attnum);
+	return findNotNullConstraintAttnum(relid, attnum, include_invalid);
 }
 
 /*
@@ -728,12 +730,13 @@ extractNotNullColumn(HeapTuple constrTup)
  * nothing if it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
+	Oid	relid = RelationGetRelid(rel);
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(relid, attnum, true);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -753,6 +756,36 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if we want change the NOT NULL constraint from NOT
+		 * VALID to VALID.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("cannot change VALID status of NOT NULL constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+							NameStr(conform->conname)));
+
+		/* VALID TO NOT VALID seems no usage, so just issue a warning */
+		if (is_notvalid && conform->convalidated)
+		{
+			if (is_local)
+				ereport(WARNING,
+						errmsg("NOT NULL constraint \"%s\" on relation \"%s\" is already valid",
+							NameStr(conform->conname), get_rel_name(relid)));
+			else if (rel->rd_rel->relispartition)
+			{
+				/*
+				* In case of partitions, an inherited not null constraint
+				* is never considered local. See MergeConstraintsIntoExisting also.				
+				*/
+				conform->conislocal = false;
+				changed =true;
+			}
+		}
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
@@ -788,9 +821,10 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
  * This is seldom needed, so we just scan pg_constraint each time.
  *
  * 'include_noinh' determines whether to include NO INHERIT constraints or not.
+ * 'include_notvalid' determines whether to include NO VALID constraints or not.
  */
 List *
-RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
+RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh, bool include_notvalid)
 {
 	List	   *notnulls = NIL;
 	Relation	constrRel;
@@ -816,6 +850,9 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 		if (conForm->connoinherit && !include_noinh)
 			continue;
 
+		if (!conForm->convalidated && !include_notvalid)
+			continue;
+
 		colnum = extractNotNullColumn(htup);
 
 		if (cooked)
@@ -830,7 +867,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -850,7 +887,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 129c97fdf28..94acf07b63d 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -410,6 +410,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -2713,10 +2716,10 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT. but we will include NOT VALID
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
-												  true, false);
+												  true, false, true);
 		foreach_ptr(CookedConstraint, cc, nnconstrs)
 			nncols = bms_add_member(nncols, cc->attnum);
 
@@ -7711,7 +7714,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	 * Find the constraint that makes this column NOT NULL, and drop it.
 	 * dropconstraint_internal() resets attnotnull.
 	 */
-	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
+	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum, false);
 	if (conTup == NULL)
 		elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
 			 colName, RelationGetRelationName(rel));
@@ -7729,6 +7732,44 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	return address;
 }
 
+/*
+ * update pg_attribute.attinvalidnotnull
+*/
+static void
+set_attinvalidnotnull(Relation rel, AttrNumber attnum,
+					  bool attinvalidnotnull)
+{
+	Form_pg_attribute attr;
+
+	CheckAlterTableIsSafe(rel);
+
+	attr = TupleDescAttr(RelationGetDescr(rel), attnum - 1);
+	if (attr->attisdropped)
+		return;
+
+	if (attr->attinvalidnotnull != attinvalidnotnull)
+	{
+		Relation	attr_rel;
+		HeapTuple	tuple;
+
+		attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum);
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup failed for attribute %d of relation %u",
+				 attnum, RelationGetRelid(rel));
+
+		attr = (Form_pg_attribute) GETSTRUCT(tuple);
+		attr->attinvalidnotnull = attinvalidnotnull;
+
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+		CommandCounterIncrement();
+
+		table_close(attr_rel, RowExclusiveLock);
+		heap_freetuple(tuple);
+	}
+}
+
 /*
  * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
  * to verify it.
@@ -7845,7 +7886,7 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 						   colName, RelationGetRelationName(rel))));
 
 	/* See if there's already a constraint */
-	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
+	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum, true);
 	if (HeapTupleIsValid(tuple))
 	{
 		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
@@ -7880,6 +7921,16 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+
+			/*
+			 * flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -9387,6 +9438,22 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
+
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)), true);
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("primary key require an validated NOT NULL constraint"),
+						errdetail("Column \"%s\" of table \"%s\" is marked as NOT VALID NOT NULL constraint",
+							      strVal(lfirst(lc)), RelationGetRelationName(rel)),
+						errhint("You may try ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+								NameStr(conForm->conname)));
+			heap_freetuple(tuple);
+		}
 
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
@@ -9762,11 +9829,19 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
+		 * If adding a valid not-null constraint, set the pg_attribute flag and tell
 		 * phase 3 to verify existing rows, if needed.
+		 * However if we are adding a invalid not-null constraint, then we only
+		 * need set the pg_attribute.attinvalidnotnull.  phase 3 don't need to
+		 * verify existing rows.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+		{
+			if (!constr->skip_validation)
+				set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			else
+				set_attinvalidnotnull(rel, ccon->attnum, true);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12176,7 +12251,7 @@ ATExecAlterConstraintInternal(List **wqueue, ATAlterConstraint *cmdcon,
 				HeapTuple	childtup;
 				Form_pg_constraint childcon;
 
-				childtup = findNotNullConstraint(childoid, colName);
+				childtup = findNotNullConstraint(childoid, colName, false);
 				if (!childtup)
 					elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation %u",
 						 colName, childoid);
@@ -12367,10 +12442,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12389,6 +12465,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12605,6 +12686,116 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * For constraints that aren't NO INHERIT, we must ensure that we only
+	 * mark the constraint as validated on the parent if it's already
+	 * validated on the children.
+	 *
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname, true);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	set_attnotnull(NULL, rel, attnum, lockmode);
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	/*
+	 * set attinvalidnotnull to false. set_attnotnull already tell phase 3 to
+	 * vertify not-null status.
+	 */
+	set_attinvalidnotnull(rel, attnum, false);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13549,7 +13740,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 		 */
 		if (con->contype == CONSTRAINT_NOTNULL)
 		{
-			tuple = findNotNullConstraint(childrelid, colname);
+			tuple = findNotNullConstraint(childrelid, colname, false);
 			if (!HeapTupleIsValid(tuple))
 				elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation %u",
 					 colname, RelationGetRelid(childrel));
@@ -16813,8 +17004,9 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			{
 				HeapTuple	contup;
 
+				Assert(!parent_att->attinvalidnotnull);
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
-													 parent_att->attnum);
+													 parent_att->attnum, false);
 				if (HeapTupleIsValid(contup) &&
 					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
 					ereport(ERROR,
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index e9bd98c7738..06226150f94 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -93,6 +93,9 @@ static bool ExecCheckPermissionsModified(Oid relOid, Oid userid,
 static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt);
 static void EvalPlanQualStart(EPQState *epqstate, Plan *planTree);
 
+static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo,
+										TupleTableSlot *slot,
+										EState *estate, int attrChk);
 /* end of local decls */
 
 
@@ -2071,57 +2074,21 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
 			if (att->attnotnull && slot_attisnull(slot, attrChk))
-			{
-				char	   *val_desc;
-				Relation	orig_rel = rel;
-				TupleDesc	orig_tupdesc = RelationGetDescr(rel);
+				ReportNotNullViolationError(resultRelInfo, slot, estate, attrChk);
+		}
+	}
 
-				/*
-				 * If the tuple has been routed, it's been converted to the
-				 * partition's rowtype, which might differ from the root
-				 * table's.  We must convert it back to the root table's
-				 * rowtype so that val_desc shown error message matches the
-				 * input tuple.
-				 */
-				if (resultRelInfo->ri_RootResultRelInfo)
-				{
-					ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
-					AttrMap    *map;
+	if (constr->has_invalid_not_null)
+	{
+		int			natts = tupdesc->natts;
+		int			attrChk;
 
-					tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
-					/* a reverse map */
-					map = build_attrmap_by_name_if_req(orig_tupdesc,
-													   tupdesc,
-													   false);
+		for (attrChk = 1; attrChk <= natts; attrChk++)
+		{
+			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
-					/*
-					 * Partition-specific slot's tupdesc can't be changed, so
-					 * allocate a new one.
-					 */
-					if (map != NULL)
-						slot = execute_attr_map_slot(map, slot,
-													 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
-					modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
-											 ExecGetUpdatedCols(rootrel, estate));
-					rel = rootrel->ri_RelationDesc;
-				}
-				else
-					modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
-											 ExecGetUpdatedCols(resultRelInfo, estate));
-				val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
-														 slot,
-														 tupdesc,
-														 modifiedCols,
-														 64);
-
-				ereport(ERROR,
-						(errcode(ERRCODE_NOT_NULL_VIOLATION),
-						 errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
-								NameStr(att->attname),
-								RelationGetRelationName(orig_rel)),
-						 val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
-						 errtablecol(orig_rel, attrChk)));
-			}
+			if (att->attinvalidnotnull && slot_attisnull(slot, attrChk))
+				ReportNotNullViolationError(resultRelInfo, slot, estate, attrChk);
 		}
 	}
 
@@ -2176,6 +2143,73 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	}
 }
 
+
+/*
+ * Report a violation of a not-null constraint that was already detected.
+ */
+static void
+ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
+							EState *estate, int attrChk)
+{
+	Bitmapset  *modifiedCols;
+	char	   *val_desc;
+
+	Relation	rel = resultRelInfo->ri_RelationDesc;
+	Relation	orig_rel = rel;
+
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+	TupleDesc	orig_tupdesc = RelationGetDescr(rel);
+	Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
+
+	Assert(attrChk > 0);
+
+	/*
+	 * If the tuple has been routed, it's been converted to the partition's
+	 * rowtype, which might differ from the root table's.  We must convert it
+	 * back to the root table's rowtype so that val_desc shown error message
+	 * matches the input tuple.
+	 */
+	if (resultRelInfo->ri_RootResultRelInfo)
+	{
+		ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
+		AttrMap    *map;
+
+		tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
+		/* a reverse map */
+		map = build_attrmap_by_name_if_req(orig_tupdesc,
+										   tupdesc,
+										   false);
+
+		/*
+		 * Partition-specific slot's tupdesc can't be changed, so allocate a
+		 * new one.
+		 */
+		if (map != NULL)
+			slot = execute_attr_map_slot(map, slot,
+										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
+		modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
+								 ExecGetUpdatedCols(rootrel, estate));
+		rel = rootrel->ri_RelationDesc;
+	}
+	else
+		modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
+								 ExecGetUpdatedCols(resultRelInfo, estate));
+
+	val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+											 slot,
+											 tupdesc,
+											 modifiedCols,
+											 64);
+	ereport(ERROR,
+			errcode(ERRCODE_NOT_NULL_VIOLATION),
+			errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
+				   NameStr(att->attname),
+				   RelationGetRelationName(orig_rel)),
+			val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
+			errtablecol(orig_rel, attrChk));
+}
+
+
 /*
  * ExecWithCheckOptions -- check that tuple satisfies any WITH CHECK OPTIONs
  * of the specified kind.
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..715eb51300b 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4224,9 +4224,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 896a7f2c59b..59d689640c6 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,18 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+			/*
+			 * we do not support NOT NULL NOT VALID for column constraint,
+			 * nn->conname should not be NULL.
+			*/
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint \"%s\"", nn->conname));
+		}
 	}
 
 	/*
@@ -1291,7 +1303,7 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 		List	   *lst;
 
 		lst = RelationGetNotNullConstraints(RelationGetRelid(relation), false,
-											true);
+											true, false);
 		cxt->nnconstraints = list_concat(cxt->nnconstraints, lst);
 	}
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9f54a9e72b7..d5cd93e55c3 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -593,6 +593,8 @@ RelationBuildTupleDesc(Relation relation)
 		/* Update constraint/default info */
 		if (attp->attnotnull)
 			constr->has_not_null = true;
+		if (attp->attinvalidnotnull)
+			constr->has_invalid_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -678,6 +680,7 @@ RelationBuildTupleDesc(Relation relation)
 	 * Set up constraint/default info
 	 */
 	if (constr->has_not_null ||
+		constr->has_invalid_not_null ||
 		constr->has_generated_stored ||
 		constr->has_generated_virtual ||
 		ndef > 0 ||
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 428ed2d60fc..1d67dcac124 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8884,6 +8884,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8903,6 +8904,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_validated;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -8998,12 +9000,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
-							 "co.conislocal AS notnull_islocal,\n");
+							 "co.conislocal AS notnull_islocal,\n"
+							 "co.convalidated as notnull_validated,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
-							 "a.attislocal AS notnull_islocal,\n");
+							 "a.attislocal AS notnull_islocal,\n"
+							 "true as notnull_validated\n");
 
 	if (fout->remoteVersion >= 140000)
 		appendPQExpBufferStr(q,
@@ -9078,6 +9082,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
+	i_notnull_validated = PQfnumber(res, "notnull_validated");
 	i_attoptions = PQfnumber(res, "attoptions");
 	i_attcollation = PQfnumber(res, "attcollation");
 	i_attcompression = PQfnumber(res, "attcompression");
@@ -9094,6 +9099,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9145,6 +9151,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->notnull_validated = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
 		hasdefaults = false;
 
@@ -9168,12 +9175,33 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_validated[j] = (PQgetvalue(res, r, i_notnull_validated)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			if (tbinfo->notnull_validated[j])
+			{
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									tbinfo, j,
+									i_notnull_name, i_notnull_noinherit,
+									i_notnull_islocal);
+			}
+			else
+			{
+				tbinfo->notnull_constrs[j] = NULL;
+
+				/*
+				 * if column notnull_validated is false, it can also mean that
+				 * column don't have not-null constraint at all. if column have
+				 * NOT NULL NOT VALID then Add the entry into invalidnotnulloids
+				 * list so it can dumped as seperate constraint.
+				*/
+				if (!PQgetisnull(res, r, i_notnull_name))
+				{
+					if (invalidnotnulloids->len > 1)
+						appendPQExpBufferChar(invalidnotnulloids, ',');
+					appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+				}
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9193,6 +9221,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			appendPQExpBuffer(tbloids, "%u", tbinfo->dobj.catId.oid);
 		}
 	}
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	PQclear(res);
 
@@ -9326,6 +9355,110 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table NOT NULL NOT VALID constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int         numConstrs;
+		int         i_tableoid;
+		int         i_oid;
+		int         i_conrelid;
+		int         i_conname;
+		int         i_consrc;
+		int         i_conislocal;
+		int         i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND NOT convalidated "
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid         conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int         numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool        validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				Assert(!validated);
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+		         * NOT NULL NOT VALID must dumped separately as an ALTER TABLE
+				 * ADD CONSTRAINT entry. because CREATE TABLE can not create
+				 * invalid not null constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -16620,6 +16753,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 
 					if (print_notnull)
 					{
+						Assert(tbinfo->notnull_validated[j]);
+
 						if (tbinfo->notnull_constrs[j][0] == '\0')
 							appendPQExpBufferStr(q, " NOT NULL");
 						else
@@ -17939,9 +18074,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK and INVALID NOT NULL constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
@@ -17965,7 +18100,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = coninfo->contype == 'c' ? "CHECK CONSTRAINT" : "CONSTRAINT",
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index bbdb30b5f54..e0c9bbd64a2 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -367,6 +367,7 @@ typedef struct _tableInfo
 									 * (pre-v17) */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
+	bool	   *notnull_validated;	/* true if NOT NULL is validated */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
 	struct _constraintInfo *checkexprs; /* CHECK constraints */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9e..09f8f92a59c 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3137,14 +3138,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NO VALID": "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..cc619477b63 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_defval;
 	uint16		num_check;
 	bool		has_not_null;
+	bool        has_invalid_not_null;
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9998b4abdef 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -120,6 +120,9 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	/* This flag represents the "NOT NULL" constraint */
 	bool		attnotnull;
 
+	/* This flag represents the "NOT NULL NOT VALID" constraint */
+	bool		attinvalidnotnull BKI_DEFAULT(f);
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..fe27dde16fa 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -259,14 +259,14 @@ extern char *ChooseConstraintName(const char *name1, const char *name2,
 								  const char *label, Oid namespaceid,
 								  List *others);
 
-extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
-extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
+extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum, bool include_invalid);
+extern HeapTuple findNotNullConstraint(Oid relid, const char *colname, bool include_invalid);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
-										   bool include_noinh);
+										   bool include_noinh, bool include_notvalid);
 
 extern void RemoveConstraintById(Oid conId);
 extern void RenameConstraintById(Oid conId, const char *newname);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..d57d7e09984 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,175 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-------tests for NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid  = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1),(NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; --ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           |          |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NO VALID
+
+INSERT INTO notnull_tbl1 VALUES (NULL, 4); --error, invalid not-null constraint forbiden new null values
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid no inherit; --error
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error can't change not-null status
+ERROR:  cannot change VALID status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL; --validate it then error out
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1 ORDER BY a, b;
+  a  | b 
+-----+---
+ 100 | 1
+ 300 | 3
+(2 rows)
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  primary key require an validated NOT NULL constraint
+DETAIL:  Column "a" of table "notnull_tbl1" is marked as NOT VALID NOT NULL constraint
+HINT:  You may try ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+-- however child table NOT NULL constraints should be valid.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+---now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1_child;
+DROP TABLE notnull_tbl1;
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  column "a" in child table "notnull_tbl1" must be marked NOT NULL
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  cannot change VALID status of NOT NULL constraint "nn" on relation "inh_parent"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  cannot change VALID status of NOT NULL constraint "nn" on relation "inh_child"
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  column "a" in child table "pp_nn_1" must be marked NOT NULL
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+DEALLOCATE get_nnconstraint_info;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..976e8e6941c 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,120 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-------tests for NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid  = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1),(NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; --ok
+\d+ notnull_tbl1
+
+INSERT INTO notnull_tbl1 VALUES (NULL, 4); --error, invalid not-null constraint forbiden new null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid no inherit; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error can't change not-null status
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL; --validate it then error out
+
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1 ORDER BY a, b;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+-- however child table NOT NULL constraints should be valid.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+---now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1_child;
+DROP TABLE notnull_tbl1;
+
+
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+DEALLOCATE get_nnconstraint_info;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
-- 
2.34.1

From fc4bf954772d25dfbf60774429d875f78e4fd69e Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 24 Mar 2025 09:21:10 +0800
Subject: [PATCH v5 1/1] NOT NULL NOT VALID
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* TODO: In doc/src/sgml/ref/alter_table.sgml, under the <title>Compatibility</title> section,
  clarify how the "NOT NULL NOT VALID" syntax conforms with the standard.
* TODO: Should CREATE TABLE LIKE copy an existing invalid not-null constraint to the new table,
  and if so, the new table's not-null will be marked as valid.

* attnotnull means that a not-null constraint exists; it doesn't imply anything
  regarding the constraint being valid or not.
  attnotnullvalid  will indicate whether the constraint is valid; this column can
  only be true if attnotnull is already true.
  attnotnullvalid only added to FormData_pg_attribute, didn't add to CompactAttribute.
  mainly because invalid not-null is not being commonly used.
  TupleDesc->TupleConstr->has_not_null now also represents invalid not-null
  constraint.

* For table in pg_catalog schema, if that column attnotnull attribute is true,
 then attnotnullvalid attribute is also true.  Similarly, if attnotnull is false,
 then attnotnullvalid is false.  I added an SQL check at the end of
 src/test/regress/sql/constraints.sql (not sure it's necessary)

* CREATE TABLE specifying not valid not-null constraint will be set to valid,
  a warning is issued within function transformCreateStmt.
  that means InsertPgAttributeTuples can not insert attribute
  that is (attnotnull && !attnotnullvalid).
  I added an Assert in InsertPgAttributeTuples.

* table rewrite won't validate invalid not-null constraint, that is aligned
  with check constraint.

* attnotnullvalid, two places toggled it from true to false.
  1. ATAddCheckNNConstraint, if you specified "NOT NULL NOT VALID", it will change
    it from false to false, but will set attnotnull to true.
  2. QueueNNConstraintValidation, subroutine of ATExecValidateConstraint.
    when validing an not valid not-null constraint, toggle it from false to true,
    also set attnotnull to true.

* A partitioned table can have an invalid NOT NULL constraint while its
  partitions have a valid one, but not the other way around.
  but pg_dump/pg_restore may not preserve the constraint name properly, but
  that's fine for not-null constraint.

* regular table invalid not null constraint pg_dump also works fine.

discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
---
 contrib/postgres_fdw/postgres_fdw.c       |   1 +
 doc/src/sgml/catalogs.sgml                |  14 +-
 doc/src/sgml/ref/alter_table.sgml         |   8 +-
 src/backend/access/common/tupdesc.c       |   8 +
 src/backend/bootstrap/bootstrap.c         |   9 +
 src/backend/catalog/genbki.pl             |   2 +
 src/backend/catalog/heap.c                |  20 +-
 src/backend/catalog/pg_constraint.c       |  57 +++++-
 src/backend/commands/tablecmds.c          | 222 ++++++++++++++++++++--
 src/backend/executor/execMain.c           |   1 +
 src/backend/optimizer/util/plancat.c      |   6 +-
 src/backend/parser/gram.y                 |   4 +-
 src/backend/parser/parse_utilcmd.c        |  16 +-
 src/backend/utils/cache/catcache.c        |   1 +
 src/backend/utils/cache/relcache.c        |   6 +-
 src/bin/pg_dump/pg_dump.c                 | 157 ++++++++++++++-
 src/bin/pg_dump/pg_dump.h                 |   3 +-
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   2 +-
 src/include/catalog/pg_attribute.h        |   3 +
 src/include/catalog/pg_constraint.h       |  10 +-
 src/test/regress/expected/constraints.out | 183 ++++++++++++++++++
 src/test/regress/sql/constraints.sql      | 125 ++++++++++++
 23 files changed, 810 insertions(+), 57 deletions(-)

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 6beae0fa37f..92dd1afd47f 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5572,6 +5572,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 							   "  LEFT JOIN pg_attribute a ON "
 							   "    attrelid = c.oid AND attnum > 0 "
 							   "      AND NOT attisdropped "
+							   "      AND attnotnullvalid "
 							   "  LEFT JOIN pg_attrdef ad ON "
 							   "    adrelid = c.oid AND adnum = attnum ");
 
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..4f42c5bdc32 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,19 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a possibly unvalidated not-null constraint
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       The not-null constraint validity status of the column.
+       If true, it means this column has a valid not-null constraint,
+       false means this column doesn't have a not-null constraint or has an unvalidated one.
+       If <structfield>attnotnull</structfield> is false, this must be false.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 4f15b89a98f..9a2c0f5bfa0 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has a invalid not-null constraint, <literal>SET NOT NULL</literal>
+      will change it to a validated not-null constraint.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      CHECK constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key or check constraint or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  Nothing happens if the constraint is already marked valid.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..86cb23d58ab 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -252,6 +252,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +299,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +420,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +467,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +617,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +847,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +911,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..b18dc1d5ee6 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,15 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/*
+	 * If a system catalog column is attnotnull then attnotnullvalid is true,
+	 * otherwise false.
+	 */
+	if (attrtypes[attnum]->attnotnull == true)
+		attrtypes[attnum]->attnotnullvalid = true;
+	else
+		attrtypes[attnum]->attnotnullvalid = false;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..b8651a9d865 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,8 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	$row->{attnotnullvalid} = $row->{attnotnull} eq 't' ? 't' : 'f';
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..bed22db755a 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,11 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
+		if (!attrs->attnotnull)
+			Assert(!attrs->attnotnullvalid);
+		else
+			Assert(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -2621,12 +2632,17 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("not-null constraints are not supported on virtual generated columns"));
 
+			if (cdef->initially_valid)
+				Assert(!cdef->skip_validation);
+			else
+				Assert(cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
 			 * to add another one; just adjust inheritance status as needed.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum,
+										 is_local, cdef->is_no_inherit, cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..5005ea7e6f1 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -576,13 +576,14 @@ ChooseConstraintName(const char *name1, const char *name2,
  * Find and return a copy of the pg_constraint tuple that implements a
  * validated not-null constraint for the given column of the given relation.
  * If no such constraint exists, return NULL.
+ * if include_invalid is true, it may return an invalid not-null tuple.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
  * I'm not sure it's worth the catalog bloat and de-normalization, however.
  */
 HeapTuple
-findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
+findNotNullConstraintAttnum(Oid relid, AttrNumber attnum, bool include_invalid)
 {
 	Relation	pg_constraint;
 	HeapTuple	conTup,
@@ -609,7 +610,7 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
+		if (!con->convalidated && !include_invalid)
 			continue;
 
 		conkey = extractNotNullColumn(conTup);
@@ -631,9 +632,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
  * Find and return the pg_constraint tuple that implements a validated
  * not-null constraint for the given column of the given relation.  If
  * no such column or no such constraint exists, return NULL.
+ * if include_invalid is true, it may return an invalid not-null tuple.
  */
 HeapTuple
-findNotNullConstraint(Oid relid, const char *colname)
+findNotNullConstraint(Oid relid, const char *colname, bool include_invalid)
 {
 	AttrNumber	attnum;
 
@@ -641,7 +643,7 @@ findNotNullConstraint(Oid relid, const char *colname)
 	if (attnum <= InvalidAttrNumber)
 		return NULL;
 
-	return findNotNullConstraintAttnum(relid, attnum);
+	return findNotNullConstraintAttnum(relid, attnum, include_invalid);
 }
 
 /*
@@ -728,12 +730,13 @@ extractNotNullColumn(HeapTuple constrTup)
  * nothing if it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
+	Oid	relid = RelationGetRelid(rel);
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(relid, attnum, true);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -753,6 +756,36 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if we want change the NOT NULL constraint from NOT
+		 * VALID to VALID.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("cannot change invalid constraint \"%s\" on relation \"%s\" to valid",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint \"%s\"",
+							NameStr(conform->conname)));
+
+		/* VALID TO NOT VALID seems no usage, so just issue a warning */
+		if (is_notvalid && conform->convalidated)
+		{
+			if (is_local)
+				ereport(WARNING,
+						errmsg("NOT NULL constraint \"%s\" on relation \"%s\" is already valid",
+							NameStr(conform->conname), get_rel_name(relid)));
+			else if (rel->rd_rel->relispartition)
+			{
+				/*
+				* In case of partitions, an inherited not null constraint
+				* is never considered local. See MergeConstraintsIntoExisting also.
+				*/
+				conform->conislocal = false;
+				changed =true;
+			}
+		}
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
@@ -788,9 +821,10 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
  * This is seldom needed, so we just scan pg_constraint each time.
  *
  * 'include_noinh' determines whether to include NO INHERIT constraints or not.
+ * 'include_notvalid' determines whether to include NO VALID constraints or not.
  */
 List *
-RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
+RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh, bool include_notvalid)
 {
 	List	   *notnulls = NIL;
 	Relation	constrRel;
@@ -816,6 +850,9 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 		if (conForm->connoinherit && !include_noinh)
 			continue;
 
+		if (!conForm->convalidated && !include_notvalid)
+			continue;
+
 		colnum = extractNotNullColumn(htup);
 
 		if (cooked)
@@ -830,7 +867,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -850,7 +887,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1202544ebd0..fc77e15793e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -410,6 +410,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -474,6 +477,7 @@ static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool r
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 						   LOCKMODE lockmode);
+static void set_attnotnullinvalid(Relation rel, AttrNumber attnum, bool is_valid);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1400,6 +1404,12 @@ BuildDescForRelation(const List *columns)
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
 		att->attnotnull = entry->is_not_null;
+
+		if (att->attnotnull)
+			att->attnotnullvalid  = true;
+		else
+			att->attnotnullvalid  = false;
+
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2713,10 +2723,10 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT. but we will include NOT VALID
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
-												  true, false);
+												  true, false, true);
 		foreach_ptr(CookedConstraint, cc, nnconstrs)
 			nncols = bms_add_member(nncols, cc->attnum);
 
@@ -6183,12 +6193,14 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		 * If we are rebuilding the tuples OR if we added any new but not
 		 * verified not-null constraints, check all not-null constraints. This
 		 * is a bit of overkill but it minimizes risk of bugs.
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid && !attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
 		}
 		if (notnull_attrs)
@@ -7669,6 +7681,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	/* If the column is already nullable there's nothing to do. */
 	if (!attTup->attnotnull)
 	{
+		// Assert(!attTup->attnotnullvalid);
 		table_close(attr_rel, RowExclusiveLock);
 		return InvalidObjectAddress;
 	}
@@ -7709,7 +7722,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 	 * Find the constraint that makes this column NOT NULL, and drop it.
 	 * dropconstraint_internal() resets attnotnull.
 	 */
-	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
+	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum, false);
 	if (conTup == NULL)
 		elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
 			 colName, RelationGetRelationName(rel));
@@ -7766,6 +7779,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
 		Assert(!attr->attnotnull);
 		attr->attnotnull = true;
+		attr->attnotnullvalid = true;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -7787,6 +7801,42 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	}
 }
 
+/*
+ * currently we have two commands can change attnotnullvalid, attnotnull status:
+ * ALTER TABLE VALIDATE CONSTRAINT, ALTER TABLE ADD NOT NULL NOT VALID.  In both
+ * case, we need set attnotnull to true, set attnotnullvalid based on "is_valid".
+*/
+static void
+set_attnotnullinvalid(Relation rel, AttrNumber attnum, bool is_valid)
+{
+	Form_pg_attribute attr;
+	Relation	attr_rel;
+	HeapTuple	tuple;
+
+	CheckAlterTableIsSafe(rel);
+
+	attr = TupleDescAttr(RelationGetDescr(rel), attnum - 1);
+	if (attr->attisdropped)
+		return;
+
+	attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum);
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cache lookup failed for attribute %d of relation %u",
+					attnum, RelationGetRelid(rel));
+
+	attr = (Form_pg_attribute) GETSTRUCT(tuple);
+	attr->attnotnullvalid = is_valid;
+	attr->attnotnull = true;
+
+	CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+	CommandCounterIncrement();
+
+	table_close(attr_rel, RowExclusiveLock);
+	heap_freetuple(tuple);
+}
+
 /*
  * ALTER TABLE ALTER COLUMN SET NOT NULL
  *
@@ -7843,7 +7893,7 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 						   colName, RelationGetRelationName(rel))));
 
 	/* See if there's already a constraint */
-	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
+	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum, true);
 	if (HeapTupleIsValid(tuple))
 	{
 		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
@@ -7878,6 +7928,16 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+
+			/*
+			 * flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -9385,6 +9445,24 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
+
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)), true);
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("primary key require an validated NOT NULL constraint"),
+						errdetail("NOT NULL constraint \"%s\" on Column \"%s\" of table \"%s\" is not validated",
+								  NameStr(conForm->conname),
+								  strVal(lfirst(lc)),
+								  RelationGetRelationName(rel)),
+						errhint("You may try ALTER TABLE VALIDATE CONSTRAINT to validate it \"%s\"",
+								NameStr(conForm->conname)));
+			heap_freetuple(tuple);
+		}
 
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
@@ -9760,11 +9838,19 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
+		 * If adding a valid not-null constraint, set the pg_attribute flag and tell
 		 * phase 3 to verify existing rows, if needed.
+		 * However if we are adding a invalid not-null constraint, then we only
+		 * need set the pg_attribute.attnotnullvalid to false, phase 3 don't need to
+		 * verify existing rows.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+		{
+			if (!constr->skip_validation)
+				set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			else
+				set_attnotnullinvalid(rel, ccon->attnum, false);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12174,7 +12260,7 @@ ATExecAlterConstraintInternal(List **wqueue, ATAlterConstraint *cmdcon,
 				HeapTuple	childtup;
 				Form_pg_constraint childcon;
 
-				childtup = findNotNullConstraint(childoid, colName);
+				childtup = findNotNullConstraint(childoid, colName, false);
 				if (!childtup)
 					elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation %u",
 						 colName, childoid);
@@ -12365,10 +12451,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12387,6 +12474,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12603,6 +12695,106 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, the parent has already done this, so skip it.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname, true);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	set_attnotnullinvalid(rel, attnum, true);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13473,10 +13665,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -13547,7 +13740,7 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 		 */
 		if (con->contype == CONSTRAINT_NOTNULL)
 		{
-			tuple = findNotNullConstraint(childrelid, colname);
+			tuple = findNotNullConstraint(childrelid, colname, false);
 			if (!HeapTupleIsValid(tuple))
 				elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation %u",
 					 colname, RelationGetRelid(childrel));
@@ -16812,7 +17005,7 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 				HeapTuple	contup;
 
 				contup = findNotNullConstraintAttnum(RelationGetRelid(parent_rel),
-													 parent_att->attnum);
+													 parent_att->attnum, true);
 				if (HeapTupleIsValid(contup) &&
 					!((Form_pg_constraint) GETSTRUCT(contup))->connoinherit)
 					ereport(ERROR,
@@ -19328,7 +19521,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index e9bd98c7738..3be2e4f4639 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,6 +2070,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
+			/* not valid not-null constraint also checked */
 			if (att->attnotnull && slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 0489ad36644..c8790264c8d 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -175,9 +175,9 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 	{
 		for (int i = 0; i < relation->rd_att->natts; i++)
 		{
-			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
+			Form_pg_attribute attr = TupleDescAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnotnull && attr->attnotnullvalid)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1355,7 +1355,7 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 271ae26cbaf..715eb51300b 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4224,9 +4224,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 896a7f2c59b..aaaee388f5d 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,20 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+
+			/*
+			 * not-null constraint created via CREATE TABLE will always be
+			 * valid.  since there is no data there while CREATE TABLE, make it
+			 * invalid does not make sense
+			*/
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint on column \"%s\"", colname));
+		}
 	}
 
 	/*
@@ -1291,7 +1305,7 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 		List	   *lst;
 
 		lst = RelationGetNotNullConstraints(RelationGetRelid(relation), false,
-											true);
+											true, false);
 		cxt->nnconstraints = list_concat(cxt->nnconstraints, lst);
 	}
 
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9f54a9e72b7..84fbabd5344 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -590,7 +590,10 @@ RelationBuildTupleDesc(Relation relation)
 
 		populate_compact_attribute(relation->rd_att, attnum - 1);
 
-		/* Update constraint/default info */
+		/*
+		 * Update constraint/default info
+		 * has_not_null also include invalid not-null constraint
+		*/
 		if (attp->attnotnull)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
@@ -3573,6 +3576,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 428ed2d60fc..42755bdfd7d 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8884,6 +8884,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8903,6 +8904,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_validated;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -8998,12 +9000,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
-							 "co.conislocal AS notnull_islocal,\n");
+							 "co.conislocal AS notnull_islocal,\n"
+							 "co.convalidated as notnull_validated,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
 							 "false AS notnull_noinherit,\n"
-							 "a.attislocal AS notnull_islocal,\n");
+							 "a.attislocal AS notnull_islocal,\n"
+							 "true as notnull_validated\n");
 
 	if (fout->remoteVersion >= 140000)
 		appendPQExpBufferStr(q,
@@ -9078,6 +9082,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_notnull_name = PQfnumber(res, "notnull_name");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
+	i_notnull_validated = PQfnumber(res, "notnull_validated");
 	i_attoptions = PQfnumber(res, "attoptions");
 	i_attcollation = PQfnumber(res, "attcollation");
 	i_attcompression = PQfnumber(res, "attcompression");
@@ -9094,6 +9099,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9145,6 +9151,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->notnull_validated = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
 		hasdefaults = false;
 
@@ -9168,12 +9175,32 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_validated[j] = (PQgetvalue(res, r, i_notnull_validated)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			if (tbinfo->notnull_validated[j])
+			{
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			}
+			else
+			{
+				tbinfo->notnull_constrs[j] = NULL;
+
+				/*
+				 * if column notnull_validated is false, it means either column
+				 * don't have not-null constraint at all, or the existing one is
+				 * invalid.  here we onlu dump the invalid not-null.
+				*/
+				if (!PQgetisnull(res, r, i_notnull_name))
+				{
+					if (invalidnotnulloids->len > 1)
+						appendPQExpBufferChar(invalidnotnulloids, ',');
+					appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+				}
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9193,6 +9220,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			appendPQExpBuffer(tbloids, "%u", tbinfo->dobj.catId.oid);
 		}
 	}
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	PQclear(res);
 
