From 6b84c2d220d924b51b9bcc436473d404ec0950ca Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 15 Mar 2023 20:11:47 +0100
Subject: [PATCH v7] Catalog NOT NULL constraints

Each declared NOT NULL constraint now gets a corresponding pg_constraint
row.
---
 doc/src/sgml/catalogs.sgml                    |    1 +
 doc/src/sgml/ref/alter_table.sgml             |    8 +-
 doc/src/sgml/ref/create_table.sgml            |    8 +-
 src/backend/catalog/heap.c                    |  491 ++++--
 src/backend/catalog/pg_constraint.c           |   98 ++
 src/backend/commands/tablecmds.c              | 1353 +++++++++++++----
 src/backend/nodes/outfuncs.c                  |    4 +
 src/backend/nodes/readfuncs.c                 |    8 +-
 src/backend/optimizer/util/plancat.c          |    2 +
 src/backend/parser/gram.y                     |   13 +
 src/backend/parser/parse_utilcmd.c            |  210 ++-
 src/backend/utils/adt/ruleutils.c             |   14 +
 src/bin/pg_dump/common.c                      |   15 +-
 src/bin/pg_dump/pg_backup_archiver.c          |    2 +
 src/bin/pg_dump/pg_dump.c                     |  198 ++-
 src/bin/pg_dump/pg_dump.h                     |    2 +-
 src/bin/pg_dump/t/002_pg_dump.pl              |    6 +-
 src/include/catalog/heap.h                    |    5 +-
 src/include/catalog/pg_constraint.h           |   11 +-
 src/include/commands/tablecmds.h              |    2 +
 src/include/nodes/parsenodes.h                |   14 +-
 .../test_ddl_deparse/expected/alter_table.out |   18 +-
 .../expected/create_table.out                 |   25 +-
 .../test_ddl_deparse/test_ddl_deparse.c       |    4 +
 src/test/regress/expected/alter_table.out     |   50 +-
 src/test/regress/expected/cluster.out         |    7 +-
 src/test/regress/expected/constraints.out     |  114 ++
 src/test/regress/expected/create_table.out    |   27 +-
 src/test/regress/expected/event_trigger.out   |    2 +
 src/test/regress/expected/foreign_data.out    |   11 +-
 src/test/regress/expected/foreign_key.out     |   16 +-
 src/test/regress/expected/indexing.out        |   41 +-
 src/test/regress/expected/inherit.out         |  397 +++++
 .../regress/expected/replica_identity.out     |   13 +
 src/test/regress/parallel_schedule            |    3 +-
 src/test/regress/sql/alter_table.sql          |   26 +-
 src/test/regress/sql/constraints.sql          |   43 +
 src/test/regress/sql/create_table.sql         |    6 +-
 src/test/regress/sql/indexing.sql             |    8 +-
 src/test/regress/sql/inherit.sql              |  207 +++
 src/test/regress/sql/replica_identity.sql     |   12 +
 41 files changed, 2862 insertions(+), 633 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 7c09ab3000..296f38c8a9 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -2552,6 +2552,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <para>
        <literal>c</literal> = check constraint,
        <literal>f</literal> = foreign key constraint,
+       <literal>n</literal> = not null constraint,
        <literal>p</literal> = primary key constraint,
        <literal>u</literal> = unique constraint,
        <literal>t</literal> = constraint trigger,
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index d4d93eeb7c..b3b531486e 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -117,7 +117,9 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> |
   EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ] ( <replaceable class="parameter">exclude_element</replaceable> WITH <replaceable class="parameter">operator</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable class="parameter">predicate</replaceable> ) ] |
   FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> [, ... ] ) ]
-    [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
+    [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] |
+  NOT NULL <replaceable class="parameter">column_name</replaceable>
+}
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
 
 <phrase>and <replaceable class="parameter">table_constraint_using_index</replaceable> is:</phrase>
@@ -1763,7 +1765,9 @@ ALTER TABLE measurement
   <title>Compatibility</title>
 
   <para>
-   The forms <literal>ADD</literal> (without <literal>USING INDEX</literal>),
+   The forms <literal>ADD</literal> (without <literal>USING INDEX</literal>, and
+   except for the <literal>NOT NULL <replaceable>column_name</replaceable></literal>
+   form to add a table constraint),
    <literal>DROP [COLUMN]</literal>, <literal>DROP IDENTITY</literal>, <literal>RESTART</literal>,
    <literal>SET DEFAULT</literal>, <literal>SET DATA TYPE</literal> (without <literal>USING</literal>),
    <literal>SET GENERATED</literal>, and <literal>SET <replaceable>sequence_option</replaceable></literal>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 10ef699fab..22fdd8bac2 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -77,6 +77,7 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXI
 
 [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
 { CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
+  NOT NULL <replaceable class="parameter">column_name</replaceable> |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> |
   EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ] ( <replaceable class="parameter">exclude_element</replaceable> WITH <replaceable class="parameter">operator</replaceable> [, ... ] ) <replaceable class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable class="parameter">predicate</replaceable> ) ] |
@@ -2314,13 +2315,6 @@ CREATE TABLE cities_partdef
     constraint, and index names must be unique across all relations within
     the same schema.
    </para>
-
-   <para>
-    Currently, <productname>PostgreSQL</productname> does not record names
-    for <literal>NOT NULL</literal> constraints at all, so they are not
-    subject to the uniqueness restriction.  This might change in a future
-    release.
-   </para>
   </refsect2>
 
   <refsect2>
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 2a0d82aedd..b3830a01b4 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2160,6 +2160,57 @@ StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 	return constrOid;
 }
 
+/*
+ * Store a NOT NULL constraint for the given relation
+ *
+ * The OID of the new constraint is returned.
+ */
+static Oid
+StoreRelNotNull(Relation rel, const char *nnname, AttrNumber attnum,
+				bool is_validated, bool is_local, bool inhcount,
+				bool is_no_inherit)
+{
+	int16		attNos;
+	Oid			constrOid;
+
+	/* We only ever store one column per constraint */
+	attNos = attnum;
+
+	constrOid =
+		CreateConstraintEntry(nnname,
+							  RelationGetNamespace(rel),
+							  CONSTRAINT_NOTNULL,
+							  false,
+							  false,
+							  is_validated,
+							  InvalidOid,
+							  RelationGetRelid(rel),
+							  &attNos,
+							  1,
+							  1,
+							  InvalidOid,	/* not a domain constraint */
+							  InvalidOid,	/* no associated index */
+							  InvalidOid,	/* Foreign key fields */
+							  NULL,
+							  NULL,
+							  NULL,
+							  NULL,
+							  0,
+							  ' ',
+							  ' ',
+							  NULL,
+							  0,
+							  ' ',
+							  NULL, /* not an exclusion constraint */
+							  NULL,
+							  NULL,
+							  is_local,
+							  inhcount,
+							  is_no_inherit,
+							  false);
+	return constrOid;
+}
+
 /*
  * Store defaults and constraints (passed as a list of CookedConstraint).
  *
@@ -2204,6 +2255,14 @@ StoreConstraints(Relation rel, List *cooked_constraints, bool is_internal)
 								  is_internal);
 				numchecks++;
 				break;
+
+			case CONSTR_NOTNULL:
+				con->conoid =
+					StoreRelNotNull(rel, con->name, con->attnum,
+									!con->skip_validation, con->is_local,
+									con->inhcount, con->is_no_inherit);
+				break;
+
 			default:
 				elog(ERROR, "unrecognized constraint type: %d",
 					 (int) con->contype);
@@ -2259,6 +2318,7 @@ AddRelationNewConstraints(Relation rel,
 	ParseNamespaceItem *nsitem;
 	int			numchecks;
 	List	   *checknames;
+	List	   *nnnames;
 	ListCell   *cell;
 	Node	   *expr;
 	CookedConstraint *cooked;
@@ -2344,130 +2404,179 @@ AddRelationNewConstraints(Relation rel,
 	 */
 	numchecks = numoldchecks;
 	checknames = NIL;
+	nnnames = NIL;
 	foreach(cell, newConstraints)
 	{
 		Constraint *cdef = (Constraint *) lfirst(cell);
-		char	   *ccname;
 		Oid			constrOid;
 
