On Fri, Apr 4, 2025 at 7:54 PM Rushabh Lathia <rushabh.lat...@gmail.com> wrote:
>
> Hi Alvaro,
>
> I’ve consolidated all the changes and attached the latest version of the 
> patch, which
> includes the updates submitted by Jian for pg_dump as well.
>
> Patch 0001 contains changes to MergeWithExistingConstraint to fix the marking 
> on local constraints.
> Patch 0002 includes support for NOT NULL NOT VALID, corresponding pg_dump 
> changes, test cases,
>                    and documentation updates.
>

hi.
+               /* FIXME use CompactAttribute */
                Form_pg_attribute att = TupleDescAttr(relation->rd_att, i - 1);
                if (att->attnotnull && att->attnotnullvalid &&
!att->attisdropped)
                {
                    NullTest   *ntest = makeNode(NullTest);
                    ntest->arg = (Expr *) makeVar(varno,
                                                  i,
                                                  att->atttypid,
                                                  att->atttypmod,
                                                  att->attcollation,
                                                  0);
                    ntest->nulltesttype = IS_NOT_NULL;

CompactAttribute doesn't have {atttypmod, attcollation} information,
now it is impossible to use CompactAttribute here,
so I removed this FIXME in get_relation_constraints.


i noticed that we have
"mode change 100644 => 100755 src/bin/pg_dump/t/002_pg_dump.pl"
in 0002-Support-NOT-VALID-and-VALIDATE-CONSTRAINT-for-named-.patch.

i am uncomfortable with the change in
'CREATE TABLE dump_test.test_table_generated'
so I only added 'CONSTRAINT NOT NULL / INVALID' tests in
002_pg_dump.pl.
so I only added a test case 'CONSTRAINT NOT NULL / INVALID'
to 002_pg_dump.pl.


v7-0001 commit message explains what kind of problem
MergeWithExistingConstraint is trying to fix.
v7-0002 bullet points summary about NOT NULL NOT VALID added to the
commit message.


add a test for CREATE TABLE LIKE.
CREATE TABLE LIKE will copy the invalid not-null constraint and will become
valid, i think this is what we want.


The added regress test is a little bit verbose, trying to make it less verbose.
polish comments here and there.
From 8583163960b136a52aea7ab02b5cd8b5a81deeca Mon Sep 17 00:00:00 2001
From: jian he <jian.universal...@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.lat...@gmail.com>
Author: Jian He <jian.universal...@gmail.com>

Discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-rt...@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.universal...@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-ngzqxwjzpf1...@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

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