@@ -9326,6 +9354,112 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table NOT NULL NOT VALID constraints.  This is skipped for
+	 * a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int         numConstrs;
+		int         i_tableoid;
+		int         i_oid;
+		int         i_conrelid;
+		int         i_conname;
+		int         i_consrc;
+		int         i_conislocal;
+		int         i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND NOT convalidated "
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid         conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int         numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool        validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				Assert(!validated);
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * invalid not-null constraint must dumped separately as an
+				 * ALTER TABLE ADD CONSTRAINT entry. because CREATE TABLE can
+				 * not create invalid not null constraint. it's also required
+				 * for potentially-violating existing data is loaded before the
+				 * constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -16620,6 +16754,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 
 					if (print_notnull)
 					{
+						/* column constraint should all be validated not-null */
+						Assert(tbinfo->notnull_validated[j]);
+
 						if (tbinfo->notnull_constrs[j][0] == '\0')
 							appendPQExpBufferStr(q, " NOT NULL");
 						else
@@ -17939,9 +18076,9 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK and invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
@@ -17965,7 +18102,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = coninfo->contype == 'c' ? "CHECK CONSTRAINT" : "CONSTRAINT",
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index bbdb30b5f54..c2d8c3e601a 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -367,8 +367,9 @@ typedef struct _tableInfo
 									 * (pre-v17) */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
+	bool	   *notnull_validated;	/* true if NOT NULL is validated */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-	struct _constraintInfo *checkexprs; /* CHECK constraints */
+	struct _constraintInfo *checkexprs; /* CHECK constraints XXX: also include invalid not-null constraint */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
 	char	   *amname;			/* relation access method */
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index e6cf468ac9e..09f8f92a59c 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3137,14 +3138,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NO VALID": "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..55418350505 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* this includes invalid not-null !!! */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..398b6e324c8 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -120,6 +120,9 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	/* This flag represents the "NOT NULL" constraint */
 	bool		attnotnull;
 
+	/* false means "NOT NULL NOT VALID". true means XXX (need to consider attnotnull) */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..fe27dde16fa 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -259,14 +259,14 @@ extern char *ChooseConstraintName(const char *name1, const char *name2,
 								  const char *label, Oid namespaceid,
 								  List *others);
 
-extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
-extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
+extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum, bool include_invalid);
+extern HeapTuple findNotNullConstraint(Oid relid, const char *colname, bool include_invalid);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
-										   bool include_noinh);
+										   bool include_noinh, bool include_notvalid);
 
 extern void RemoveConstraintById(Oid conId);
 extern void RenameConstraintById(Oid conId, const char *newname);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..7cf69fa7dd3 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,175 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-------tests for NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid  = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1),(NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; --ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NO VALID
+
+INSERT INTO notnull_tbl1 VALUES (NULL, 4); --error, invalid not-null constraint forbiden new null values
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid no inherit; --error
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error can't change not-null status
+ERROR:  cannot change invalid constraint "nn" on relation "notnull_tbl1" to valid
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL; --validate it then error out
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1 ORDER BY a, b;
+  a  | b 
+-----+---
+ 100 | 1
+ 300 | 3
+(2 rows)
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  primary key require an validated NOT NULL constraint
+DETAIL:  NOT NULL constraint "nn" on Column "a" of table "notnull_tbl1" is not validated
+HINT:  You may try ALTER TABLE VALIDATE CONSTRAINT to validate it "nn"
+-- however child table NOT NULL constraints should be valid.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+---now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1_child;
+DROP TABLE notnull_tbl1;
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  cannot change invalid constraint "nn" on relation "inh_parent" to valid
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  cannot change invalid constraint "nn" on relation "inh_child" to valid
+HINT:  You may need to use ALTER TABLE VALIDATE CONSTRAINT to validate constraint "nn"
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+DEALLOCATE get_nnconstraint_info;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -1392,3 +1561,17 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
+ relname | attname | attnum | attnotnull | attnotnullvalid 
+---------+---------+--------+------------+-----------------
+(0 rows)
+
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..34ad33f2d55 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,120 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-------tests for NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid  = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1),(NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; --ok
+\d+ notnull_tbl1
+
+INSERT INTO notnull_tbl1 VALUES (NULL, 4); --error, invalid not-null constraint forbiden new null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a not valid no inherit; --error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; --error can't change not-null status
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL; --validate it then error out
+
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+DELETE FROM notnull_tbl1 WHERE b = 2;
+SELECT * FROM notnull_tbl1 ORDER BY a, b;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+-- however child table NOT NULL constraints should be valid.
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS(notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+---now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1_child;
+DROP TABLE notnull_tbl1;
+
+
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+DEALLOCATE get_nnconstraint_info;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -836,3 +950,14 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
\ No newline at end of file
-- 
2.34.1

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index ac14c06c715..e9296e2d4bd 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5549,7 +5549,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 							   "SELECT relname, "
 							   "  attname, "
 							   "  format_type(atttypid, atttypmod), "
-							   "  attnotnull, "
+							   "  attnotnull, ");
+
+		/* NOT VALID NOT NULL columns are supported since Postgres 18 */
+		if (PQserverVersion(conn) >= 180000)
+			appendStringInfoString(&buf, "attnotnullvalid, ");
+		else
+			appendStringInfoString(&buf, "attnotnull AS attnotnullvalid, ");
+
+		appendStringInfoString(&buf,
 							   "  pg_get_expr(adbin, adrelid), ");
 
 		/* Generated columns are supported since Postgres 12 */
@@ -5651,6 +5659,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				char	   *attname;
 				char	   *typename;
 				char	   *attnotnull;
+				char	   *attnotnullvalid;
 				char	   *attgenerated;
 				char	   *attdefault;
 				char	   *collname;
@@ -5663,14 +5672,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				attname = PQgetvalue(res, i, 1);
 				typename = PQgetvalue(res, i, 2);
 				attnotnull = PQgetvalue(res, i, 3);
-				attdefault = PQgetisnull(res, i, 4) ? NULL :
-					PQgetvalue(res, i, 4);
-				attgenerated = PQgetisnull(res, i, 5) ? NULL :
+				attnotnullvalid = PQgetvalue(res, i, 4);
+				attdefault = PQgetisnull(res, i, 5) ? NULL :
 					PQgetvalue(res, i, 5);
-				collname = PQgetisnull(res, i, 6) ? NULL :
+				attgenerated = PQgetisnull(res, i, 6) ? NULL :
 					PQgetvalue(res, i, 6);
-				collnamespace = PQgetisnull(res, i, 7) ? NULL :
+				collname = PQgetisnull(res, i, 7) ? NULL :
 					PQgetvalue(res, i, 7);
+				collnamespace = PQgetisnull(res, i, 8) ? NULL :
+					PQgetvalue(res, i, 8);
 
 				if (first_item)
 					first_item = false;
@@ -5714,7 +5724,11 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 
 				/* Add NOT NULL if needed */
 				if (import_not_null && attnotnull[0] == 't')
+				{
 					appendStringInfoString(&buf, " NOT NULL");
+					if (attnotnullvalid[0] == 'f')
+						appendStringInfoString(&buf, " NOT VALID");
+				}
 			}
 			while (++i < numrows &&
 				   strcmp(PQgetvalue(res, i, 0), tablename) == 0);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..f33f1ea1b57 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 11d1bc7dbe1..344387cd99d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has a invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  Nothing happens if the constraint is already marked valid.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index bd3554c0bfd..d3a814986e9 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2621,12 +2629,17 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("not-null constraints are not supported on virtual generated columns"));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum, is_local,
+										 cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..81e975e1238 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,8 +574,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -721,19 +720,23 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -751,7 +754,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 			ereport(ERROR,
 					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
-						   NameStr(conform->conname), get_rel_name(relid)));
+						   NameStr(conform->conname), RelationGetRelationName(rel)));
+
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), RelationGetRelationName(rel)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
 
 		if (!is_local)
 		{
@@ -830,7 +844,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -850,7 +864,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index afb25007613..bb5bd0f6d61 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -419,6 +419,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -482,7 +485,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1324,7 +1327,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, true);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1408,7 +1411,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2722,7 +2725,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6190,14 +6193,16 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null
+		 * constraints. This is a bit of overkill but it minimizes risk of
+		 * bugs.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 				notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
 		}
 		if (notnull_attrs)
@@ -7716,7 +7721,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7746,7 +7751,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
@@ -7760,7 +7765,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7773,15 +7778,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7887,6 +7894,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7949,8 +7965,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9389,12 +9405,45 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
+	/* Verify that columns are not-null, or request that they be made so */
 	foreach(lc, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
 
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("NO INHERIT not-null constraint is incompatible with primary key"),
+						errhint("You will need to use ALTER TABLE ... ALTER CONSTRAINT ... INHERIT."));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("not-null constraint \"%s\" of table \"%s\" has not been validated",
+							   NameStr(conForm->conname),
+							   RelationGetRelationName(rel)),
+						errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
 		newcmd = makeNode(AlterTableCmd);
@@ -9769,11 +9818,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12437,10 +12490,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12459,6 +12513,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12675,6 +12734,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13543,10 +13705,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16897,19 +17060,25 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			if (parent_att->attgenerated && !child_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must be a generated column",
+								parent_attname)));
 			if (child_att->attgenerated && !parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must not be a generated column",
+								parent_attname)));
 
-			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+			if (parent_att->attgenerated && child_att->attgenerated &&
+				child_att->attgenerated != parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errmsg("column \"%s\" inherits from generated column of different kind",
+								parent_attname),
 						 errdetail("Parent column is %s, child column is %s.",
-								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL")));
 
 			/*
 			 * Regular inheritance children are independent enough not to
@@ -19398,7 +19567,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index e9bd98c7738..3be2e4f4639 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2070,6 +2070,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 		{
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);
 
+			/* not valid not-null constraint also checked */
 			if (att->attnotnull && slot_attisnull(slot, attrChk))
 			{
 				char	   *val_desc;
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 0489ad36644..44b65b99413 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1355,7 +1355,7 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull /* && att->attnotnullvalid */ && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0fc502a3a40..e6d3c56df86 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4214,9 +4214,9 @@ ConstraintElem:
 					n->keys = list_make1(makeString($3));
 					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 896a7f2c59b..92f422540c2 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,20 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+
+			/*
+			 * not-null constraint created via CREATE TABLE will always be
+			 * valid.  since there is no data there while CREATE TABLE, make
+			 * it invalid does not make sense
+			 */
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint on column \"%s\"", colname));
+		}
 	}
 
 	/*
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9f54a9e72b7..ea035f6feb8 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -590,7 +590,10 @@ RelationBuildTupleDesc(Relation relation)
 
 		populate_compact_attribute(relation->rd_att, attnum - 1);
 
-		/* Update constraint/default info */
+		/*
+		 * Update constraint/default info has_not_null also include invalid
+		 * not-null constraint
+		 */
 		if (attp->attnotnull)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
@@ -3573,6 +3576,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index e41e645f649..4c370889c52 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8919,6 +8919,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8938,6 +8939,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_validated;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9018,11 +9020,12 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 
 	/*
 	 * Find out any NOT NULL markings for each column.  In 18 and up we read
-	 * pg_constraint to obtain the constraint name.  notnull_noinherit is set
-	 * according to the NO INHERIT property.  For versions prior to 18, we
-	 * store an empty string as the name when a constraint is marked as
-	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
-	 * without a name); also, such cases are never NO INHERIT.
+	 * pg_constraint to obtain the constraint name.  notnull_validated and
+	 * notnull_noinherit are set according to the NOT VALID and NO INHERIT
+	 * properties, respectively.  For versions prior to 18, we store an empty
+	 * string as the name when a constraint is marked as attnotnull (this cues
+	 * dumpTableSchema to print the NOT NULL clause without a name); also,
+	 * such cases are never NO INHERIT nor NOT VALID.
 	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
@@ -9032,11 +9035,13 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "co.convalidated AS notnull_validated,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "a.attnotnull AS notnull_validated\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9111,6 +9116,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_validated = PQfnumber(res, "notnull_validated");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9129,6 +9135,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * r is handled by the inner loop.
 	 */
 	curtblindx = -1;
+	appendPQExpBufferChar(invalidnotnulloids, '{');
 	for (int r = 0; r < ntups;)
 	{
 		Oid			attrelid = atooid(PQgetvalue(res, r, i_attrelid));
@@ -9178,6 +9185,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_validated = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9203,12 +9211,33 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_validated[j] = (PQgetvalue(res, r, i_notnull_validated)[0] == 't');
 
-			/* Handle not-null constraint name and flags */
-			determineNotNullFlags(fout, res, r,
-								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+			if (tbinfo->notnull_validated[j])
+			{
+				/* Handle not-null constraint name and flags */
+				determineNotNullFlags(fout, res, r,
+									  tbinfo, j,
+									  i_notnull_name, i_notnull_noinherit,
+									  i_notnull_islocal);
+			}
+			else
+			{
+				tbinfo->notnull_constrs[j] = NULL;
+
+				/*
+				 * if column notnull_validated is false, it means either
+				 * column don't have not-null constraint at all, or the
+				 * existing one is invalid.  here we onlu dump the invalid
+				 * not-null.
+				 */
+				if (!PQgetisnull(res, r, i_notnull_name))
+				{
+					if (invalidnotnulloids->len > 1)
+						appendPQExpBufferChar(invalidnotnulloids, ',');
+					appendPQExpBuffer(invalidnotnulloids, "%u", tbinfo->dobj.catId.oid);
+				}
+			}
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9228,6 +9257,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			appendPQExpBuffer(tbloids, "%u", tbinfo->dobj.catId.oid);
 		}
 	}
+	appendPQExpBufferChar(invalidnotnulloids, '}');
 
 	PQclear(res);
 
@@ -9361,6 +9391,112 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table NOT NULL NOT VALID constraints.  This is skipped
+	 * for a data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids->len > 2)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+		int			i_convalidated;
+
+		pg_log_info("finding table invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
+						  "WHERE contype = 'n' AND NOT convalidated "
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+		i_convalidated = PQfnumber(res, "convalidated");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				bool		validated = PQgetvalue(res, j, i_convalidated)[0] == 't';
+
+				Assert(!validated);
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * invalid not-null constraint must dumped separately as an
+				 * ALTER TABLE ADD CONSTRAINT entry. because CREATE TABLE can
+				 * not create invalid not null constraint. it's also required
+				 * for potentially-violating existing data is loaded before
+				 * the constraint.
+				 */
+				constrs[j].separate = !validated;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -16658,6 +16794,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 
 					if (print_notnull)
 					{
+						/* column constraint should all be validated not-null */
+						Assert(tbinfo->notnull_validated[j]);
+
 						if (tbinfo->notnull_constrs[j][0] == '\0')
 							appendPQExpBufferStr(q, " NOT NULL");
 						else
@@ -17977,13 +18116,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "INVALID NOT NULL CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18003,7 +18149,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index bbdb30b5f54..aec0f38a353 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,10 +365,11 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_validated;	/* true if NOT NULL is valid */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-	struct _constraintInfo *checkexprs; /* CHECK constraints */
+	struct _constraintInfo *checkexprs; /* CHECK, invalid not-null constraints */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
 	char	   *amname;			/* relation access method */
 
@@ -496,6 +497,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index bf565afcc4e..8ba47572ed3 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3137,14 +3138,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..83b33ffc8a4 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* this includes invalid not-null !!! */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..cf27d53e848 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -263,8 +263,8 @@ extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
 extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..b8398efcdeb 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,189 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  not-null constraint "nn" of table "notnull_tbl1" has not been validated
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_parent"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_child"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+DEALLOCATE get_nnconstraint_info;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -1392,3 +1575,17 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
+ relname | attname | attnum | attnotnull | attnotnullvalid 
+---------+---------+--------+------------+-----------------
+(0 rows)
+
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..fec1213aa49 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,146 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+DEALLOCATE get_nnconstraint_info;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -836,3 +976,14 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);

From c0109712638be88ba94a12fbc6d20ecfd956f121 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Tue, 1 Apr 2025 22:13:29 +0200
Subject: [PATCH v6] NOT NULL NOT VALID

Author: Rushabh Lathia <rushabh.lathia@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
---
 contrib/postgres_fdw/postgres_fdw.c       |  26 ++-
 doc/src/sgml/catalogs.sgml                |  11 +-
 doc/src/sgml/ref/alter_table.sgml         |   8 +-
 src/backend/access/common/tupdesc.c       |  11 +-
 src/backend/bootstrap/bootstrap.c         |   3 +
 src/backend/catalog/genbki.pl             |   3 +
 src/backend/catalog/heap.c                |  19 +-
 src/backend/catalog/pg_constraint.c       |  52 +++--
 src/backend/commands/tablecmds.c          | 242 +++++++++++++++++++---
 src/backend/executor/execMain.c           |   1 +
 src/backend/jit/llvm/llvmjit_deform.c     |  10 +-
 src/backend/optimizer/util/plancat.c      |   6 +-
 src/backend/parser/gram.y                 |   5 +-
 src/backend/parser/parse_utilcmd.c        |  14 ++
 src/backend/utils/cache/catcache.c        |   1 +
 src/backend/utils/cache/relcache.c        |   3 +-
 src/bin/pg_dump/pg_dump.c                 | 190 +++++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   5 +-
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   9 +-
 src/include/catalog/pg_attribute.h        |   5 +-
 src/include/catalog/pg_constraint.h       |   4 +-
 src/test/regress/expected/alter_table.out |  69 ++++++
 src/test/regress/expected/constraints.out | 197 ++++++++++++++++++
 src/test/regress/sql/alter_table.sql      |  14 ++
 src/test/regress/sql/constraints.sql      | 151 ++++++++++++++
 26 files changed, 970 insertions(+), 98 deletions(-)

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index ac14c06c715..e9296e2d4bd 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5549,7 +5549,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 							   "SELECT relname, "
 							   "  attname, "
 							   "  format_type(atttypid, atttypmod), "
-							   "  attnotnull, "
+							   "  attnotnull, ");
+
+		/* NOT VALID NOT NULL columns are supported since Postgres 18 */
+		if (PQserverVersion(conn) >= 180000)
+			appendStringInfoString(&buf, "attnotnullvalid, ");
+		else
+			appendStringInfoString(&buf, "attnotnull AS attnotnullvalid, ");
+
+		appendStringInfoString(&buf,
 							   "  pg_get_expr(adbin, adrelid), ");
 
 		/* Generated columns are supported since Postgres 12 */
@@ -5651,6 +5659,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				char	   *attname;
 				char	   *typename;
 				char	   *attnotnull;
+				char	   *attnotnullvalid;
 				char	   *attgenerated;
 				char	   *attdefault;
 				char	   *collname;
@@ -5663,14 +5672,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				attname = PQgetvalue(res, i, 1);
 				typename = PQgetvalue(res, i, 2);
 				attnotnull = PQgetvalue(res, i, 3);
-				attdefault = PQgetisnull(res, i, 4) ? NULL :
-					PQgetvalue(res, i, 4);
-				attgenerated = PQgetisnull(res, i, 5) ? NULL :
+				attnotnullvalid = PQgetvalue(res, i, 4);
+				attdefault = PQgetisnull(res, i, 5) ? NULL :
 					PQgetvalue(res, i, 5);
-				collname = PQgetisnull(res, i, 6) ? NULL :
+				attgenerated = PQgetisnull(res, i, 6) ? NULL :
 					PQgetvalue(res, i, 6);
-				collnamespace = PQgetisnull(res, i, 7) ? NULL :
+				collname = PQgetisnull(res, i, 7) ? NULL :
 					PQgetvalue(res, i, 7);
+				collnamespace = PQgetisnull(res, i, 8) ? NULL :
+					PQgetvalue(res, i, 8);
 
 				if (first_item)
 					first_item = false;
@@ -5714,7 +5724,11 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 
 				/* Add NOT NULL if needed */
 				if (import_not_null && attnotnull[0] == 't')
+				{
 					appendStringInfoString(&buf, " NOT NULL");
+					if (attnotnullvalid[0] == 'f')
+						appendStringInfoString(&buf, " NOT VALID");
+				}
 			}
 			while (++i < numrows &&
 				   strcmp(PQgetvalue(res, i, 0), tablename) == 0);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..f33f1ea1b57 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 11d1bc7dbe1..185d7a1064d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has an invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  Nothing happens if the constraint is already marked valid.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b807ab66668..734e34110fa 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2616,12 +2624,17 @@ AddRelationNewConstraints(Relation rel,
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum, is_local,
+										 cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..81e975e1238 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,8 +574,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -721,19 +720,23 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -751,7 +754,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 			ereport(ERROR,
 					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
-						   NameStr(conform->conname), get_rel_name(relid)));
+						   NameStr(conform->conname), RelationGetRelationName(rel)));
+
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), RelationGetRelationName(rel)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
 
 		if (!is_local)
 		{
@@ -830,7 +844,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -850,7 +864,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 10624353b0a..72a8ac9a57d 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -419,6 +419,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -482,7 +485,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1324,7 +1327,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, false);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1408,7 +1411,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2722,7 +2725,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6191,18 +6194,22 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null constraints.
+		 * This is a bit of overkill but it minimizes risk of bugs.
 		 *
 		 * notnull_attrs does *not* collect attribute numbers for not-null
 		 * constraints over virtual generated columns; instead, they are
 		 * collected in notnull_virtual_attrs.
+		 *
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 			{
 				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
 					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
@@ -7770,7 +7777,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7791,19 +7798,23 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 }
 
 /*
- * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
- * to verify it.
+ * set_attnotnull
+ *		Helper to update/validate the pg_attribute status of a not-null
+ *		constraint
  *
- * When called to alter an existing table, 'wqueue' must be given so that we
- * can queue a check that existing tuples pass the constraint.  When called
- * from table creation, 'wqueue' should be passed as NULL.
+ * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
+ * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
+ * true, also set up wqueue to validate the constraint.  wqueue may be given
+ * as NULL when validation is not needed (e.g., on table creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
+	Assert(!queue_validation || wqueue);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7814,7 +7825,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7827,15 +7838,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7933,6 +7946,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7995,8 +8017,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9438,12 +9460,45 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
+	/* Verify that columns are not-null, or request that they be made so */
 	foreach(lc, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
 
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("NO INHERIT not-null constraint is incompatible with primary key"),
+						errhint("You will need to use ALTER TABLE ... ALTER CONSTRAINT ... INHERIT."));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("not-null constraint \"%s\" of table \"%s\" has not been validated",
+							   NameStr(conForm->conname),
+							   RelationGetRelationName(rel)),
+						errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
 		newcmd = makeNode(AlterTableCmd);
@@ -9818,11 +9873,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12486,10 +12545,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12508,6 +12568,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12724,6 +12789,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13592,10 +13760,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16946,19 +17115,25 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			if (parent_att->attgenerated && !child_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must be a generated column",
+								parent_attname)));
 			if (child_att->attgenerated && !parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must not be a generated column",
+								parent_attname)));
 
-			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+			if (parent_att->attgenerated && child_att->attgenerated &&
+				child_att->attgenerated != parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errmsg("column \"%s\" inherits from generated column of different kind",
+								parent_attname),
 						 errdetail("Parent column is %s, child column is %s.",
-								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL")));
 
 			/*
 			 * Regular inheritance children are independent enough not to
@@ -19447,7 +19622,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2da848970be..c8d44e3086b 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2074,6 +2074,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	{
 		for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++)
 		{
+			/* FIXME use CompactAttribute */
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
 
 			if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 0489ad36644..476494b1200 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1251,6 +1251,7 @@ get_relation_data_width(Oid relid, int32 *attr_widths)
  * get_relation_constraints
  *
  * Retrieve the applicable constraint expressions of the given relation.
+ * Only constraints that have been validated are considered.
  *
  * Returns a List (possibly empty) of constraint expressions.  Each one
  * has been canonicalized, and its Vars are changed to have the varno
@@ -1353,9 +1354,10 @@ get_relation_constraints(PlannerInfo *root,
 
 			for (i = 1; i <= natts; i++)
 			{
+				/* FIXME use CompactAttribute */
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0fc502a3a40..2945efc5c4d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4212,11 +4212,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 9c1541e1fea..40f70e0954e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,20 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+
+			/*
+			 * not-null constraint created via CREATE TABLE will always be
+			 * valid.  since there is no data there while CREATE TABLE, make
+			 * it invalid does not make sense
+			 */
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint on column \"%s\"", colname));
+		}
 	}
 
 	/*
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9f54a9e72b7..752a4037b02 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;
+			constr->has_not_null = true;	/* invalid included */
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -3573,6 +3573,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 4ca34be230c..7463b347989 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -347,8 +347,10 @@ static void buildMatViewRefreshDependencies(Archive *fout);
 static void getTableDataFKConstraints(void);
 static void determineNotNullFlags(Archive *fout, PGresult *res, int r,
 								  TableInfo *tbinfo, int j,
-								  int i_notnull_name, int i_notnull_noinherit,
-								  int i_notnull_islocal);
+								  int i_notnull_name, int i_notnull_invalidoid,
+								  int i_notnull_noinherit,
+								  int i_notnull_islocal,
+								  PQExpBuffer *invalidnotnulloids);
 static char *format_function_arguments(const FuncInfo *finfo, const char *funcargs,
 									   bool is_agg);
 static char *format_function_signature(Archive *fout,
@@ -8987,6 +8989,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = NULL;
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -9006,6 +9009,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_invalidoid;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9092,6 +9096,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
 	 * without a name); also, such cases are never NO INHERIT.
 	 *
+	 * For invalid constraints, we need to store their OIDs for processing
+	 * elsewhere, so we bring the pg_constraint.oid value when the constraint
+	 * is invalid, and NULL otherwise.
+	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
 	 * might modify this later for servers older than 18; it's also in charge
@@ -9100,11 +9108,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "CASE WHEN NOT co.convalidated THEN co.oid"
+							 " ELSE NULL END AS notnull_invalidoid,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "NULL AS notnull_invalidoid,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9179,6 +9190,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_invalidoid = PQfnumber(res, "notnull_invalidoid");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9275,8 +9287,11 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
 								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+								  i_notnull_name,
+								  i_notnull_invalidoid,
+								  i_notnull_noinherit,
+								  i_notnull_islocal,
+								  &invalidnotnulloids);
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9297,6 +9312,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		}
 	}
 
+	/* If invalidnotnulloids has any data, finalize it */
+	if (invalidnotnulloids != NULL)
+		appendPQExpBufferChar(invalidnotnulloids, '}');
+
 	PQclear(res);
 
 	/*
@@ -9429,6 +9448,108 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about NOT NULL NOT VALID constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.  Add any that
+	 * are found as constraint objects to tbinfo->checkexprs.  This is a bit
+	 * of a crock, because they aren't really CHECK constraints, but it's not
+	 * too bad.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+
+		pg_log_info("finding invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(conoid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.conoid = c.oid)\n"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * All invalid not-null constraints must be dumped separately,
+				 * because CREATE TABLE would not create them as invalid, and
+				 * also because they must be created after potentially
+				 * violating data has been loaded.
+				 */
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -9573,18 +9694,23 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  *
  * Result row 'r' is for tbinfo's attribute 'j'.
  *
- * There are three possibilities:
+ * There are four possibilities:
  * 1) the column has no not-null constraints. In that case, ->notnull_constrs
  *    (the constraint name) remains NULL.
  * 2) The column has a constraint with no name (this is the case when
  *    constraints come from pre-18 servers).  In this case, ->notnull_constrs
  *    is set to the empty string; dumpTableSchema will print just "NOT NULL".
- * 3) The column has a constraint with a known name; in that case
+ * 3) The column has an invalid not-null constraint.  This must be treated
+ *    as a separate object (because it must be created after the table data
+ *    is loaded).  So we add its OID to invalidnotnulloids for processing
+ *    elsewhere and do nothing further with it here.  We distinguish this
+ *    case because the "invalidoid" column has been set to a non-NULL value,
+ *    which is the constraint OID.  Valid constraints have a null OID.
+ * 4) The column has a constraint with a known name; in that case
  *    notnull_constrs carries that name and dumpTableSchema will print
  *    "CONSTRAINT the_name NOT NULL".  However, if the name is the default
  *    (table_column_not_null), there's no need to print that name in the dump,
- *    so notnull_constrs is set to the empty string and it behaves as the case
- *    above.
+ *    so notnull_constrs is set to the empty string and it behaves as case 2.
  *
  * In a child table that inherits from a parent already containing NOT NULL
  * constraints and the columns in the child don't have their own NOT NULL
@@ -9604,11 +9730,42 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 static void
 determineNotNullFlags(Archive *fout, PGresult *res, int r,
 					  TableInfo *tbinfo, int j,
-					  int i_notnull_name, int i_notnull_noinherit,
-					  int i_notnull_islocal)
+					  int i_notnull_name,
+					  int i_notnull_invalidoid,
+					  int i_notnull_noinherit,
+					  int i_notnull_islocal,
+					  PQExpBuffer *invalidnotnulloids)
 {
 	DumpOptions *dopt = fout->dopt;
 
+	/*
+	 * If this not-null constraint is not valid, list its OID in
+	 * invalidnotnulloids and do nothing further.  It'll be processed
+	 * elsewhere later.
+	 *
+	 * Because invalid not-null constraints are rare, we don't want to malloc
+	 * invalidnotnulloids until we're sure we're going it need it, which
+	 * happens here.
+	 */
+	if (!PQgetisnull(res, r, i_notnull_invalidoid))
+	{
+		char	   *constroid = PQgetvalue(res, r, i_notnull_invalidoid);
+
+		if (*invalidnotnulloids == NULL)
+		{
+			*invalidnotnulloids = createPQExpBuffer();
+			appendPQExpBufferChar(*invalidnotnulloids, '{');
+			appendPQExpBuffer(*invalidnotnulloids, "%s", constroid);
+		}
+		else
+			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
+
+		/* nothing else to do */
+		tbinfo->notnull_constrs[j] = NULL;
+
+		return;
+	}
+
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
 	 * though flagInhAttrs may change that one later in versions < 18.
@@ -18013,13 +18170,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18039,7 +18203,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e6f0f86a459..195b4495768 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,10 +365,11 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_validated;	/* true if NOT NULL is valid */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-	struct _constraintInfo *checkexprs; /* CHECK constraints */
+	struct _constraintInfo *checkexprs; /* CHECK, invalid not-null constraints */
 	struct _relStatsInfo *stats;	/* only set for matviews */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
 	char	   *amname;			/* relation access method */
@@ -498,6 +499,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index bf565afcc4e..8ba47572ed3 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3137,14 +3138,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..5523cfcf5aa 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* any not-null, including not valid ones */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..cf27d53e848 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -263,8 +263,8 @@ extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
 extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..b90b9eac643 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1202,6 +1202,75 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id" NOT VALID
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id"
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..b8398efcdeb 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,189 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  not-null constraint "nn" of table "notnull_tbl1" has not been validated
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_parent"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_child"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+DEALLOCATE get_nnconstraint_info;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -1392,3 +1575,17 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
+ relname | attname | attnum | attnotnull | attnotnullvalid 
+---------+---------+--------+------------+-----------------
+(0 rows)
+
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 84e93ef575e..1e6bb2c7818 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -910,6 +910,20 @@ alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
 
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
+
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..fec1213aa49 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,146 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+DEALLOCATE get_nnconstraint_info;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -836,3 +976,14 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
-- 
2.39.5

From c0109712638be88ba94a12fbc6d20ecfd956f121 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Tue, 1 Apr 2025 22:13:29 +0200
Subject: [PATCH v6] NOT NULL NOT VALID

Author: Rushabh Lathia <rushabh.lathia@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
---
 contrib/postgres_fdw/postgres_fdw.c       |  26 ++-
 doc/src/sgml/catalogs.sgml                |  11 +-
 doc/src/sgml/ref/alter_table.sgml         |   8 +-
 src/backend/access/common/tupdesc.c       |  11 +-
 src/backend/bootstrap/bootstrap.c         |   3 +
 src/backend/catalog/genbki.pl             |   3 +
 src/backend/catalog/heap.c                |  19 +-
 src/backend/catalog/pg_constraint.c       |  52 +++--
 src/backend/commands/tablecmds.c          | 242 +++++++++++++++++++---
 src/backend/executor/execMain.c           |   1 +
 src/backend/jit/llvm/llvmjit_deform.c     |  10 +-
 src/backend/optimizer/util/plancat.c      |   6 +-
 src/backend/parser/gram.y                 |   5 +-
 src/backend/parser/parse_utilcmd.c        |  14 ++
 src/backend/utils/cache/catcache.c        |   1 +
 src/backend/utils/cache/relcache.c        |   3 +-
 src/bin/pg_dump/pg_dump.c                 | 190 +++++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   5 +-
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   9 +-
 src/include/catalog/pg_attribute.h        |   5 +-
 src/include/catalog/pg_constraint.h       |   4 +-
 src/test/regress/expected/alter_table.out |  69 ++++++
 src/test/regress/expected/constraints.out | 197 ++++++++++++++++++
 src/test/regress/sql/alter_table.sql      |  14 ++
 src/test/regress/sql/constraints.sql      | 151 ++++++++++++++
 26 files changed, 970 insertions(+), 98 deletions(-)

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index ac14c06c715..e9296e2d4bd 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5549,7 +5549,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 							   "SELECT relname, "
 							   "  attname, "
 							   "  format_type(atttypid, atttypmod), "
-							   "  attnotnull, "
+							   "  attnotnull, ");
+
+		/* NOT VALID NOT NULL columns are supported since Postgres 18 */
+		if (PQserverVersion(conn) >= 180000)
+			appendStringInfoString(&buf, "attnotnullvalid, ");
+		else
+			appendStringInfoString(&buf, "attnotnull AS attnotnullvalid, ");
+
+		appendStringInfoString(&buf,
 							   "  pg_get_expr(adbin, adrelid), ");
 
 		/* Generated columns are supported since Postgres 12 */
@@ -5651,6 +5659,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				char	   *attname;
 				char	   *typename;
 				char	   *attnotnull;
+				char	   *attnotnullvalid;
 				char	   *attgenerated;
 				char	   *attdefault;
 				char	   *collname;
@@ -5663,14 +5672,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				attname = PQgetvalue(res, i, 1);
 				typename = PQgetvalue(res, i, 2);
 				attnotnull = PQgetvalue(res, i, 3);
-				attdefault = PQgetisnull(res, i, 4) ? NULL :
-					PQgetvalue(res, i, 4);
-				attgenerated = PQgetisnull(res, i, 5) ? NULL :
+				attnotnullvalid = PQgetvalue(res, i, 4);
+				attdefault = PQgetisnull(res, i, 5) ? NULL :
 					PQgetvalue(res, i, 5);
-				collname = PQgetisnull(res, i, 6) ? NULL :
+				attgenerated = PQgetisnull(res, i, 6) ? NULL :
 					PQgetvalue(res, i, 6);
-				collnamespace = PQgetisnull(res, i, 7) ? NULL :
+				collname = PQgetisnull(res, i, 7) ? NULL :
 					PQgetvalue(res, i, 7);
+				collnamespace = PQgetisnull(res, i, 8) ? NULL :
+					PQgetvalue(res, i, 8);
 
 				if (first_item)
 					first_item = false;
@@ -5714,7 +5724,11 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 
 				/* Add NOT NULL if needed */
 				if (import_not_null && attnotnull[0] == 't')
+				{
 					appendStringInfoString(&buf, " NOT NULL");
+					if (attnotnullvalid[0] == 'f')
+						appendStringInfoString(&buf, " NOT VALID");
+				}
 			}
 			while (++i < numrows &&
 				   strcmp(PQgetvalue(res, i, 0), tablename) == 0);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index fb050635551..f33f1ea1b57 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 11d1bc7dbe1..185d7a1064d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has an invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  Nothing happens if the constraint is already marked valid.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b807ab66668..734e34110fa 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2616,12 +2624,17 @@ AddRelationNewConstraints(Relation rel,
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum, is_local,
+										 cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index ac80652baf2..81e975e1238 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -574,8 +574,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -604,13 +604,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -628,9 +626,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -721,19 +720,23 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -751,7 +754,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 			ereport(ERROR,
 					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
-						   NameStr(conform->conname), get_rel_name(relid)));
+						   NameStr(conform->conname), RelationGetRelationName(rel)));
+
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), RelationGetRelationName(rel)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
 
 		if (!is_local)
 		{
@@ -830,7 +844,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -850,7 +864,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 10624353b0a..72a8ac9a57d 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -419,6 +419,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -482,7 +485,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1324,7 +1327,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, false);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1408,7 +1411,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2722,7 +2725,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6191,18 +6194,22 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null constraints.
+		 * This is a bit of overkill but it minimizes risk of bugs.
 		 *
 		 * notnull_attrs does *not* collect attribute numbers for not-null
 		 * constraints over virtual generated columns; instead, they are
 		 * collected in notnull_virtual_attrs.
+		 *
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 			{
 				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
 					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
@@ -7770,7 +7777,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7791,19 +7798,23 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 }
 