-		if (cdef->contype != CONSTR_CHECK)
-			continue;
-
-		if (cdef->raw_expr != NULL)
+		if (cdef->contype == CONSTR_CHECK)
 		{
-			Assert(cdef->cooked_expr == NULL);
+			char	   *ccname;
 
 			/*
-			 * Transform raw parsetree to executable expression, and verify
-			 * it's valid as a CHECK constraint.
+			 * XXX Should we detect the case with CHECK (foo IS NOT NULL) and
+			 * handle it as a NOT NULL constraint?
 			 */
-			expr = cookConstraint(pstate, cdef->raw_expr,
-								  RelationGetRelationName(rel));
-		}
-		else
-		{
-			Assert(cdef->cooked_expr != NULL);
 
-			/*
-			 * Here, we assume the parser will only pass us valid CHECK
-			 * expressions, so we do no particular checking.
-			 */
-			expr = stringToNode(cdef->cooked_expr);
-		}
-
-		/*
-		 * Check name uniqueness, or generate a name if none was given.
-		 */
-		if (cdef->conname != NULL)
-		{
-			ListCell   *cell2;
-
-			ccname = cdef->conname;
-			/* Check against other new constraints */
-			/* Needed because we don't do CommandCounterIncrement in loop */
-			foreach(cell2, checknames)
+			if (cdef->raw_expr != NULL)
 			{
-				if (strcmp((char *) lfirst(cell2), ccname) == 0)
-					ereport(ERROR,
-							(errcode(ERRCODE_DUPLICATE_OBJECT),
-							 errmsg("check constraint \"%s\" already exists",
-									ccname)));
+				Assert(cdef->cooked_expr == NULL);
+
+				/*
+				 * Transform raw parsetree to executable expression, and
+				 * verify it's valid as a CHECK constraint.
+				 */
+				expr = cookConstraint(pstate, cdef->raw_expr,
+									  RelationGetRelationName(rel));
+			}
+			else
+			{
+				Assert(cdef->cooked_expr != NULL);
+
+				/*
+				 * Here, we assume the parser will only pass us valid CHECK
+				 * expressions, so we do no particular checking.
+				 */
+				expr = stringToNode(cdef->cooked_expr);
 			}
 
-			/* save name for future checks */
-			checknames = lappend(checknames, ccname);
-
 			/*
-			 * Check against pre-existing constraints.  If we are allowed to
-			 * merge with an existing constraint, there's no more to do here.
-			 * (We omit the duplicate constraint from the result, which is
-			 * what ATAddCheckConstraint wants.)
+			 * Check name uniqueness, or generate a name if none was given.
 			 */
-			if (MergeWithExistingConstraint(rel, ccname, expr,
-											allow_merge, is_local,
-											cdef->initially_valid,
-											cdef->is_no_inherit))
-				continue;
-		}
-		else
-		{
-			/*
-			 * When generating a name, we want to create "tab_col_check" for a
-			 * column constraint and "tab_check" for a table constraint.  We
-			 * no longer have any info about the syntactic positioning of the
-			 * constraint phrase, so we approximate this by seeing whether the
-			 * expression references more than one column.  (If the user
-			 * played by the rules, the result is the same...)
-			 *
-			 * Note: pull_var_clause() doesn't descend into sublinks, but we
-			 * eliminated those above; and anyway this only needs to be an
-			 * approximate answer.
-			 */
-			List	   *vars;
-			char	   *colname;
+			if (cdef->conname != NULL)
+			{
+				ListCell   *cell2;
 
-			vars = pull_var_clause(expr, 0);
+				ccname = cdef->conname;
+				/* Check against other new constraints */
+				/* Needed because we don't do CommandCounterIncrement in loop */
+				foreach(cell2, checknames)
+				{
+					if (strcmp((char *) lfirst(cell2), ccname) == 0)
+						ereport(ERROR,
+								(errcode(ERRCODE_DUPLICATE_OBJECT),
+								 errmsg("check constraint \"%s\" already exists",
+										ccname)));
+				}
 
-			/* eliminate duplicates */
-			vars = list_union(NIL, vars);
+				/* save name for future checks */
+				checknames = lappend(checknames, ccname);
 
-			if (list_length(vars) == 1)
-				colname = get_attname(RelationGetRelid(rel),
-									  ((Var *) linitial(vars))->varattno,
-									  true);
+				/*
+				 * Check against pre-existing constraints.  If we are allowed
+				 * to merge with an existing constraint, there's no more to do
+				 * here. (We omit the duplicate constraint from the result,
+				 * which is what ATAddCheckConstraint wants.)
+				 */
+				if (MergeWithExistingConstraint(rel, ccname, expr,
+												allow_merge, is_local,
+												cdef->initially_valid,
+												cdef->is_no_inherit))
+					continue;
+			}
 			else
-				colname = NULL;
+			{
+				/*
+				 * When generating a name, we want to create "tab_col_check"
+				 * for a column constraint and "tab_check" for a table
+				 * constraint.  We no longer have any info about the syntactic
+				 * positioning of the constraint phrase, so we approximate
+				 * this by seeing whether the expression references more than
+				 * one column.  (If the user played by the rules, the result
+				 * is the same...)
+				 *
+				 * Note: pull_var_clause() doesn't descend into sublinks, but
+				 * we eliminated those above; and anyway this only needs to be
+				 * an approximate answer.
+				 */
+				List	   *vars;
+				char	   *colname;
 
-			ccname = ChooseConstraintName(RelationGetRelationName(rel),
-										  colname,
-										  "check",
-										  RelationGetNamespace(rel),
-										  checknames);
+				vars = pull_var_clause(expr, 0);
 
-			/* save name for future checks */
-			checknames = lappend(checknames, ccname);
+				/* eliminate duplicates */
+				vars = list_union(NIL, vars);
+
+				if (list_length(vars) == 1)
+					colname = get_attname(RelationGetRelid(rel),
+										  ((Var *) linitial(vars))->varattno,
+										  true);
+				else
+					colname = NULL;
+
+				ccname = ChooseConstraintName(RelationGetRelationName(rel),
+											  colname,
+											  "check",
+											  RelationGetNamespace(rel),
+											  checknames);
+
+				/* save name for future checks */
+				checknames = lappend(checknames, ccname);
+			}
+
+			/*
+			 * OK, store it.
+			 */
+			constrOid =
+				StoreRelCheck(rel, ccname, expr, cdef->initially_valid, is_local,
+							  is_local ? 0 : 1, cdef->is_no_inherit, is_internal);
+
+			numchecks++;
+
+			cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
+			cooked->contype = CONSTR_CHECK;
+			cooked->conoid = constrOid;
+			cooked->name = ccname;
+			cooked->attnum = 0;
+			cooked->expr = expr;
+			cooked->skip_validation = cdef->skip_validation;
+			cooked->is_local = is_local;
+			cooked->inhcount = is_local ? 0 : 1;
+			cooked->is_no_inherit = cdef->is_no_inherit;
+			cookedConstraints = lappend(cookedConstraints, cooked);
 		}
+		else if (cdef->contype == CONSTR_NOTNULL)
+		{
+			CookedConstraint *nncooked;
+			AttrNumber	colnum;
+			char	   *nnname;
 