 /*
- * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
- * to verify it.
+ * set_attnotnull
+ *		Helper to update/validate the pg_attribute status of a not-null
+ *		constraint
  *
- * When called to alter an existing table, 'wqueue' must be given so that we
- * can queue a check that existing tuples pass the constraint.  When called
- * from table creation, 'wqueue' should be passed as NULL.
+ * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
+ * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
+ * true, also set up wqueue to validate the constraint.  wqueue may be given
+ * as NULL when validation is not needed (e.g., on table creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
+	Assert(!queue_validation || wqueue);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7814,7 +7825,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7827,15 +7838,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7933,6 +7946,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -7995,8 +8017,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9438,12 +9460,45 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
+	/* Verify that columns are not-null, or request that they be made so */
 	foreach(lc, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
 
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("NO INHERIT not-null constraint is incompatible with primary key"),
+						errhint("You will need to use ALTER TABLE ... ALTER CONSTRAINT ... INHERIT."));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("not-null constraint \"%s\" of table \"%s\" has not been validated",
+							   NameStr(conForm->conname),
+							   RelationGetRelationName(rel)),
+						errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
 		newcmd = makeNode(AlterTableCmd);
@@ -9818,11 +9873,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12486,10 +12545,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12508,6 +12568,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -12724,6 +12789,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13592,10 +13760,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -16946,19 +17115,25 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			if (parent_att->attgenerated && !child_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must be a generated column",
+								parent_attname)));
 			if (child_att->attgenerated && !parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must not be a generated column",
+								parent_attname)));
 
-			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+			if (parent_att->attgenerated && child_att->attgenerated &&
+				child_att->attgenerated != parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errmsg("column \"%s\" inherits from generated column of different kind",
+								parent_attname),
 						 errdetail("Parent column is %s, child column is %s.",
-								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL")));
 
 			/*
 			 * Regular inheritance children are independent enough not to
@@ -19447,7 +19622,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2da848970be..c8d44e3086b 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2074,6 +2074,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	{
 		for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++)
 		{
+			/* FIXME use CompactAttribute */
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
 
 			if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 0489ad36644..476494b1200 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1251,6 +1251,7 @@ get_relation_data_width(Oid relid, int32 *attr_widths)
  * get_relation_constraints
  *
  * Retrieve the applicable constraint expressions of the given relation.
+ * Only constraints that have been validated are considered.
  *
  * Returns a List (possibly empty) of constraint expressions.  Each one
  * has been canonicalized, and its Vars are changed to have the varno
@@ -1353,9 +1354,10 @@ get_relation_constraints(PlannerInfo *root,
 
 			for (i = 1; i <= natts; i++)
 			{
+				/* FIXME use CompactAttribute */
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0fc502a3a40..2945efc5c4d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4212,11 +4212,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 9c1541e1fea..40f70e0954e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,20 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+
+			/*
+			 * not-null constraint created via CREATE TABLE will always be
+			 * valid.  since there is no data there while CREATE TABLE, make
+			 * it invalid does not make sense
+			 */
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint on column \"%s\"", colname));
+		}
 	}
 
 	/*
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 9f54a9e72b7..752a4037b02 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;
+			constr->has_not_null = true;	/* invalid included */
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -3573,6 +3573,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 4ca34be230c..7463b347989 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -347,8 +347,10 @@ static void buildMatViewRefreshDependencies(Archive *fout);
 static void getTableDataFKConstraints(void);
 static void determineNotNullFlags(Archive *fout, PGresult *res, int r,
 								  TableInfo *tbinfo, int j,
-								  int i_notnull_name, int i_notnull_noinherit,
-								  int i_notnull_islocal);
+								  int i_notnull_name, int i_notnull_invalidoid,
+								  int i_notnull_noinherit,
+								  int i_notnull_islocal,
+								  PQExpBuffer *invalidnotnulloids);
 static char *format_function_arguments(const FuncInfo *finfo, const char *funcargs,
 									   bool is_agg);
 static char *format_function_signature(Archive *fout,
@@ -8987,6 +8989,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = NULL;
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -9006,6 +9009,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_invalidoid;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9092,6 +9096,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
 	 * without a name); also, such cases are never NO INHERIT.
 	 *
+	 * For invalid constraints, we need to store their OIDs for processing
+	 * elsewhere, so we bring the pg_constraint.oid value when the constraint
+	 * is invalid, and NULL otherwise.
+	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
 	 * might modify this later for servers older than 18; it's also in charge
@@ -9100,11 +9108,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "CASE WHEN NOT co.convalidated THEN co.oid"
+							 " ELSE NULL END AS notnull_invalidoid,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "NULL AS notnull_invalidoid,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9179,6 +9190,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_invalidoid = PQfnumber(res, "notnull_invalidoid");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9275,8 +9287,11 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
 								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+								  i_notnull_name,
+								  i_notnull_invalidoid,
+								  i_notnull_noinherit,
+								  i_notnull_islocal,
+								  &invalidnotnulloids);
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9297,6 +9312,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		}
 	}
 
+	/* If invalidnotnulloids has any data, finalize it */
+	if (invalidnotnulloids != NULL)
+		appendPQExpBufferChar(invalidnotnulloids, '}');
+
 	PQclear(res);
 
 	/*
@@ -9429,6 +9448,108 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about NOT NULL NOT VALID constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.  Add any that
+	 * are found as constraint objects to tbinfo->checkexprs.  This is a bit
+	 * of a crock, because they aren't really CHECK constraints, but it's not
+	 * too bad.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+
+		pg_log_info("finding invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(conoid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.conoid = c.oid)\n"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			tbinfo->checkexprs = constrs + j;
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * All invalid not-null constraints must be dumped separately,
+				 * because CREATE TABLE would not create them as invalid, and
+				 * also because they must be created after potentially
+				 * violating data has been loaded.
+				 */
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -9573,18 +9694,23 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  *
  * Result row 'r' is for tbinfo's attribute 'j'.
  *
- * There are three possibilities:
+ * There are four possibilities:
  * 1) the column has no not-null constraints. In that case, ->notnull_constrs
  *    (the constraint name) remains NULL.
  * 2) The column has a constraint with no name (this is the case when
  *    constraints come from pre-18 servers).  In this case, ->notnull_constrs
  *    is set to the empty string; dumpTableSchema will print just "NOT NULL".
- * 3) The column has a constraint with a known name; in that case
+ * 3) The column has an invalid not-null constraint.  This must be treated
+ *    as a separate object (because it must be created after the table data
+ *    is loaded).  So we add its OID to invalidnotnulloids for processing
+ *    elsewhere and do nothing further with it here.  We distinguish this
+ *    case because the "invalidoid" column has been set to a non-NULL value,
+ *    which is the constraint OID.  Valid constraints have a null OID.
+ * 4) The column has a constraint with a known name; in that case
  *    notnull_constrs carries that name and dumpTableSchema will print
  *    "CONSTRAINT the_name NOT NULL".  However, if the name is the default
  *    (table_column_not_null), there's no need to print that name in the dump,
- *    so notnull_constrs is set to the empty string and it behaves as the case
- *    above.
+ *    so notnull_constrs is set to the empty string and it behaves as case 2.
  *
  * In a child table that inherits from a parent already containing NOT NULL
  * constraints and the columns in the child don't have their own NOT NULL
@@ -9604,11 +9730,42 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 static void
 determineNotNullFlags(Archive *fout, PGresult *res, int r,
 					  TableInfo *tbinfo, int j,
-					  int i_notnull_name, int i_notnull_noinherit,
-					  int i_notnull_islocal)
+					  int i_notnull_name,
+					  int i_notnull_invalidoid,
+					  int i_notnull_noinherit,
+					  int i_notnull_islocal,
+					  PQExpBuffer *invalidnotnulloids)
 {
 	DumpOptions *dopt = fout->dopt;
 
+	/*
+	 * If this not-null constraint is not valid, list its OID in
+	 * invalidnotnulloids and do nothing further.  It'll be processed
+	 * elsewhere later.
+	 *
+	 * Because invalid not-null constraints are rare, we don't want to malloc
+	 * invalidnotnulloids until we're sure we're going it need it, which
+	 * happens here.
+	 */
+	if (!PQgetisnull(res, r, i_notnull_invalidoid))
+	{
+		char	   *constroid = PQgetvalue(res, r, i_notnull_invalidoid);
+
+		if (*invalidnotnulloids == NULL)
+		{
+			*invalidnotnulloids = createPQExpBuffer();
+			appendPQExpBufferChar(*invalidnotnulloids, '{');
+			appendPQExpBuffer(*invalidnotnulloids, "%s", constroid);
+		}
+		else
+			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
+
+		/* nothing else to do */
+		tbinfo->notnull_constrs[j] = NULL;
+
+		return;
+	}
+
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
 	 * though flagInhAttrs may change that one later in versions < 18.
@@ -18013,13 +18170,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18039,7 +18203,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e6f0f86a459..195b4495768 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,10 +365,11 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_validated;	/* true if NOT NULL is valid */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-	struct _constraintInfo *checkexprs; /* CHECK constraints */
+	struct _constraintInfo *checkexprs; /* CHECK, invalid not-null constraints */
 	struct _relStatsInfo *stats;	/* only set for matviews */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
 	char	   *amname;			/* relation access method */
@@ -498,6 +499,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index bf565afcc4e..8ba47572ed3 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3114,7 +3114,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3137,14 +3138,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..5523cfcf5aa 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* any not-null, including not valid ones */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..cf27d53e848 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -263,8 +263,8 @@ extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
 extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..b90b9eac643 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1202,6 +1202,75 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id" NOT VALID
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id"
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 4f39100fcdf..b8398efcdeb 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -896,6 +896,189 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  not-null constraint "nn" of table "notnull_tbl1" has not been validated
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_parent"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_child"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+DEALLOCATE get_nnconstraint_info;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -1392,3 +1575,17 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
+ relname | attname | attnum | attnotnull | attnotnullvalid 
+---------+---------+--------+------------+-----------------
+(0 rows)
+
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 84e93ef575e..1e6bb2c7818 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -910,6 +910,20 @@ alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
 
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
+
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..fec1213aa49 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,146 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+DEALLOCATE get_nnconstraint_info;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -836,3 +976,14 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
-- 
2.39.5

diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
old mode 100644
new mode 100755
index 576326daec7..587698024af
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1118,6 +1118,23 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / INVALID' => {
+		create_sql => 'CREATE TABLE dump_test.test_table_nn (
+							col1 int);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
+			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+			/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_post_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
@@ -3803,13 +3820,16 @@ my %tests = (
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
 						   col2 int generated always as (col1 * 2) stored,
-						   col3 int generated always as (col1 * 3) virtual
-					   );',
+						   col3 int generated always as (col1 * 3) virtual,
+						   col4 int
+					   );
+					   ALTER TABLE dump_test.test_table_generated ADD CONSTRAINT dump_test_nn NOT NULL col4 NOT VALID;',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
 			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
-			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3)),\E\n
+			\s+\Qcol4 integer\E\n
 			\);
 			/xms,
 		like =>
@@ -3820,6 +3840,19 @@ my %tests = (
 		},
 	},
 
+	'ALTER TABLE dump_test.test_table_generated' => {
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_generated\E \n^\s+
+			\QADD CONSTRAINT dump_test_nn NOT NULL col4 NOT VALID;\E
+			/xm,
+		like =>
+			{ %full_runs, %dump_test_schema_runs, section_post_data => 1, },
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CREATE TABLE test_table_generated_child1 (without local columns)' => {
 		create_order => 4,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated_child1 ()
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index b8398efcdeb..94d26621b91 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1073,11 +1073,43 @@ ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_
 ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
 ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
 DROP TABLE pp_nn;
-DEALLOCATE get_nnconstraint_info;
 -- Create table with NOT NULL INVALID constraint, for pg_upgrade.
 CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
 INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
 ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a INTEGER);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass);
+      conrelid      | contype | convalidated | conislocal 
+--------------------+---------+--------------+------------
+ notnull_parent_upg | n       | f            | t
+ notnull_child_upg  | n       | t            | t
+(2 rows)
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+      conrelid       |   conname   | convalidated | coninhcount 
+---------------------+-------------+--------------+-------------
+ notnull_part1_upg   | notnull_con | f            |           0
+ notnull_part1_1_upg | notnull_con | t            |           1
+ notnull_part1_2_upg | nn2         | t            |           1
+ notnull_part1_3_upg | nn3         | f            |           1
+(4 rows)
+
+DEALLOCATE get_nnconstraint_info;
 -- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index fec1213aa49..cc1bfd2ef89 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -771,12 +771,29 @@ ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
 ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
 DROP TABLE pp_nn;
 
-DEALLOCATE get_nnconstraint_info;
-
 -- Create table with NOT NULL INVALID constraint, for pg_upgrade.
 CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
 INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
 ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a INTEGER);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass);
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+DEALLOCATE get_nnconstraint_info;
 -- end of NOT NULL VALID/NOT VALID --------------------------------
 
 

From 5d6da8791aa46d63e872c5a9f463b05bb2d0f9e8 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Wed, 2 Apr 2025 21:47:22 +0800
Subject: [PATCH v6 1/1] ensure pg_dump table constraint info remain the same

resolve case where parent constraint convalidated is false
and children constraint convalidated is true
all the dumped information is correct.

for example:

CREATE TABLE ttchk (a INTEGER);
ALTER TABLE ttchk ADD CONSTRAINT cc check (a is NOT NULL) NOT VALID;
CREATE TABLE ttchk_child(a INTEGER) INHERITS(ttchk);

we need dump as:

CREATE TABLE ttchk (a INTEGER);
CREATE TABLE public.ttchk_child (a integer, CONSTRAINT cc CHECK ((a IS NOT NULL))) INHERITS (public.ttchk);
ALTER TABLE public.ttchk ADD CONSTRAINT cc CHECK ((a IS NOT NULL)) NOT VALID;
---
 src/backend/catalog/heap.c            | 21 +++++++--
 src/backend/catalog/pg_constraint.c   |  9 ++++
 src/bin/pg_dump/pg_dump.c             | 66 ++++++++++++++++++++++++++-
 src/bin/pg_dump/pg_dump.h             |  1 +
 src/test/regress/expected/inherit.out |  2 +-
 5 files changed, 92 insertions(+), 7 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 734e34110fa..0bdcd59fa39 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2839,11 +2839,24 @@ MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
 		{
 			if (is_local)
 				con->conislocal = true;
-			else if (pg_add_s16_overflow(con->coninhcount, 1,
+			else
+			{
+				if(pg_add_s16_overflow(con->coninhcount, 1,
 										 &con->coninhcount))
-				ereport(ERROR,
-						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-						errmsg("too many inheritance parents"));
+					ereport(ERROR,
+							errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+							errmsg("too many inheritance parents"));
+
+				/*
+				 * If the children already has a valid constraint and we are
+				 * creating an invalid one on it.  The children's constraint
+				 * will remain valid as is, but it can longer be marked as
+				 * local.
+				*/
+				if (!is_initially_valid && con->convalidated &&
+					is_enforced && con->conenforced)
+					con->conislocal = false;
+			}
 		}
 
 		if (is_no_inherit)
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index c7ccc5bef32..48ac5a22e66 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -775,6 +775,15 @@ AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
 				ereport(ERROR,
 						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 						errmsg("too many inheritance parents"));
+
+			/*
+			 * If the children already has a valid constraint and we are
+			 * creating an invalid one on it.  The children's constraint will
+			 * remain valid as is, but it can longer be marked as local.
+			*/
+			if (is_notvalid && conform->convalidated && conform->conenforced)
+				conform->conislocal = false;
+
 			changed = true;
 		}
 		else if (!conform->conislocal)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 96e45f888d4..282e774f3cb 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -401,6 +401,7 @@ static void setupDumpWorker(Archive *AH);
 static TableInfo *getRootTableInfo(const TableInfo *tbinfo);
 static bool forcePartitionRootLoad(const TableInfo *tbinfo);
 static void read_dump_filters(const char *filename, DumpOptions *dopt);
+static bool constr_dump_force_not_seperate(Archive *fout, Oid conrelid, char conkind);
 
 
 int
@@ -7950,6 +7951,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				constrinfo->conperiod = *(PQgetvalue(res, j, i_conperiod)) == 't';
 				constrinfo->conislocal = true;
 				constrinfo->separate = true;
+				constrinfo->force_notseperate = false;
 
 				indxinfo[j].indexconstraint = constrinfo->dobj.dumpId;
 				if (relstats != NULL)
@@ -8167,6 +8169,7 @@ getConstraints(Archive *fout, TableInfo tblinfo[], int numTables)
 		constrinfo[j].condeferred = false;
 		constrinfo[j].conislocal = true;
 		constrinfo[j].separate = true;
+		constrinfo[j].force_notseperate = false;
 
 		/*
 		 * Restoring an FK that points to a partitioned table requires that
@@ -8306,6 +8309,7 @@ getDomainConstraints(Archive *fout, TypeInfo *tyinfo)
 		constrinfo[i].conislocal = true;
 
 		constrinfo[i].separate = !validated;
+		constrinfo[i].force_notseperate = false;
 
 		/*
 		 * Make the domain depend on the constraint, ensuring it won't be
@@ -9559,6 +9563,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		int			i_consrc;
 		int			i_conislocal;
 		int			i_convalidated;
+		int			i_coninhcount;
 
 		pg_log_info("finding table check constraints");
 
@@ -9566,7 +9571,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		appendPQExpBuffer(q,
 						  "SELECT c.tableoid, c.oid, conrelid, conname, "
 						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
-						  "conislocal, convalidated "
+						  "conislocal, convalidated, coninhcount "
 						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
 						  "JOIN pg_catalog.pg_constraint c ON (src.tbloid = c.conrelid)\n"
 						  "WHERE contype = 'c' "
@@ -9585,6 +9590,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		i_consrc = PQfnumber(res, "consrc");
 		i_conislocal = PQfnumber(res, "conislocal");
 		i_convalidated = PQfnumber(res, "convalidated");
+		i_coninhcount = PQfnumber(res, "coninhcount");
 
 		/* As above, this loop iterates once per table, not once per row */
 		curtblindx = -1;
@@ -9653,6 +9659,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 
 				constrs[j].dobj.dump = tbinfo->dobj.dump;
 
+				constrs[j].force_notseperate = false;
+				if(validated && (atoi(PQgetvalue(res, j, i_coninhcount)) > 0))
+					constrs[j].force_notseperate = constr_dump_force_not_seperate(fout, conrelid, 'c');
+
 				/*
 				 * Mark the constraint as needing to appear before the table
 				 * --- this is so that any other dependencies of the
@@ -9681,6 +9691,54 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	destroyPQExpBuffer(checkoids);
 }
 
+/*
+ * (XXX need refinement)
+ * comments for cases: parent constraint is not valid, child is valid:
+ * child's constraint conislocal is false, pg_dump won't dump it, later creating
+ * parent constraint will also create children's.  pg_dump will dump invalidated
+ * constraint seperately.
+ * So: for cases: parent constraint is not valid, child is valid, pu_dump's
+ * output will make parent and childconstraint is not valid.
+ *
+ * To resolve this issue:
+ * The child's (conislocal is false) constraint should be dumped within CREATE
+ * TABLE statement.  This ensures ALTER TABLE ADD CONSTRAINT on the parent
+ * cascades to the child, no issues occur.
+ *
+ * the caller should make sure 'conrelid' have inherited constraint!
+ *
+*/
+static bool
+constr_dump_force_not_seperate(Archive *fout, Oid conrelid, char conkind)
+{
+	int64		cnt = 0;
+	PQExpBuffer qs = createPQExpBuffer();
+	PGresult   *res;
+
+	appendPQExpBuffer(qs,
+						"SELECT count(*) as cnt\n"
+						"FROM pg_constraint pc\n"
+						"JOIN pg_inherits pi ON pi.inhrelid = pc.conrelid\n"
+						"JOIN pg_constraint pc1 ON pc1.conrelid = pi.inhparent\n"
+						"WHERE pc.contype = '%c' "
+						"AND pc.convalidated AND NOT pc1.convalidated "
+						"AND pc.conrelid = %u ",
+						conkind, conrelid);
+
+	res = ExecuteSqlQuery(fout, qs->data, PGRES_TUPLES_OK);
+
+	Assert(PQntuples(res) == 1);
+
+	cnt = strtoi64(PQgetvalue(res, 0, PQfnumber(res, "cnt")), NULL, 10);
+
+	destroyPQExpBuffer(qs);
+
+	if (cnt > 0)
+		return true;
+	else
+		return false;
+}
+
 /*
  * Based on the getTableAttrs query's row corresponding to one column, set
  * the name and flags to handle a not-null constraint for that column in
@@ -16843,6 +16901,10 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
 
+					if (!print_notnull && tbinfo->numParents > 0 &&
+						tbinfo->notnull_constrs[j] != NULL)
+						print_notnull = constr_dump_force_not_seperate(fout, tbinfo->dobj.catId.oid, 'n');
+
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -16913,7 +16975,7 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 				ConstraintInfo *constr = &(tbinfo->checkexprs[j]);
 
 				if (constr->separate ||
-					(!constr->conislocal && !tbinfo->ispartition))
+					(!constr->conislocal && !tbinfo->ispartition && !constr->force_notseperate))
 					continue;
 
 				if (actual_atts == 0)
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 195b4495768..1720c621abe 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -518,6 +518,7 @@ typedef struct _constraintInfo
 	bool		conperiod;		/* true if the constraint is WITHOUT OVERLAPS */
 	bool		conislocal;		/* true if constraint has local definition */
 	bool		separate;		/* true if must dump as separate item */
+	bool		force_notseperate;	/* true if must not dump as separate item */
 } ConstraintInfo;
 
 typedef struct _procLangInfo
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index c01e9d5244f..2cb2c482ea5 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -1558,7 +1558,7 @@ order by 1, 2;
          relname         |       conname        | convalidated | conislocal | coninhcount | connoinherit 
 -------------------------+----------------------+--------------+------------+-------------+--------------
  invalid_check_con       | inh_check_constraint | f            | t          |           0 | f
- invalid_check_con_child | inh_check_constraint | t            | t          |           1 | f
+ invalid_check_con_child | inh_check_constraint | t            | f          |           1 | f
 (2 rows)
 
 -- We don't drop the invalid_check_con* tables, to test dump/reload with
-- 
2.34.1

From ba485a1c864642c3586f349df01fa24ee2cd7032 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 3 Apr 2025 15:33:17 +0800
Subject: [PATCH v6 1/1] ensure pg_dump table constraint info remain the same

resolve case where parent constraint convalidated is false
and children constraint convalidated is true
all the dumped information is correct.
---
 src/backend/catalog/heap.c            | 21 +++++++++++++++++----
 src/backend/catalog/pg_constraint.c   | 10 ++++++++++
 src/bin/pg_dump/common.c              |  4 ++++
 src/bin/pg_dump/pg_dump.c             | 18 +++++++++++++++++-
 src/bin/pg_dump/pg_dump.h             |  5 ++++-
 src/test/regress/expected/inherit.out |  2 +-
 6 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 734e34110fa..25067bd9d43 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2839,11 +2839,24 @@ MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
 		{
 			if (is_local)
 				con->conislocal = true;
-			else if (pg_add_s16_overflow(con->coninhcount, 1,
+			else
+			{
+				if(pg_add_s16_overflow(con->coninhcount, 1,
 										 &con->coninhcount))
-				ereport(ERROR,
-						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-						errmsg("too many inheritance parents"));
+					ereport(ERROR,
+							errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+							errmsg("too many inheritance parents"));
+
+				/*
+				 * If the child already has a valid constraint and we are
+				 * creating an invalid one with same definition on it.  The
+				 * child's constraint will remain valid, but can no longer be
+				 * marked as local.
+				*/
+				if (!is_initially_valid && con->convalidated &&
+					is_enforced && con->conenforced)
+					con->conislocal = false;
+			}
 		}
 
 		if (is_no_inherit)
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index c7ccc5bef32..8b8bd78f20a 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -775,6 +775,16 @@ AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
 				ereport(ERROR,
 						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 						errmsg("too many inheritance parents"));
+
+			/*
+			 * If the child already has a valid constraint and we are
+			 * creating an invalid one with same definition on it.  The
+			 * child's constraint will remain valid, but can no longer be
+			 * marked as local.
+			*/
+			if (is_notvalid && conform->convalidated && conform->conenforced)
+				conform->conislocal = false;
+
 			changed = true;
 		}
 		else if (!conform->conislocal)
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 56b6c368acf..ff6a4eacda0 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -546,6 +546,10 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 						parent->notnull_constrs[inhAttrInd] != NULL)
 						foundNotNull = true;
 
+					if (fout->remoteVersion >= 180000 &&
+						parent->notnull_invalid[inhAttrInd])
+						tbinfo->notnull_parent_invalid[j] = true;
+
 					foundDefault |= (parentDef != NULL &&
 									 strcmp(parentDef->adef_expr, "NULL") != 0 &&
 									 !parent->attgenerated[inhAttrInd]);
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 96e45f888d4..9ca435aa936 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -9252,6 +9252,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->notnull_parent_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9277,6 +9279,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_parent_invalid[j] = false;	/* only change in flagInhAttrs */
+			tbinfo->notnull_invalid[j] = false;			/* only change in determineNotNullFlags */
 
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
@@ -9756,7 +9760,7 @@ determineNotNullFlags(Archive *fout, PGresult *res, int r,
 
 		/* nothing else to do */
 		tbinfo->notnull_constrs[j] = NULL;
-
+		tbinfo->notnull_invalid[j] = true;
 		return;
 	}
 
@@ -16843,6 +16847,18 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 									  dopt->binary_upgrade ||
 									  tbinfo->ispartition));
 
+					/*
+					 * if parent have invalid not-null, child have valid
+					 * not-null, then we print not null on child too.  later
+					 * parent's invalid not-null will generate a ALTER TABLE ADD
+					 * CONSTRAINT, which will cascade to children, which is
+					 * fine.
+					*/
+					if (!print_notnull &&
+						tbinfo->notnull_constrs[j] != NULL &&
+						tbinfo->notnull_parent_invalid[j])
+						print_notnull = true;
+
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 195b4495768..dd603c9dd53 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,7 +365,10 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
-	bool	   *notnull_validated;	/* true if NOT NULL is valid */
+	bool	   *notnull_invalid;	/* true mean NOT NULL INVALID,
+									   false mean valid not null or no not null */
+	bool	   *notnull_parent_invalid;	/*  true mean NOT NULL INVALID,
+											false mean valid not null or no not null */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index c01e9d5244f..2cb2c482ea5 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -1558,7 +1558,7 @@ order by 1, 2;
          relname         |       conname        | convalidated | conislocal | coninhcount | connoinherit 
 -------------------------+----------------------+--------------+------------+-------------+--------------
  invalid_check_con       | inh_check_constraint | f            | t          |           0 | f
- invalid_check_con_child | inh_check_constraint | t            | t          |           1 | f
+ invalid_check_con_child | inh_check_constraint | t            | f          |           1 | f
 (2 rows)
 
 -- We don't drop the invalid_check_con* tables, to test dump/reload with
-- 
2.34.1

From 06b312ad3d7fbb0d28754a7d066b0f6ec1694493 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Fri, 4 Apr 2025 17:10:44 +0530
Subject: [PATCH 1/2] Fix MergeWithExistingConstraint()

If the child already has a valid constraint and we are creating an invalid
one with same definition on it.  The child's constraint will remain valid,
but can no longer be marked as local.
---
 src/backend/catalog/heap.c            | 21 +++++++++++++++++----
 src/test/regress/expected/inherit.out |  2 +-
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b807ab66668..8a75e2dafab 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2826,11 +2826,24 @@ MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
 		{
 			if (is_local)
 				con->conislocal = true;
-			else if (pg_add_s16_overflow(con->coninhcount, 1,
+			else
+			{
+				if(pg_add_s16_overflow(con->coninhcount, 1,
 										 &con->coninhcount))
-				ereport(ERROR,
-						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-						errmsg("too many inheritance parents"));
+					ereport(ERROR,
+							errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+							errmsg("too many inheritance parents"));
+
+				/*
+				 * If the child already has a valid constraint and we are
+				 * creating an invalid one with same definition on it.  The
+				 * child's constraint will remain valid, but can no longer be
+				 * marked as local.
+				*/
+				if (!is_initially_valid && con->convalidated &&
+					is_enforced && con->conenforced)
+					con->conislocal = false;
+			}
 		}
 
 		if (is_no_inherit)
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index 2a8bfba768e..e063f48d343 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -1571,7 +1571,7 @@ order by 1, 2;
          relname         |       conname        | convalidated | conislocal | coninhcount | connoinherit 
 -------------------------+----------------------+--------------+------------+-------------+--------------
  invalid_check_con       | inh_check_constraint | f            | t          |           0 | f
- invalid_check_con_child | inh_check_constraint | t            | t          |           1 | f
+ invalid_check_con_child | inh_check_constraint | t            | f          |           1 | f
 (2 rows)
 
 -- We don't drop the invalid_check_con* tables, to test dump/reload with
-- 
2.43.0

From 29c4cb49d04354524667ac14d5c5afd840029ed1 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Fri, 4 Apr 2025 17:17:35 +0530
Subject: [PATCH 2/2] Support NOT VALID and VALIDATE CONSTRAINT for named NOT 
 NULL constraints.

Commit also add support for pg_dump to dump NOT VALID named NOT NULL
constraints, testcases as well as documentation changes.
---
 contrib/postgres_fdw/postgres_fdw.c       |  26 ++-
 doc/src/sgml/catalogs.sgml                |  11 +-
 doc/src/sgml/ref/alter_table.sgml         |   8 +-
 src/backend/access/common/tupdesc.c       |  11 +-
 src/backend/bootstrap/bootstrap.c         |   3 +
 src/backend/catalog/genbki.pl             |   3 +
 src/backend/catalog/heap.c                |  19 +-
 src/backend/catalog/pg_constraint.c       |  62 ++++--
 src/backend/commands/tablecmds.c          | 242 +++++++++++++++++++---
 src/backend/executor/execMain.c           |   1 +
 src/backend/jit/llvm/llvmjit_deform.c     |  10 +-
 src/backend/optimizer/util/plancat.c      |   6 +-
 src/backend/parser/gram.y                 |   5 +-
 src/backend/parser/parse_utilcmd.c        |  14 ++
 src/backend/utils/cache/catcache.c        |   1 +
 src/backend/utils/cache/relcache.c        |   3 +-
 src/bin/pg_dump/common.c                  |   4 +
 src/bin/pg_dump/pg_dump.c                 | 201 ++++++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   8 +-
 src/bin/pg_dump/t/002_pg_dump.pl          |  39 +++-
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   9 +-
 src/include/catalog/pg_attribute.h        |   5 +-
 src/include/catalog/pg_constraint.h       |   4 +-
 src/test/regress/expected/alter_table.out |  69 ++++++
 src/test/regress/expected/constraints.out | 229 ++++++++++++++++++++
 src/test/regress/sql/alter_table.sql      |  14 ++
 src/test/regress/sql/constraints.sql      | 168 +++++++++++++++
 28 files changed, 1083 insertions(+), 101 deletions(-)
 mode change 100644 => 100755 src/bin/pg_dump/t/002_pg_dump.pl

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index b4e0e60928b..60d25c2f0a4 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5549,7 +5549,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 							   "SELECT relname, "
 							   "  attname, "
 							   "  format_type(atttypid, atttypmod), "
-							   "  attnotnull, "
+							   "  attnotnull, ");
+
+		/* NOT VALID NOT NULL columns are supported since Postgres 18 */
+		if (PQserverVersion(conn) >= 180000)
+			appendStringInfoString(&buf, "attnotnullvalid, ");
+		else
+			appendStringInfoString(&buf, "attnotnull AS attnotnullvalid, ");
+
+		appendStringInfoString(&buf,
 							   "  pg_get_expr(adbin, adrelid), ");
 
 		/* Generated columns are supported since Postgres 12 */
@@ -5651,6 +5659,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				char	   *attname;
 				char	   *typename;
 				char	   *attnotnull;
+				char	   *attnotnullvalid;
 				char	   *attgenerated;
 				char	   *attdefault;
 				char	   *collname;
@@ -5663,14 +5672,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				attname = PQgetvalue(res, i, 1);
 				typename = PQgetvalue(res, i, 2);
 				attnotnull = PQgetvalue(res, i, 3);
-				attdefault = PQgetisnull(res, i, 4) ? NULL :
-					PQgetvalue(res, i, 4);
-				attgenerated = PQgetisnull(res, i, 5) ? NULL :
+				attnotnullvalid = PQgetvalue(res, i, 4);
+				attdefault = PQgetisnull(res, i, 5) ? NULL :
 					PQgetvalue(res, i, 5);
-				collname = PQgetisnull(res, i, 6) ? NULL :
+				attgenerated = PQgetisnull(res, i, 6) ? NULL :
 					PQgetvalue(res, i, 6);
-				collnamespace = PQgetisnull(res, i, 7) ? NULL :
+				collname = PQgetisnull(res, i, 7) ? NULL :
 					PQgetvalue(res, i, 7);
+				collnamespace = PQgetisnull(res, i, 8) ? NULL :
+					PQgetvalue(res, i, 8);
 
 				if (first_item)
 					first_item = false;
@@ -5714,7 +5724,11 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 
 				/* Add NOT NULL if needed */
 				if (import_not_null && attnotnull[0] == 't')
+				{
 					appendStringInfoString(&buf, " NOT NULL");
+					if (attnotnullvalid[0] == 'f')
+						appendStringInfoString(&buf, " NOT VALID");
+				}
 			}
 			while (++i < numrows &&
 				   strcmp(PQgetvalue(res, i, 0), tablename) == 0);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 45ba9c5118f..3ab7d7b68aa 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index ece438f0075..a75e75d800d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has an invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  If the constraint is not enforced, an error is thrown.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 8a75e2dafab..25067bd9d43 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2616,12 +2624,17 @@ AddRelationNewConstraints(Relation rel,
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum, is_local,
+										 cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 0467e7442ff..8b8bd78f20a 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -575,8 +575,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -605,13 +605,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -629,9 +627,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -722,19 +721,23 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -752,7 +755,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 			ereport(ERROR,
 					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
-						   NameStr(conform->conname), get_rel_name(relid)));
+						   NameStr(conform->conname), RelationGetRelationName(rel)));
+
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), RelationGetRelationName(rel)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
 
 		if (!is_local)
 		{
@@ -761,6 +775,16 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 				ereport(ERROR,
 						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 						errmsg("too many inheritance parents"));
+
+			/*
+			 * If the child already has a valid constraint and we are
+			 * creating an invalid one with same definition on it.  The
+			 * child's constraint will remain valid, but can no longer be
+			 * marked as local.
+			*/
+			if (is_notvalid && conform->convalidated && conform->conenforced)
+				conform->conislocal = false;
+
 			changed = true;
 		}
 		else if (!conform->conislocal)
@@ -831,7 +855,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -851,7 +875,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 11fcb51a165..94fef7c7f72 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -435,6 +435,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -498,7 +501,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1340,7 +1343,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, false);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1424,7 +1427,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2738,7 +2741,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6207,18 +6210,22 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null constraints.
+		 * This is a bit of overkill but it minimizes risk of bugs.
 		 *
 		 * notnull_attrs does *not* collect attribute numbers for not-null
 		 * constraints over virtual generated columns; instead, they are
 		 * collected in notnull_virtual_attrs.
+		 *
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 			{
 				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
 					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
@@ -7788,7 +7795,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7809,19 +7816,23 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 }
 
 /*
- * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
- * to verify it.
+ * set_attnotnull
+ *		Helper to update/validate the pg_attribute status of a not-null
+ *		constraint
  *
- * When called to alter an existing table, 'wqueue' must be given so that we
- * can queue a check that existing tuples pass the constraint.  When called
- * from table creation, 'wqueue' should be passed as NULL.
+ * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
+ * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
+ * true, also set up wqueue to validate the constraint.  wqueue may be given
+ * as NULL when validation is not needed (e.g., on table creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
+	Assert(!queue_validation || wqueue);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7832,7 +7843,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7845,15 +7856,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7951,6 +7964,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -8013,8 +8035,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9456,12 +9478,45 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
+	/* Verify that columns are not-null, or request that they be made so */
 	foreach(lc, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
+
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
 
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("NO INHERIT not-null constraint is incompatible with primary key"),
+						errhint("You will need to use ALTER TABLE ... ALTER CONSTRAINT ... INHERIT."));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("not-null constraint \"%s\" of table \"%s\" has not been validated",
+							   NameStr(conForm->conname),
+							   RelationGetRelationName(rel)),
+						errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
 		newcmd = makeNode(AlterTableCmd);
@@ -9836,11 +9891,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12790,10 +12849,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12812,6 +12872,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -13028,6 +13093,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+				 colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13896,10 +14064,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -17250,19 +17419,25 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			if (parent_att->attgenerated && !child_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must be a generated column",
+								parent_attname)));
 			if (child_att->attgenerated && !parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must not be a generated column",
+								parent_attname)));
 
-			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+			if (parent_att->attgenerated && child_att->attgenerated &&
+				child_att->attgenerated != parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errmsg("column \"%s\" inherits from generated column of different kind",
+								parent_attname),
 						 errdetail("Parent column is %s, child column is %s.",
-								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL")));
 
 			/*
 			 * Regular inheritance children are independent enough not to
@@ -19751,7 +19926,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2da848970be..c8d44e3086b 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2074,6 +2074,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	{
 		for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++)
 		{
+			/* FIXME use CompactAttribute */
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
 
 			if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 441684a72b1..9b4887fc6a7 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1255,6 +1255,7 @@ get_relation_data_width(Oid relid, int32 *attr_widths)
  * get_relation_constraints
  *
  * Retrieve the applicable constraint expressions of the given relation.
+ * Only constraints that have been validated are considered.
  *
  * Returns a List (possibly empty) of constraint expressions.  Each one
  * has been canonicalized, and its Vars are changed to have the varno
@@ -1355,9 +1356,10 @@ get_relation_constraints(PlannerInfo *root,
 
 			for (i = 1; i <= natts; i++)
 			{
+				/* FIXME use CompactAttribute */
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index f1156e2fca3..3c4268b271a 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4217,11 +4217,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 62015431fdf..c9b2c0884e1 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,20 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+
+			/*
+			 * not-null constraint created via CREATE TABLE will always be
+			 * valid.  since there is no data there while CREATE TABLE, make
+			 * it invalid does not make sense
+			 */
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint on column \"%s\"", colname));
+		}
 	}
 
 	/*
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 18a14ae186e..4f065f57479 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;
+			constr->has_not_null = true;	/* invalid included */
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -3573,6 +3573,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 56b6c368acf..ff6a4eacda0 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -546,6 +546,10 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 						parent->notnull_constrs[inhAttrInd] != NULL)
 						foundNotNull = true;
 
+					if (fout->remoteVersion >= 180000 &&
+						parent->notnull_invalid[inhAttrInd])
+						tbinfo->notnull_parent_invalid[j] = true;
+
 					foundDefault |= (parentDef != NULL &&
 									 strcmp(parentDef->adef_expr, "NULL") != 0 &&
 									 !parent->attgenerated[inhAttrInd]);
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 9436b25290d..2920689f214 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -347,8 +347,10 @@ static void buildMatViewRefreshDependencies(Archive *fout);
 static void getTableDataFKConstraints(void);
 static void determineNotNullFlags(Archive *fout, PGresult *res, int r,
 								  TableInfo *tbinfo, int j,
-								  int i_notnull_name, int i_notnull_noinherit,
-								  int i_notnull_islocal);
+								  int i_notnull_name, int i_notnull_invalidoid,
+								  int i_notnull_noinherit,
+								  int i_notnull_islocal,
+								  PQExpBuffer *invalidnotnulloids);
 static char *format_function_arguments(const FuncInfo *finfo, const char *funcargs,
 									   bool is_agg);
 static char *format_function_signature(Archive *fout,
@@ -8981,6 +8983,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = NULL;
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -9000,6 +9003,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_invalidoid;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9086,6 +9090,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
 	 * without a name); also, such cases are never NO INHERIT.
 	 *
+	 * For invalid constraints, we need to store their OIDs for processing
+	 * elsewhere, so we bring the pg_constraint.oid value when the constraint
+	 * is invalid, and NULL otherwise.
+	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
 	 * might modify this later for servers older than 18; it's also in charge
@@ -9094,11 +9102,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "CASE WHEN NOT co.convalidated THEN co.oid"
+							 " ELSE NULL END AS notnull_invalidoid,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "NULL AS notnull_invalidoid,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9173,6 +9184,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_invalidoid = PQfnumber(res, "notnull_invalidoid");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9240,6 +9252,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->notnull_parent_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9265,12 +9279,17 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_parent_invalid[j] = false;	/* only change in flagInhAttrs */
+			tbinfo->notnull_invalid[j] = false;			/* only change in determineNotNullFlags */
 
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
 								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+								  i_notnull_name,
+								  i_notnull_invalidoid,
+								  i_notnull_noinherit,
+								  i_notnull_islocal,
+								  &invalidnotnulloids);
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9291,6 +9310,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		}
 	}
 
+	/* If invalidnotnulloids has any data, finalize it */
+	if (invalidnotnulloids != NULL)
+		appendPQExpBufferChar(invalidnotnulloids, '}');
+
 	PQclear(res);
 
 	/*
@@ -9423,6 +9446,103 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about NOT NULL NOT VALID constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+
+		pg_log_info("finding invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(conoid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.conoid = c.oid)\n"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * All invalid not-null constraints must be dumped separately,
+				 * because CREATE TABLE would not create them as invalid, and
+				 * also because they must be created after potentially
+				 * violating data has been loaded.
+				 */
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -9567,18 +9687,23 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  *
  * Result row 'r' is for tbinfo's attribute 'j'.
  *
- * There are three possibilities:
+ * There are four possibilities:
  * 1) the column has no not-null constraints. In that case, ->notnull_constrs
  *    (the constraint name) remains NULL.
  * 2) The column has a constraint with no name (this is the case when
  *    constraints come from pre-18 servers).  In this case, ->notnull_constrs
  *    is set to the empty string; dumpTableSchema will print just "NOT NULL".
- * 3) The column has a constraint with a known name; in that case
+ * 3) The column has an invalid not-null constraint.  This must be treated
+ *    as a separate object (because it must be created after the table data
+ *    is loaded).  So we add its OID to invalidnotnulloids for processing
+ *    elsewhere and do nothing further with it here.  We distinguish this
+ *    case because the "invalidoid" column has been set to a non-NULL value,
+ *    which is the constraint OID.  Valid constraints have a null OID.
+ * 4) The column has a constraint with a known name; in that case
  *    notnull_constrs carries that name and dumpTableSchema will print
  *    "CONSTRAINT the_name NOT NULL".  However, if the name is the default
  *    (table_column_not_null), there's no need to print that name in the dump,
- *    so notnull_constrs is set to the empty string and it behaves as the case
- *    above.
+ *    so notnull_constrs is set to the empty string and it behaves as case 2.
  *
  * In a child table that inherits from a parent already containing NOT NULL
  * constraints and the columns in the child don't have their own NOT NULL
@@ -9598,11 +9723,42 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 static void
 determineNotNullFlags(Archive *fout, PGresult *res, int r,
 					  TableInfo *tbinfo, int j,
-					  int i_notnull_name, int i_notnull_noinherit,
-					  int i_notnull_islocal)
+					  int i_notnull_name,
+					  int i_notnull_invalidoid,
+					  int i_notnull_noinherit,
+					  int i_notnull_islocal,
+					  PQExpBuffer *invalidnotnulloids)
 {
 	DumpOptions *dopt = fout->dopt;
 
+	/*
+	 * If this not-null constraint is not valid, list its OID in
+	 * invalidnotnulloids and do nothing further.  It'll be processed
+	 * elsewhere later.
+	 *
+	 * Because invalid not-null constraints are rare, we don't want to malloc
+	 * invalidnotnulloids until we're sure we're going it need it, which
+	 * happens here.
+	 */
+	if (!PQgetisnull(res, r, i_notnull_invalidoid))
+	{
+		char	   *constroid = PQgetvalue(res, r, i_notnull_invalidoid);
+
+		if (*invalidnotnulloids == NULL)
+		{
+			*invalidnotnulloids = createPQExpBuffer();
+			appendPQExpBufferChar(*invalidnotnulloids, '{');
+			appendPQExpBuffer(*invalidnotnulloids, "%s", constroid);
+		}
+		else
+			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
+
+		/* nothing else to do */
+		tbinfo->notnull_constrs[j] = NULL;
+		tbinfo->notnull_invalid[j] = true;
+		return;
+	}
+
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
 	 * though flagInhAttrs may change that one later in versions < 18.
@@ -16684,6 +16840,18 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
+					/*
+					 * if parent have invalid not-null, child have valid
+					 * not-null, then we print not null on child too.  later
+					 * parent's invalid not-null will generate a ALTER TABLE ADD
+					 * CONSTRAINT, which will cascade to children, which is
+					 * fine.
+					*/
+					if (!print_notnull &&
+						tbinfo->notnull_constrs[j] != NULL &&
+						tbinfo->notnull_parent_invalid[j])
+						print_notnull = true;
+
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -18005,13 +18173,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18031,7 +18206,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e6f0f86a459..dd603c9dd53 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,10 +365,14 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_invalid;	/* true mean NOT NULL INVALID,
+									   false mean valid not null or no not null */
+	bool	   *notnull_parent_invalid;	/*  true mean NOT NULL INVALID,
+											false mean valid not null or no not null */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-	struct _constraintInfo *checkexprs; /* CHECK constraints */
+	struct _constraintInfo *checkexprs; /* CHECK, invalid not-null constraints */
 	struct _relStatsInfo *stats;	/* only set for matviews */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
 	char	   *amname;			/* relation access method */
@@ -498,6 +502,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
old mode 100644
new mode 100755
index 576326daec7..587698024af
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1118,6 +1118,23 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / INVALID' => {
+		create_sql => 'CREATE TABLE dump_test.test_table_nn (
+							col1 int);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
+			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+			/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_post_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
@@ -3803,13 +3820,16 @@ my %tests = (
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
 						   col2 int generated always as (col1 * 2) stored,
-						   col3 int generated always as (col1 * 3) virtual
-					   );',
+						   col3 int generated always as (col1 * 3) virtual,
+						   col4 int
+					   );
+					   ALTER TABLE dump_test.test_table_generated ADD CONSTRAINT dump_test_nn NOT NULL col4 NOT VALID;',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
 			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
-			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3)),\E\n
+			\s+\Qcol4 integer\E\n
 			\);
 			/xms,
 		like =>
@@ -3820,6 +3840,19 @@ my %tests = (
 		},
 	},
 
+	'ALTER TABLE dump_test.test_table_generated' => {
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_generated\E \n^\s+
+			\QADD CONSTRAINT dump_test_nn NOT NULL col4 NOT VALID;\E
+			/xm,
+		like =>
+			{ %full_runs, %dump_test_schema_runs, section_post_data => 1, },
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CREATE TABLE test_table_generated_child1 (without local columns)' => {
 		create_order => 4,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated_child1 ()
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 8970677ac64..1d08268393e 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3106,7 +3106,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3129,14 +3130,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..5523cfcf5aa 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* any not-null, including not valid ones */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..cf27d53e848 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -263,8 +263,8 @@ extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
 extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..b90b9eac643 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1202,6 +1202,75 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id" NOT VALID
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id"
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index a719d2f74e9..50ad01f22d2 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -892,6 +892,221 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  not-null constraint "nn" of table "notnull_tbl1" has not been validated
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+   conrelid   |  conname  | convalidated | coninhcount 
+--------------+-----------+--------------+-------------
+ notnull_tbl1 | nn_parent | t            |           0
+ notnull_chld | nn_child  | t            |           1
+(2 rows)
+
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_parent"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_child"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a INTEGER);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass);
+      conrelid      | contype | convalidated | conislocal 
+--------------------+---------+--------------+------------
+ notnull_parent_upg | n       | f            | t
+ notnull_child_upg  | n       | t            | f
+(2 rows)
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+      conrelid       |   conname   | convalidated | coninhcount 
+---------------------+-------------+--------------+-------------
+ notnull_part1_upg   | notnull_con | f            |           0
+ notnull_part1_1_upg | notnull_con | t            |           1
+ notnull_part1_2_upg | nn2         | t            |           1
+ notnull_part1_3_upg | nn3         | f            |           1
+(4 rows)
+
+DEALLOCATE get_nnconstraint_info;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -1388,3 +1603,17 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
+ relname | attname | attnum | attnotnull | attnotnullvalid 
+---------+---------+--------+------------+-----------------
+(0 rows)
+
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 84e93ef575e..1e6bb2c7818 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -910,6 +910,20 @@ alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
 
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
+
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..cc1bfd2ef89 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,163 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+
+-- even an invalid not-null forbids new nulls:
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+
+-- a constraint already exists:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+
+-- Can't change constraint validity this way:
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- This can change the validity, but must fail if there are nulls
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+
+-- cannot add primary key on column marked as NOT VALID NOT NULL
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a INTEGER, b INTEGER) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+-- Can't make it valid if there are nulls
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+-- Make the constraint valid
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn;
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT notnull_tbl1_a_not_null INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_a_not_null;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+-- Test the different not null constraint name for parent and child table
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_chld0 (a int);
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+CREATE TABLE notnull_chld (a int);
+ALTER TABLE notnull_chld ADD CONSTRAINT nn_child NOT NULL a not valid;
+ALTER TABLE notnull_chld INHERIT notnull_tbl1;
+
+ALTER TABLE notnull_chld VALIDATE CONSTRAINT nn_child;
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld}');
+DROP TABLE notnull_chld0;
+DROP TABLE notnull_chld;
+DROP TABLE notnull_tbl1;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, table already have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE pp_nn ADD CONSTRAINT pp_nn_notnull NOT NULL a;
+
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 add CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a INTEGER, b INTEGER);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a INTEGER);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass);
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a INTEGER, b INTEGER) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+DEALLOCATE get_nnconstraint_info;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -836,3 +993,14 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
-- 
2.43.0

From 8583163960b136a52aea7ab02b5cd8b5a81deeca Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Sat, 5 Apr 2025 15:21:09 +0800
Subject: [PATCH v7 2/2] NOT NULL NOT VALID

This also introduces a new column, attnotnullvalid, to the pg_attribute catalog.

* You can only add an invalid NOT NULL constraint by using ALTER TABLE.
  CREATE TABLE with NOT NULL NOT VALID will create a valid NOT NULL constraint.

  The syntax to add an invalid NOT NULL constraint:
  ALTER TABLE table_name ADD CONSTRAINT constraint_name NOT NULL column_name NOT VALID;

* To validate a NOT NULL constraint, you can use either of the following:
  ALTER TABLE ... SET NOT NULL
  ALTER TABLE ... VALIDATE CONSTRAINT constraint_name

* ALTER TABLE ... DROP NOT NULL will not remove an invalid NOT NULL constraint.

* CREATE TABLE LIKE will copy the invalid NOT NULL constraints, but in the new table, they will become valid.

Author: Rushabh Lathia <rushabh.lathia@gmail.com>
Author: Jian He <jian.universality@gmail.com>

Discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
---
 contrib/postgres_fdw/postgres_fdw.c       |  26 ++-
 doc/src/sgml/catalogs.sgml                |  11 +-
 doc/src/sgml/ref/alter_table.sgml         |   8 +-
 src/backend/access/common/tupdesc.c       |  11 +-
 src/backend/bootstrap/bootstrap.c         |   3 +
 src/backend/catalog/genbki.pl             |   3 +
 src/backend/catalog/heap.c                |  19 +-
 src/backend/catalog/pg_constraint.c       |  62 ++++--
 src/backend/commands/tablecmds.c          | 241 +++++++++++++++++++---
 src/backend/executor/execMain.c           |   1 +
 src/backend/jit/llvm/llvmjit_deform.c     |  10 +-
 src/backend/optimizer/util/plancat.c      |   6 +-
 src/backend/parser/gram.y                 |   5 +-
 src/backend/parser/parse_utilcmd.c        |  15 ++
 src/backend/utils/cache/catcache.c        |   1 +
 src/backend/utils/cache/relcache.c        |   3 +-
 src/bin/pg_dump/common.c                  |   4 +
 src/bin/pg_dump/pg_dump.c                 | 203 ++++++++++++++++--
 src/bin/pg_dump/pg_dump.h                 |   5 +
 src/bin/pg_dump/t/002_pg_dump.pl          |  17 ++
 src/bin/psql/describe.c                   |   9 +-
 src/include/access/tupdesc.h              |   9 +-
 src/include/catalog/pg_attribute.h        |   5 +-
 src/include/catalog/pg_constraint.h       |   4 +-
 src/test/regress/expected/alter_table.out |  69 +++++++
 src/test/regress/expected/constraints.out | 230 +++++++++++++++++++++
 src/test/regress/sql/alter_table.sql      |  14 ++
 src/test/regress/sql/constraints.sql      | 164 +++++++++++++++
 28 files changed, 1060 insertions(+), 98 deletions(-)

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index b4e0e60928b..60d25c2f0a4 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -5549,7 +5549,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 							   "SELECT relname, "
 							   "  attname, "
 							   "  format_type(atttypid, atttypmod), "
-							   "  attnotnull, "
+							   "  attnotnull, ");
+
+		/* NOT VALID NOT NULL columns are supported since Postgres 18 */
+		if (PQserverVersion(conn) >= 180000)
+			appendStringInfoString(&buf, "attnotnullvalid, ");
+		else
+			appendStringInfoString(&buf, "attnotnull AS attnotnullvalid, ");
+
+		appendStringInfoString(&buf,
 							   "  pg_get_expr(adbin, adrelid), ");
 
 		/* Generated columns are supported since Postgres 12 */
@@ -5651,6 +5659,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				char	   *attname;
 				char	   *typename;
 				char	   *attnotnull;
+				char	   *attnotnullvalid;
 				char	   *attgenerated;
 				char	   *attdefault;
 				char	   *collname;
@@ -5663,14 +5672,15 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				attname = PQgetvalue(res, i, 1);
 				typename = PQgetvalue(res, i, 2);
 				attnotnull = PQgetvalue(res, i, 3);
-				attdefault = PQgetisnull(res, i, 4) ? NULL :
-					PQgetvalue(res, i, 4);
-				attgenerated = PQgetisnull(res, i, 5) ? NULL :
+				attnotnullvalid = PQgetvalue(res, i, 4);
+				attdefault = PQgetisnull(res, i, 5) ? NULL :
 					PQgetvalue(res, i, 5);
-				collname = PQgetisnull(res, i, 6) ? NULL :
+				attgenerated = PQgetisnull(res, i, 6) ? NULL :
 					PQgetvalue(res, i, 6);
-				collnamespace = PQgetisnull(res, i, 7) ? NULL :
+				collname = PQgetisnull(res, i, 7) ? NULL :
 					PQgetvalue(res, i, 7);
+				collnamespace = PQgetisnull(res, i, 8) ? NULL :
+					PQgetvalue(res, i, 8);
 
 				if (first_item)
 					first_item = false;
@@ -5714,7 +5724,11 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 
 				/* Add NOT NULL if needed */
 				if (import_not_null && attnotnull[0] == 't')
+				{
 					appendStringInfoString(&buf, " NOT NULL");
+					if (attnotnullvalid[0] == 'f')
+						appendStringInfoString(&buf, " NOT VALID");
+				}
 			}
 			while (++i < numrows &&
 				   strcmp(PQgetvalue(res, i, 0), tablename) == 0);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 45ba9c5118f..3ab7d7b68aa 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index ece438f0075..a75e75d800d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has an invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  If the constraint is not enforced, an error is thrown.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 2b28b05b9cb..6620c1cfa8f 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2616,12 +2624,17 @@ AddRelationNewConstraints(Relation rel,
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
-			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+			if (AdjustNotNullInheritance(rel, colnum, is_local,
+										 cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index b97960d2766..a6745c04584 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -576,8 +576,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -606,13 +606,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -630,9 +628,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -723,19 +722,23 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
-AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
-	tup = findNotNullConstraintAttnum(relid, attnum);
+	tup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tup))
 	{
 		Relation	pg_constraint;
@@ -753,7 +756,18 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 			ereport(ERROR,
 					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
-						   NameStr(conform->conname), get_rel_name(relid)));
+						   NameStr(conform->conname), RelationGetRelationName(rel)));
+
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), RelationGetRelationName(rel)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
 
 		if (!is_local)
 		{
@@ -762,6 +776,16 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 				ereport(ERROR,
 						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 						errmsg("too many inheritance parents"));
+
+			/*
+			 * If the child already has a valid constraint and we are creating
+			 * an invalid one with same definition on it, then the child's
+			 * constraint will remain valid, but can no longer be marked as
+			 * local.
+			*/
+			if (is_notvalid && conform->convalidated && conform->conenforced)
+				conform->conislocal = false;
+
 			changed = true;
 		}
 		else if (!conform->conislocal)
@@ -832,7 +856,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -852,7 +876,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4397123398e..fcac48db2ac 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -435,6 +435,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -498,7 +501,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1340,7 +1343,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, false);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1424,7 +1427,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2738,7 +2741,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6207,18 +6210,22 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null constraints.
+		 * This is a bit of overkill but it minimizes risk of bugs.
 		 *
 		 * notnull_attrs does *not* collect attribute numbers for not-null
 		 * constraints over virtual generated columns; instead, they are
 		 * collected in notnull_virtual_attrs.
+		 *
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 			{
 				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
 					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
@@ -7788,7 +7795,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7809,19 +7816,23 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 }
 
 /*
- * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
- * to verify it.
+ * set_attnotnull
+ *		Helper to update/validate the pg_attribute status of a not-null
+ *		constraint
  *
- * When called to alter an existing table, 'wqueue' must be given so that we
- * can queue a check that existing tuples pass the constraint.  When called
- * from table creation, 'wqueue' should be passed as NULL.
+ * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
+ * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
+ * true, also set up wqueue to validate the constraint.  wqueue may be given
+ * as NULL when validation is not needed (e.g., on table creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
+	Assert(!queue_validation || wqueue);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7832,7 +7843,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7845,15 +7856,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7951,6 +7964,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -8013,8 +8035,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9456,12 +9478,44 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
+	/* Verify that columns are not-null, or request that they be made so */
 	foreach(lc, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
 
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(lfirst(lc)));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("NO INHERIT not-null constraint is incompatible with primary key"),
+						errhint("You will need to use ALTER TABLE ... ALTER CONSTRAINT ... INHERIT."));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("cannot add primary key because of invalid not-null constraint \"%s\"",
+							   NameStr(conForm->conname)),
+						errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
 		nnconstr = makeNotNullConstraint(lfirst(lc));
 
 		newcmd = makeNode(AlterTableCmd);
@@ -9836,11 +9890,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12811,10 +12869,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12833,6 +12892,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -13049,6 +13113,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+						colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13917,10 +14084,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -17271,19 +17439,25 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 			if (parent_att->attgenerated && !child_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must be a generated column",
+								parent_attname)));
 			if (child_att->attgenerated && !parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
+						 errmsg("column \"%s\" in child table must not be a generated column",
+								parent_attname)));
 
-			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+			if (parent_att->attgenerated && child_att->attgenerated &&
+				child_att->attgenerated != parent_att->attgenerated)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errmsg("column \"%s\" inherits from generated column of different kind",
+								parent_attname),
 						 errdetail("Parent column is %s, child column is %s.",
-								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ?
+								   "STORED" : "VIRTUAL")));
 
 			/*
 			 * Regular inheritance children are independent enough not to
@@ -19772,7 +19946,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2da848970be..c8d44e3086b 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2074,6 +2074,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	{
 		for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++)
 		{
+			/* FIXME use CompactAttribute */
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
 
 			if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 441684a72b1..9b4887fc6a7 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1255,6 +1255,7 @@ get_relation_data_width(Oid relid, int32 *attr_widths)
  * get_relation_constraints
  *
  * Retrieve the applicable constraint expressions of the given relation.
+ * Only constraints that have been validated are considered.
  *
  * Returns a List (possibly empty) of constraint expressions.  Each one
  * has been canonicalized, and its Vars are changed to have the varno
@@ -1355,9 +1356,10 @@ get_relation_constraints(PlannerInfo *root,
 
 			for (i = 1; i <= natts; i++)
 			{
+				/* FIXME use CompactAttribute */
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index f1156e2fca3..3c4268b271a 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4217,11 +4217,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 62015431fdf..d2c9f50202e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -329,6 +329,21 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 			cd->is_not_null = true;
 			break;
 		}
+
+		if (!cxt.isforeign && !nn->initially_valid)
+		{
+			nn->initially_valid = true;
+			nn->skip_validation = false;
+
+			/*
+			 * not-null constraint created via CREATE TABLE will always be
+			 * valid.  since there is no data there while CREATE TABLE, make
+			 * it invalid does not make sense
+			 */
+			ereport(WARNING,
+					errcode(ERRCODE_WARNING),
+					errmsg("Ignoring NOT VALID flag for NOT NULL constraint on column \"%s\"", colname));
+		}
 	}
 
 	/*
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 18a14ae186e..4f065f57479 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;
+			constr->has_not_null = true;	/* invalid included */
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -3573,6 +3573,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 56b6c368acf..ff6a4eacda0 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -546,6 +546,10 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 						parent->notnull_constrs[inhAttrInd] != NULL)
 						foundNotNull = true;
 
+					if (fout->remoteVersion >= 180000 &&
+						parent->notnull_invalid[inhAttrInd])
+						tbinfo->notnull_parent_invalid[j] = true;
+
 					foundDefault |= (parentDef != NULL &&
 									 strcmp(parentDef->adef_expr, "NULL") != 0 &&
 									 !parent->attgenerated[inhAttrInd]);
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 8e6364d32d7..c5cb2d8800c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -350,8 +350,10 @@ static void buildMatViewRefreshDependencies(Archive *fout);
 static void getTableDataFKConstraints(void);
 static void determineNotNullFlags(Archive *fout, PGresult *res, int r,
 								  TableInfo *tbinfo, int j,
-								  int i_notnull_name, int i_notnull_noinherit,
-								  int i_notnull_islocal);
+								  int i_notnull_name, int i_notnull_invalidoid,
+								  int i_notnull_noinherit,
+								  int i_notnull_islocal,
+								  PQExpBuffer *invalidnotnulloids);
 static char *format_function_arguments(const FuncInfo *finfo, const char *funcargs,
 									   bool is_agg);
 static char *format_function_signature(Archive *fout,
@@ -8984,6 +8986,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = NULL;
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -9003,6 +9006,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_invalidoid;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9089,6 +9093,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
 	 * without a name); also, such cases are never NO INHERIT.
 	 *
+	 * For invalid constraints, we need to store their OIDs for processing
+	 * elsewhere, so we bring the pg_constraint.oid value when the constraint
+	 * is invalid, and NULL otherwise.
+	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
 	 * might modify this later for servers older than 18; it's also in charge
@@ -9097,11 +9105,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "CASE WHEN NOT co.convalidated THEN co.oid "
+							 "ELSE NULL END AS notnull_invalidoid,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "NULL AS notnull_invalidoid,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9176,6 +9187,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_invalidoid = PQfnumber(res, "notnull_invalidoid");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9243,6 +9255,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->notnull_parent_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9268,12 +9282,17 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_parent_invalid[j] = false;	/* only change in flagInhAttrs */
+			tbinfo->notnull_invalid[j] = false;			/* only change in determineNotNullFlags */
 
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
 								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+								  i_notnull_name,
+								  i_notnull_invalidoid,
+								  i_notnull_noinherit,
+								  i_notnull_islocal,
+								  &invalidnotnulloids);
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9294,6 +9313,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		}
 	}
 
+	/* If invalidnotnulloids has any data, finalize it */
+	if (invalidnotnulloids != NULL)
+		appendPQExpBufferChar(invalidnotnulloids, '}');
+
 	PQclear(res);
 
 	/*
@@ -9426,6 +9449,103 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about NOT NULL NOT VALID constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+
+		pg_log_info("finding invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(conoid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.conoid = c.oid)\n"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * All invalid not-null constraints must be dumped separately,
+				 * because CREATE TABLE would not create them as invalid, and
+				 * also because they must be created after potentially
+				 * violating data has been loaded.
+				 */
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -9570,18 +9690,23 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  *
  * Result row 'r' is for tbinfo's attribute 'j'.
  *
- * There are three possibilities:
+ * There are four possibilities:
  * 1) the column has no not-null constraints. In that case, ->notnull_constrs
  *    (the constraint name) remains NULL.
  * 2) The column has a constraint with no name (this is the case when
  *    constraints come from pre-18 servers).  In this case, ->notnull_constrs
  *    is set to the empty string; dumpTableSchema will print just "NOT NULL".
- * 3) The column has a constraint with a known name; in that case
+ * 3) The column has an invalid not-null constraint.  This must be treated
+ *    as a separate object (because it must be created after the table data
+ *    is loaded).  So we add its OID to invalidnotnulloids for processing
+ *    elsewhere and do nothing further with it here.  We distinguish this
+ *    case because the "notnull_invalidoid" column has been set to a non-NULL
+ *    value, which is the constraint OID.  Valid constraints have a null OID.
+ * 4) The column has a constraint with a known name; in that case
  *    notnull_constrs carries that name and dumpTableSchema will print
  *    "CONSTRAINT the_name NOT NULL".  However, if the name is the default
  *    (table_column_not_null), there's no need to print that name in the dump,
- *    so notnull_constrs is set to the empty string and it behaves as the case
- *    above.
+ *    so notnull_constrs is set to the empty string and it behaves as case 2.
  *
  * In a child table that inherits from a parent already containing NOT NULL
  * constraints and the columns in the child don't have their own NOT NULL
@@ -9593,7 +9718,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  * Any of these constraints might have the NO INHERIT bit.  If so we set
  * ->notnull_noinh and NO INHERIT will be printed by dumpTableSchema.
  *
- * In case 3 above, the name comparison is a bit of a hack; it actually fails
+ * In case 4 above, the name comparison is a bit of a hack; it actually fails
  * to do the right thing in all but the trivial case.  However, the downside
  * of getting it wrong is simply that the name is printed rather than
  * suppressed, so it's not a big deal.
@@ -9601,11 +9726,42 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 static void
 determineNotNullFlags(Archive *fout, PGresult *res, int r,
 					  TableInfo *tbinfo, int j,
-					  int i_notnull_name, int i_notnull_noinherit,
-					  int i_notnull_islocal)
+					  int i_notnull_name,
+					  int i_notnull_invalidoid,
+					  int i_notnull_noinherit,
+					  int i_notnull_islocal,
+					  PQExpBuffer *invalidnotnulloids)
 {
 	DumpOptions *dopt = fout->dopt;
 
+	/*
+	 * If this not-null constraint is not valid, list its OID in
+	 * invalidnotnulloids and do nothing further.  It'll be processed
+	 * elsewhere later.
+	 *
+	 * Because invalid not-null constraints are rare, we don't want to malloc
+	 * invalidnotnulloids until we're sure we're going it need it, which
+	 * happens here.
+	 */
+	if (!PQgetisnull(res, r, i_notnull_invalidoid))
+	{
+		char	   *constroid = PQgetvalue(res, r, i_notnull_invalidoid);
+
+		if (*invalidnotnulloids == NULL)
+		{
+			*invalidnotnulloids = createPQExpBuffer();
+			appendPQExpBufferChar(*invalidnotnulloids, '{');
+			appendPQExpBuffer(*invalidnotnulloids, "%s", constroid);
+		}
+		else
+			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
+
+		/* nothing else to do */
+		tbinfo->notnull_constrs[j] = NULL;
+		tbinfo->notnull_invalid[j] = true;
+		return;
+	}
+
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
 	 * though flagInhAttrs may change that one later in versions < 18.
@@ -16831,6 +16987,18 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
+					/*
+					 * if parent have invalid not-null, child have valid
+					 * not-null, then we print not null on child too.  later
+					 * parent's invalid not-null will generate a ALTER TABLE ADD
+					 * CONSTRAINT, which will cascade to children, which is
+					 * fine.
+					*/
+					if (!print_notnull &&
+						tbinfo->notnull_constrs[j] != NULL &&
+						tbinfo->notnull_parent_invalid[j])
+						print_notnull = true;
+
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
@@ -18152,13 +18320,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18178,7 +18353,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e6f0f86a459..5f20d54e30f 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,6 +365,9 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_invalid;	/* true if NOT NULL NOT VALID */
+	bool	   *notnull_parent_invalid;	/* true if
+										 * parent table NOT NULL constraint is NOT VALID */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
@@ -498,6 +501,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 576326daec7..b6c215c06ff 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1118,6 +1118,23 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / INVALID' => {
+		create_sql => 'CREATE TABLE dump_test.test_table_nn (
+							col1 int);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
+			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+			/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_post_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 8970677ac64..1d08268393e 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3106,7 +3106,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3129,14 +3130,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..5523cfcf5aa 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* any not-null, including not valid ones */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..cf27d53e848 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -263,8 +263,8 @@ extern HeapTuple findNotNullConstraintAttnum(Oid relid, AttrNumber attnum);
 extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
-extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+extern bool AdjustNotNullInheritance(Relation rel, AttrNumber attnum,
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..b90b9eac643 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1202,6 +1202,75 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id" NOT VALID
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id"
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index a719d2f74e9..90da9e4482f 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -892,6 +892,222 @@ Not-null constraints:
     "foobar" NOT NULL "a"
 
 DROP TABLE notnull_tbl1;
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+CREATE TABLE notnull_tbl1 (a int, b int);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+--new table not-null will become valid
+CREATE TABLE notnull_tbl1_copy (LIKE notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_copy}');
+     conrelid      | conname | convalidated | coninhcount 
+-------------------+---------+--------------+-------------
+ notnull_tbl1_copy | nn      | t            |           0
+(1 row)
+
+-- even an invalid not-null forbids new nulls
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+-- can't override
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- This will validate invalid not-null
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+-- cannot add primary key on column have invalid not-null
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  cannot add primary key because of invalid not-null constraint "nn"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a int, b int) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      conrelid      | conname | convalidated | coninhcount 
+--------------------+---------+--------------+-------------
+ notnull_tbl1       | nn      | f            |           0
+ notnull_tbl1_child | nn      | t            |           1
+(2 rows)
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; --error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; --now ok
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nntbl1_a NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT nntbl1_a;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld0 (a int, CONSTRAINT nn_chld0 NOT NULL a);
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+ALTER TABLE notnull_chld0 DROP CONSTRAINT nn_chld0;
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --now ok
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld0}');
+   conrelid    |  conname  | convalidated | coninhcount 
+---------------+-----------+--------------+-------------
+ notnull_tbl1  | nn_parent | t            |           1
+ notnull_chld0 | nn_chld0  | f            |           0
+(2 rows)
+
+DROP TABLE notnull_tbl1, notnull_chld0;
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+NOTICE:  merging definition of column "i" for child "inh_child"
+NOTICE:  merging definition of column "i" for child "inh_grandchild"
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_parent"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "inh_child"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | f            |           0
+ inh_child      | nn      | f            |           1
+ inh_grandchild | nn      | f            |           2
+(3 rows)
+
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+    conrelid    | conname | convalidated | coninhcount 
+----------------+---------+--------------+-------------
+ inh_parent     | nn      | t            |           0
+ inh_child      | nn      | t            |           1
+ inh_grandchild | nn      | t            |           2
+(3 rows)
+
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | f            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | f            |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, notnull_tbl1_3 have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    conrelid    |   conname   | convalidated | coninhcount 
+----------------+-------------+--------------+-------------
+ notnull_tbl1   | notnull_con | t            |           0
+ notnull_tbl1_1 | notnull_con | t            |           1
+ notnull_tbl1_2 | nn2         | t            |           1
+ notnull_tbl1_3 | nn3         | t            |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a int, b int, NOT NULL a) PARTITION BY LIST (a);
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a int, b int);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a int);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal
+FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass)
+ORDER BY 1;
+      conrelid      | contype | convalidated | conislocal 
+--------------------+---------+--------------+------------
+ notnull_parent_upg | n       | f            | t
+ notnull_child_upg  | n       | t            | f
+(2 rows)
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+      conrelid       |   conname   | convalidated | coninhcount 
+---------------------+-------------+--------------+-------------
+ notnull_part1_upg   | notnull_con | f            |           0
+ notnull_part1_1_upg | notnull_con | t            |           1
+ notnull_part1_2_upg | nn2         | t            |           1
+ notnull_part1_3_upg | nn3         | f            |           1
+(4 rows)
+
+DEALLOCATE get_nnconstraint_info;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -1388,3 +1604,17 @@ DROP TABLE constraint_comments_tbl;
 DROP DOMAIN constraint_comments_dom;
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
+ relname | attname | attnum | attnotnull | attnotnullvalid 
+---------+---------+--------+------------+-----------------
+(0 rows)
+
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 84e93ef575e..1e6bb2c7818 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -910,6 +910,20 @@ alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
 
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+ROLLBACK;
+-- leave a table in this state for the pg_restore test
+
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..aa28a4a9154 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -640,6 +640,159 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
 \d+ notnull_tbl1
 DROP TABLE notnull_tbl1;
 
+-- test NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass, conname, convalidated, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY 1;
+
+CREATE TABLE notnull_tbl1 (a int, b int);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+\d+ notnull_tbl1
+
+--new table not-null will become valid
+CREATE TABLE notnull_tbl1_copy (LIKE notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_copy}');
+
+-- even an invalid not-null forbids new nulls
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+
+-- can't override
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- This will validate invalid not-null
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+
+-- cannot add primary key on column have invalid not-null
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- Creating a child table should mark the constraint there as valid
+CREATE TABLE notnull_tbl1_child(a int, b int) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; --error
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; --now ok
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nntbl1_a NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT nntbl1_a;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+
+-- parent have valid not null constraint then child table cannot have invalid one
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld0 (a int, CONSTRAINT nn_chld0 NOT NULL a);
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+ALTER TABLE notnull_chld0 DROP CONSTRAINT nn_chld0;
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --now ok
+
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld0}');
+DROP TABLE notnull_tbl1, notnull_chld0;
+
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE inh_parent ();
+CREATE TABLE inh_child (i int) INHERITS (inh_parent);
+CREATE TABLE inh_grandchild () INHERITS (inh_parent, inh_child);
+ALTER TABLE inh_parent ADD COLUMN i int;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE inh_parent ADD CONSTRAINT nn NOT NULL i; --error
+ALTER TABLE inh_child ADD CONSTRAINT nn1 NOT NULL i; --error
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be invalid.
+ALTER TABLE inh_parent ALTER i SET NOT NULL; --ok
+EXECUTE get_nnconstraint_info('{inh_parent, inh_child, inh_grandchild}'); --all should be valid now.
+DROP TABLE inh_parent, inh_child, inh_grandchild;
+
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, notnull_tbl1_3 have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-----partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a int, b int, NOT NULL a) PARTITION BY LIST (a);
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a int, b int);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a int);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal
+FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass)
+ORDER BY 1;
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+DEALLOCATE get_nnconstraint_info;
+-- end of NOT NULL VALID/NOT VALID --------------------------------
+
+
 -- Verify that constraint names and NO INHERIT are properly considered when
 -- multiple constraint are specified, either explicitly or via SERIAL/PK/etc,
 -- and that conflicting cases are rejected.  Mind that table constraints
@@ -836,3 +989,14 @@ DROP DOMAIN constraint_comments_dom;
 
 DROP ROLE regress_constraint_comments;
 DROP ROLE regress_constraint_comments_noaccess;
+
+--sanity check attnotnull and attnotnullvalid.
+select pc.relname, pa.attname, pa.attnum, pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa join pg_class pc
+on      pa.attrelid = pc.oid
+where ( (pa.attnotnull and not pa.attnotnullvalid) or
+        (not pa.attnotnull and pa.attnotnullvalid) )
+and     pc.relnamespace in
+        ('pg_catalog'::regnamespace,
+         'pg_toast'::regnamespace,
+         'information_schema'::regnamespace);
-- 
2.34.1

From a87c6fb2b0169306c5c4d0008a9d4692aeaa23cd Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Sat, 5 Apr 2025 15:15:13 +0800
Subject: [PATCH v7 1/2] mark conislocal as false while merging valid
 constraint

If the child already has a valid constraint and we are creating an invalid
one with same definition on it, the child's constraint will remain valid,
but can no longer be marked as local.