-		/*
-		 * OK, store it.
-		 */
-		constrOid =
-			StoreRelCheck(rel, ccname, expr, cdef->initially_valid, is_local,
-						  is_local ? 0 : 1, cdef->is_no_inherit, is_internal);
+			colnum = get_attnum(RelationGetRelid(rel),
+								cdef->colname);
+			if (colnum == InvalidAttrNumber)
+				elog(ERROR, "invalid column name \"%s\"", cdef->colname);
 
-		numchecks++;
+			if (cdef->conname)
+				nnname = cdef->conname; /* verify clash? */
+			else
+				nnname = ChooseConstraintName(RelationGetRelationName(rel),
+											  cdef->colname,
+											  "not_null",
+											  RelationGetNamespace(rel),
+											  nnnames);
+			nnnames = lappend(nnnames, nnname);
 
-		cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
-		cooked->contype = CONSTR_CHECK;
-		cooked->conoid = constrOid;
-		cooked->name = ccname;
-		cooked->attnum = 0;
-		cooked->expr = expr;
-		cooked->skip_validation = cdef->skip_validation;
-		cooked->is_local = is_local;
-		cooked->inhcount = is_local ? 0 : 1;
-		cooked->is_no_inherit = cdef->is_no_inherit;
-		cookedConstraints = lappend(cookedConstraints, cooked);
+			constrOid =
+				StoreRelNotNull(rel, nnname, colnum,
+								cdef->initially_valid,
+								is_local,
+								is_local ? 0 : 1,
+								cdef->is_no_inherit);
+
+			nncooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
+			nncooked->contype = CONSTR_NOTNULL;
+			nncooked->conoid = constrOid;
+			nncooked->name = nnname;
+			nncooked->attnum = colnum;
+			nncooked->expr = NULL;
+			nncooked->skip_validation = cdef->skip_validation;
+			nncooked->is_local = is_local;
+			nncooked->inhcount = is_local ? 0 : 1;
+			nncooked->is_no_inherit = cdef->is_no_inherit;
+
+			cookedConstraints = lappend(cookedConstraints, nncooked);
+		}
 	}
 
 	/*
@@ -2637,6 +2746,190 @@ MergeWithExistingConstraint(Relation rel, const char *ccname, Node *expr,
 	return found;
 }
 
+/* list_sort comparator to sort CookedConstraint by attnum */
+static int
+list_cookedconstr_attnum_cmp(const ListCell *p1, const ListCell *p2)
+{
+	AttrNumber	v1 = ((CookedConstraint *) lfirst(p1))->attnum;
+	AttrNumber	v2 = ((CookedConstraint *) lfirst(p2))->attnum;
+
+	if (v1 < v2)
+		return -1;
+	if (v1 > v2)
+		return 1;
+	return 0;
+}
+
+/*
+ * Create the NOT NULL constraints for the relation
+ *
+ * These come from two sources: the 'constraints' list (of Constraint) is
+ * specified directly by the user; the 'old_notnulls' list (of
+ * CookedConstraint) comes from inheritance.  We create one constraint
+ * for each column, giving priority to user-specified ones, and setting
+ * inhcount according to how many parents cause each column to get a
+ * NOT NULL constraint.  If a user-specified name clashes with another
+ * user-specified name, an error is raised.
+ *
+ * Note that inherited constraints have two shapes: those coming from another
+ * NOT NULL constraint in the parent, which have a name already, and those
+ * coming from a PRIMARY KEY in the parent, which don't.  Any name specified
+ * in a parent is disregarded in case of a conflict.
+ *
+ * Returns a list of AttrNumber for columns that need to have the attnotnull
+ * column set.
+ */
+List *
+AddRelationNotNullConstraints(Relation rel, List *constraints,
+							  List *old_notnulls)
+{
+	List	   *nnnames = NIL;
+	List	   *givennames = NIL;
+	List	   *nncols = NIL;
+	AttrNumber	prev_attnum;
+	ListCell   *lc;
+
+	/*
+	 * First, create all NOT NULLs that are directly specified by the user.
+	 * Note that inheritance might have given us another source for each, so
+	 * we must scan the old_notnulls list and increment inhcount for each
+	 * element with identical attnum.  We delete from there any element that
+	 * we process.
+	 */
+	foreach(lc, constraints)
+	{
+		Constraint *constr = lfirst_node(Constraint, lc);
+		AttrNumber	attnum;
+		char	   *conname;
+		bool		is_local = true;
+		int			inhcount = 0;
+		ListCell   *lc2;
+
+		attnum = get_attnum(RelationGetRelid(rel), constr->colname);
+
+		foreach(lc2, old_notnulls)
+		{
+			CookedConstraint *old = (CookedConstraint *) lfirst(lc2);
+
+			if (old->attnum == attnum)
+			{
+				inhcount++;
+				old_notnulls = foreach_delete_current(old_notnulls, lc2);
+			}
+		}
+
+		/*
+		 * Determine a constraint name, which may have been specified by the
+		 * user, or raise an error if a conflict exists with another
+		 * user-specified name.
+		 */
+		if (constr->conname)
+		{
+			foreach(lc2, givennames)
+			{
+				if (strcmp(lfirst(lc2), conname) == 0)
+					ereport(ERROR,
+							errmsg("constraint name \"%s\" is already in use in relation \"%s\"",
+								   constr->conname,
+								   RelationGetRelationName(rel)));
+			}
+
+			conname = constr->conname;
+			givennames = lappend(givennames, conname);
+		}
+		else
+			conname = ChooseConstraintName(RelationGetRelationName(rel),
+										   get_attname(RelationGetRelid(rel),
+													   attnum, false),
+										   "not_null",
+										   RelationGetNamespace(rel),
+										   nnnames);
+		nnnames = lappend(nnnames, conname);
+
+		StoreRelNotNull(rel, conname,
+						attnum, true, is_local,
+						inhcount, constr->is_no_inherit);
+
+		nncols = lappend_int(nncols, attnum);
+	}
+
+	/*
+	 * If any column remains in the additional_notnulls list, we must create a
+	 * NOT NULL constraint marked not-local.  Because multiple parents could
+	 * specify a NOT NULL for the same column, we must count how many there
+	 * are and set inhcount accordingly.  Note that unlike the loop above, we
+	 * cannot delete elements in the inner foreach here!  So we keep track of
+	 * the element we just saw and skip any that are identical.  This requires
+	 * the list to be sorted!  Most of the time, this list will be empty.
+	 */
+	list_sort(old_notnulls, list_cookedconstr_attnum_cmp);
+	prev_attnum = InvalidAttrNumber;
+	foreach(lc, old_notnulls)
+	{
+		CookedConstraint *cooked = (CookedConstraint *) lfirst(lc);
+		char	   *conname = NULL;
+		int			inhcount = 1;
+		ListCell   *lc2;
+
+		if (cooked->attnum == prev_attnum)
+			continue;
+
+		/* We just preserve the first constraint name we come across, if any */
+		if (conname == NULL && cooked->name)
+			conname = cooked->name;
+
+		foreach(lc2, old_notnulls)
+		{
+			CookedConstraint *other = (CookedConstraint *) lfirst(lc2);
+
+			if (lc2 == lc)
+				continue;
+
+			if (other->attnum == cooked->attnum)
+			{
+				if (conname == NULL && other->name)
+					conname = other->name;
+
+				inhcount++;
+				/* can't delete element here; must skip later */
+			}
+		}
+
+		/* If we got a name, make sure it isn't one we've already used */
+		if (conname != NULL)
+		{
+			foreach(lc2, nnnames)
+			{
+				if (strcmp(lfirst(lc2), conname) == 0)
+				{
+					conname = NULL;
+					break;
+				}
+			}
+		}
+
+		/* and choose a name, if needed */
+		if (conname == NULL)
+			conname = ChooseConstraintName(RelationGetRelationName(rel),
+										   get_attname(RelationGetRelid(rel),
+													   cooked->attnum, false),
+										   "not_null",
+										   RelationGetNamespace(rel),
+										   nnnames);
+		nnnames = lappend(nnnames, conname);
+
+		StoreRelNotNull(rel, conname, cooked->attnum, true,
+						false, inhcount,
+						cooked->is_no_inherit);
+
+		nncols = lappend_int(nncols, cooked->attnum);
+
+		prev_attnum = cooked->attnum;
+	}
+
+	return nncols;
+}
+
 /*
  * Update the count of constraints in the relation's pg_class tuple.
  *
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 4002317f70..d044dc46c6 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -562,6 +562,104 @@ ChooseConstraintName(const char *name1, const char *name2,
 	return conname;
 }
 