CREATE TABLE ttchk (a int);
ALTER TABLE ttchk ADD CONSTRAINT cc check (a is NOT NULL) NOT VALID;
CREATE TABLE ttchk_child(a int) INHERITS(ttchk);
--queryA
select conrelid::regclass::text as relname, conname,
       convalidated, conislocal, coninhcount, connoinherit
from pg_constraint where conname like '%cc%'
order by 1, 2;

with the patch applied, the result of queryA will remain the same before and after running pg_dump.

Discussion: https://postgr.es/m/CACJufxECVsdWSC4J0wo2LF-+QoacsfX_Scv-NGzQxWjzPF1coA@mail.gmail.com
---
 src/backend/catalog/heap.c            | 21 +++++++++++++++++----
 src/test/regress/expected/inherit.out |  2 +-
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b807ab66668..2b28b05b9cb 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2826,11 +2826,24 @@ MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
 		{
 			if (is_local)
 				con->conislocal = true;
-			else if (pg_add_s16_overflow(con->coninhcount, 1,
+			else
+			{
+				if(pg_add_s16_overflow(con->coninhcount, 1,
 										 &con->coninhcount))
-				ereport(ERROR,
-						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-						errmsg("too many inheritance parents"));
+					ereport(ERROR,
+							errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+							errmsg("too many inheritance parents"));
+
+				/*
+				 * If the child already has a valid constraint and we are
+				 * creating an invalid one with same definition on it, then the
+				 * child's constraint will remain valid, but can no longer
+				 * marked as local.
+				*/
+				if (!is_initially_valid && con->convalidated &&
+					is_enforced && con->conenforced)
+					con->conislocal = false;
+			}
 		}
 
 		if (is_no_inherit)
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index 2a8bfba768e..e063f48d343 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -1571,7 +1571,7 @@ order by 1, 2;
          relname         |       conname        | convalidated | conislocal | coninhcount | connoinherit 
 -------------------------+----------------------+--------------+------------+-------------+--------------
  invalid_check_con       | inh_check_constraint | f            | t          |           0 | f
- invalid_check_con_child | inh_check_constraint | t            | t          |           1 | f
+ invalid_check_con_child | inh_check_constraint | t            | f          |           1 | f
 (2 rows)
 
 -- We don't drop the invalid_check_con* tables, to test dump/reload with
-- 
2.34.1

From adfc93bb7ed8d716f3017fdc6263c21f1abd69ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Sat, 5 Apr 2025 19:25:10 +0200
Subject: [PATCH v8 1/3] Allow NOT NULL constraints to be added as NOT VALID
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This required adding a new system column, pg_attribute.attnotnullvalid,
in order to allow constructing a TupleDesc without having to scan
pg_constraint; at the same time, we keep pg_attribute.attnotnull
unchanged, to avoid breaking the countless applications that rely on
that.

Also add support for ALTER TABLE .. VALIDATE CONSTRAINT for them.

Author: Rushabh Lathia <rushabh.lathia@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
---
 doc/src/sgml/catalogs.sgml                 |  11 +-
 doc/src/sgml/ref/alter_table.sgml          |   8 +-
 src/backend/access/common/tupdesc.c        |  11 +-
 src/backend/bootstrap/bootstrap.c          |   3 +
 src/backend/catalog/genbki.pl              |   3 +
 src/backend/catalog/heap.c                 |  17 +-
 src/backend/catalog/pg_constraint.c        |  46 ++--
 src/backend/commands/tablecmds.c           | 246 +++++++++++++++++---
 src/backend/executor/execMain.c            |   1 +
 src/backend/jit/llvm/llvmjit_deform.c      |  10 +-
 src/backend/optimizer/util/plancat.c       |   5 +-
 src/backend/parser/gram.y                  |   5 +-
 src/backend/utils/cache/catcache.c         |   1 +
 src/backend/utils/cache/relcache.c         |   3 +-
 src/bin/pg_dump/pg_dump.c                  | 186 +++++++++++++--
 src/bin/pg_dump/pg_dump.h                  |   2 +
 src/bin/pg_dump/t/002_pg_dump.pl           |  21 +-
 src/bin/psql/describe.c                    |   9 +-
 src/include/access/tupdesc.h               |   9 +-
 src/include/catalog/catversion.h           |   2 +-
 src/include/catalog/pg_attribute.h         |   5 +-
 src/include/catalog/pg_constraint.h        |   2 +-
 src/test/regress/expected/alter_table.out  |  69 ++++++
 src/test/regress/expected/constraints.out  | 250 +++++++++++++++++++++
 src/test/regress/expected/sanity_check.out |  20 ++
 src/test/regress/sql/alter_table.sql       |  14 ++
 src/test/regress/sql/constraints.sql       | 166 ++++++++++++++
 src/test/regress/sql/sanity_check.sql      |  14 ++
 28 files changed, 1047 insertions(+), 92 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 45ba9c5118f..3ab7d7b68aa 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index ece438f0075..a75e75d800d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has an invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  If the constraint is not enforced, an error is thrown.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b807ab66668..503e7cb3f58 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2616,12 +2624,17 @@ AddRelationNewConstraints(Relation rel,
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 is_local, cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index b97960d2766..2f73085961b 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -576,8 +576,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -606,13 +606,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -630,9 +628,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -723,15 +722,19 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
@@ -755,6 +758,17 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
@@ -832,7 +846,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -852,7 +866,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4397123398e..0c7b1231c2e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -435,6 +435,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -498,7 +501,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1340,7 +1343,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, false);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1424,7 +1427,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2738,7 +2741,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6207,18 +6210,22 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null constraints.
+		 * This is a bit of overkill but it minimizes risk of bugs.
 		 *
 		 * notnull_attrs does *not* collect attribute numbers for not-null
 		 * constraints over virtual generated columns; instead, they are
 		 * collected in notnull_virtual_attrs.
+		 *
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 			{
 				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
 					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
@@ -7788,7 +7795,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7809,19 +7816,23 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 }
 
 /*
- * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
- * to verify it.
+ * set_attnotnull
+ *		Helper to update/validate the pg_attribute status of a not-null
+ *		constraint
  *
- * When called to alter an existing table, 'wqueue' must be given so that we
- * can queue a check that existing tuples pass the constraint.  When called
- * from table creation, 'wqueue' should be passed as NULL.
+ * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
+ * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
+ * true, also set up wqueue to validate the constraint.  wqueue may be given
+ * as NULL when validation is not needed (e.g., on table creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
+	Assert(!queue_validation || wqueue);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7832,7 +7843,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7845,15 +7856,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7951,6 +7964,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -8013,8 +8035,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9417,7 +9439,6 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 					bool recurse, LOCKMODE lockmode,
 					AlterTableUtilityContext *context)
 {
-	ListCell   *lc;
 	Constraint *pkconstr;
 
 	pkconstr = castNode(Constraint, cmd->def);
@@ -9436,33 +9457,73 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 											 lockmode);
 		foreach_oid(childrelid, children)
 		{
-			foreach(lc, pkconstr->keys)
+			foreach_node(String, attname, pkconstr->keys)
 			{
 				HeapTuple	tup;
 				Form_pg_attribute attrForm;
-				char	   *attname = strVal(lfirst(lc));
 
-				tup = SearchSysCacheAttName(childrelid, attname);
+				tup = SearchSysCacheAttName(childrelid, strVal(attname));
 				if (!tup)
 					elog(ERROR, "cache lookup failed for attribute %s of relation %u",
-						 attname, childrelid);
+						 strVal(attname), childrelid);
 				attrForm = (Form_pg_attribute) GETSTRUCT(tup);
 				if (!attrForm->attnotnull)
 					ereport(ERROR,
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
-								   attname, get_rel_name(childrelid)));
+								   strVal(attname), get_rel_name(childrelid)));
 				ReleaseSysCache(tup);
 			}
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
-	foreach(lc, pkconstr->keys)
+	/* Verify that columns are not-null, or request that they be made so */
+	foreach_node(String, column, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
 
-		nnconstr = makeNotNullConstraint(lfirst(lc));
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(column));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("cannot create primary key on column \"%s\"",
+							   strVal(column)),
+						/*- translator: third %s is a constraint characteristic such as NOT VALID */
+						errdetail("The constraint \"%s\" on column \"%s\", marked %s, is incompatible with a primary key.",
+								  NameStr(conForm->conname), strVal(column), "NO INHERIT"),
+						errhint("You will need to make it inheritable using %s.",
+								"ALTER TABLE ... ALTER CONSTRAINT ... INHERIT"));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("cannot create primary key on column \"%s\"",
+							   strVal(column)),
+						/*- translator: third %s is a constraint characteristic such as NOT VALID */
+						errdetail("The constraint \"%s\" on column \"%s\", marked %s, is incompatible with a primary key.",
+								  NameStr(conForm->conname), strVal(column), "NOT VALID"),
+						errhint("You will need to validate it using %s.",
+								"ALTER TABLE ... VALIDATE CONSTRAINT"));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
+		nnconstr = makeNotNullConstraint(column);
 
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
@@ -9836,11 +9897,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12811,10 +12876,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12833,6 +12899,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -13049,6 +13120,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+						colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13917,10 +14091,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -19772,7 +19947,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2da848970be..c8d44e3086b 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2074,6 +2074,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	{
 		for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++)
 		{
+			/* FIXME use CompactAttribute */
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
 
 			if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 67d879be8b8..191a14b876e 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1251,6 +1251,7 @@ get_relation_data_width(Oid relid, int32 *attr_widths)
  * get_relation_constraints
  *
  * Retrieve the applicable constraint expressions of the given relation.
+ * Only constraints that have been validated are considered.
  *
  * Returns a List (possibly empty) of constraint expressions.  Each one
  * has been canonicalized, and its Vars are changed to have the varno
@@ -1353,7 +1354,7 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index f1156e2fca3..3c4268b271a 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4217,11 +4217,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 18a14ae186e..c80e40cd47a 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;
+			constr->has_not_null = true;	/* invalid ones included */
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -3573,6 +3573,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 8e6364d32d7..17c2996faa7 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -350,8 +350,10 @@ static void buildMatViewRefreshDependencies(Archive *fout);
 static void getTableDataFKConstraints(void);
 static void determineNotNullFlags(Archive *fout, PGresult *res, int r,
 								  TableInfo *tbinfo, int j,
-								  int i_notnull_name, int i_notnull_noinherit,
-								  int i_notnull_islocal);
+								  int i_notnull_name, int i_notnull_invalidoid,
+								  int i_notnull_noinherit,
+								  int i_notnull_islocal,
+								  PQExpBuffer *invalidnotnulloids);
 static char *format_function_arguments(const FuncInfo *finfo, const char *funcargs,
 									   bool is_agg);
 static char *format_function_signature(Archive *fout,
@@ -8984,6 +8986,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = NULL;
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -9003,6 +9006,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_invalidoid;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9089,6 +9093,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
 	 * without a name); also, such cases are never NO INHERIT.
 	 *
+	 * For invalid constraints, we need to store their OIDs for processing
+	 * elsewhere, so we bring the pg_constraint.oid value when the constraint
+	 * is invalid, and NULL otherwise.
+	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
 	 * might modify this later for servers older than 18; it's also in charge
@@ -9097,11 +9105,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "CASE WHEN NOT co.convalidated THEN co.oid "
+							 "ELSE NULL END AS notnull_invalidoid,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "NULL AS notnull_invalidoid,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9176,6 +9187,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_invalidoid = PQfnumber(res, "notnull_invalidoid");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9272,8 +9284,11 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
 								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+								  i_notnull_name,
+								  i_notnull_invalidoid,
+								  i_notnull_noinherit,
+								  i_notnull_islocal,
+								  &invalidnotnulloids);
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9294,6 +9309,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		}
 	}
 
+	/* If invalidnotnulloids has any data, finalize it */
+	if (invalidnotnulloids != NULL)
+		appendPQExpBufferChar(invalidnotnulloids, '}');
+
 	PQclear(res);
 
 	/*
@@ -9426,6 +9445,103 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about NOT NULL NOT VALID constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+
+		pg_log_info("finding invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(conoid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.conoid = c.oid)\n"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * All invalid not-null constraints must be dumped separately,
+				 * because CREATE TABLE would not create them as invalid, and
+				 * also because they must be created after potentially
+				 * violating data has been loaded.
+				 */
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -9570,18 +9686,23 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  *
  * Result row 'r' is for tbinfo's attribute 'j'.
  *
- * There are three possibilities:
+ * There are four possibilities:
  * 1) the column has no not-null constraints. In that case, ->notnull_constrs
  *    (the constraint name) remains NULL.
  * 2) The column has a constraint with no name (this is the case when
  *    constraints come from pre-18 servers).  In this case, ->notnull_constrs
  *    is set to the empty string; dumpTableSchema will print just "NOT NULL".
- * 3) The column has a constraint with a known name; in that case
+ * 3) The column has an invalid not-null constraint.  This must be treated
+ *    as a separate object (because it must be created after the table data
+ *    is loaded).  So we add its OID to invalidnotnulloids for processing
+ *    elsewhere and do nothing further with it here.  We distinguish this
+ *    case because the "notnull_invalidoid" column has been set to a non-NULL
+ *    value, which is the constraint OID.  Valid constraints have a null OID.
+ * 4) The column has a constraint with a known name; in that case
  *    notnull_constrs carries that name and dumpTableSchema will print
  *    "CONSTRAINT the_name NOT NULL".  However, if the name is the default
  *    (table_column_not_null), there's no need to print that name in the dump,
- *    so notnull_constrs is set to the empty string and it behaves as the case
- *    above.
+ *    so notnull_constrs is set to the empty string and it behaves as case 2.
  *
  * In a child table that inherits from a parent already containing NOT NULL
  * constraints and the columns in the child don't have their own NOT NULL
@@ -9593,7 +9714,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  * Any of these constraints might have the NO INHERIT bit.  If so we set
  * ->notnull_noinh and NO INHERIT will be printed by dumpTableSchema.
  *
- * In case 3 above, the name comparison is a bit of a hack; it actually fails
+ * In case 4 above, the name comparison is a bit of a hack; it actually fails
  * to do the right thing in all but the trivial case.  However, the downside
  * of getting it wrong is simply that the name is printed rather than
  * suppressed, so it's not a big deal.
@@ -9601,11 +9722,41 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 static void
 determineNotNullFlags(Archive *fout, PGresult *res, int r,
 					  TableInfo *tbinfo, int j,
-					  int i_notnull_name, int i_notnull_noinherit,
-					  int i_notnull_islocal)
+					  int i_notnull_name,
+					  int i_notnull_invalidoid,
+					  int i_notnull_noinherit,
+					  int i_notnull_islocal,
+					  PQExpBuffer *invalidnotnulloids)
 {
 	DumpOptions *dopt = fout->dopt;
 
+	/*
+	 * If this not-null constraint is not valid, list its OID in
+	 * invalidnotnulloids and do nothing further.  It'll be processed
+	 * elsewhere later.
+	 *
+	 * Because invalid not-null constraints are rare, we don't want to malloc
+	 * invalidnotnulloids until we're sure we're going it need it, which
+	 * happens here.
+	 */
+	if (!PQgetisnull(res, r, i_notnull_invalidoid))
+	{
+		char	   *constroid = PQgetvalue(res, r, i_notnull_invalidoid);
+
+		if (*invalidnotnulloids == NULL)
+		{
+			*invalidnotnulloids = createPQExpBuffer();
+			appendPQExpBufferChar(*invalidnotnulloids, '{');
+			appendPQExpBuffer(*invalidnotnulloids, "%s", constroid);
+		}
+		else
+			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
+
+		/* nothing else to do */
+		tbinfo->notnull_constrs[j] = NULL;
+		return;
+	}
+
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
 	 * though flagInhAttrs may change that one later in versions < 18.
@@ -18152,13 +18303,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18178,7 +18336,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e6f0f86a459..b426b5e4736 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -498,6 +498,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 576326daec7..6c03eca8e50 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -744,8 +744,8 @@ my %pgdump_runs = (
 	schema_only_with_statistics => {
 		dump_cmd => [
 			'pg_dump', '--no-sync',
-			"--file=$tempdir/schema_only_with_statistics.sql", '--schema-only',
-			'--with-statistics', 'postgres',
+			"--file=$tempdir/schema_only_with_statistics.sql",
+			'--schema-only', '--with-statistics', 'postgres',
 		],
 	},
 	no_schema => {
@@ -1118,6 +1118,23 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / INVALID' => {
+		create_sql => 'CREATE TABLE dump_test.test_table_nn (
+							col1 int);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
+			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+			/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_post_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 8970677ac64..1d08268393e 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3106,7 +3106,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3129,14 +3130,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..5523cfcf5aa 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* any not-null, including not valid ones */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 208936962ef..b573a0a2828 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202504041
+#define CATALOG_VERSION_NO	202504051
 
 #endif
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..4afceb5c692 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -264,7 +264,7 @@ extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..8a44321034b 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1202,6 +1202,75 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id" NOT VALID
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id"
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+ROLLBACK;
+-- leave a table in this state for the pg_upgrade test
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index a719d2f74e9..d8547a9bc81 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1229,6 +1229,13 @@ alter table cnn_uq add unique using index cnn_uq_idx;
 Indexes:
     "cnn_uq_idx" UNIQUE CONSTRAINT, btree (a)
 
+-- can't create a primary key on a noinherit not-null
+create table cnn_pk (a int not null no inherit);
+alter table cnn_pk add primary key (a);
+ERROR:  cannot create primary key on column "a"
+DETAIL:  The constraint "cnn_pk_a_not_null" on column "a", marked NO INHERIT, is incompatible with a primary key.
+HINT:  You will need to make it inheritable using ALTER TABLE ... ALTER CONSTRAINT ... INHERIT.
+drop table cnn_pk;
 -- Ensure partitions are scanned for null values when adding a PK
 create table cnn2_parted(a int) partition by list (a);
 create table cnn_part1 partition of cnn2_parted for values in (1, null);
@@ -1355,6 +1362,249 @@ Not-null constraints:
     "ann" NOT NULL "a"
     "bnn" NOT NULL "b"
 
+-- NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass as tabname, conname, convalidated, conislocal, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY conrelid::regclass::text, conname;
+CREATE TABLE notnull_tbl1 (a int, b int);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+-- even an invalid not-null forbids new nulls
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- If we have an invalid constraint, we can't have another
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- cannot add primary key on a column with an invalid not-null
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  cannot create primary key on column "a"
+DETAIL:  The constraint "nn" on column "a", marked NOT VALID, is incompatible with a primary key.
+HINT:  You will need to validate it using ALTER TABLE ... VALIDATE CONSTRAINT.
+-- ALTER column SET NOT NULL validates an invalid constraint (but this fails
+-- because of rows with null values)
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- Creating a derived table using LIKE gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_copy (LIKE notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_copy}');
+      tabname      | conname | convalidated | conislocal | coninhcount 
+-------------------+---------+--------------+------------+-------------
+ notnull_tbl1_copy | nn      | t            | t          |           0
+(1 row)
+
+-- An inheritance child table gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_child (a int, b int) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      tabname       | conname | convalidated | conislocal | coninhcount 
+--------------------+---------+--------------+------------+-------------
+ notnull_tbl1       | nn      | f            | t          |           0
+ notnull_tbl1_child | nn      | t            | f          |           1
+(2 rows)
+
+-- Also try inheritance added after table creation
+CREATE TABLE notnull_tbl1_child2 (c int, b int, a int);
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;	-- nope
+ERROR:  column "a" in child table "notnull_tbl1_child2" must be marked NOT NULL
+ALTER TABLE notnull_tbl1_child2 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child2}');
+       tabname       |            conname             | convalidated | conislocal | coninhcount 
+---------------------+--------------------------------+--------------+------------+-------------
+ notnull_tbl1_child2 | notnull_tbl1_child2_a_not_null | f            | t          |           1
+(1 row)
+
+-- VALIDATE CONSTRAINT scans the table
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- error, nulls exist
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- now ok
+EXECUTE get_nnconstraint_info('{notnull_tbl1}');
+   tabname    | conname | convalidated | conislocal | coninhcount 
+--------------+---------+--------------+------------+-------------
+ notnull_tbl1 | nn      | t            | t          |           0
+(1 row)
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child, notnull_tbl1_child2;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nntbl1_a NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT nntbl1_a;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- if a parent has a valid not null constraint then a child table cannot
+-- have an invalid one
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld0 (a int, CONSTRAINT nn_chld0 NOT NULL a);
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+ALTER TABLE notnull_chld0 DROP CONSTRAINT nn_chld0;
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --now ok
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld0}');
+    tabname    |  conname  | convalidated | conislocal | coninhcount 
+---------------+-----------+--------------+------------+-------------
+ notnull_chld0 | nn_chld0  | f            | t          |           0
+ notnull_tbl1  | nn_parent | t            | t          |           1
+(2 rows)
+
+DROP TABLE notnull_tbl1, notnull_chld0;
+-- Test invalid not null on inheritance table.
+CREATE TABLE notnull_inhparent (i int);
+CREATE TABLE notnull_inhchild (i int) INHERITS (notnull_inhparent);
+NOTICE:  merging column "i" with inherited definition
+CREATE TABLE notnull_inhgrand () INHERITS (notnull_inhparent, notnull_inhchild);
+NOTICE:  merging multiple inherited definitions of column "i"
+ALTER TABLE notnull_inhparent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE notnull_inhchild ADD CONSTRAINT nn1 NOT NULL i; -- error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_inhchild"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+      tabname      | conname | convalidated | conislocal | coninhcount 
+-------------------+---------+--------------+------------+-------------
+ notnull_inhchild  | nn      | f            | f          |           1
+ notnull_inhgrand  | nn      | f            | f          |           2
+ notnull_inhparent | nn      | f            | t          |           0
+(3 rows)
+
+ALTER TABLE notnull_inhparent ALTER i SET NOT NULL; -- ok
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+      tabname      | conname | convalidated | conislocal | coninhcount 
+-------------------+---------+--------------+------------+-------------
+ notnull_inhchild  | nn      | t            | f          |           1
+ notnull_inhgrand  | nn      | t            | f          |           2
+ notnull_inhparent | nn      | t            | t          |           0
+(3 rows)
+
+DROP TABLE notnull_inhparent, notnull_inhchild, notnull_inhgrand;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    tabname     |   conname   | convalidated | conislocal | coninhcount 
+----------------+-------------+--------------+------------+-------------
+ notnull_tbl1   | notnull_con | f            | t          |           0
+ notnull_tbl1_1 | notnull_con | t            | f          |           1
+ notnull_tbl1_2 | nn2         | t            | f          |           1
+ notnull_tbl1_3 | nn3         | f            | f          |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, notnull_tbl1_3 have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    tabname     |   conname   | convalidated | conislocal | coninhcount 
+----------------+-------------+--------------+------------+-------------
+ notnull_tbl1   | notnull_con | t            | t          |           0
+ notnull_tbl1_1 | notnull_con | t            | f          |           1
+ notnull_tbl1_2 | nn2         | t            | f          |           1
+ notnull_tbl1_3 | nn3         | t            | f          |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-- partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a int, b int, NOT NULL a) PARTITION BY LIST (a);
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a int, b int);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a int);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal
+FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass)
+ORDER BY 1;
+      conrelid      | contype | convalidated | conislocal 
+--------------------+---------+--------------+------------
+ notnull_parent_upg | n       | f            | t
+ notnull_child_upg  | n       | t            | t
+(2 rows)
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+       tabname       |   conname   | convalidated | conislocal | coninhcount 
+---------------------+-------------+--------------+------------+-------------
+ notnull_part1_1_upg | notnull_con | t            | f          |           1
+ notnull_part1_2_upg | nn2         | t            | f          |           1
+ notnull_part1_3_upg | nn3         | f            | f          |           1
+ notnull_part1_upg   | notnull_con | f            | t          |           0
+(4 rows)
+
+DEALLOCATE get_nnconstraint_info;
+-- end NOT NULL NOT VALID
 -- Comments
 -- Setup a low-level role to enforce non-superuser checks.
 CREATE ROLE regress_constraint_comments;
diff --git a/src/test/regress/expected/sanity_check.out b/src/test/regress/expected/sanity_check.out
index 8370c1561cc..2e39037e3fb 100644
--- a/src/test/regress/expected/sanity_check.out
+++ b/src/test/regress/expected/sanity_check.out
@@ -25,3 +25,23 @@ SELECT relname, relkind
 ---------+---------
 (0 rows)
 
+-- pg_attribute sanity check: attnotnullvalid can only be true when
+-- attnotnull is valid.
+select pa.attrelid::regclass, pa.attname, pa.attnum,
+       pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa
+where not pa.attnotnull and pa.attnotnullvalid;
+ attrelid | attname | attnum | attnotnull | attnotnullvalid 
+----------+---------+--------+------------+-----------------
+(0 rows)
+
+-- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
+select att.attrelid::regclass, att.attname, att.attnotnull,
+       att.attnotnullvalid, con.convalidated
+  from pg_attribute att join pg_constraint con
+    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
+ where contype = 'n' and con.convalidated <> att.attnotnullvalid;
+ attrelid | attname | attnotnull | attnotnullvalid | convalidated 
+----------+---------+------------+-----------------+--------------
+(0 rows)
+
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 84e93ef575e..8432e8e3d54 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -910,6 +910,20 @@ alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
 
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+ROLLBACK;
+-- leave a table in this state for the pg_upgrade test
+
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..8f199c7ba34 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -761,6 +761,11 @@ create unique index cnn_uq_idx on cnn_uq (a);
 alter table cnn_uq add unique using index cnn_uq_idx;
 \d+ cnn_uq
 
+-- can't create a primary key on a noinherit not-null
+create table cnn_pk (a int not null no inherit);
+alter table cnn_pk add primary key (a);
+drop table cnn_pk;
+
 -- Ensure partitions are scanned for null values when adding a PK
 create table cnn2_parted(a int) partition by list (a);
 create table cnn_part1 partition of cnn2_parted for values in (1, null);
@@ -801,6 +806,167 @@ ALTER TABLE ONLY notnull_tbl6 DROP CONSTRAINT ann;
 ALTER TABLE ONLY notnull_tbl6 ALTER b DROP NOT NULL;
 \d+ notnull_tbl6_1
 
+
+-- NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass as tabname, conname, convalidated, conislocal, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY conrelid::regclass::text, conname;
+
+CREATE TABLE notnull_tbl1 (a int, b int);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+-- even an invalid not-null forbids new nulls
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+\d+ notnull_tbl1
+
+-- If we have an invalid constraint, we can't have another
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- cannot add primary key on a column with an invalid not-null
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- ALTER column SET NOT NULL validates an invalid constraint (but this fails
+-- because of rows with null values)
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+\d+ notnull_tbl1
+
+-- Creating a derived table using LIKE gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_copy (LIKE notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_copy}');
+
+-- An inheritance child table gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_child (a int, b int) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+-- Also try inheritance added after table creation
+CREATE TABLE notnull_tbl1_child2 (c int, b int, a int);
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;	-- nope
+ALTER TABLE notnull_tbl1_child2 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child2}');
+
+-- VALIDATE CONSTRAINT scans the table
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- error, nulls exist
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- now ok
+EXECUTE get_nnconstraint_info('{notnull_tbl1}');
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child, notnull_tbl1_child2;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nntbl1_a NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT nntbl1_a;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+-- if a parent has a valid not null constraint then a child table cannot
+-- have an invalid one
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld0 (a int, CONSTRAINT nn_chld0 NOT NULL a);
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+ALTER TABLE notnull_chld0 DROP CONSTRAINT nn_chld0;
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --now ok
+
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld0}');
+DROP TABLE notnull_tbl1, notnull_chld0;
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE notnull_inhparent (i int);
+CREATE TABLE notnull_inhchild (i int) INHERITS (notnull_inhparent);
+CREATE TABLE notnull_inhgrand () INHERITS (notnull_inhparent, notnull_inhchild);
+ALTER TABLE notnull_inhparent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE notnull_inhchild ADD CONSTRAINT nn1 NOT NULL i; -- error
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+ALTER TABLE notnull_inhparent ALTER i SET NOT NULL; -- ok
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+DROP TABLE notnull_inhparent, notnull_inhchild, notnull_inhgrand;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, notnull_tbl1_3 have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-- partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a int, b int, NOT NULL a) PARTITION BY LIST (a);
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a int, b int);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a int);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal
+FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass)
+ORDER BY 1;
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+DEALLOCATE get_nnconstraint_info;
+
+-- end NOT NULL NOT VALID
+
+
 -- Comments
 -- Setup a low-level role to enforce non-superuser checks.
 CREATE ROLE regress_constraint_comments;
diff --git a/src/test/regress/sql/sanity_check.sql b/src/test/regress/sql/sanity_check.sql
index 162e5324b5d..6ef36ab84b7 100644
--- a/src/test/regress/sql/sanity_check.sql
+++ b/src/test/regress/sql/sanity_check.sql
@@ -19,3 +19,17 @@ SELECT relname, relkind
   FROM pg_class
  WHERE relkind IN ('v', 'c', 'f', 'p', 'I')
        AND relfilenode <> 0;
+
+-- pg_attribute sanity check: attnotnullvalid can only be true when
+-- attnotnull is valid.
+select pa.attrelid::regclass, pa.attname, pa.attnum,
+       pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa
+where not pa.attnotnull and pa.attnotnullvalid;
+
+-- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
+select att.attrelid::regclass, att.attname, att.attnotnull,
+       att.attnotnullvalid, con.convalidated
+  from pg_attribute att join pg_constraint con
+    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
+ where contype = 'n' and con.convalidated <> att.attnotnullvalid;
-- 
2.39.5

From 1842214bfbaff31a26f2641f9f81872835e041d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Sun, 6 Apr 2025 19:45:52 +0200
Subject: [PATCH v8 2/3] Remove attnotnullvalid again

TupleDesc construction already has a pg_constraint scan.  This
introduces a bit of ugliness, but the benefit is that we don't need
another pg_attribute column.  However, some regression tests aren't
passing, and it seems to be because we don't set attnullability
correctly everywhere.
---
 doc/src/sgml/catalogs.sgml                 | 11 +---
 src/backend/access/common/tupdesc.c        | 17 ++----
 src/backend/bootstrap/bootstrap.c          |  3 -
 src/backend/catalog/genbki.pl              |  3 -
 src/backend/catalog/heap.c                 |  8 ---
 src/backend/commands/tablecmds.c           | 47 +++++++--------
 src/backend/optimizer/util/plancat.c       | 11 ++--
 src/backend/utils/cache/catcache.c         |  1 -
 src/backend/utils/cache/relcache.c         | 66 +++++++++++++++++++---
 src/include/access/tupdesc.h               |  9 +--
 src/include/catalog/pg_attribute.h         |  3 -
 src/test/regress/expected/sanity_check.out | 20 -------
 src/test/regress/sql/sanity_check.sql      | 14 -----
 13 files changed, 100 insertions(+), 113 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 3ab7d7b68aa..cbd4e40a320 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,16 +1260,7 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a (possibly unvalidated) not-null constraint.
-      </para></entry>
-     </row>
-
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>attnotnullvalid</structfield> <type>bool</type>
-      </para>
-      <para>
-       Whether the not-null constraint, if one exists, has been validated.
+       This column has a (possibly invalid) not-null constraint.
       </para></entry>
      </row>
 
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 320de2cbda0..5831788cbff 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,8 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
-		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
+		ATTNULLABLE_UNKNOWN;
 
 	switch (src->attalign)
 	{
@@ -145,9 +145,10 @@ verify_compact_attribute(TupleDesc tupdesc, int attnum)
 
 	/*
 	 * Make the attcacheoff match since it's been reset to -1 by
-	 * populate_compact_attribute_internal.
+	 * populate_compact_attribute_internal.  Same with attnullability.
 	 */
 	tmp.attcacheoff = cattr->attcacheoff;
+	tmp.attnullability = cattr->attnullability;
 
 	/* Check the freshly populated CompactAttribute matches the TupleDesc's */
 	Assert(memcmp(&tmp, cattr, sizeof(CompactAttribute)) == 0);
@@ -253,7 +254,6 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
-		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -300,7 +300,6 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
-		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -421,7 +420,6 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
-		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -468,7 +466,6 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
-	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -567,6 +564,8 @@ DecrTupleDescRefCount(TupleDesc tupdesc)
 
 /*
  * Compare two TupleDesc structures for logical equality
+ *
+ * XXX should we compare CompactAttribute->attnullability here?
  */
 bool
 equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
@@ -618,8 +617,6 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
-		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
-			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -848,7 +845,6 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
-	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -912,7 +908,6 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
-	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 44ec9e58520..6db864892d0 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,9 +615,6 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
-
-	/* Not-null constraints on system catalogs are always valid. */
-	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index bdf55d7dc8d..df3231fcd41 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,9 +986,6 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
-	# Not-null constraints on system catalogs are always valid.
-	$row->{attnotnullvalid} = $row->{attnotnull};
-
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 503e7cb3f58..fbaed5359ad 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,7 +151,6 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -165,7 +164,6 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -179,7 +177,6 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -193,7 +190,6 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -207,7 +203,6 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -227,7 +222,6 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -759,7 +753,6 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
-		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1721,7 +1714,6 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
-	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0c7b1231c2e..b86c55c7430 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1427,7 +1427,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
+		att->attnotnull = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -6222,16 +6222,18 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
-			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
+			CompactAttribute *attr = TupleDescCompactAttr(newTupDesc, i);
 