+/*
+ * Find and return the pg_constraint tuple that implements a validated
+ * NOT NULL constraint for the given column of the given relation.
+ *
+ * XXX This would be easier if we had pg_attribute.notnullconstr with the OID
+ * of the constraint that implements the NOT NULL constraint for that column.
+ * I'm not sure it's worth the catalog bloat and de-normalization, however.
+ */
+HeapTuple
+findNotNullConstraintAttnum(Relation rel, AttrNumber attnum)
+{
+	Relation	pg_constraint;
+	HeapTuple	conTup,
+				retval = NULL;
+	SysScanDesc scan;
+	ScanKeyData key;
+
+	pg_constraint = table_open(ConstraintRelationId, AccessShareLock);
+	ScanKeyInit(&key,
+				Anum_pg_constraint_conrelid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(RelationGetRelid(rel)));
+	scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId,
+							  true, NULL, 1, &key);
+
+	while (HeapTupleIsValid(conTup = systable_getnext(scan)))
+	{
+		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(conTup);
+		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.
+		 */
+		if (con->contype != CONSTRAINT_NOTNULL)
+			continue;
+		if (!con->convalidated)
+			continue;
+
+		conkey = extractNotNullColumn(conTup);
+		if (conkey != attnum)
+			continue;
+
+		/* Found it */
+		retval = heap_copytuple(conTup);
+		break;
+	}
+
+	systable_endscan(scan);
+	table_close(pg_constraint, AccessShareLock);
+
+	return retval;
+}
+
+/*
+ * Find and return the pg_constraint tuple that implements a validated
+ * NOT NULL constraint for the given column of the given relation.
+ */
+HeapTuple
+findNotNullConstraint(Relation rel, const char *colname)
+{
+	AttrNumber	attnum = get_attnum(RelationGetRelid(rel), colname);
+
+	return findNotNullConstraintAttnum(rel, attnum);
+}
+
+/*
+ * Given a pg_constraint tuple for a NOT NULL constraint, return the column
+ * number it is for.
+ */
+AttrNumber
+extractNotNullColumn(HeapTuple constrTup)
+{
+	Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(constrTup);
+	AttrNumber	colnum;
+	Datum		adatum;
+	ArrayType  *arr;
+
+	/* only tuples for CHECK constraints should be given */
+	Assert(conForm->contype == CONSTRAINT_NOTNULL);
+
+	adatum = SysCacheGetAttrNotNull(CONSTROID, constrTup,
+									Anum_pg_constraint_conkey);
+	arr = DatumGetArrayTypeP(adatum);	/* ensure not toasted */
+	if (ARR_NDIM(arr) != 1 ||
+		ARR_HASNULL(arr) ||
+		ARR_ELEMTYPE(arr) != INT2OID ||
+		ARR_DIMS(arr)[0] != 1)
+		elog(ERROR, "conkey is not a 1-D smallint array");
+
+	memcpy(&colnum, ARR_DATA_PTR(arr), sizeof(AttrNumber));
+
+	if ((Pointer) arr != DatumGetPointer(adatum))
+		pfree(arr);				/* free de-toasted copy, if any */
+
+	return colnum;
+}
+
 /*
  * Delete a single constraint record.
  */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index d9bbeafd82..30711d7be0 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -203,7 +203,8 @@ typedef struct AlteredTableInfo
 typedef struct NewConstraint
 {
 	char	   *name;			/* Constraint name, or NULL if none */
-	ConstrType	contype;		/* CHECK or FOREIGN */
+	ConstrType	contype;		/* CHECK, NOTNULL, FOREIGN */
+	AttrNumber	attnum;			/* column number, if NOTNULL */
 	Oid			refrelid;		/* PK rel, if FOREIGN */
 	Oid			refindid;		/* OID of PK's index, if FOREIGN */
 	Oid			conid;			/* OID of pg_constraint entry, if FOREIGN */
@@ -350,7 +351,8 @@ static void truncate_check_activity(Relation rel);
 static void RangeVarCallbackForTruncate(const RangeVar *relation,
 										Oid relId, Oid oldRelId, void *arg);
 static List *MergeAttributes(List *schema, List *supers, char relpersistence,
-							 bool is_partition, List **supconstr);
+							 bool is_partition, List **supconstr,
+							 List **additional_notnulls);
 static bool MergeCheckConstraint(List *constraints, char *name, Node *expr);
 static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel);
 static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel);
@@ -431,14 +433,16 @@ static bool check_for_column_name_collision(Relation rel, const char *colname,
 											bool if_not_exists);
 static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
 static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid);
-static void ATPrepDropNotNull(Relation rel, bool recurse, bool recursing);
-static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode);
-static void ATPrepSetNotNull(List **wqueue, Relation rel,
-							 AlterTableCmd *cmd, bool recurse, bool recursing,
-							 LOCKMODE lockmode,
-							 AlterTableUtilityContext *context);
-static ObjectAddress ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
-									  const char *colName, LOCKMODE lockmode);
+static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
+									   LOCKMODE lockmode);
+static void set_attnotnull(List **wqueue, Relation rel,
+						   AttrNumber attnum, bool recurse, LOCKMODE lockmode);
+static ObjectAddress ATExecSetNotNull(List **wqueue, Relation rel,
+									  char *constrname, char *colName,
+									  bool recurse, bool recursing,
+									  List **readyRels, LOCKMODE lockmode);
+static void ATExecSetAttNotNull(List **wqueue, Relation rel,
+								const char *colName, LOCKMODE lockmode);
 static void ATExecCheckNotNull(AlteredTableInfo *tab, Relation rel,
 							   const char *colName, LOCKMODE lockmode);
 static bool NotNullImpliedByRelConstraints(Relation rel, Form_pg_attribute attr);
@@ -541,6 +545,11 @@ static void ATExecDropConstraint(Relation rel, const char *constrName,
 								 DropBehavior behavior,
 								 bool recurse, bool recursing,
 								 bool missing_ok, LOCKMODE lockmode);
+static ObjectAddress dropconstraint_internal(Relation rel,
+											 HeapTuple constraintTup, DropBehavior behavior,
+											 bool recurse, bool recursing,
+											 bool missing_ok, List **readyRels,
+											 LOCKMODE lockmode);
 static void ATPrepAlterColumnType(List **wqueue,
 								  AlteredTableInfo *tab, Relation rel,
 								  bool recurse, bool recursing,
@@ -616,7 +625,7 @@ static void RemoveInheritance(Relation child_rel, Relation parent_rel,
 static ObjectAddress ATExecAttachPartition(List **wqueue, Relation rel,
 										   PartitionCmd *cmd,
 										   AlterTableUtilityContext *context);
-static void AttachPartitionEnsureIndexes(Relation rel, Relation attachrel);
+static void AttachPartitionEnsureIndexes(List **wqueue, Relation rel, Relation attachrel);
 static void QueuePartitionConstraintValidation(List **wqueue, Relation scanrel,
 											   List *partConstraint,
 											   bool validate_default);
@@ -634,6 +643,7 @@ static ObjectAddress ATExecAttachPartitionIdx(List **wqueue, Relation parentIdx,
 static void validatePartitionedIndex(Relation partedIdx, Relation partedTbl);
 static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
+static void verifyPartitionIndexNotNull(IndexInfo *iinfo, Relation partIdx);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
 static char GetAttributeCompression(Oid atttypid, char *compression);
@@ -671,8 +681,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	TupleDesc	descriptor;
 	List	   *inheritOids;
 	List	   *old_constraints;
+	List	   *old_notnulls;
 	List	   *rawDefaults;
 	List	   *cookedDefaults;
+	List	   *nncols;
 	Datum		reloptions;
 	ListCell   *listptr;
 	AttrNumber	attnum;
@@ -862,12 +874,13 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 		MergeAttributes(stmt->tableElts, inheritOids,
 						stmt->relation->relpersistence,
 						stmt->partbound != NULL,
-						&old_constraints);
+						&old_constraints, &old_notnulls);
 
 	/*
 	 * Create a tuple descriptor from the relation schema.  Note that this
-	 * deals with column names, types, and NOT NULL constraints, but not
-	 * default values or CHECK constraints; we handle those below.
+	 * deals with column names, types, and in-descriptor NOT NULL flags, but
+	 * not default values, NOT NULL or CHECK constraints; we handle those
+	 * below.
 	 */
 	descriptor = BuildDescForRelation(stmt->tableElts);
 
@@ -1250,6 +1263,17 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 		AddRelationNewConstraints(rel, NIL, stmt->constraints,
 								  true, true, false, queryString);
 
+	/*
+	 * Finally, merge the NOT NULL constraints that are directly declared with
+	 * those that come from parent relations (making sure to count inheritance
+	 * appropriately for each), create them, and set the attnotnull flag on
+	 * columns that don't yet have it.
+	 */
+	nncols = AddRelationNotNullConstraints(rel, stmt->nnconstraints,
+										   old_notnulls);
+	foreach(listptr, nncols)
+		set_attnotnull(NULL, rel, lfirst_int(listptr), false, NoLock);
+
 	ObjectAddressSet(address, RelationRelationId, relationId);
 
 	/*
@@ -2298,6 +2322,8 @@ storage_name(char c)
  * Output arguments:
  * 'supconstr' receives a list of constraints belonging to the parents,
  *		updated as necessary to be valid for the child.
+ * 'nnconstraints' receives a list of CookedConstraints that corresponds to
+ *		constraints coming from inheritance parents.
  *
  * Return value:
  * Completed schema list.
@@ -2328,7 +2354,10 @@ storage_name(char c)
  *
  *	   Constraints (including NOT NULL constraints) for the child table
  *	   are the union of all relevant constraints, from both the child schema
- *	   and parent tables.
+ *	   and parent tables.  In addition, in legacy inheritance, each column that
+ *	   appears in a primary key in any of the parents also gets a NOT NULL
+ *	   constraint (partitioning doesn't need this, because the PK itself gets
+ *	   inherited.)
  *
  *	   The default value for a child column is defined as:
  *		(1) If the child schema specifies a default, that value is used.
@@ -2347,10 +2376,11 @@ storage_name(char c)
  */
 static List *
 MergeAttributes(List *schema, List *supers, char relpersistence,
-				bool is_partition, List **supconstr)
+				bool is_partition, List **supconstr, List **supnotnulls)
 {
 	List	   *inhSchema = NIL;
 	List	   *constraints = NIL;
+	List	   *nnconstraints = NIL;
 	bool		have_bogus_defaults = false;
 	int			child_attno;
 	static Node bogus_marker = {0}; /* marks conflicting defaults */
@@ -2462,9 +2492,13 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 		AttrMap    *newattmap;
 		List	   *inherited_defaults;
 		List	   *cols_with_defaults;
+		List	   *nnconstrs;
 		AttrNumber	parent_attno;
 		ListCell   *lc1;
 		ListCell   *lc2;
+		Bitmapset  *pkattrs;
+		Bitmapset  *nncols = NULL;
+
 
 		/* caller already got lock */
 		relation = table_open(parent, NoLock);
@@ -2553,6 +2587,20 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 		/* We can't process inherited defaults until newattmap is complete. */
 		inherited_defaults = cols_with_defaults = NIL;
 
+		/*
+		 * All columns that are part of the parent's primary key need to be
+		 * NOT NULL; if partition just the attnotnull bit, otherwise a full
+		 * constraint (if they don't have one already).  Also, we request
+		 * attnotnull on columns that have a NOT NULL constraint that's not
+		 * marked NO INHERIT.
+		 */
+		pkattrs = RelationGetIndexAttrBitmap(relation,
+											 INDEX_ATTR_BITMAP_PRIMARY_KEY);
+		nnconstrs = RelationGetNotNullConstraints(relation, true);
+		foreach(lc1, nnconstrs)
+			nncols = bms_add_member(nncols,
+									((CookedConstraint *) lfirst(lc1))->attnum);
+
 		for (parent_attno = 1; parent_attno <= tupleDesc->natts;
 			 parent_attno++)
 		{
@@ -2648,9 +2696,38 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 				}
 
 				/*
-				 * Merge of NOT NULL constraints = OR 'em together
+				 * In regular inheritance, columns in the parent's primary key
+				 * get an extra CHECK (NOT NULL) constraint.  Partitioning
+				 * doesn't need this, because the PK itself is going to be
+				 * cloned to the partition.
 				 */
-				def->is_not_null |= attribute->attnotnull;
+				if (!is_partition &&
+					bms_is_member(parent_attno - FirstLowInvalidHeapAttributeNumber,
+								  pkattrs))
+				{
+					CookedConstraint *nn;
+
+					nn = palloc(sizeof(CookedConstraint));
+					nn->contype = CONSTR_NOTNULL;
+					nn->conoid = InvalidOid;
+					nn->name = NULL;
+					nn->attnum = exist_attno;
+					nn->expr = NULL;
+					nn->skip_validation = false;
+					nn->is_local = false;
+					nn->inhcount = 1;
+					nn->is_no_inherit = false;
+
+					nnconstraints = lappend(nnconstraints, nn);
+				}
+
+				/*
+				 * mark attnotnull if parent has it and it's not NO INHERIT
+				 */
+				if (bms_is_member(parent_attno, nncols) ||
+					bms_is_member(parent_attno - FirstLowInvalidHeapAttributeNumber,
+								  pkattrs))
+					def->is_not_null = true;
 