-			if (attr->attnotnull && attr->attnotnullvalid &&
+			if (attr->attnullability != ATTNULLABLE_UNRESTRICTED &&
 				!attr->attisdropped)
 			{
-				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
-					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
+				Form_pg_attribute	wholeatt = TupleDescAttr(newTupDesc, i);
+
+				if (wholeatt->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
+					notnull_attrs = lappend_int(notnull_attrs, wholeatt->attnum);
 				else
 					notnull_virtual_attrs = lappend_int(notnull_virtual_attrs,
-														attr->attnum);
+														wholeatt->attnum);
 			}
 		}
 		if (notnull_attrs || notnull_virtual_attrs)
@@ -7795,7 +7797,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
+	 * dropconstraint_internal() resets attnotnull.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7820,10 +7822,10 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  *		Helper to update/validate the pg_attribute status of a not-null
  *		constraint
  *
- * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
- * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
- * true, also set up wqueue to validate the constraint.  wqueue may be given
- * as NULL when validation is not needed (e.g., on table creation).
+ * pg_attribute.attnotnull is set true, if it isn't already.
+ * If queue_validation is true, also set up wqueue to validate the constraint.
+ * wqueue may be given as NULL when validation is not needed (e.g., on table
+ * creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
@@ -7843,7 +7845,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
+	if (!attr->attnotnull)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7858,7 +7860,6 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
 
 		attr->attnotnull = true;
-		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -9899,8 +9900,8 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		/*
 		 * If adding a valid not-null constraint, set the pg_attribute flag
 		 * and tell phase 3 to verify existing rows, if needed.  For an
-		 * invalid constraint, just set attnotnull and attnotnullvalid,
-		 * without queueing verification.
+		 * invalid constraint, just set attnotnull, without queueing
+		 * verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
 			set_attnotnull(wqueue, rel, ccon->attnum,
@@ -14091,11 +14092,10 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull and attnotnullvalid if needed */
+		/* All good -- reset attnotnull if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
-			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -19945,18 +19945,19 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 
 		for (i = 1; i <= natts; i++)
 		{
-			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
+			CompactAttribute *att = TupleDescCompactAttr(scanrel->rd_att, i - 1);
 
-			/* invalid not-null constraint must be ignored */
-			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
+			/* invalid not-null constraint must be ignored here */
+			if (att->attnullability == ATTNULLABLE_VALID && !att->attisdropped)
 			{
+				Form_pg_attribute wholeatt = TupleDescAttr(scanrel->rd_att, i - 1);
 				NullTest   *ntest = makeNode(NullTest);
 
 				ntest->arg = (Expr *) makeVar(1,
 											  i,
-											  att->atttypid,
-											  att->atttypmod,
-											  att->attcollation,
+											  wholeatt->atttypid,
+											  wholeatt->atttypmod,
+											  wholeatt->attcollation,
 											  0);
 				ntest->nulltesttype = IS_NOT_NULL;
 
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 191a14b876e..b3d41596b87 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -1352,17 +1352,18 @@ get_relation_constraints(PlannerInfo *root,
 
 			for (i = 1; i <= natts; i++)
 			{
-				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
+				CompactAttribute *att = TupleDescCompactAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
+				if (att->attnullability == ATTNULLABLE_VALID && !att->attisdropped)
 				{
+					Form_pg_attribute wholeatt = TupleDescAttr(relation->rd_att, i - 1);
 					NullTest   *ntest = makeNode(NullTest);
 
 					ntest->arg = (Expr *) makeVar(varno,
 												  i,
-												  att->atttypid,
-												  att->atttypmod,
-												  att->attcollation,
+												  wholeatt->atttypid,
+												  wholeatt->atttypmod,
+												  wholeatt->attcollation,
 												  0);
 					ntest->nulltesttype = IS_NOT_NULL;
 
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 70c11529b90..9ad7681f155 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,7 +1142,6 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
-			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index c80e40cd47a..4128cfa8314 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -307,7 +307,7 @@ static TupleDesc GetPgClassDescriptor(void);
 static TupleDesc GetPgIndexDescriptor(void);
 static void AttrDefaultFetch(Relation relation, int ndef);
 static int	AttrDefaultCmp(const void *a, const void *b);
-static void CheckConstraintFetch(Relation relation);
+static void CheckNNConstraintFetch(Relation relation);
 static int	CheckConstraintCmp(const void *a, const void *b);
 static void InitIndexAmRoutine(Relation relation);
 static void IndexSupportInitialize(oidvector *indclass,
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;	/* invalid ones included */
+			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -693,9 +693,38 @@ RelationBuildTupleDesc(Relation relation)
 
 		constr->missing = attrmiss;
 
-		if (relation->rd_rel->relchecks > 0)	/* CHECKs */
-			CheckConstraintFetch(relation);
-		else
+		/* CHECK and NOT NULLs */
+		if (!IsCatalogRelation(relation) &&
+			(relation->rd_rel->relchecks > 0 || constr->has_not_null))
+			CheckNNConstraintFetch(relation);
+
+		/*
+		 * Any not-null constraint that wasn't marked invalid by
+		 * CheckNNConstraintFetch must necessarily be valid; make it so in the
+		 * CompactAttribute array.  In catalog relations however, any not-null
+		 * constraint is necessarily valid.
+		 */
+		for (int i = 0; i < relation->rd_rel->relnatts - 1; i++)
+		{
+			CompactAttribute *attr;
+
+			attr = TupleDescCompactAttr(relation->rd_att, i);
+
+			if (IsCatalogRelation(relation))
+			{
+				if (attr->attnullability == ATTNULLABLE_UNKNOWN)
+					attr->attnullability = ATTNULLABLE_VALID;
+				continue;
+			}
+
+			if (attr->attnullability == ATTNULLABLE_UNKNOWN)
+				attr->attnullability = ATTNULLABLE_VALID;
+			else
+				Assert(attr->attnullability == ATTNULLABLE_INVALID ||
+					   attr->attnullability == ATTNULLABLE_UNRESTRICTED);
+		}
+
+		if (relation->rd_rel->relchecks == 0)
 			constr->num_check = 0;
 	}
 	else
@@ -3573,7 +3602,6 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
-		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
@@ -4534,13 +4562,14 @@ AttrDefaultCmp(const void *a, const void *b)
 }
 
 /*
- * Load any check constraints for the relation.
+ * Load any check constraints for the relation, and update not-null validity
+ * of invalid constraints.
  *
  * As with defaults, if we don't find the expected number of them, just warn
  * here.  The executor should throw an error if an INSERT/UPDATE is attempted.
  */
 static void
-CheckConstraintFetch(Relation relation)
+CheckNNConstraintFetch(Relation relation)
 {
 	ConstrCheck *check;
 	int			ncheck = relation->rd_rel->relchecks;
@@ -4571,6 +4600,27 @@ CheckConstraintFetch(Relation relation)
 		Datum		val;
 		bool		isnull;
 
+		/*
+		 * Consider only invalid not-null constraints and mark the TupleDesc
+		 * entry invalid.
+		 */
+		if (!IsCatalogRelation(relation) &&
+			conform->contype == CONSTRAINT_NOTNULL)
+		{
+			if (!conform->convalidated)
+			{
+				AttrNumber	attnum;
+
+				attnum = extractNotNullColumn(htup);
+				Assert(relation->rd_att->compact_attrs[attnum - 1].attnullability ==
+					   ATTNULLABLE_UNKNOWN);
+				relation->rd_att->compact_attrs[attnum - 1].attnullability =
+					ATTNULLABLE_INVALID;
+			}
+
+			continue;
+		}
+
 		/* We want check constraints only */
 		if (conform->contype != CONSTRAINT_CHECK)
 			continue;
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 5523cfcf5aa..1600f967032 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -76,14 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	char		attnullability; /* attnotnull + attnotnullvalid */
+	char		attnullability; /* status of not-null constraint, see below */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
 /* Valid values for CompactAttribute->attnullability */
-#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
-#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
-#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+#define	ATTNULLABLE_UNRESTRICTED 'f' /* No constraint exists */
+#define	ATTNULLABLE_UNKNOWN		'u' /* constraint exists, validity unknown */
+#define	ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define	ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
 
 /*
  * This struct is passed around within the backend to describe the structure
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 9b1236e7a90..df7a77ee224 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -120,9 +120,6 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
-	/* Whether the not-null constraint, if it exists, is valid */
-	bool		attnotnullvalid;
-
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/test/regress/expected/sanity_check.out b/src/test/regress/expected/sanity_check.out
index 2e39037e3fb..8370c1561cc 100644
--- a/src/test/regress/expected/sanity_check.out
+++ b/src/test/regress/expected/sanity_check.out
@@ -25,23 +25,3 @@ SELECT relname, relkind
 ---------+---------
 (0 rows)
 
--- pg_attribute sanity check: attnotnullvalid can only be true when
--- attnotnull is valid.
-select pa.attrelid::regclass, pa.attname, pa.attnum,
-       pa.attnotnull, pa.attnotnullvalid
-from    pg_attribute pa
-where not pa.attnotnull and pa.attnotnullvalid;
- attrelid | attname | attnum | attnotnull | attnotnullvalid 
-----------+---------+--------+------------+-----------------
-(0 rows)
-
--- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
-select att.attrelid::regclass, att.attname, att.attnotnull,
-       att.attnotnullvalid, con.convalidated
-  from pg_attribute att join pg_constraint con
-    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
- where contype = 'n' and con.convalidated <> att.attnotnullvalid;
- attrelid | attname | attnotnull | attnotnullvalid | convalidated 
-----------+---------+------------+-----------------+--------------
-(0 rows)
-
diff --git a/src/test/regress/sql/sanity_check.sql b/src/test/regress/sql/sanity_check.sql
index 6ef36ab84b7..162e5324b5d 100644
--- a/src/test/regress/sql/sanity_check.sql
+++ b/src/test/regress/sql/sanity_check.sql
@@ -19,17 +19,3 @@ SELECT relname, relkind
   FROM pg_class
  WHERE relkind IN ('v', 'c', 'f', 'p', 'I')
        AND relfilenode <> 0;
-
--- pg_attribute sanity check: attnotnullvalid can only be true when
--- attnotnull is valid.
-select pa.attrelid::regclass, pa.attname, pa.attnum,
-       pa.attnotnull, pa.attnotnullvalid
-from    pg_attribute pa
-where not pa.attnotnull and pa.attnotnullvalid;
-
--- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
-select att.attrelid::regclass, att.attname, att.attnotnull,
-       att.attnotnullvalid, con.convalidated
-  from pg_attribute att join pg_constraint con
-    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
- where contype = 'n' and con.convalidated <> att.attnotnullvalid;
-- 
2.39.5

From 70ecb5835cc71521d552d7ba176b815e58076b05 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Sun, 6 Apr 2025 19:47:22 +0200
Subject: [PATCH v8 3/3] get_relation_info: assert correct attnullability

This fails immediately, proving we're missing some spot to set
attnullability.
---
 src/backend/optimizer/util/plancat.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index b3d41596b87..ba1702c993b 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,6 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
+			Assert(attr->attnullability != ATTNULLABLE_UNKNOWN);
 			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
-- 
2.39.5

From f9b4cdeeb4420ad41a8ef965c5ed71a3fee3a961 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 7 Apr 2025 09:51:47 +0530
Subject: [PATCH 2/3] Remove attnotnullvalid again

TupleDesc construction already has a pg_constraint scan.  This
introduces a bit of ugliness, but the benefit is that we don't need
another pg_attribute column.  However, some regression tests aren't
passing, and it seems to be because we don't set attnullability
correctly everywhere.
---
 doc/src/sgml/catalogs.sgml                 | 11 +---
 src/backend/access/common/tupdesc.c        | 17 ++----
 src/backend/bootstrap/bootstrap.c          |  3 -
 src/backend/catalog/genbki.pl              |  3 -
 src/backend/catalog/heap.c                 |  8 ---
 src/backend/commands/tablecmds.c           | 47 +++++++--------
 src/backend/optimizer/util/plancat.c       | 11 ++--
 src/backend/utils/cache/catcache.c         |  1 -
 src/backend/utils/cache/relcache.c         | 66 +++++++++++++++++++---
 src/include/access/tupdesc.h               |  9 +--
 src/include/catalog/pg_attribute.h         |  3 -
 src/test/regress/expected/sanity_check.out | 20 -------
 src/test/regress/sql/sanity_check.sql      | 14 -----
 13 files changed, 100 insertions(+), 113 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 3ab7d7b68aa..cbd4e40a320 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,16 +1260,7 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a (possibly unvalidated) not-null constraint.
-      </para></entry>
-     </row>
-
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>attnotnullvalid</structfield> <type>bool</type>
-      </para>
-      <para>
-       Whether the not-null constraint, if one exists, has been validated.
+       This column has a (possibly invalid) not-null constraint.
       </para></entry>
      </row>
 
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 320de2cbda0..5831788cbff 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,8 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
-		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
+		ATTNULLABLE_UNKNOWN;
 
 	switch (src->attalign)
 	{
@@ -145,9 +145,10 @@ verify_compact_attribute(TupleDesc tupdesc, int attnum)
 
 	/*
 	 * Make the attcacheoff match since it's been reset to -1 by
-	 * populate_compact_attribute_internal.
+	 * populate_compact_attribute_internal.  Same with attnullability.
 	 */
 	tmp.attcacheoff = cattr->attcacheoff;
+	tmp.attnullability = cattr->attnullability;
 
 	/* Check the freshly populated CompactAttribute matches the TupleDesc's */
 	Assert(memcmp(&tmp, cattr, sizeof(CompactAttribute)) == 0);
@@ -253,7 +254,6 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
-		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -300,7 +300,6 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
-		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -421,7 +420,6 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
-		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -468,7 +466,6 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
-	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -567,6 +564,8 @@ DecrTupleDescRefCount(TupleDesc tupdesc)
 
 /*
  * Compare two TupleDesc structures for logical equality
+ *
+ * XXX should we compare CompactAttribute->attnullability here?
  */
 bool
 equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
@@ -618,8 +617,6 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
-		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
-			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -848,7 +845,6 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
-	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -912,7 +908,6 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
-	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 44ec9e58520..6db864892d0 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,9 +615,6 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
-
-	/* Not-null constraints on system catalogs are always valid. */
-	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index bdf55d7dc8d..df3231fcd41 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,9 +986,6 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
-	# Not-null constraints on system catalogs are always valid.
-	$row->{attnotnullvalid} = $row->{attnotnull};
-
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 503e7cb3f58..fbaed5359ad 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,7 +151,6 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -165,7 +164,6 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -179,7 +177,6 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -193,7 +190,6 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -207,7 +203,6 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -227,7 +222,6 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
-	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -759,7 +753,6 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
-		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1721,7 +1714,6 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
-	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0c7b1231c2e..b86c55c7430 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1427,7 +1427,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
+		att->attnotnull = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -6222,16 +6222,18 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
-			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
+			CompactAttribute *attr = TupleDescCompactAttr(newTupDesc, i);
 
-			if (attr->attnotnull && attr->attnotnullvalid &&
+			if (attr->attnullability != ATTNULLABLE_UNRESTRICTED &&
 				!attr->attisdropped)
 			{
-				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
-					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
+				Form_pg_attribute	wholeatt = TupleDescAttr(newTupDesc, i);
+
+				if (wholeatt->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
+					notnull_attrs = lappend_int(notnull_attrs, wholeatt->attnum);
 				else
 					notnull_virtual_attrs = lappend_int(notnull_virtual_attrs,
-														attr->attnum);
+														wholeatt->attnum);
 			}
 		}
 		if (notnull_attrs || notnull_virtual_attrs)
@@ -7795,7 +7797,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
+	 * dropconstraint_internal() resets attnotnull.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7820,10 +7822,10 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
  *		Helper to update/validate the pg_attribute status of a not-null
  *		constraint
  *
- * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
- * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
- * true, also set up wqueue to validate the constraint.  wqueue may be given
- * as NULL when validation is not needed (e.g., on table creation).
+ * pg_attribute.attnotnull is set true, if it isn't already.
+ * If queue_validation is true, also set up wqueue to validate the constraint.
+ * wqueue may be given as NULL when validation is not needed (e.g., on table
+ * creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
@@ -7843,7 +7845,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
+	if (!attr->attnotnull)
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7858,7 +7860,6 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
 
 		attr->attnotnull = true;
-		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
@@ -9899,8 +9900,8 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		/*
 		 * If adding a valid not-null constraint, set the pg_attribute flag
 		 * and tell phase 3 to verify existing rows, if needed.  For an
-		 * invalid constraint, just set attnotnull and attnotnullvalid,
-		 * without queueing verification.
+		 * invalid constraint, just set attnotnull, without queueing
+		 * verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
 			set_attnotnull(wqueue, rel, ccon->attnum,
@@ -14091,11 +14092,10 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull and attnotnullvalid if needed */
+		/* All good -- reset attnotnull if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
-			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -19945,18 +19945,19 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 
 		for (i = 1; i <= natts; i++)
 		{
-			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
+			CompactAttribute *att = TupleDescCompactAttr(scanrel->rd_att, i - 1);
 
-			/* invalid not-null constraint must be ignored */
-			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
+			/* invalid not-null constraint must be ignored here */
+			if (att->attnullability == ATTNULLABLE_VALID && !att->attisdropped)
 			{
+				Form_pg_attribute wholeatt = TupleDescAttr(scanrel->rd_att, i - 1);
 				NullTest   *ntest = makeNode(NullTest);
 
 				ntest->arg = (Expr *) makeVar(1,
 											  i,
-											  att->atttypid,
-											  att->atttypmod,
-											  att->attcollation,
+											  wholeatt->atttypid,
+											  wholeatt->atttypmod,
+											  wholeatt->attcollation,
 											  0);
 				ntest->nulltesttype = IS_NOT_NULL;
 
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 191a14b876e..b3d41596b87 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -1352,17 +1352,18 @@ get_relation_constraints(PlannerInfo *root,
 
 			for (i = 1; i <= natts; i++)
 			{
-				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
+				CompactAttribute *att = TupleDescCompactAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
+				if (att->attnullability == ATTNULLABLE_VALID && !att->attisdropped)
 				{
+					Form_pg_attribute wholeatt = TupleDescAttr(relation->rd_att, i - 1);
 					NullTest   *ntest = makeNode(NullTest);
 
 					ntest->arg = (Expr *) makeVar(varno,
 												  i,
-												  att->atttypid,
-												  att->atttypmod,
-												  att->attcollation,
+												  wholeatt->atttypid,
+												  wholeatt->atttypmod,
+												  wholeatt->attcollation,
 												  0);
 					ntest->nulltesttype = IS_NOT_NULL;
 
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 70c11529b90..9ad7681f155 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,7 +1142,6 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
-			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index c80e40cd47a..4128cfa8314 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -307,7 +307,7 @@ static TupleDesc GetPgClassDescriptor(void);
 static TupleDesc GetPgIndexDescriptor(void);
 static void AttrDefaultFetch(Relation relation, int ndef);
 static int	AttrDefaultCmp(const void *a, const void *b);
-static void CheckConstraintFetch(Relation relation);
+static void CheckNNConstraintFetch(Relation relation);
 static int	CheckConstraintCmp(const void *a, const void *b);
 static void InitIndexAmRoutine(Relation relation);
 static void IndexSupportInitialize(oidvector *indclass,
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;	/* invalid ones included */
+			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -693,9 +693,38 @@ RelationBuildTupleDesc(Relation relation)
 
 		constr->missing = attrmiss;
 
-		if (relation->rd_rel->relchecks > 0)	/* CHECKs */
-			CheckConstraintFetch(relation);
-		else
+		/* CHECK and NOT NULLs */
+		if (!IsCatalogRelation(relation) &&
+			(relation->rd_rel->relchecks > 0 || constr->has_not_null))
+			CheckNNConstraintFetch(relation);
+
+		/*
+		 * Any not-null constraint that wasn't marked invalid by
+		 * CheckNNConstraintFetch must necessarily be valid; make it so in the
+		 * CompactAttribute array.  In catalog relations however, any not-null
+		 * constraint is necessarily valid.
+		 */
+		for (int i = 0; i < relation->rd_rel->relnatts - 1; i++)
+		{
+			CompactAttribute *attr;
+
+			attr = TupleDescCompactAttr(relation->rd_att, i);
+
+			if (IsCatalogRelation(relation))
+			{
+				if (attr->attnullability == ATTNULLABLE_UNKNOWN)
+					attr->attnullability = ATTNULLABLE_VALID;
+				continue;
+			}
+
+			if (attr->attnullability == ATTNULLABLE_UNKNOWN)
+				attr->attnullability = ATTNULLABLE_VALID;
+			else
+				Assert(attr->attnullability == ATTNULLABLE_INVALID ||
+					   attr->attnullability == ATTNULLABLE_UNRESTRICTED);
+		}
+
+		if (relation->rd_rel->relchecks == 0)
 			constr->num_check = 0;
 	}
 	else
@@ -3573,7 +3602,6 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
-		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
@@ -4534,13 +4562,14 @@ AttrDefaultCmp(const void *a, const void *b)
 }
 
 /*
- * Load any check constraints for the relation.
+ * Load any check constraints for the relation, and update not-null validity
+ * of invalid constraints.
  *
  * As with defaults, if we don't find the expected number of them, just warn
  * here.  The executor should throw an error if an INSERT/UPDATE is attempted.
  */
 static void
-CheckConstraintFetch(Relation relation)
+CheckNNConstraintFetch(Relation relation)
 {
 	ConstrCheck *check;
 	int			ncheck = relation->rd_rel->relchecks;
@@ -4571,6 +4600,27 @@ CheckConstraintFetch(Relation relation)
 		Datum		val;
 		bool		isnull;
 
+		/*
+		 * Consider only invalid not-null constraints and mark the TupleDesc
+		 * entry invalid.
+		 */
+		if (!IsCatalogRelation(relation) &&
+			conform->contype == CONSTRAINT_NOTNULL)
+		{
+			if (!conform->convalidated)
+			{
+				AttrNumber	attnum;
+
+				attnum = extractNotNullColumn(htup);
+				Assert(relation->rd_att->compact_attrs[attnum - 1].attnullability ==
+					   ATTNULLABLE_UNKNOWN);
+				relation->rd_att->compact_attrs[attnum - 1].attnullability =
+					ATTNULLABLE_INVALID;
+			}
+
+			continue;
+		}
+
 		/* We want check constraints only */
 		if (conform->contype != CONSTRAINT_CHECK)
 			continue;
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 5523cfcf5aa..1600f967032 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -76,14 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	char		attnullability; /* attnotnull + attnotnullvalid */
+	char		attnullability; /* status of not-null constraint, see below */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
 /* Valid values for CompactAttribute->attnullability */
-#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
-#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
-#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+#define	ATTNULLABLE_UNRESTRICTED 'f' /* No constraint exists */
+#define	ATTNULLABLE_UNKNOWN		'u' /* constraint exists, validity unknown */
+#define	ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define	ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
 
 /*
  * This struct is passed around within the backend to describe the structure
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 9b1236e7a90..df7a77ee224 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -120,9 +120,6 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
-	/* Whether the not-null constraint, if it exists, is valid */
-	bool		attnotnullvalid;
-
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/test/regress/expected/sanity_check.out b/src/test/regress/expected/sanity_check.out
index 2e39037e3fb..8370c1561cc 100644
--- a/src/test/regress/expected/sanity_check.out
+++ b/src/test/regress/expected/sanity_check.out
@@ -25,23 +25,3 @@ SELECT relname, relkind
 ---------+---------
 (0 rows)
 
--- pg_attribute sanity check: attnotnullvalid can only be true when
--- attnotnull is valid.
-select pa.attrelid::regclass, pa.attname, pa.attnum,
-       pa.attnotnull, pa.attnotnullvalid
-from    pg_attribute pa
-where not pa.attnotnull and pa.attnotnullvalid;
- attrelid | attname | attnum | attnotnull | attnotnullvalid 
-----------+---------+--------+------------+-----------------
-(0 rows)
-
--- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
-select att.attrelid::regclass, att.attname, att.attnotnull,
-       att.attnotnullvalid, con.convalidated
-  from pg_attribute att join pg_constraint con
-    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
- where contype = 'n' and con.convalidated <> att.attnotnullvalid;
- attrelid | attname | attnotnull | attnotnullvalid | convalidated 
-----------+---------+------------+-----------------+--------------
-(0 rows)
-
diff --git a/src/test/regress/sql/sanity_check.sql b/src/test/regress/sql/sanity_check.sql
index 6ef36ab84b7..162e5324b5d 100644
--- a/src/test/regress/sql/sanity_check.sql
+++ b/src/test/regress/sql/sanity_check.sql
@@ -19,17 +19,3 @@ SELECT relname, relkind
   FROM pg_class
  WHERE relkind IN ('v', 'c', 'f', 'p', 'I')
        AND relfilenode <> 0;
-
--- pg_attribute sanity check: attnotnullvalid can only be true when
--- attnotnull is valid.
-select pa.attrelid::regclass, pa.attname, pa.attnum,
-       pa.attnotnull, pa.attnotnullvalid
-from    pg_attribute pa
-where not pa.attnotnull and pa.attnotnullvalid;
-
--- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
-select att.attrelid::regclass, att.attname, att.attnotnull,
-       att.attnotnullvalid, con.convalidated
-  from pg_attribute att join pg_constraint con
-    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
- where contype = 'n' and con.convalidated <> att.attnotnullvalid;
-- 
2.43.0

From efa75dc7ab06c1484554f9161fdfb9021cdee7c1 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 7 Apr 2025 09:48:03 +0530
Subject: [PATCH 1/3] Allow NOT NULL constraints to be added as NOT VALID

This required adding a new system column, pg_attribute.attnotnullvalid,
in order to allow constructing a TupleDesc without having to scan
pg_constraint; at the same time, we keep pg_attribute.attnotnull
unchanged, to avoid breaking the countless applications that rely on
that.

Also add support for ALTER TABLE .. VALIDATE CONSTRAINT for them.
---
 doc/src/sgml/catalogs.sgml                 |  11 +-
 doc/src/sgml/ref/alter_table.sgml          |   8 +-
 src/backend/access/common/tupdesc.c        |  11 +-
 src/backend/bootstrap/bootstrap.c          |   3 +
 src/backend/catalog/genbki.pl              |   3 +
 src/backend/catalog/heap.c                 |  17 +-
 src/backend/catalog/pg_constraint.c        |  46 ++--
 src/backend/commands/tablecmds.c           | 246 +++++++++++++++++---
 src/backend/executor/execMain.c            |   1 +
 src/backend/jit/llvm/llvmjit_deform.c      |  10 +-
 src/backend/optimizer/util/plancat.c       |   5 +-
 src/backend/parser/gram.y                  |   5 +-
 src/backend/utils/cache/catcache.c         |   1 +
 src/backend/utils/cache/relcache.c         |   3 +-
 src/bin/pg_dump/pg_dump.c                  | 186 +++++++++++++--
 src/bin/pg_dump/pg_dump.h                  |   2 +
 src/bin/pg_dump/t/002_pg_dump.pl           |  21 +-
 src/bin/psql/describe.c                    |   9 +-
 src/include/access/tupdesc.h               |   9 +-
 src/include/catalog/catversion.h           |   2 +-
 src/include/catalog/pg_attribute.h         |   5 +-
 src/include/catalog/pg_constraint.h        |   2 +-
 src/test/regress/expected/alter_table.out  |  69 ++++++
 src/test/regress/expected/constraints.out  | 250 +++++++++++++++++++++
 src/test/regress/expected/sanity_check.out |  20 ++
 src/test/regress/sql/alter_table.sql       |  14 ++
 src/test/regress/sql/constraints.sql       | 166 ++++++++++++++
 src/test/regress/sql/sanity_check.sql      |  14 ++
 28 files changed, 1047 insertions(+), 92 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 45ba9c5118f..3ab7d7b68aa 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1260,7 +1260,16 @@
        <structfield>attnotnull</structfield> <type>bool</type>
       </para>
       <para>
-       This column has a not-null constraint.
+       This column has a (possibly unvalidated) not-null constraint.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnotnullvalid</structfield> <type>bool</type>
+      </para>
+      <para>
+       Whether the not-null constraint, if one exists, has been validated.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index ece438f0075..a75e75d800d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -243,6 +243,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       entire table; however, if a valid <literal>CHECK</literal> constraint is
       found which proves no <literal>NULL</literal> can exist, then the
       table scan is skipped.
+      If a column has an invalid not-null constraint,
+      <literal>SET NOT NULL</literal> validates it.
      </para>
 
      <para>
@@ -458,8 +460,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      <para>
       This form adds a new constraint to a table using the same constraint
       syntax as <link linkend="sql-createtable"><command>CREATE TABLE</command></link>, plus the option <literal>NOT
-      VALID</literal>, which is currently only allowed for foreign key
-      and CHECK constraints.
+      VALID</literal>, which is currently only allowed for foreign key,
+      <literal>CHECK</literal> constraints and not-null constraints.
      </para>
 
      <para>
@@ -586,7 +588,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>VALIDATE CONSTRAINT</literal></term>
     <listitem>
      <para>
-      This form validates a foreign key or check constraint that was
+      This form validates a foreign key, check, or not-null constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
       satisfied.  If the constraint is not enforced, an error is thrown.
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index ed2195f14b2..320de2cbda0 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -74,7 +74,8 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnotnull = src->attnotnull;
+	dst->attnullability = !src->attnotnull ? ATTNULLABLE_NONE :
+		src->attnotnullvalid ? ATTNULLABLE_VALID : ATTNULLABLE_INVALID;
 
 	switch (src->attalign)
 	{
@@ -252,6 +253,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -298,6 +300,7 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -418,6 +421,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		Form_pg_attribute att = TupleDescAttr(dst, i);
 
 		att->attnotnull = false;
+		att->attnotnullvalid = false;
 		att->atthasdef = false;
 		att->atthasmissing = false;
 		att->attidentity = '\0';
@@ -464,6 +468,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 
 	/* since we're not copying constraints or defaults, clear these */
 	dstAtt->attnotnull = false;
+	dstAtt->attnotnullvalid = false;
 	dstAtt->atthasdef = false;
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
@@ -613,6 +618,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attnotnull != attr2->attnotnull)
 			return false;
+		if (attr1->attnotnullvalid != attr2->attnotnullvalid)
+			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
 		if (attr1->attidentity != attr2->attidentity)
@@ -841,6 +848,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
@@ -904,6 +912,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->attndims = attdim;
 
 	att->attnotnull = false;
+	att->attnotnullvalid = false;
 	att->atthasdef = false;
 	att->atthasmissing = false;
 	att->attidentity = '\0';
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6db864892d0..44ec9e58520 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -615,6 +615,9 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 				attrtypes[attnum]->attnotnull = true;
 		}
 	}
+
+	/* Not-null constraints on system catalogs are always valid. */
+	attrtypes[attnum]->attnotnullvalid = attrtypes[attnum]->attnotnull;
 }
 
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index df3231fcd41..bdf55d7dc8d 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -986,6 +986,9 @@ sub morph_row_for_pgattr
 		$row->{attnotnull} = 'f';
 	}
 
+	# Not-null constraints on system catalogs are always valid.
+	$row->{attnotnullvalid} = $row->{attnotnull};
+
 	Catalog::AddDefaultValues($row, $pgattr_schema, 'pg_attribute');
 	return;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b807ab66668..503e7cb3f58 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -151,6 +151,7 @@ static const FormData_pg_attribute a1 = {
 	.attalign = TYPALIGN_SHORT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -164,6 +165,7 @@ static const FormData_pg_attribute a2 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -177,6 +179,7 @@ static const FormData_pg_attribute a3 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -190,6 +193,7 @@ static const FormData_pg_attribute a4 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -203,6 +207,7 @@ static const FormData_pg_attribute a5 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -222,6 +227,7 @@ static const FormData_pg_attribute a6 = {
 	.attalign = TYPALIGN_INT,
 	.attstorage = TYPSTORAGE_PLAIN,
 	.attnotnull = true,
+	.attnotnullvalid = true,
 	.attislocal = true,
 };
 
@@ -753,6 +759,7 @@ InsertPgAttributeTuples(Relation pg_attribute_rel,
 		slot[slotCount]->tts_values[Anum_pg_attribute_attstorage - 1] = CharGetDatum(attrs->attstorage);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attcompression - 1] = CharGetDatum(attrs->attcompression);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(attrs->attnotnull);
+		slot[slotCount]->tts_values[Anum_pg_attribute_attnotnullvalid - 1] = BoolGetDatum(attrs->attnotnullvalid);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(attrs->atthasdef);
 		slot[slotCount]->tts_values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(attrs->atthasmissing);
 		slot[slotCount]->tts_values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(attrs->attidentity);
@@ -1714,6 +1721,7 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
 
 	/* Remove any not-null constraint the column may have */
 	attStruct->attnotnull = false;
+	attStruct->attnotnullvalid = false;
 
 	/* Unset this so no one tries to look up the generation expression */
 	attStruct->attgenerated = '\0';
@@ -2616,12 +2624,17 @@ AddRelationNewConstraints(Relation rel,
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
 
+			Assert(cdef->initially_valid != cdef->skip_validation);
+
 			/*
 			 * If the column already has a not-null constraint, we don't want
-			 * to add another one; just adjust inheritance status as needed.
+			 * to add another one; adjust inheritance status as needed.  This
+			 * also checks whether the existing constraint matches the
+			 * requested validity.
 			 */
 			if (AdjustNotNullInheritance(RelationGetRelid(rel), colnum,
-										 is_local, cdef->is_no_inherit))
+										 is_local, cdef->is_no_inherit,
+										 cdef->skip_validation))
 				continue;
 
 			/*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index b97960d2766..2f73085961b 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -576,8 +576,8 @@ ChooseConstraintName(const char *name1, const char *name2,
 
 /*
  * Find and return a copy of the pg_constraint tuple that implements a
- * validated not-null constraint for the given column of the given relation.
- * If no such constraint exists, return NULL.
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.  If no such constraint exists, return NULL.
  *
  * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
  * of the constraint that implements the not-null constraint for that column.
@@ -606,13 +606,11 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 		AttrNumber	conkey;
 
 		/*
-		 * We're looking for a NOTNULL constraint that's marked validated,
-		 * with the column we're looking for as the sole element in conkey.
+		 * We're looking for a NOTNULL constraint with the column we're
+		 * looking for as the sole element in conkey.
 		 */
 		if (con->contype != CONSTRAINT_NOTNULL)
 			continue;
-		if (!con->convalidated)
-			continue;
 
 		conkey = extractNotNullColumn(conTup);
 		if (conkey != attnum)
@@ -630,9 +628,10 @@ findNotNullConstraintAttnum(Oid relid, AttrNumber attnum)
 }
 
 /*
- * Find and return the pg_constraint tuple that implements a validated
- * not-null constraint for the given column of the given relation.  If
- * no such column or no such constraint exists, return NULL.
+ * Find and return a copy of the pg_constraint tuple that implements a
+ * (possibly not valid) not-null constraint for the given column of the
+ * given relation.
+ * If no such column or no such constraint exists, return NULL.
  */
 HeapTuple
 findNotNullConstraint(Oid relid, const char *colname)
@@ -723,15 +722,19 @@ extractNotNullColumn(HeapTuple constrTup)
  *
  * If no not-null constraint is found for the column, return false.
  * Caller can create one.
+ *
  * If a constraint exists but the connoinherit flag is not what the caller
- * wants, throw an error about the incompatibility.  Otherwise, we adjust
- * conislocal/coninhcount and return true.
- * In the latter case, if is_local is true we flip conislocal true, or do
- * nothing if it's already true; otherwise we increment coninhcount by 1.
+ * wants, throw an error about the incompatibility.  If the desired
+ * constraint is valid but the existing constraint is not valid, also
+ * throw an error about that (the opposite case is acceptable).
+ *
+ * If everything checks out, we adjust conislocal/coninhcount and return
+ * true.  If is_local is true we flip conislocal true, or do nothing if
+ * it's already true; otherwise we increment coninhcount by 1.
  */
 bool
 AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-						 bool is_local, bool is_no_inherit)
+						 bool is_local, bool is_no_inherit, bool is_notvalid)
 {
 	HeapTuple	tup;
 
@@ -755,6 +758,17 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 					errmsg("cannot change NO INHERIT status of NOT NULL constraint \"%s\" on relation \"%s\"",
 						   NameStr(conform->conname), get_rel_name(relid)));
 