 				/*
 				 * Check for GENERATED conflicts
@@ -2684,7 +2761,11 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 													attribute->atttypmod);
 				def->inhcount = 1;
 				def->is_local = false;
-				def->is_not_null = attribute->attnotnull;
+				/* mark attnotnull if parent has it and it's not NO INHERIT */
+				if (bms_is_member(parent_attno, nncols) ||
+					bms_is_member(parent_attno - FirstLowInvalidHeapAttributeNumber,
+								  pkattrs))
+					def->is_not_null = true;
 				def->is_from_type = false;
 				def->storage = attribute->attstorage;
 				def->raw_default = NULL;
@@ -2701,6 +2782,33 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 					def->compression = NULL;
 				inhSchema = lappend(inhSchema, def);
 				newattmap->attnums[parent_attno - 1] = ++child_attno;
+
+				/*
+				 * In regular inheritance, columns in the parent's primary key
+				 * get an extra NOT NULL constraint.  Partitioning doesn't
+				 * need this, because the PK itself is going to be cloned to
+				 * the partition.
+				 */
+				if (!is_partition &&
+					bms_is_member(parent_attno -
+								  FirstLowInvalidHeapAttributeNumber,
+								  pkattrs))
+				{
+					CookedConstraint *nn;
+
+					nn = palloc(sizeof(CookedConstraint));
+					nn->contype = CONSTR_NOTNULL;
+					nn->conoid = InvalidOid;
+					nn->name = NULL;
+					nn->attnum = newattmap->attnums[parent_attno - 1];
+					nn->expr = NULL;
+					nn->skip_validation = false;
+					nn->is_local = false;
+					nn->inhcount = 1;
+					nn->is_no_inherit = false;
+
+					nnconstraints = lappend(nnconstraints, nn);
+				}
 			}
 
 			/*
@@ -2845,6 +2953,19 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 			}
 		}
 
+		/*
+		 * Also copy the NOT NULL constraints from this parent.  The
+		 * attnotnull markings were already installed above.
+		 */
+		foreach(lc1, nnconstrs)
+		{
+			CookedConstraint *nn = lfirst(lc1);
+
+			nn->attnum = newattmap->attnums[nn->attnum - 1];
+
+			nnconstraints = lappend(nnconstraints, nn);
+		}
+
 		free_attrmap(newattmap);
 
 		/*
@@ -3051,8 +3172,7 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 	/*
 	 * Now that we have the column definition list for a partition, we can
 	 * check whether the columns referenced in the column constraint specs
-	 * actually exist.  Also, we merge parent's NOT NULL constraints and
-	 * defaults into each corresponding column definition.
+	 * actually exist.
 	 */
 	if (is_partition)
 	{
@@ -3158,6 +3278,8 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 	}
 
 	*supconstr = constraints;
+	*supnotnulls = nnconstraints;
+
 	return schema;
 }
 
@@ -3209,6 +3331,85 @@ MergeCheckConstraint(List *constraints, char *name, Node *expr)
 	return false;
 }
 
+/*
+ * RelationGetNotNullConstraints -- get list of NOT NULL constraints
+ *
+ * Caller can request cooked constraints, or raw.
+ *
+ * This is seldom needed, so we just scan pg_constraint each time.
+ *
+ * XXX This is only used to create derived tables, so NO INHERIT constraints
+ * are always skipped.
+ */
+List *
+RelationGetNotNullConstraints(Relation relation, bool cooked)
+{
+	List	   *notnulls = NIL;
+	Relation	constrRel;
+	HeapTuple	htup;
+	SysScanDesc conscan;
+	ScanKeyData skey;
+
+	constrRel = table_open(ConstraintRelationId, AccessShareLock);
+	ScanKeyInit(&skey,
+				Anum_pg_constraint_conrelid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(RelationGetRelid(relation)));
+	conscan = systable_beginscan(constrRel, ConstraintRelidTypidNameIndexId, true,
+								 NULL, 1, &skey);
+
+	while (HeapTupleIsValid(htup = systable_getnext(conscan)))
+	{
+		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(htup);
+		AttrNumber	colnum;
+
+		if (conForm->contype != CONSTRAINT_NOTNULL)
+			continue;
+		if (conForm->connoinherit)
+			continue;
+
+		colnum = extractNotNullColumn(htup);
+
+		if (cooked)
+		{
+			CookedConstraint *cooked;
+
+			cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
+
+			cooked->contype = CONSTR_NOTNULL;
+			cooked->name = pstrdup(NameStr(conForm->conname));
+			cooked->attnum = colnum;
+			cooked->expr = NULL;
+			cooked->skip_validation = false;
+			cooked->is_local = true;
+			cooked->inhcount = 0;
+			cooked->is_no_inherit = conForm->connoinherit;
+
+			notnulls = lappend(notnulls, cooked);
+		}
+		else
+		{
+			Constraint *constr;
+
+			constr = makeNode(Constraint);
+			constr->contype = CONSTR_NOTNULL;
+			constr->conname = pstrdup(NameStr(conForm->conname));
+			constr->deferrable = false;
+			constr->initdeferred = false;
+			constr->location = -1;
+			constr->colname = get_attname(RelationGetRelid(relation),
+										  colnum, false);
+			constr->skip_validation = false;
+			constr->initially_valid = true;
+			notnulls = lappend(notnulls, constr);
+		}
+	}
+
+	systable_endscan(conscan);
+	table_close(constrRel, AccessShareLock);
+
+	return notnulls;
+}
 
 /*
  * StoreCatalogInheritance
@@ -3769,7 +3970,10 @@ rename_constraint_internal(Oid myrelid,
 			 constraintOid);
 	con = (Form_pg_constraint) GETSTRUCT(tuple);
 
-	if (myrelid && con->contype == CONSTRAINT_CHECK && !con->connoinherit)
+	if (myrelid &&
+		(con->contype == CONSTRAINT_CHECK ||
+		 con->contype == CONSTRAINT_NOTNULL) &&
+		!con->connoinherit)
 	{
 		if (recurse)
 		{
@@ -4354,6 +4558,7 @@ AlterTableGetLockLevel(List *cmds)
 			case AT_AddIndexConstraint:
 			case AT_ReplicaIdentity:
 			case AT_SetNotNull:
+			case AT_SetAttNotNull:
 			case AT_EnableRowSecurity:
 			case AT_DisableRowSecurity:
 			case AT_ForceRowSecurity:
@@ -4652,15 +4857,23 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			break;
 		case AT_DropNotNull:	/* ALTER COLUMN DROP NOT NULL */
 			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_FOREIGN_TABLE);
-			ATPrepDropNotNull(rel, recurse, recursing);
-			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
+			/* Set up recursion for phase 2; no other prep needed */
+			if (recurse)
+				cmd->recurse = true;
 			pass = AT_PASS_DROP;
 			break;
 		case AT_SetNotNull:		/* ALTER COLUMN SET NOT NULL */
 			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_FOREIGN_TABLE);
 			/* Need command-specific recursion decision */
-			ATPrepSetNotNull(wqueue, rel, cmd, recurse, recursing,
-							 lockmode, context);
+			if (recurse)
+				cmd->recurse = true;
+			pass = AT_PASS_COL_ATTRS;
+			break;
+		case AT_SetAttNotNull:	/* set pg_attribute.attnotnull without adding
+								 * a constraint */
+			ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_FOREIGN_TABLE);
+			/* Need command-specific recursion decision */
+			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
 			pass = AT_PASS_COL_ATTRS;
 			break;
 		case AT_CheckNotNull:	/* check column is already marked NOT NULL */
@@ -5045,10 +5258,14 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab,
 			address = ATExecDropIdentity(rel, cmd->name, cmd->missing_ok, lockmode);
 			break;
 		case AT_DropNotNull:	/* ALTER COLUMN DROP NOT NULL */
-			address = ATExecDropNotNull(rel, cmd->name, lockmode);
+			address = ATExecDropNotNull(rel, cmd->name, cmd->recurse, lockmode);
 			break;
 		case AT_SetNotNull:		/* ALTER COLUMN SET NOT NULL */
-			address = ATExecSetNotNull(tab, rel, cmd->name, lockmode);
+			address = ATExecSetNotNull(wqueue, rel, NULL, cmd->name,
+									   cmd->recurse, false, NULL, lockmode);
+			break;
+		case AT_SetAttNotNull:	/* set pg_attribute.attnotnull */
+			ATExecSetAttNotNull(wqueue, rel, cmd->name, lockmode);
 			break;
 		case AT_CheckNotNull:	/* check column is already marked NOT NULL */
 			ATExecCheckNotNull(tab, rel, cmd->name, lockmode);
@@ -5387,11 +5604,8 @@ ATParseTransformCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 */
 		switch (cmd2->subtype)
 		{
-			case AT_SetNotNull:
-				/* Need command-specific recursion decision */
-				ATPrepSetNotNull(wqueue, rel, cmd2,
-								 recurse, false,
-								 lockmode, context);
+			case AT_SetAttNotNull:
+				ATSimpleRecursion(wqueue, rel, cmd2, recurse, lockmode, context);
 				pass = AT_PASS_COL_ATTRS;
 				break;
 			case AT_AddIndex:
@@ -5759,6 +5973,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 	TupleDesc	oldTupDesc;
 	TupleDesc	newTupDesc;
 	bool		needscan = false;
+	bool		verify_new_notnull = false;
 	List	   *notnull_attrs;
 	int			i;
 	ListCell   *l;
@@ -5819,6 +6034,12 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
 				break;
+			case CONSTR_NOTNULL:
+				if (!NotNullImpliedByRelConstraints(oldrel,
+													TupleDescAttr(oldTupDesc,
+																  con->attnum - 1)))
+					verify_new_notnull = true;
+				break;
 			default:
 				elog(ERROR, "unrecognized constraint type: %d",
 					 (int) con->contype);
@@ -5841,7 +6062,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 	}
 
 	notnull_attrs = NIL;
-	if (newrel || tab->verify_new_notnull)
+	if (newrel || tab->verify_new_notnull || verify_new_notnull)
 	{
 		/*
 		 * If we are rebuilding the tuples OR if we added any new but not
@@ -6067,6 +6288,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 											RelationGetRelationName(oldrel)),
 									 errtableconstraint(oldrel, con->name)));
 						break;
+					case CONSTR_NOTNULL:
 					case CONSTR_FOREIGN:
 						/* Nothing to do here */
 						break;
@@ -6175,6 +6397,8 @@ alter_table_type_to_string(AlterTableType cmdtype)
 			return "ALTER COLUMN ... DROP NOT NULL";
 		case AT_SetNotNull:
 			return "ALTER COLUMN ... SET NOT NULL";
+		case AT_SetAttNotNull:
+			return NULL;		/* not real grammar */
 		case AT_DropExpression:
 			return "ALTER COLUMN ... DROP EXPRESSION";
 		case AT_CheckNotNull:
@@ -6774,8 +6998,7 @@ ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
  */
 static ObjectAddress
 ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
-				AlterTableCmd **cmd,
-				bool recurse, bool recursing,
+				AlterTableCmd **cmd, bool recurse, bool recursing,
 				LOCKMODE lockmode, int cur_pass,
 				AlterTableUtilityContext *context)
 {
@@ -7290,41 +7513,19 @@ add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 
 /*
  * ALTER TABLE ALTER COLUMN DROP NOT NULL
- */
-
-static void
-ATPrepDropNotNull(Relation rel, bool recurse, bool recursing)
-{
-	/*
-	 * If the parent is a partitioned table, like check constraints, we do not
-	 * support removing the NOT NULL while partitions exist.
-	 */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-	{
-		PartitionDesc partdesc = RelationGetPartitionDesc(rel, true);
-
-		Assert(partdesc != NULL);
-		if (partdesc->nparts > 0 && !recurse && !recursing)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
-					 errmsg("cannot remove constraint from only the partitioned table when partitions exist"),
-					 errhint("Do not specify the ONLY keyword.")));
-	}
-}
-
-/*
+ *
  * Return the address of the modified column.  If the column was already
  * nullable, InvalidObjectAddress is returned.
  */
 static ObjectAddress
-ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
+ATExecDropNotNull(Relation rel, const char *colName, bool recurse,
+				  LOCKMODE lockmode)
 {
 	HeapTuple	tuple;
+	HeapTuple	conTup;
 	Form_pg_attribute attTup;
 	AttrNumber	attnum;
 	Relation	attr_rel;
-	List	   *indexoidlist;
-	ListCell   *indexoidscan;
 	ObjectAddress address;
 
 	/*
@@ -7340,6 +7541,15 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
 						colName, RelationGetRelationName(rel))));
 	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
 	attnum = attTup->attnum;
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), attnum);
+
+	/* If the column is already nullable there's nothing to do. */
+	if (!attTup->attnotnull)
+	{
+		table_close(attr_rel, RowExclusiveLock);
+		return InvalidObjectAddress;
+	}
 
 	/* Prevent them from altering a system attribute */
 	if (attnum <= 0)
@@ -7355,68 +7565,43 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
 						colName, RelationGetRelationName(rel))));
 
 	/*
-	 * Check that the attribute is not in a primary key or in an index used as
-	 * a replica identity.
-	 *
-	 * Note: we'll throw error even if the pkey index is not valid.
+	 * It's not OK to remove a constraint only for the parent and leave it in
+	 * the children, so disallow that.
 	 */
-
-	/* Loop over all indexes on the relation */
-	indexoidlist = RelationGetIndexList(rel);
-
-	foreach(indexoidscan, indexoidlist)
+	if (!recurse)
 	{
-		Oid			indexoid = lfirst_oid(indexoidscan);
-		HeapTuple	indexTuple;
-		Form_pg_index indexStruct;
-		int			i;
-
-		indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", indexoid);
-		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
-
-		/*
-		 * If the index is not a primary key or an index used as replica
-		 * identity, skip the check.
-		 */
-		if (indexStruct->indisprimary || indexStruct->indisreplident)
+		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		{
-			/*
-			 * Loop over each attribute in the primary key or the index used
-			 * as replica identity and see if it matches the to-be-altered
-			 * attribute.
-			 */
-			for (i = 0; i < indexStruct->indnkeyatts; i++)
-			{
-				if (indexStruct->indkey.values[i] == attnum)
-				{
-					if (indexStruct->indisprimary)
-						ereport(ERROR,
-								(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
-								 errmsg("column \"%s\" is in a primary key",
-										colName)));
-					else
-						ereport(ERROR,
-								(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
-								 errmsg("column \"%s\" is in index used as replica identity",
-										colName)));
-				}
-			}
-		}
+			PartitionDesc partdesc;
 
-		ReleaseSysCache(indexTuple);
+			partdesc = RelationGetPartitionDesc(rel, true);
+
+			if (partdesc->nparts > 0)
+				ereport(ERROR,
+						errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						errmsg("cannot remove constraint from only the partitioned table when partitions exist"),
+						errhint("Do not specify the ONLY keyword."));
+		}
+		else if (rel->rd_rel->relhassubclass &&
+				 find_inheritance_children(RelationGetRelid(rel), NoLock) != NIL)
+		{
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("NOT NULL constraint on column \"%s\" must be removed in child tables too",
+						   colName),
+					errhint("Do not specify the ONLY keyword."));
+		}
 	}
 