+		/*
+		 * Throw an error if the existing constraint is NOT VALID and caller
+		 * wants a valid one.
+		 */
+		if (!is_notvalid && !conform->convalidated)
+			ereport(ERROR,
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+						   NameStr(conform->conname), get_rel_name(relid)),
+					errhint("You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it."));
+
 		if (!is_local)
 		{
 			if (pg_add_s16_overflow(conform->coninhcount, 1,
@@ -832,7 +846,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			cooked->attnum = colnum;
 			cooked->expr = NULL;
 			cooked->is_enforced = true;
-			cooked->skip_validation = false;
+			cooked->skip_validation = !conForm->convalidated;
 			cooked->is_local = true;
 			cooked->inhcount = 0;
 			cooked->is_no_inherit = conForm->connoinherit;
@@ -852,7 +866,7 @@ RelationGetNotNullConstraints(Oid relid, bool cooked, bool include_noinh)
 			constr->keys = list_make1(makeString(get_attname(relid, colnum,
 															 false)));
 			constr->is_enforced = true;
-			constr->skip_validation = false;
+			constr->skip_validation = !conForm->convalidated;
 			constr->initially_valid = true;
 			constr->is_no_inherit = conForm->connoinherit;
 			notnulls = lappend(notnulls, constr);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4397123398e..0c7b1231c2e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -435,6 +435,9 @@ static void QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation
 static void QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 										   char *constrName, HeapTuple contuple,
 										   bool recurse, bool recursing, LOCKMODE lockmode);
+static void QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+										HeapTuple contuple, bool recurse, bool recursing,
+										LOCKMODE lockmode);
 static int	transformColumnNameList(Oid relId, List *colList,
 									int16 *attnums, Oid *atttypids, Oid *attcollids);
 static int	transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
@@ -498,7 +501,7 @@ static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 									   LOCKMODE lockmode);
 static void set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-						   LOCKMODE lockmode);
+						   bool is_valid, bool queue_validation);
 static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
 									  char *constrname, char *colName,
 									  bool recurse, bool recursing,
@@ -1340,7 +1343,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
 										   old_notnulls);
 	foreach_int(attrnum, nncols)
-		set_attnotnull(NULL, rel, attrnum, NoLock);
+		set_attnotnull(NULL, rel, attrnum, true, false);
 
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
@@ -1424,7 +1427,7 @@ BuildDescForRelation(const List *columns)
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		att->attnotnull = entry->is_not_null;
+		att->attnotnull = att->attnotnullvalid = entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -2738,7 +2741,7 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 		/*
 		 * Request attnotnull on columns that have a not-null constraint
-		 * that's not marked NO INHERIT.
+		 * that's not marked NO INHERIT (even if not valid).
 		 */
 		nnconstrs = RelationGetNotNullConstraints(RelationGetRelid(relation),
 												  true, false);
@@ -6207,18 +6210,22 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
-		 * verified not-null constraints, check all not-null constraints. This
-		 * is a bit of overkill but it minimizes risk of bugs.
+		 * verified not-null constraints, check all valid not-null constraints.
+		 * This is a bit of overkill but it minimizes risk of bugs.
 		 *
 		 * notnull_attrs does *not* collect attribute numbers for not-null
 		 * constraints over virtual generated columns; instead, they are
 		 * collected in notnull_virtual_attrs.
+		 *
+		 * But we don't need check invalid not-null constraint! this is aligned
+		 * with check constraint behavior.
 		 */
 		for (i = 0; i < newTupDesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(newTupDesc, i);
 
-			if (attr->attnotnull && !attr->attisdropped)
+			if (attr->attnotnull && attr->attnotnullvalid &&
+				!attr->attisdropped)
 			{
 				if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
 					notnull_attrs = lappend_int(notnull_attrs, attr->attnum);
@@ -7788,7 +7795,7 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 
 	/*
 	 * Find the constraint that makes this column NOT NULL, and drop it.
-	 * dropconstraint_internal() resets attnotnull.
+	 * dropconstraint_internal() resets attnotnull/attnotnullvalid.
 	 */
 	conTup = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (conTup == NULL)
@@ -7809,19 +7816,23 @@ ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
 }
 
 /*
- * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
- * to verify it.
+ * set_attnotnull
+ *		Helper to update/validate the pg_attribute status of a not-null
+ *		constraint
  *
- * When called to alter an existing table, 'wqueue' must be given so that we
- * can queue a check that existing tuples pass the constraint.  When called
- * from table creation, 'wqueue' should be passed as NULL.
+ * pg_attribute.attnotnull is set true, if it isn't already.  If is_valid
+ * is true, also set pg_attribute.attnotnullvalid.  If queue_validation is
+ * true, also set up wqueue to validate the constraint.  wqueue may be given
+ * as NULL when validation is not needed (e.g., on table creation).
  */
 static void
 set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
-			   LOCKMODE lockmode)
+			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
 
+	Assert(!queue_validation || wqueue);
+
 	CheckAlterTableIsSafe(rel);
 
 	/*
@@ -7832,7 +7843,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 	if (attr->attisdropped)
 		return;
 
-	if (!attr->attnotnull)
+	if (!attr->attnotnull || (is_valid && !attr->attnotnullvalid))
 	{
 		Relation	attr_rel;
 		HeapTuple	tuple;
@@ -7845,15 +7856,17 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 				 attnum, RelationGetRelid(rel));
 
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
-		Assert(!attr->attnotnull);
+
 		attr->attnotnull = true;
+		attr->attnotnullvalid = is_valid;
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
 		/*
 		 * If the nullness isn't already proven by validated constraints, have
 		 * ALTER TABLE phase 3 test for it.
 		 */
-		if (wqueue && !NotNullImpliedByRelConstraints(rel, attr))
+		if (queue_validation && wqueue &&
+			!NotNullImpliedByRelConstraints(rel, attr))
 		{
 			AlteredTableInfo *tab;
 
@@ -7951,6 +7964,15 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 			conForm->conislocal = true;
 			changed = true;
 		}
+		else if (!conForm->convalidated)
+		{
+			/*
+			 * Flip attnotnull and convalidated, and also validate the
+			 * constraint.
+			 */
+			return ATExecValidateConstraint(wqueue, rel, NameStr(conForm->conname),
+											recurse, recursing, lockmode);
+		}
 
 		if (changed)
 		{
@@ -8013,8 +8035,8 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	InvokeObjectPostAlterHook(RelationRelationId,
 							  RelationGetRelid(rel), attnum);
 
-	/* Mark pg_attribute.attnotnull for the column */
-	set_attnotnull(wqueue, rel, attnum, lockmode);
+	/* Mark pg_attribute.attnotnull for the column and queue validation */
+	set_attnotnull(wqueue, rel, attnum, true, true);
 
 	/*
 	 * Recurse to propagate the constraint to children that don't have one.
@@ -9417,7 +9439,6 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 					bool recurse, LOCKMODE lockmode,
 					AlterTableUtilityContext *context)
 {
-	ListCell   *lc;
 	Constraint *pkconstr;
 
 	pkconstr = castNode(Constraint, cmd->def);
@@ -9436,33 +9457,73 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 											 lockmode);
 		foreach_oid(childrelid, children)
 		{
-			foreach(lc, pkconstr->keys)
+			foreach_node(String, attname, pkconstr->keys)
 			{
 				HeapTuple	tup;
 				Form_pg_attribute attrForm;
-				char	   *attname = strVal(lfirst(lc));
 
-				tup = SearchSysCacheAttName(childrelid, attname);
+				tup = SearchSysCacheAttName(childrelid, strVal(attname));
 				if (!tup)
 					elog(ERROR, "cache lookup failed for attribute %s of relation %u",
-						 attname, childrelid);
+						 strVal(attname), childrelid);
 				attrForm = (Form_pg_attribute) GETSTRUCT(tup);
 				if (!attrForm->attnotnull)
 					ereport(ERROR,
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
-								   attname, get_rel_name(childrelid)));
+								   strVal(attname), get_rel_name(childrelid)));
 				ReleaseSysCache(tup);
 			}
 		}
 	}
 
-	/* Insert not-null constraints in the queue for the PK columns */
-	foreach(lc, pkconstr->keys)
+	/* Verify that columns are not-null, or request that they be made so */
+	foreach_node(String, column, pkconstr->keys)
 	{
 		AlterTableCmd *newcmd;
 		Constraint *nnconstr;
+		HeapTuple	tuple;
 
-		nnconstr = makeNotNullConstraint(lfirst(lc));
+		/*
+		 * First check if a suitable constraint exists.  If it does, we don't
+		 * need to request another one.  We do need to bail out if it's not
+		 * valid, though.
+		 */
+		tuple = findNotNullConstraint(RelationGetRelid(rel), strVal(column));
+		if (tuple != NULL)
+		{
+			Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+
+			/* a NO INHERIT constraint is no good */
+			if (conForm->connoinherit)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("cannot create primary key on column \"%s\"",
+							   strVal(column)),
+						/*- translator: third %s is a constraint characteristic such as NOT VALID */
+						errdetail("The constraint \"%s\" on column \"%s\", marked %s, is incompatible with a primary key.",
+								  NameStr(conForm->conname), strVal(column), "NO INHERIT"),
+						errhint("You will need to make it inheritable using %s.",
+								"ALTER TABLE ... ALTER CONSTRAINT ... INHERIT"));
+
+			/* an unvalidated constraint is no good */
+			if (!conForm->convalidated)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("cannot create primary key on column \"%s\"",
+							   strVal(column)),
+						/*- translator: third %s is a constraint characteristic such as NOT VALID */
+						errdetail("The constraint \"%s\" on column \"%s\", marked %s, is incompatible with a primary key.",
+								  NameStr(conForm->conname), strVal(column), "NOT VALID"),
+						errhint("You will need to validate it using %s.",
+								"ALTER TABLE ... VALIDATE CONSTRAINT"));
+
+			/* All good with this one; don't request another */
+			heap_freetuple(tuple);
+			continue;
+		}
+
+		/* This column is not already not-null, so add it to the queue */
+		nnconstr = makeNotNullConstraint(column);
 
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
@@ -9836,11 +9897,15 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			constr->conname = ccon->name;
 
 		/*
-		 * If adding a not-null constraint, set the pg_attribute flag and tell
-		 * phase 3 to verify existing rows, if needed.
+		 * If adding a valid not-null constraint, set the pg_attribute flag
+		 * and tell phase 3 to verify existing rows, if needed.  For an
+		 * invalid constraint, just set attnotnull and attnotnullvalid,
+		 * without queueing verification.
 		 */
 		if (constr->contype == CONSTR_NOTNULL)
-			set_attnotnull(wqueue, rel, ccon->attnum, lockmode);
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !constr->skip_validation,
+						   !constr->skip_validation);
 
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
@@ -12811,10 +12876,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 	if (con->contype != CONSTRAINT_FOREIGN &&
-		con->contype != CONSTRAINT_CHECK)
+		con->contype != CONSTRAINT_CHECK &&
+		con->contype != CONSTRAINT_NOTNULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key or check constraint",
+				 errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key, check, or not-null constraint",
 						constrName, RelationGetRelationName(rel))));
 
 	if (!con->conenforced)
@@ -12833,6 +12899,11 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			QueueCheckConstraintValidation(wqueue, conrel, rel, constrName,
 										   tuple, recurse, recursing, lockmode);
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			QueueNNConstraintValidation(wqueue, conrel, rel,
+										tuple, recurse, recursing, lockmode);
+		}
 
 		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
@@ -13049,6 +13120,109 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	heap_freetuple(copyTuple);
 }
 
+/*
+ * QueueNNConstraintValidation
+ *
+ * Add an entry to the wqueue to validate the given not-null constraint in
+ * Phase 3 and update the convalidated field in the pg_constraint catalog for
+ * the specified relation and all its inheriting children.
+ */
+static void
+QueueNNConstraintValidation(List **wqueue, Relation conrel, Relation rel,
+							HeapTuple contuple, bool recurse, bool recursing,
+							LOCKMODE lockmode)
+{
+	Form_pg_constraint con;
+	AlteredTableInfo *tab;
+	HeapTuple	copyTuple;
+	Form_pg_constraint copy_con;
+	List	   *children = NIL;
+	AttrNumber	attnum;
+	char	   *colname;
+
+	con = (Form_pg_constraint) GETSTRUCT(contuple);
+	Assert(con->contype == CONSTRAINT_NOTNULL);
+
+	attnum = extractNotNullColumn(contuple);
+
+	/*
+	 * If we're recursing, we've already done this for parent, so skip it.
+	 * Also, if the constraint is a NO INHERIT constraint, we shouldn't try to
+	 * look for it in the children.
+	 *
+	 * We recurse before validating on the parent, to reduce risk of
+	 * deadlocks.
+	 */
+	if (!recursing && !con->connoinherit)
+		children = find_all_inheritors(RelationGetRelid(rel), lockmode, NULL);
+
+	colname = get_attname(RelationGetRelid(rel), attnum, false);
+	foreach_oid(childoid, children)
+	{
+		Relation	childrel;
+		HeapTuple	contup;
+		Form_pg_constraint childcon;
+		char	   *conname;
+
+		if (childoid == RelationGetRelid(rel))
+			continue;
+
+		/*
+		 * If we are told not to recurse, there had better not be any child
+		 * tables, because we can't mark the constraint on the parent valid
+		 * unless it is valid for all child tables.
+		 */
+		if (!recurse)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("constraint must be validated on child tables too"));
+
+		/*
+		 * The column on child might have a different attnum, so search by
+		 * column name.
+		 */
+		contup = findNotNullConstraint(childoid, colname);
+		if (!contup)
+			elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+						colname, get_rel_name(childoid));
+		childcon = (Form_pg_constraint) GETSTRUCT(contup);
+		if (childcon->convalidated)
+			continue;
+
+		/* find_all_inheritors already got lock */
+		childrel = table_open(childoid, NoLock);
+		conname = pstrdup(NameStr(childcon->conname));
+
+		/* XXX improve ATExecValidateConstraint API to avoid double search */
+		ATExecValidateConstraint(wqueue, childrel, conname,
+								 false, true, lockmode);
+		table_close(childrel, NoLock);
+	}
+
+	/* Set the flags appropriately without queueing another validation */
+	set_attnotnull(NULL, rel, attnum, true, false);
+
+	tab = ATGetQueueEntry(wqueue, rel);
+	tab->verify_new_notnull = true;
+
+	/*
+	 * Invalidate relcache so that others see the new validated constraint.
+	 */
+	CacheInvalidateRelcache(rel);
+
+	/*
+	 * Now update the catalogs, while we have the door open.
+	 */
+	copyTuple = heap_copytuple(contuple);
+	copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+	copy_con->convalidated = true;
+	CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+
+	InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
+
+	heap_freetuple(copyTuple);
+}
+
 /*
  * transformColumnNameList - transform list of column names
  *
@@ -13917,10 +14091,11 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha
 									   false),
 						   RelationGetRelationName(rel)));
 
-		/* All good -- reset attnotnull if needed */
+		/* All good -- reset attnotnull and attnotnullvalid if needed */
 		if (attForm->attnotnull)
 		{
 			attForm->attnotnull = false;
+			attForm->attnotnullvalid = false;
 			CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
 		}
 
@@ -19772,7 +19947,8 @@ PartConstraintImpliedByRelConstraint(Relation scanrel,
 		{
 			Form_pg_attribute att = TupleDescAttr(scanrel->rd_att, i - 1);
 
-			if (att->attnotnull && !att->attisdropped)
+			/* invalid not-null constraint must be ignored */
+			if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 			{
 				NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2da848970be..c8d44e3086b 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -2074,6 +2074,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 	{
 		for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++)
 		{
+			/* FIXME use CompactAttribute */
 			Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
 
 			if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 5d169c7a40b..c562edd094b 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -123,7 +123,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * combination of attisdropped && attnotnull combination shouldn't
 		 * exist.
 		 */
-		if (att->attnotnull &&
+		if (att->attnullability == ATTNULLABLE_VALID &&
 			!att->atthasmissing &&
 			!att->attisdropped)
 			guaranteed_column_number = attnum;
@@ -438,7 +438,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		 * into account, because if they're present the heaptuple's natts
 		 * would have indicated that a slot_getmissingattrs() is needed.
 		 */
-		if (!att->attnotnull)
+		if (att->attnullability != ATTNULLABLE_VALID)
 		{
 			LLVMBasicBlockRef b_ifnotnull;
 			LLVMBasicBlockRef b_ifnull;
@@ -604,7 +604,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			known_alignment = -1;
 			attguaranteedalign = false;
 		}
-		else if (att->attnotnull && attguaranteedalign && known_alignment >= 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 attguaranteedalign && known_alignment >= 0)
 		{
 			/*
 			 * If the offset to the column was previously known, a NOT NULL &
@@ -614,7 +615,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			Assert(att->attlen > 0);
 			known_alignment += att->attlen;
 		}
-		else if (att->attnotnull && (att->attlen % alignto) == 0)
+		else if (att->attnullability == ATTNULLABLE_VALID &&
+				 (att->attlen % alignto) == 0)
 		{
 			/*
 			 * After a NOT NULL fixed-width column with a length that is a
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 67d879be8b8..191a14b876e 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -177,7 +177,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
-			if (attr->attnotnull)
+			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
 													 i + 1);
@@ -1251,6 +1251,7 @@ get_relation_data_width(Oid relid, int32 *attr_widths)
  * get_relation_constraints
  *
  * Retrieve the applicable constraint expressions of the given relation.
+ * Only constraints that have been validated are considered.
  *
  * Returns a List (possibly empty) of constraint expressions.  Each one
  * has been canonicalized, and its Vars are changed to have the varno
@@ -1353,7 +1354,7 @@ get_relation_constraints(PlannerInfo *root,
 			{
 				Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
 
-				if (att->attnotnull && !att->attisdropped)
+				if (att->attnotnull && att->attnotnullvalid && !att->attisdropped)
 				{
 					NullTest   *ntest = makeNode(NullTest);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index f1156e2fca3..3c4268b271a 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4217,11 +4217,10 @@ ConstraintElem:
 					n->contype = CONSTR_NOTNULL;
 					n->location = @1;
 					n->keys = list_make1(makeString($3));
-					/* no NOT VALID support yet */
 					processCASbits($4, @4, "NOT NULL",
-								   NULL, NULL, NULL, NULL,
+								   NULL, NULL, NULL, &n->skip_validation,
 								   &n->is_no_inherit, yyscanner);
-					n->initially_valid = true;
+					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
 			| UNIQUE opt_unique_null_treatment '(' columnList opt_without_overlaps ')' opt_c_include opt_definition OptConsTableSpace
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 9ad7681f155..70c11529b90 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1142,6 +1142,7 @@ CatalogCacheInitializeCache(CatCache *cache)
 			keytype = attr->atttypid;
 			/* cache key columns should always be NOT NULL */
 			Assert(attr->attnotnull);
+			Assert(attr->attnotnullvalid);
 		}
 		else
 		{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 18a14ae186e..c80e40cd47a 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,7 +592,7 @@ RelationBuildTupleDesc(Relation relation)
 
 		/* Update constraint/default info */
 		if (attp->attnotnull)
-			constr->has_not_null = true;
+			constr->has_not_null = true;	/* invalid ones included */
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
@@ -3573,6 +3573,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attidentity = satt->attidentity;
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
+		datt->attnotnullvalid = satt->attnotnullvalid;
 		has_not_null |= satt->attnotnull;
 		populate_compact_attribute(rel->rd_att, i);
 	}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 8e6364d32d7..17c2996faa7 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -350,8 +350,10 @@ static void buildMatViewRefreshDependencies(Archive *fout);
 static void getTableDataFKConstraints(void);
 static void determineNotNullFlags(Archive *fout, PGresult *res, int r,
 								  TableInfo *tbinfo, int j,
-								  int i_notnull_name, int i_notnull_noinherit,
-								  int i_notnull_islocal);
+								  int i_notnull_name, int i_notnull_invalidoid,
+								  int i_notnull_noinherit,
+								  int i_notnull_islocal,
+								  PQExpBuffer *invalidnotnulloids);
 static char *format_function_arguments(const FuncInfo *finfo, const char *funcargs,
 									   bool is_agg);
 static char *format_function_signature(Archive *fout,
@@ -8984,6 +8986,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer invalidnotnulloids = NULL;
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -9003,6 +9006,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_notnull_name;
 	int			i_notnull_noinherit;
 	int			i_notnull_islocal;
+	int			i_notnull_invalidoid;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -9089,6 +9093,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * attnotnull (this cues dumpTableSchema to print the NOT NULL clause
 	 * without a name); also, such cases are never NO INHERIT.
 	 *
+	 * For invalid constraints, we need to store their OIDs for processing
+	 * elsewhere, so we bring the pg_constraint.oid value when the constraint
+	 * is invalid, and NULL otherwise.
+	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
 	 * might modify this later for servers older than 18; it's also in charge
@@ -9097,11 +9105,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
 							 "co.conname AS notnull_name,\n"
+							 "CASE WHEN NOT co.convalidated THEN co.oid "
+							 "ELSE NULL END AS notnull_invalidoid,\n"
 							 "co.connoinherit AS notnull_noinherit,\n"
 							 "co.conislocal AS notnull_islocal,\n");
 	else
 		appendPQExpBufferStr(q,
 							 "CASE WHEN a.attnotnull THEN '' ELSE NULL END AS notnull_name,\n"
+							 "NULL AS notnull_invalidoid,\n"
 							 "false AS notnull_noinherit,\n"
 							 "a.attislocal AS notnull_islocal,\n");
 
@@ -9176,6 +9187,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_notnull_name = PQfnumber(res, "notnull_name");
+	i_notnull_invalidoid = PQfnumber(res, "notnull_invalidoid");
 	i_notnull_noinherit = PQfnumber(res, "notnull_noinherit");
 	i_notnull_islocal = PQfnumber(res, "notnull_islocal");
 	i_attoptions = PQfnumber(res, "attoptions");
@@ -9272,8 +9284,11 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
 								  tbinfo, j,
-								  i_notnull_name, i_notnull_noinherit,
-								  i_notnull_islocal);
+								  i_notnull_name,
+								  i_notnull_invalidoid,
+								  i_notnull_noinherit,
+								  i_notnull_islocal,
+								  &invalidnotnulloids);
 
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
@@ -9294,6 +9309,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		}
 	}
 
+	/* If invalidnotnulloids has any data, finalize it */
+	if (invalidnotnulloids != NULL)
+		appendPQExpBufferChar(invalidnotnulloids, '}');
+
 	PQclear(res);
 
 	/*
@@ -9426,6 +9445,103 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about NOT NULL NOT VALID constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.
+	 */
+	if (dopt->dumpSchema && invalidnotnulloids)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_consrc;
+		int			i_conislocal;
+
+		pg_log_info("finding invalid not null constraints");
+
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT c.tableoid, c.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(c.oid) AS consrc, "
+						  "conislocal, convalidated "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(conoid)\n"
+						  "JOIN pg_catalog.pg_constraint c ON (src.conoid = c.oid)\n"
+						  "ORDER BY c.conrelid, c.conname",
+						  invalidnotnulloids->data);
+
+		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
+
+		numConstrs = PQntuples(res);
+		constrs = (ConstraintInfo *) pg_malloc(numConstrs * sizeof(ConstraintInfo));
+
+		i_tableoid = PQfnumber(res, "tableoid");
+		i_oid = PQfnumber(res, "oid");
+		i_conrelid = PQfnumber(res, "conrelid");
+		i_conname = PQfnumber(res, "conname");
+		i_consrc = PQfnumber(res, "consrc");
+		i_conislocal = PQfnumber(res, "conislocal");
+
+		/* As above, this loop iterates once per table, not once per row */
+		curtblindx = -1;
+		for (int j = 0; j < numConstrs;)
+		{
+			Oid			conrelid = atooid(PQgetvalue(res, j, i_conrelid));
+			TableInfo  *tbinfo = NULL;
+			int			numcons;
+
+			/* Count rows for this table */
+			for (numcons = 1; numcons < numConstrs - j; numcons++)
+				if (atooid(PQgetvalue(res, j + numcons, i_conrelid)) != conrelid)
+					break;
+
+			/*
+			 * Locate the associated TableInfo; we rely on tblinfo[] being in
+			 * OID order.
+			 */
+			while (++curtblindx < numTables)
+			{
+				tbinfo = &tblinfo[curtblindx];
+				if (tbinfo->dobj.catId.oid == conrelid)
+					break;
+			}
+			if (curtblindx >= numTables)
+				pg_fatal("unrecognized table OID %u", conrelid);
+
+			for (int c = 0; c < numcons; c++, j++)
+			{
+				constrs[j].dobj.objType = DO_CONSTRAINT;
+				constrs[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
+				constrs[j].dobj.catId.oid = atooid(PQgetvalue(res, j, i_oid));
+				AssignDumpId(&constrs[j].dobj);
+				constrs[j].dobj.name = pg_strdup(PQgetvalue(res, j, i_conname));
+				constrs[j].dobj.namespace = tbinfo->dobj.namespace;
+				constrs[j].contable = tbinfo;
+				constrs[j].condomain = NULL;
+				constrs[j].contype = 'n';
+				constrs[j].condef = pg_strdup(PQgetvalue(res, j, i_consrc));
+				constrs[j].confrelid = InvalidOid;
+				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, i_conislocal)[0] == 't');
+
+				/*
+				 * All invalid not-null constraints must be dumped separately,
+				 * because CREATE TABLE would not create them as invalid, and
+				 * also because they must be created after potentially
+				 * violating data has been loaded.
+				 */
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Get info about table CHECK constraints.  This is skipped for a
 	 * data-only dump, as it is only needed for table schemas.
@@ -9570,18 +9686,23 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  *
  * Result row 'r' is for tbinfo's attribute 'j'.
  *
- * There are three possibilities:
+ * There are four possibilities:
  * 1) the column has no not-null constraints. In that case, ->notnull_constrs
  *    (the constraint name) remains NULL.
  * 2) The column has a constraint with no name (this is the case when
  *    constraints come from pre-18 servers).  In this case, ->notnull_constrs
  *    is set to the empty string; dumpTableSchema will print just "NOT NULL".
- * 3) The column has a constraint with a known name; in that case
+ * 3) The column has an invalid not-null constraint.  This must be treated
+ *    as a separate object (because it must be created after the table data
+ *    is loaded).  So we add its OID to invalidnotnulloids for processing
+ *    elsewhere and do nothing further with it here.  We distinguish this
+ *    case because the "notnull_invalidoid" column has been set to a non-NULL
+ *    value, which is the constraint OID.  Valid constraints have a null OID.
+ * 4) The column has a constraint with a known name; in that case
  *    notnull_constrs carries that name and dumpTableSchema will print
  *    "CONSTRAINT the_name NOT NULL".  However, if the name is the default
  *    (table_column_not_null), there's no need to print that name in the dump,
- *    so notnull_constrs is set to the empty string and it behaves as the case
- *    above.
+ *    so notnull_constrs is set to the empty string and it behaves as case 2.
  *
  * In a child table that inherits from a parent already containing NOT NULL
  * constraints and the columns in the child don't have their own NOT NULL
@@ -9593,7 +9714,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  * Any of these constraints might have the NO INHERIT bit.  If so we set
  * ->notnull_noinh and NO INHERIT will be printed by dumpTableSchema.
  *
- * In case 3 above, the name comparison is a bit of a hack; it actually fails
+ * In case 4 above, the name comparison is a bit of a hack; it actually fails
  * to do the right thing in all but the trivial case.  However, the downside
  * of getting it wrong is simply that the name is printed rather than
  * suppressed, so it's not a big deal.
@@ -9601,11 +9722,41 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 static void
 determineNotNullFlags(Archive *fout, PGresult *res, int r,
 					  TableInfo *tbinfo, int j,
-					  int i_notnull_name, int i_notnull_noinherit,
-					  int i_notnull_islocal)
+					  int i_notnull_name,
+					  int i_notnull_invalidoid,
+					  int i_notnull_noinherit,
+					  int i_notnull_islocal,
+					  PQExpBuffer *invalidnotnulloids)
 {
 	DumpOptions *dopt = fout->dopt;
 
+	/*
+	 * If this not-null constraint is not valid, list its OID in
+	 * invalidnotnulloids and do nothing further.  It'll be processed
+	 * elsewhere later.
+	 *
+	 * Because invalid not-null constraints are rare, we don't want to malloc
+	 * invalidnotnulloids until we're sure we're going it need it, which
+	 * happens here.
+	 */
+	if (!PQgetisnull(res, r, i_notnull_invalidoid))
+	{
+		char	   *constroid = PQgetvalue(res, r, i_notnull_invalidoid);
+
+		if (*invalidnotnulloids == NULL)
+		{
+			*invalidnotnulloids = createPQExpBuffer();
+			appendPQExpBufferChar(*invalidnotnulloids, '{');
+			appendPQExpBuffer(*invalidnotnulloids, "%s", constroid);
+		}
+		else
+			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
+
+		/* nothing else to do */
+		tbinfo->notnull_constrs[j] = NULL;
+		return;
+	}
+
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
 	 * though flagInhAttrs may change that one later in versions < 18.
@@ -18152,13 +18303,20 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
-	else if (coninfo->contype == 'c' && tbinfo)
+	else if ((coninfo->contype == 'c' || coninfo->contype == 'n') && tbinfo)
 	{
-		/* CHECK constraint on a table */
+		/* CHECK or invalid not-null constraint on a table */
 
 		/* Ignore if not to be dumped separately, or if it was inherited */
 		if (coninfo->separate && coninfo->conislocal)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			/* not ONLY since we want it to propagate to children */
 			appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
 							  fmtQualifiedDumpable(tbinfo));
@@ -18178,7 +18336,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tbinfo->dobj.namespace->dobj.name,
 										  .owner = tbinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e6f0f86a459..b426b5e4736 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -498,6 +498,8 @@ typedef struct _evttriggerInfo
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
  *
+ * Not-null constraints don't need this, unless they are NOT VALID.
+ *
  * Note: condeferrable and condeferred are currently only valid for
  * unique/primary-key constraints.  Otherwise that info is in condef.
  */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 576326daec7..6c03eca8e50 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -744,8 +744,8 @@ my %pgdump_runs = (
 	schema_only_with_statistics => {
 		dump_cmd => [
 			'pg_dump', '--no-sync',
-			"--file=$tempdir/schema_only_with_statistics.sql", '--schema-only',
-			'--with-statistics', 'postgres',
+			"--file=$tempdir/schema_only_with_statistics.sql",
+			'--schema-only', '--with-statistics', 'postgres',
 		],
 	},
 	no_schema => {
@@ -1118,6 +1118,23 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / INVALID' => {
+		create_sql => 'CREATE TABLE dump_test.test_table_nn (
+							col1 int);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+		regexp => qr/^
+			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
+			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
+			/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_post_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 8970677ac64..1d08268393e 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3106,7 +3106,8 @@ describeOneTableDetails(const char *schemaname,
 		{
 			printfPQExpBuffer(&buf,
 							  "SELECT c.conname, a.attname, c.connoinherit,\n"
-							  "  c.conislocal, c.coninhcount <> 0\n"
+							  "  c.conislocal, c.coninhcount <> 0,\n"
+							  "  c.convalidated\n"
 							  "FROM pg_catalog.pg_constraint c JOIN\n"
 							  "  pg_catalog.pg_attribute a ON\n"
 							  "    (a.attrelid = c.conrelid AND a.attnum = c.conkey[1])\n"
@@ -3129,14 +3130,16 @@ describeOneTableDetails(const char *schemaname,
 			{
 				bool		islocal = PQgetvalue(result, i, 3)[0] == 't';
 				bool		inherited = PQgetvalue(result, i, 4)[0] == 't';
+				bool		validated = PQgetvalue(result, i, 5)[0] == 't';
 
-				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s",
+				printfPQExpBuffer(&buf, "    \"%s\" NOT NULL \"%s\"%s%s",
 								  PQgetvalue(result, i, 0),
 								  PQgetvalue(result, i, 1),
 								  PQgetvalue(result, i, 2)[0] == 't' ?
 								  " NO INHERIT" :
 								  islocal && inherited ? _(" (local, inherited)") :
-								  inherited ? _(" (inherited)") : "");
+								  inherited ? _(" (inherited)") : "",
+								  !validated ? " NOT VALID" : "");
 
 				printTableAddFooter(&cont, buf.data);
 			}
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 396eeb7a0bb..5523cfcf5aa 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -42,7 +42,7 @@ typedef struct TupleConstr
 	struct AttrMissing *missing;	/* missing attributes values, NULL if none */
 	uint16		num_defval;
 	uint16		num_check;
-	bool		has_not_null;
+	bool		has_not_null;	/* any not-null, including not valid ones */
 	bool		has_generated_stored;
 	bool		has_generated_virtual;
 } TupleConstr;
@@ -76,10 +76,15 @@ typedef struct CompactAttribute
 	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
 	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
 	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	bool		attnotnull;		/* as FormData_pg_attribute.attnotnull */
+	char		attnullability; /* attnotnull + attnotnullvalid */
 	uint8		attalignby;		/* alignment requirement in bytes */
 } CompactAttribute;
 
+/* Valid values for CompactAttribute->attnullability */
+#define		ATTNULLABLE_VALID		'v' /* valid constraint exists */
+#define		ATTNULLABLE_INVALID		'i' /* constraint exists, marked invalid */
+#define		ATTNULLABLE_NONE		'f' /* no constraint exists */
+
 /*
  * This struct is passed around within the backend to describe the structure
  * of tuples.  For tuples coming from on-disk relations, the information is
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 208936962ef..b573a0a2828 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202504041
+#define CATALOG_VERSION_NO	202504051
 
 #endif
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index deaa515fe53..9b1236e7a90 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -117,9 +117,12 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 */
 	char		attcompression BKI_DEFAULT('\0');
 
-	/* This flag represents the "NOT NULL" constraint */
+	/* Whether a not-null constraint exists for the column */
 	bool		attnotnull;
 
+	/* Whether the not-null constraint, if it exists, is valid */
+	bool		attnotnullvalid;
+
 	/* Has DEFAULT value or not */
 	bool		atthasdef BKI_DEFAULT(f);
 
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 6da164e7e4d..4afceb5c692 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -264,7 +264,7 @@ extern HeapTuple findNotNullConstraint(Oid relid, const char *colname);
 extern HeapTuple findDomainNotNullConstraint(Oid typid);
 extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
 extern bool AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
-									 bool is_local, bool is_no_inherit);
+									 bool is_local, bool is_no_inherit, bool is_notvalid);
 extern List *RelationGetNotNullConstraints(Oid relid, bool cooked,
 										   bool include_noinh);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 362f38856d2..8a44321034b 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1202,6 +1202,75 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id" NOT VALID
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+                                 Table "public.atnnpart1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ col1   | integer |           |          |         | plain   |              | 
+ id     | integer |           | not null |         | plain   |              | 
+Partition of: atnnparted FOR VALUES IN (1)
+Partition constraint: ((id IS NOT NULL) AND (id = 1))
+Indexes:
+    "atnnpart1_pkey" PRIMARY KEY, btree (id)
+Not-null constraints:
+    "another_constr" NOT NULL "id" (inherited)
+
+                 Index "public.atnnpart1_pkey"
+ Column |  Type   | Key? | Definition | Storage | Stats target 
+--------+---------+------+------------+---------+--------------
+ id     | integer | yes  | id         | plain   | 
+primary key, btree, for table "public.atnnpart1"
+
+                          Partitioned table "public.atnnparted"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ id     | integer |           | not null |         | plain   |              | 
+ col1   | integer |           |          |         | plain   |              | 
+Partition key: LIST (id)
+Not-null constraints:
+    "dummy_constr" NOT NULL "id"
+Partitions: atnnpart1 FOR VALUES IN (1)
+
+ROLLBACK;
+-- leave a table in this state for the pg_upgrade test
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index a719d2f74e9..d8547a9bc81 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1229,6 +1229,13 @@ alter table cnn_uq add unique using index cnn_uq_idx;
 Indexes:
     "cnn_uq_idx" UNIQUE CONSTRAINT, btree (a)
 
+-- can't create a primary key on a noinherit not-null
+create table cnn_pk (a int not null no inherit);
+alter table cnn_pk add primary key (a);
+ERROR:  cannot create primary key on column "a"
+DETAIL:  The constraint "cnn_pk_a_not_null" on column "a", marked NO INHERIT, is incompatible with a primary key.
+HINT:  You will need to make it inheritable using ALTER TABLE ... ALTER CONSTRAINT ... INHERIT.
+drop table cnn_pk;
 -- Ensure partitions are scanned for null values when adding a PK
 create table cnn2_parted(a int) partition by list (a);
 create table cnn_part1 partition of cnn2_parted for values in (1, null);
@@ -1355,6 +1362,249 @@ Not-null constraints:
     "ann" NOT NULL "a"
     "bnn" NOT NULL "b"
 
+-- NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass as tabname, conname, convalidated, conislocal, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY conrelid::regclass::text, conname;
+CREATE TABLE notnull_tbl1 (a int, b int);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+-- even an invalid not-null forbids new nulls
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+ERROR:  null value in column "a" of relation "notnull_tbl1" violates not-null constraint
+DETAIL:  Failing row contains (null, 4).
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- If we have an invalid constraint, we can't have another
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ERROR:  cannot change NO INHERIT status of NOT NULL constraint "nn" on relation "notnull_tbl1"
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+-- cannot add primary key on a column with an invalid not-null
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+ERROR:  cannot create primary key on column "a"
+DETAIL:  The constraint "nn" on column "a", marked NOT VALID, is incompatible with a primary key.
+HINT:  You will need to validate it using ALTER TABLE ... VALIDATE CONSTRAINT.
+-- ALTER column SET NOT NULL validates an invalid constraint (but this fails
+-- because of rows with null values)
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+\d+ notnull_tbl1
+                               Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Not-null constraints:
+    "nn" NOT NULL "a" NOT VALID
+
+-- Creating a derived table using LIKE gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_copy (LIKE notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_copy}');
+      tabname      | conname | convalidated | conislocal | coninhcount 
+-------------------+---------+--------------+------------+-------------
+ notnull_tbl1_copy | nn      | t            | t          |           0
+(1 row)
+
+-- An inheritance child table gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_child (a int, b int) INHERITS (notnull_tbl1);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+      tabname       | conname | convalidated | conislocal | coninhcount 
+--------------------+---------+--------------+------------+-------------
+ notnull_tbl1       | nn      | f            | t          |           0
+ notnull_tbl1_child | nn      | t            | f          |           1
+(2 rows)
+
+-- Also try inheritance added after table creation
+CREATE TABLE notnull_tbl1_child2 (c int, b int, a int);
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;	-- nope
+ERROR:  column "a" in child table "notnull_tbl1_child2" must be marked NOT NULL
+ALTER TABLE notnull_tbl1_child2 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child2}');
+       tabname       |            conname             | convalidated | conislocal | coninhcount 
+---------------------+--------------------------------+--------------+------------+-------------
+ notnull_tbl1_child2 | notnull_tbl1_child2_a_not_null | f            | t          |           1
+(1 row)
+
+-- VALIDATE CONSTRAINT scans the table
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- error, nulls exist
+ERROR:  column "a" of relation "notnull_tbl1" contains null values
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- now ok
+EXECUTE get_nnconstraint_info('{notnull_tbl1}');
+   tabname    | conname | convalidated | conislocal | coninhcount 
+--------------+---------+--------------+------------+-------------
+ notnull_tbl1 | nn      | t            | t          |           0
+(1 row)
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child, notnull_tbl1_child2;
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nntbl1_a NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a NO INHERIT;
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT nntbl1_a;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+-- if a parent has a valid not null constraint then a child table cannot
+-- have an invalid one
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld0 (a int, CONSTRAINT nn_chld0 NOT NULL a);
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+ERROR:  constraint "nn_parent" conflicts with NOT VALID constraint on child table "notnull_tbl1"
+ALTER TABLE notnull_chld0 DROP CONSTRAINT nn_chld0;
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --now ok
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld0}');
+    tabname    |  conname  | convalidated | conislocal | coninhcount 
+---------------+-----------+--------------+------------+-------------
+ notnull_chld0 | nn_chld0  | f            | t          |           0
+ notnull_tbl1  | nn_parent | t            | t          |           1
+(2 rows)
+
+DROP TABLE notnull_tbl1, notnull_chld0;
+-- Test invalid not null on inheritance table.
+CREATE TABLE notnull_inhparent (i int);
+CREATE TABLE notnull_inhchild (i int) INHERITS (notnull_inhparent);
+NOTICE:  merging column "i" with inherited definition
+CREATE TABLE notnull_inhgrand () INHERITS (notnull_inhparent, notnull_inhchild);
+NOTICE:  merging multiple inherited definitions of column "i"
+ALTER TABLE notnull_inhparent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE notnull_inhchild ADD CONSTRAINT nn1 NOT NULL i; -- error
+ERROR:  incompatible NOT VALID constraint "nn" on relation "notnull_inhchild"
+HINT:  You will need to use ALTER TABLE ... VALIDATE CONSTRAINT to validate it.
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+      tabname      | conname | convalidated | conislocal | coninhcount 
+-------------------+---------+--------------+------------+-------------
+ notnull_inhchild  | nn      | f            | f          |           1
+ notnull_inhgrand  | nn      | f            | f          |           2
+ notnull_inhparent | nn      | f            | t          |           0
+(3 rows)
+
+ALTER TABLE notnull_inhparent ALTER i SET NOT NULL; -- ok
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+      tabname      | conname | convalidated | conislocal | coninhcount 
+-------------------+---------+--------------+------------+-------------
+ notnull_inhchild  | nn      | t            | f          |           1
+ notnull_inhgrand  | nn      | t            | f          |           2
+ notnull_inhparent | nn      | t            | t          |           0
+(3 rows)
+
+DROP TABLE notnull_inhparent, notnull_inhchild, notnull_inhgrand;
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+ERROR:  table "notnull_tbl1" does not exist
+CREATE TABLE notnull_tbl1 (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    tabname     |   conname   | convalidated | conislocal | coninhcount 
+----------------+-------------+--------------+------------+-------------
+ notnull_tbl1   | notnull_con | f            | t          |           0
+ notnull_tbl1_1 | notnull_con | t            | f          |           1
+ notnull_tbl1_2 | nn2         | t            | f          |           1
+ notnull_tbl1_3 | nn3         | f            | f          |           1
+(4 rows)
+
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, notnull_tbl1_3 have null values
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+ERROR:  column "a" of relation "notnull_tbl1_3" contains null values
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+    tabname     |   conname   | convalidated | conislocal | coninhcount 
+----------------+-------------+--------------+------------+-------------
+ notnull_tbl1   | notnull_con | t            | t          |           0
+ notnull_tbl1_1 | notnull_con | t            | f          |           1
+ notnull_tbl1_2 | nn2         | t            | f          |           1
+ notnull_tbl1_3 | nn3         | t            | f          |           1
+(4 rows)
+
+DROP TABLE notnull_tbl1;
+-- partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a int, b int, NOT NULL a) PARTITION BY LIST (a);
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ERROR:  constraint "nn1" conflicts with NOT VALID constraint on child table "pp_nn_1"
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a int, b int);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a int);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal
+FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass)
+ORDER BY 1;
+      conrelid      | contype | convalidated | conislocal 
+--------------------+---------+--------------+------------
+ notnull_parent_upg | n       | f            | t
+ notnull_child_upg  | n       | t            | t
+(2 rows)
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+       tabname       |   conname   | convalidated | conislocal | coninhcount 
+---------------------+-------------+--------------+------------+-------------
+ notnull_part1_1_upg | notnull_con | t            | f          |           1
+ notnull_part1_2_upg | nn2         | t            | f          |           1
+ notnull_part1_3_upg | nn3         | f            | f          |           1
+ notnull_part1_upg   | notnull_con | f            | t          |           0
+(4 rows)
+
+DEALLOCATE get_nnconstraint_info;
+-- end NOT NULL NOT VALID
 -- Comments
 -- Setup a low-level role to enforce non-superuser checks.
 CREATE ROLE regress_constraint_comments;
diff --git a/src/test/regress/expected/sanity_check.out b/src/test/regress/expected/sanity_check.out
index 8370c1561cc..2e39037e3fb 100644
--- a/src/test/regress/expected/sanity_check.out
+++ b/src/test/regress/expected/sanity_check.out
@@ -25,3 +25,23 @@ SELECT relname, relkind
 ---------+---------
 (0 rows)
 
+-- pg_attribute sanity check: attnotnullvalid can only be true when
+-- attnotnull is valid.
+select pa.attrelid::regclass, pa.attname, pa.attnum,
+       pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa
+where not pa.attnotnull and pa.attnotnullvalid;
+ attrelid | attname | attnum | attnotnull | attnotnullvalid 
+----------+---------+--------+------------+-----------------
+(0 rows)
+
+-- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
+select att.attrelid::regclass, att.attname, att.attnotnull,
+       att.attnotnullvalid, con.convalidated
+  from pg_attribute att join pg_constraint con
+    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
+ where contype = 'n' and con.convalidated <> att.attnotnullvalid;
+ attrelid | attname | attnotnull | attnotnullvalid | convalidated 
+----------+---------+------------+-----------------+--------------
+(0 rows)
+
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 84e93ef575e..8432e8e3d54 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -910,6 +910,20 @@ alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null
 alter table atacc1 alter test_b set not null, alter test_a set not null;
 drop table atacc1;
 
+-- not null not valid with partitions
+CREATE TABLE atnnparted (id int, col1 int) PARTITION BY LIST (id);
+ALTER TABLE atnnparted ADD CONSTRAINT dummy_constr NOT NULL id NOT VALID;
+CREATE TABLE atnnpart1 (col1 int, id int);
+ALTER TABLE atnnpart1 ADD CONSTRAINT another_constr NOT NULL id;
+ALTER TABLE atnnpart1 ADD PRIMARY KEY (id);
+ALTER TABLE atnnparted ATTACH PARTITION atnnpart1 FOR VALUES IN ('1');
+\d+ atnnpart*
+BEGIN;
+ALTER TABLE atnnparted VALIDATE CONSTRAINT dummy_constr;
+\d+ atnnpart*
+ROLLBACK;
+-- leave a table in this state for the pg_upgrade test
+
 -- test inheritance
 create table parent (a int);
 create table child (b varchar(255)) inherits (parent);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 21ce4177de4..8f199c7ba34 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -761,6 +761,11 @@ create unique index cnn_uq_idx on cnn_uq (a);
 alter table cnn_uq add unique using index cnn_uq_idx;
 \d+ cnn_uq
 
+-- can't create a primary key on a noinherit not-null
+create table cnn_pk (a int not null no inherit);
+alter table cnn_pk add primary key (a);
+drop table cnn_pk;
+
 -- Ensure partitions are scanned for null values when adding a PK
 create table cnn2_parted(a int) partition by list (a);
 create table cnn_part1 partition of cnn2_parted for values in (1, null);
@@ -801,6 +806,167 @@ ALTER TABLE ONLY notnull_tbl6 DROP CONSTRAINT ann;
 ALTER TABLE ONLY notnull_tbl6 ALTER b DROP NOT NULL;
 \d+ notnull_tbl6_1
 
+
+-- NOT NULL NOT VALID
+PREPARE get_nnconstraint_info(regclass[]) AS
+SELECT conrelid::regclass as tabname, conname, convalidated, conislocal, coninhcount
+FROM  pg_constraint
+WHERE conrelid = ANY($1)
+ORDER BY conrelid::regclass::text, conname;
+
+CREATE TABLE notnull_tbl1 (a int, b int);
+INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a; -- error
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
+-- even an invalid not-null forbids new nulls
+INSERT INTO notnull_tbl1 VALUES (NULL, 4);
+\d+ notnull_tbl1
+
+-- If we have an invalid constraint, we can't have another
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID NO INHERIT;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
+
+-- cannot add primary key on a column with an invalid not-null
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+
+-- ALTER column SET NOT NULL validates an invalid constraint (but this fails
+-- because of rows with null values)
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+\d+ notnull_tbl1
+
+-- Creating a derived table using LIKE gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_copy (LIKE notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_copy}');
+
+-- An inheritance child table gets the constraint, but it's valid
+CREATE TABLE notnull_tbl1_child (a int, b int) INHERITS (notnull_tbl1);
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child, notnull_tbl1}');
+
+-- Also try inheritance added after table creation
+CREATE TABLE notnull_tbl1_child2 (c int, b int, a int);
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;	-- nope
+ALTER TABLE notnull_tbl1_child2 ADD NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;
+EXECUTE get_nnconstraint_info('{notnull_tbl1_child2}');
+
+-- VALIDATE CONSTRAINT scans the table
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- error, nulls exist
+UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- now ok
+EXECUTE get_nnconstraint_info('{notnull_tbl1}');
+
+--- now we can add primary key
+ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+DROP TABLE notnull_tbl1, notnull_tbl1_child, notnull_tbl1_child2;
+
+-- dropping an invalid constraint is possible
+CREATE TABLE notnull_tbl1 (a int, b int);
+ALTER TABLE notnull_tbl1 ADD NOT NULL a NOT VALID,
+	ADD NOT NULL b NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT notnull_tbl1_b_not_null;
+DROP TABLE notnull_tbl1;
+
+-- ALTER .. NO INHERIT works for invalid constraints
+CREATE TABLE notnull_tbl1 (a int);
+CREATE TABLE notnull_tbl1_chld () INHERITS (notnull_tbl1);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nntbl1_a NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a NO INHERIT;
+
+-- DROP CONSTRAINT recurses correctly on invalid constraints
+ALTER TABLE notnull_tbl1 ALTER CONSTRAINT nntbl1_a INHERIT;
+ALTER TABLE notnull_tbl1 DROP CONSTRAINT nntbl1_a;
+DROP TABLE notnull_tbl1, notnull_tbl1_chld;
+
+-- if a parent has a valid not null constraint then a child table cannot
+-- have an invalid one
+CREATE TABLE notnull_tbl1 (a int);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn_parent NOT NULL a not valid;
+CREATE TABLE notnull_chld0 (a int, CONSTRAINT nn_chld0 NOT NULL a);
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --error
+
+ALTER TABLE notnull_chld0 DROP CONSTRAINT nn_chld0;
+ALTER TABLE notnull_chld0 ADD CONSTRAINT nn_chld0 NOT NULL a not valid;
+ALTER TABLE notnull_tbl1 INHERIT notnull_chld0; --now ok
+
+-- parents and child not-null will all be validated.
+ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn_parent;
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_chld0}');
+DROP TABLE notnull_tbl1, notnull_chld0;
+
+-- Test invalid not null on inheritance table.
+CREATE TABLE notnull_inhparent (i int);
+CREATE TABLE notnull_inhchild (i int) INHERITS (notnull_inhparent);
+CREATE TABLE notnull_inhgrand () INHERITS (notnull_inhparent, notnull_inhchild);
+ALTER TABLE notnull_inhparent ADD CONSTRAINT nn NOT NULL i NOT VALID;
+ALTER TABLE notnull_inhchild ADD CONSTRAINT nn1 NOT NULL i; -- error
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+ALTER TABLE notnull_inhparent ALTER i SET NOT NULL; -- ok
+EXECUTE get_nnconstraint_info('{notnull_inhparent, notnull_inhchild, notnull_inhgrand}');
+DROP TABLE notnull_inhparent, notnull_inhchild, notnull_inhgrand;
+
+-- Verify NOT NULL VALID/NOT VALID with partition table.
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl1 (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_tbl1_1 PARTITION OF notnull_tbl1 FOR VALUES IN (1,2);
+CREATE TABLE notnull_tbl1_2(a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_2 FOR VALUES IN (3,4);
+
+CREATE TABLE notnull_tbl1_3(a int, b int);
+INSERT INTO notnull_tbl1_3 values(NULL,1);
+ALTER TABLE notnull_tbl1_3 add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_tbl1 ATTACH PARTITION notnull_tbl1_3 FOR VALUES IN (NULL,5);
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --error, notnull_tbl1_3 have null values
+ALTER TABLE notnull_tbl1_3 VALIDATE CONSTRAINT nn3; --error
+
+TRUNCATE notnull_tbl1;
+ALTER TABLE notnull_tbl1 ALTER COLUMN a SET NOT NULL; --OK
+
+EXECUTE get_nnconstraint_info('{notnull_tbl1, notnull_tbl1_1, notnull_tbl1_2, notnull_tbl1_3}');
+DROP TABLE notnull_tbl1;
+
+-- partitioned table have not-null, then the partitions can not be NOT NULL NOT VALID.
+CREATE TABLE pp_nn (a int, b int, NOT NULL a) PARTITION BY LIST (a);
+CREATE TABLE pp_nn_1(a int, b int);
+ALTER TABLE pp_nn_1 ADD CONSTRAINT nn1 NOT NULL a NOT VALID;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --error
+ALTER TABLE pp_nn_1 VALIDATE CONSTRAINT nn1;
+ALTER TABLE pp_nn ATTACH PARTITION pp_nn_1 FOR VALUES IN (NULL,5); --ok
+DROP TABLE pp_nn;
+
+-- Create table with NOT NULL INVALID constraint, for pg_upgrade.
+CREATE TABLE notnull_tbl1_upg (a int, b int);
+INSERT INTO notnull_tbl1_upg VALUES (NULL, 1), (NULL, 2), (300, 3);
+ALTER TABLE notnull_tbl1_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+-- Inherit test for pg_upgrade
+CREATE TABLE notnull_parent_upg (a int);
+CREATE TABLE notnull_child_upg () INHERITS (notnull_parent_upg);
+ALTER TABLE notnull_child_upg ADD CONSTRAINT nn NOT NULL a;
+ALTER TABLE notnull_parent_upg ADD CONSTRAINT nn NOT NULL a NOT VALID;
+SELECT conrelid::regclass, contype, convalidated, conislocal
+FROM pg_catalog.pg_constraint
+WHERE conrelid in ('notnull_parent_upg'::regclass, 'notnull_child_upg'::regclass)
+ORDER BY 1;
+
+-- Partition table test, for pg_upgrade
+CREATE TABLE notnull_part1_upg (a int, b int) PARTITION BY LIST (a);
+ALTER TABLE notnull_part1_upg ADD CONSTRAINT notnull_con NOT NULL a NOT VALID; --ok
+CREATE TABLE notnull_part1_1_upg PARTITION OF notnull_part1_upg FOR VALUES IN (1,2);
+CREATE TABLE notnull_part1_2_upg (a int, CONSTRAINT nn2 NOT NULL a, b int);
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_2_upg FOR VALUES IN (3,4);
+CREATE TABLE notnull_part1_3_upg (a int, b int);
+INSERT INTO notnull_part1_3_upg values(NULL,1);
+ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
+ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
+EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+DEALLOCATE get_nnconstraint_info;
+
+-- end NOT NULL NOT VALID
+
+
 -- Comments
 -- Setup a low-level role to enforce non-superuser checks.
 CREATE ROLE regress_constraint_comments;
diff --git a/src/test/regress/sql/sanity_check.sql b/src/test/regress/sql/sanity_check.sql
index 162e5324b5d..6ef36ab84b7 100644
--- a/src/test/regress/sql/sanity_check.sql
+++ b/src/test/regress/sql/sanity_check.sql
@@ -19,3 +19,17 @@ SELECT relname, relkind
   FROM pg_class
  WHERE relkind IN ('v', 'c', 'f', 'p', 'I')
        AND relfilenode <> 0;
+
+-- pg_attribute sanity check: attnotnullvalid can only be true when
+-- attnotnull is valid.
+select pa.attrelid::regclass, pa.attname, pa.attnum,
+       pa.attnotnull, pa.attnotnullvalid
+from    pg_attribute pa
+where not pa.attnotnull and pa.attnotnullvalid;
+
+-- pg_attribute's attnotnullvalid should match pg_constraint.convalidated
+select att.attrelid::regclass, att.attname, att.attnotnull,
+       att.attnotnullvalid, con.convalidated
+  from pg_attribute att join pg_constraint con
+    on (att.attnum = con.conkey[1] and att.attrelid = con.conrelid)
+ where contype = 'n' and con.convalidated <> att.attnotnullvalid;
-- 
2.43.0

From b2ea2c97eda39e4575da0f736553eecafd186ab8 Mon Sep 17 00:00:00 2001
From: Rushabh Lathia <rushabh.lathia@enterprisedb.com>
Date: Mon, 7 Apr 2025 13:51:22 +0530
Subject: [PATCH 3/3] Fix relation attribute loop correctly and also set the
 nullability to ATTNULLABLE_VALID for the catalog/temp tables.

---
 src/backend/access/common/tupdesc.c | 9 +++++++--
 src/backend/utils/cache/relcache.c  | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 5831788cbff..d481fadaf73 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -22,6 +22,7 @@
 #include "access/htup_details.h"
 #include "access/toast_compression.h"
 #include "access/tupdesc_details.h"
+#include "catalog/catalog.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
 #include "common/hashfn.h"
@@ -74,8 +75,12 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
-		ATTNULLABLE_UNKNOWN;
+	if (IsCatalogRelationOid(src->attrelid))
+		dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
+			ATTNULLABLE_VALID;
+	else
+		dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
+			ATTNULLABLE_UNKNOWN;
 
 	switch (src->attalign)
 	{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 4128cfa8314..483f19711f0 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -704,7 +704,7 @@ RelationBuildTupleDesc(Relation relation)
 		 * CompactAttribute array.  In catalog relations however, any not-null
 		 * constraint is necessarily valid.
 		 */
-		for (int i = 0; i < relation->rd_rel->relnatts - 1; i++)
+		for (int i = 0; i < relation->rd_rel->relnatts; i++)
 		{
 			CompactAttribute *attr;
 
-- 
2.43.0

From 89ae829386d62a2c9cb5b8f9c827fa805f39d327 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 7 Apr 2025 20:40:15 +0800
Subject: [PATCH v8 3/3] not null not valid miscellous fix

---
 src/backend/access/common/tupdesc.c       | 10 ++++++++--
 src/backend/commands/tablecmds.c          | 15 ++++++++++++++-
 src/backend/optimizer/util/plancat.c      |  1 +
 src/backend/utils/cache/relcache.c        |  2 +-
 src/test/regress/expected/constraints.out |  2 ++
 src/test/regress/sql/constraints.sql      |  3 +++
 6 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 5831788cbff..8e4dcd412fa 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -22,6 +22,7 @@
 #include "access/htup_details.h"
 #include "access/toast_compression.h"
 #include "access/tupdesc_details.h"
+#include "catalog/catalog.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
 #include "common/hashfn.h"
@@ -74,8 +75,13 @@ populate_compact_attribute_internal(Form_pg_attribute src,
 	dst->atthasmissing = src->atthasmissing;
 	dst->attisdropped = src->attisdropped;
 	dst->attgenerated = (src->attgenerated != '\0');
-	dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
-		ATTNULLABLE_UNKNOWN;
+
+	if (IsCatalogRelationOid(src->attrelid))
+		dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
+			ATTNULLABLE_VALID;
+	else
+		dst->attnullability = !src->attnotnull ? ATTNULLABLE_UNRESTRICTED :
+			ATTNULLABLE_UNKNOWN;
 
 	switch (src->attalign)
 	{
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 91905533da7..6be6609a747 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -6224,7 +6224,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(newTupDesc, i);
 
-			if (attr->attnullability != ATTNULLABLE_UNRESTRICTED &&
+			if (attr->attnullability == ATTNULLABLE_VALID &&
 				!attr->attisdropped)
 			{
 				Form_pg_attribute	wholeatt = TupleDescAttr(newTupDesc, i);
@@ -7832,6 +7832,7 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 			   bool is_valid, bool queue_validation)
 {
 	Form_pg_attribute attr;
+	CompactAttribute *thisatt;
 
 	Assert(!queue_validation || wqueue);
 
@@ -7857,6 +7858,9 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 			elog(ERROR, "cache lookup failed for attribute %d of relation %u",
 				 attnum, RelationGetRelid(rel));
 
+		thisatt = TupleDescCompactAttr(RelationGetDescr(rel), attnum - 1);
+		thisatt->attnullability = ATTNULLABLE_VALID;
+
 		attr = (Form_pg_attribute) GETSTRUCT(tuple);
 
 		attr->attnotnull = true;
@@ -7880,6 +7884,15 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum,
 		table_close(attr_rel, RowExclusiveLock);
 		heap_freetuple(tuple);
 	}
+	else
+	{
+		thisatt = TupleDescCompactAttr(RelationGetDescr(rel), attnum - 1);
+
+		if(is_valid)
+			thisatt->attnullability = ATTNULLABLE_VALID;
+		else
+			thisatt->attnullability = ATTNULLABLE_INVALID;
+	}
 }
 
 /*
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 881747e71d4..316b51b724f 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -176,6 +176,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 		for (int i = 0; i < relation->rd_att->natts; i++)
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
+			Assert(attr->attnullability != ATTNULLABLE_UNKNOWN);
 
 			if (attr->attnullability == ATTNULLABLE_VALID)
 			{
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 4128cfa8314..483f19711f0 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -704,7 +704,7 @@ RelationBuildTupleDesc(Relation relation)
 		 * CompactAttribute array.  In catalog relations however, any not-null
 		 * constraint is necessarily valid.
 		 */
-		for (int i = 0; i < relation->rd_rel->relnatts - 1; i++)
+		for (int i = 0; i < relation->rd_rel->relnatts; i++)
 		{
 			CompactAttribute *attr;
 
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index d8547a9bc81..1346134e23c 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1441,6 +1441,8 @@ EXECUTE get_nnconstraint_info('{notnull_tbl1_child2}');
  notnull_tbl1_child2 | notnull_tbl1_child2_a_not_null | f            | t          |           1
 (1 row)
 
+--table rewrite won't validate invalid constraint
+ALTER TABLE notnull_tbl1 ADD column d float8 default random();
 -- VALIDATE CONSTRAINT scans the table
 ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- error, nulls exist
 ERROR:  column "a" of relation "notnull_tbl1" contains null values
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 8f199c7ba34..0f2fe3e6e2d 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -849,6 +849,9 @@ ALTER TABLE notnull_tbl1_child2 ADD NOT NULL a NOT VALID;
 ALTER TABLE notnull_tbl1_child2 INHERIT notnull_tbl1;
 EXECUTE get_nnconstraint_info('{notnull_tbl1_child2}');
 
+--table rewrite won't validate invalid constraint
+ALTER TABLE notnull_tbl1 ADD column d float8 default random();
+
 -- VALIDATE CONSTRAINT scans the table
 ALTER TABLE notnull_tbl1 VALIDATE CONSTRAINT nn; -- error, nulls exist
 UPDATE notnull_tbl1 SET a = 100 WHERE b = 1;
-- 
2.34.1

From 9505f36287403aa8efd7642dddf71b77996796dd Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Wed, 9 Apr 2025 13:07:58 +0800
Subject: [PATCH v1 1/1] pg_dump not null not valid

make sure pg_dump have the same pg_constraint meta before
and after pg_dump.

if the parent not-null constraint is invalid, child is valid.
then pg_dump need locally print the not-null constraint on that child
too.
otherwise pg_dump may make child's convalidated may set to false.

that means we also need adjust conislocal in AdjustNotNullInheritance.
---
 src/backend/catalog/pg_constraint.c | 10 ++++++++++
 src/bin/pg_dump/common.c            |  4 ++++
 src/bin/pg_dump/pg_dump.c           | 17 +++++++++++++++++
 src/bin/pg_dump/pg_dump.h           |  5 +++++
 4 files changed, 36 insertions(+)

diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 2f73085961b..9e65b96143f 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -776,6 +776,16 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 				ereport(ERROR,
 						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 						errmsg("too many inheritance parents"));
+
+			/*
+			 * If the child already has a valid constraint and we are
+			 * creating an invalid one with same definition on it.  The
+			 * child's constraint will remain valid, but can no longer be
+			 * marked as local.
+			*/
+			if (is_notvalid && conform->convalidated && conform->conenforced)
+				conform->conislocal = false;
+
 			changed = true;
 		}
 		else if (!conform->conislocal)
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 56b6c368acf..ff6a4eacda0 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -546,6 +546,10 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 						parent->notnull_constrs[inhAttrInd] != NULL)
 						foundNotNull = true;
 
+					if (fout->remoteVersion >= 180000 &&
+						parent->notnull_invalid[inhAttrInd])
+						tbinfo->notnull_parent_invalid[j] = true;
+
 					foundDefault |= (parentDef != NULL &&
 									 strcmp(parentDef->adef_expr, "NULL") != 0 &&
 									 !parent->attgenerated[inhAttrInd]);
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 25264f8c9fb..8d131523366 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -9255,6 +9255,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->notnull_parent_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9280,6 +9282,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_parent_invalid[j] = false;	/* it only change in flagInhAttrs */
+			tbinfo->notnull_invalid[j] = false;			/* it only change in determineNotNullFlags */
 
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
@@ -9758,6 +9762,7 @@ determineNotNullFlags(Archive *fout, PGresult *res, int r,
 
 		/* nothing else to do */
 		tbinfo->notnull_constrs[j] = NULL;
+		tbinfo->notnull_invalid[j] = true;
 		return;
 	}
 
@@ -16986,6 +16991,18 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 											  tbinfo->attrdefs[j]->adef_expr);
 					}
 
+					/*
+					 * if parent have invalid not-null, child have valid
+					 * not-null, then we print not null on child too.  later
+					 * parent's invalid not-null will generate a ALTER TABLE ADD
+					 * CONSTRAINT, which will cascade to children, which is
+					 * fine.
+					*/
+					if (!print_notnull &&
+						tbinfo->notnull_constrs[j] != NULL &&
+						tbinfo->notnull_parent_invalid[j])
+						print_notnull = true;
+
 					if (print_notnull)
 					{
 						if (tbinfo->notnull_constrs[j][0] == '\0')
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index b426b5e4736..6c2f963dcc4 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,6 +365,11 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_invalid; /* true for NOT NULL NOT VALID */
+
+	/* true if parent table NOT NULL constraint is NOT VALID */
+	bool	   *notnull_parent_invalid;
+
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
-- 
2.34.1

From 00c46ba90a24a99857cdc849943cf3fd7b96bd8e Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Wed, 9 Apr 2025 13:07:58 +0800
Subject: [PATCH 1/2] Fix pg_dump for inherited validated not-null constraints

When a child constraint is validated and its parent constraint isn't,
pg_dump requires special handling.
---
 src/bin/pg_dump/common.c                  | 12 +++++++
 src/bin/pg_dump/pg_dump.c                 | 12 ++++++-
 src/bin/pg_dump/pg_dump.h                 |  1 +
 src/bin/pg_dump/t/002_pg_dump.pl          | 41 +++++++++++++++++++++--
 src/test/regress/expected/constraints.out | 24 +++++++++++++
 src/test/regress/sql/constraints.sql      | 14 ++++++++
 6 files changed, 101 insertions(+), 3 deletions(-)

diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 56b6c368acf..b0973d44f32 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -546,6 +546,18 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 						parent->notnull_constrs[inhAttrInd] != NULL)
 						foundNotNull = true;
 
+					/*
+					 * For validated not-null constraints in child tables which
+					 * derive from a parent constraint marked NOT VALID, we
+					 * artificially mark the child constraint as local so that
+					 * it is printed independently.  Failing to do this would
+					 * result in the child constraint being restored as NOT
+					 * VALID.
+					 */
+					if (fout->remoteVersion >= 180000 &&
+						parent->notnull_invalid[inhAttrInd])
+						tbinfo->notnull_islocal[j] = true;
+
 					foundDefault |= (parentDef != NULL &&
 									 strcmp(parentDef->adef_expr, "NULL") != 0 &&
 									 !parent->attgenerated[inhAttrInd]);
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 105e917aa7b..0e2485479f8 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -9255,6 +9255,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9280,6 +9281,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, r, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
+			tbinfo->notnull_invalid[j] = false; /* it only change in
+												 * determineNotNullFlags */
 
 			/* Handle not-null constraint name and flags */
 			determineNotNullFlags(fout, res, r,
@@ -9756,6 +9759,12 @@ determineNotNullFlags(Archive *fout, PGresult *res, int r,
 		else
 			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
 
+		/*
+		 * Track when a parent constraint is invalid for the cases where a
+		 * child constraint has been validated independenly.
+		 */
+		tbinfo->notnull_invalid[j] = true;
+
 		/* nothing else to do */
 		tbinfo->notnull_constrs[j] = NULL;
 		return;
@@ -9763,10 +9772,11 @@ determineNotNullFlags(Archive *fout, PGresult *res, int r,
 
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
-	 * though flagInhAttrs may change that one later in versions < 18.
+	 * though flagInhAttrs may change that one later.
 	 */
 	tbinfo->notnull_noinh[j] = PQgetvalue(res, r, i_notnull_noinherit)[0] == 't';
 	tbinfo->notnull_islocal[j] = PQgetvalue(res, r, i_notnull_islocal)[0] == 't';
+	tbinfo->notnull_invalid[j] = false;
 
 	/*
 	 * Determine a constraint name to use.  If the column is not marked not-
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index b426b5e4736..7417eab6aef 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -365,6 +365,7 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_invalid;	/* true for NOT NULL NOT VALID */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 6c03eca8e50..4494acaed8d 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1118,10 +1118,17 @@ my %tests = (
 		},
 	},
 
-	'CONSTRAINT NOT NULL / INVALID' => {
+	'CONSTRAINT NOT NULL / NOT VALID' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_nn (
 							col1 int);
-			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+							CREATE TABLE dump_test.test_table_nn_chld1 (
+							) INHERITS (dump_test.test_table_nn);
+							CREATE TABLE dump_test.test_table_nn_chld2 (
+								col1 int
+							) INHERITS (dump_test.test_table_nn);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;
+			ALTER TABLE dump_test.test_table_nn_chld1 VALIDATE CONSTRAINT nn;
+			ALTER TABLE dump_test.test_table_nn_chld2 VALIDATE CONSTRAINT nn;',
 		regexp => qr/^
 			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
 			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
@@ -1135,6 +1142,36 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / NOT VALID (child1)' => {
+		regexp => qr/^
+		\QCREATE TABLE dump_test.test_table_nn_chld1 (\E\n
+		^\s+\QCONSTRAINT nn NOT NULL col1\E$
+		/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_pre_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+			binary_upgrade => 1,
+		},
+	},
+
+	'CONSTRAINT NOT NULL / NOT VALID (child2)' => {
+		regexp => qr/^
+		\QCREATE TABLE dump_test.test_table_nn_chld2 (\E\n
+		^\s+\Qcol1 integer CONSTRAINT nn NOT NULL\E$
+		/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_pre_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 92e441a16cd..89f88cf9eb2 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1625,6 +1625,30 @@ EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_
  notnull_part1_upg   | notnull_con | f            | t          |           0
 (4 rows)
 
+-- Inheritance test tables for pg_upgrade
+create table constr_parent (a int);
+create table constr_child (a int) inherits (constr_parent);
+NOTICE:  merging column "a" with inherited definition
+alter table constr_parent add not null a not valid;
+alter table constr_child validate constraint constr_parent_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent, constr_child}');
+    tabname    |         conname          | convalidated | conislocal | coninhcount 
+---------------+--------------------------+--------------+------------+-------------
+ constr_child  | constr_parent_a_not_null | t            | f          |           1
+ constr_parent | constr_parent_a_not_null | f            | t          |           0
+(2 rows)
+
+create table constr_parent2 (a int);
+create table constr_child2 () inherits (constr_parent2);
+alter table constr_parent2 add not null a not valid;
+alter table constr_child2 validate constraint constr_parent2_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent2, constr_child2}');
+    tabname     |          conname          | convalidated | conislocal | coninhcount 
+----------------+---------------------------+--------------+------------+-------------
+ constr_child2  | constr_parent2_a_not_null | t            | f          |           1
+ constr_parent2 | constr_parent2_a_not_null | f            | t          |           0
+(2 rows)
+
 DEALLOCATE get_nnconstraint_info;
 -- end NOT NULL NOT VALID
 -- Comments
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 5d6d749c150..f93b4095044 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -979,6 +979,20 @@ INSERT INTO notnull_part1_3_upg values(NULL,1);
 ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
 ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
 EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+
+-- Inheritance test tables for pg_upgrade
+create table constr_parent (a int);
+create table constr_child (a int) inherits (constr_parent);
+alter table constr_parent add not null a not valid;
+alter table constr_child validate constraint constr_parent_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent, constr_child}');
+
+create table constr_parent2 (a int);
+create table constr_child2 () inherits (constr_parent2);
+alter table constr_parent2 add not null a not valid;
+alter table constr_child2 validate constraint constr_parent2_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent2, constr_child2}');
+
 DEALLOCATE get_nnconstraint_info;
 
 -- end NOT NULL NOT VALID
-- 
2.39.5

From 91efc55ab422fcdff83fdc4fb9bd28b17c74c980 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Herrera?= <alvherre@alvh.no-ip.org>
Date: Thu, 24 Apr 2025 21:09:22 +0200
Subject: [PATCH 2/2] Unnecessary change

I think we don't have a good reason to do this.
---
 src/backend/catalog/pg_constraint.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 70528679e57..6d5f83f9329 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -779,6 +779,17 @@ AdjustNotNullInheritance(Oid relid, AttrNumber attnum,
 				ereport(ERROR,
 						errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 						errmsg("too many inheritance parents"));
+
+
+			/*
+			 * If the child already has a valid constraint and we are creating
+			 * an invalid one with same definition on it.  The child's
+			 * constraint will remain valid, but can no longer be marked as
+			 * local.
+			 */
+			if (is_notvalid && conform->convalidated && conform->conenforced)
+				conform->conislocal = false;
+
 			changed = true;
 		}
 		else if (!conform->conislocal)
-- 
2.39.5