-	list_free(indexoidlist);
-
-	/* If rel is partition, shouldn't drop NOT NULL if parent has the same */
+	/*
+	 * If rel is partition, shouldn't drop NOT NULL if parent has the same.
+	 */
 	if (rel->rd_rel->relispartition)
 	{
-		Oid			parentId = get_partition_parent(RelationGetRelid(rel), false);
-		Relation	parent = table_open(parentId, AccessShareLock);
-		TupleDesc	tupDesc = RelationGetDescr(parent);
-		AttrNumber	parent_attnum;
+		Oid         parentId = get_partition_parent(RelationGetRelid(rel), false);
+		Relation    parent = table_open(parentId, AccessShareLock);
+		TupleDesc   tupDesc = RelationGetDescr(parent);
+		AttrNumber  parent_attnum;
 
 		parent_attnum = get_attnum(parentId, colName);
 		if (TupleDescAttr(tupDesc, parent_attnum - 1)->attnotnull)
@@ -7428,22 +7613,33 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
 	}
 
 	/*
-	 * Okay, actually perform the catalog change ... if needed
+	 * Find the constraint that makes this column NOT NULL.
 	 */
-	if (attTup->attnotnull)
+	conTup = findNotNullConstraint(rel, colName);
+	if (conTup == NULL)
 	{
-		attTup->attnotnull = false;
+		Bitmapset  *pkcols;
 
-		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+		/*
+		 * There's no NOT NULL constraint, so throw an error.  If the column
+		 * is in a primary key, we can throw a specific error.  Otherwise,
+		 * this is unexpected.
+		 */
+		pkcols = RelationGetIndexAttrBitmap(rel, INDEX_ATTR_BITMAP_PRIMARY_KEY);
+		if (bms_is_member(attnum - FirstLowInvalidHeapAttributeNumber,
+						  pkcols))
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("column \"%s\" is in a primary key", colName));
 
-		ObjectAddressSubSet(address, RelationRelationId,
-							RelationGetRelid(rel), attnum);
+		/* this shouldn't happen */
+		elog(ERROR, "no NOT NULL constraint found to drop");
 	}
-	else
-		address = InvalidObjectAddress;
 
-	InvokeObjectPostAlterHook(RelationRelationId,
-							  RelationGetRelid(rel), attnum);
+	dropconstraint_internal(rel, conTup, DROP_RESTRICT, recurse, false,
+							false, NULL, lockmode);
+
+	heap_freetuple(conTup);
 
 	table_close(attr_rel, RowExclusiveLock);
 
@@ -7451,102 +7647,126 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
 }
 
 /*
- * ALTER TABLE ALTER COLUMN SET NOT NULL
+ * Helper to set pg_attribute.attnotnull if it isn't set, and to tell phase 3
+ * to verify it; recurses to apply the same to children.
+ *
+ * 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.
  */
-
 static void
-ATPrepSetNotNull(List **wqueue, Relation rel,
-				 AlterTableCmd *cmd, bool recurse, bool recursing,
-				 LOCKMODE lockmode, AlterTableUtilityContext *context)
+set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum, bool recurse,
+			   LOCKMODE lockmode)
 {
-	/*
-	 * If we're already recursing, there's nothing to do; the topmost
-	 * invocation of ATSimpleRecursion already visited all children.
-	 */
-	if (recursing)
+	HeapTuple	tuple;
+	Form_pg_attribute attForm;
+	List	   *children;
+	ListCell   *lc;
+
+	tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum);
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cache lookup failed for attribute %d of relation %u",
+			 attnum, RelationGetRelid(rel));
+	attForm = (Form_pg_attribute) GETSTRUCT(tuple);
+	if (!attForm->attnotnull)
+	{
+		Relation	attr_rel;
+
+		attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
+
+		attForm->attnotnull = true;
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+
+		table_close(attr_rel, RowExclusiveLock);
+
+		/*
+		 * And set up for existing values to be checked, unless another constraint
+		 * already proves this.
+		 */
+		if (wqueue && !NotNullImpliedByRelConstraints(rel, attForm))
+		{
+			AlteredTableInfo *tab;
+
+			tab = ATGetQueueEntry(wqueue, rel);
+			tab->verify_new_notnull = true;
+		}
+	}
+
+	/* if no recursion is desired, we're done */
+	if (!recurse)
 		return;
 
-	/*
-	 * If the target column is already marked NOT NULL, we can skip recursing
-	 * to children, because their columns should already be marked NOT NULL as
-	 * well.  But there's no point in checking here unless the relation has
-	 * some children; else we can just wait till execution to check.  (If it
-	 * does have children, however, this can save taking per-child locks
-	 * unnecessarily.  This greatly improves concurrency in some parallel
-	 * restore scenarios.)
-	 *
-	 * Unfortunately, we can only apply this optimization to partitioned
-	 * tables, because traditional inheritance doesn't enforce that child
-	 * columns be NOT NULL when their parent is.  (That's a bug that should
-	 * get fixed someday.)
-	 */
-	if (rel->rd_rel->relhassubclass &&
-		rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+	children = find_inheritance_children(RelationGetRelid(rel), lockmode);
+	foreach(lc, children)
 	{
-		HeapTuple	tuple;
-		bool		attnotnull;
+		Oid			childrelid = lfirst_oid(lc);
+		Relation	childrel;
+		AttrNumber	childattno;
 
-		tuple = SearchSysCacheAttName(RelationGetRelid(rel), cmd->name);
+		/* find_inheritance_children already got lock */
+		childrel = table_open(childrelid, NoLock);
+		CheckTableNotInUse(childrel, "ALTER TABLE");
 
-		/* Might as well throw the error now, if name is bad */
-		if (!HeapTupleIsValid(tuple))
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_COLUMN),
-					 errmsg("column \"%s\" of relation \"%s\" does not exist",
-							cmd->name, RelationGetRelationName(rel))));
-
-		attnotnull = ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull;
-		ReleaseSysCache(tuple);
-		if (attnotnull)
-			return;
+		childattno = get_attnum(RelationGetRelid(childrel),
+								get_attname(RelationGetRelid(rel), attnum,
+											false));
+		set_attnotnull(wqueue, childrel, childattno,
+					   recurse, lockmode);
+		table_close(childrel, NoLock);
 	}
-
-	/*
-	 * If we have ALTER TABLE ONLY ... SET NOT NULL on a partitioned table,
-	 * apply ALTER TABLE ... CHECK NOT NULL to every child.  Otherwise, use
-	 * normal recursion logic.
-	 */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
-		!recurse)
-	{
-		AlterTableCmd *newcmd = makeNode(AlterTableCmd);
-
-		newcmd->subtype = AT_CheckNotNull;
-		newcmd->name = pstrdup(cmd->name);
-		ATSimpleRecursion(wqueue, rel, newcmd, true, lockmode, context);
-	}
-	else
-		ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
 }
 
 /*
- * Return the address of the modified column.  If the column was already NOT
- * NULL, InvalidObjectAddress is returned.
+ * ALTER TABLE ALTER COLUMN SET NOT NULL
+ *
+ * Add a NOT NULL constraint to a single table and its children.  Returns
+ * the address of the constraint added to the parent relation, if one gets
+ * added, or InvalidObjectAddress otherwise.
+ *
+ * We must recurse to child tables during execution, rather than using
+ * ALTER TABLE's normal prep-time recursion.
  */
 static ObjectAddress
-ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
-				 const char *colName, LOCKMODE lockmode)
+ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
+				 bool recurse, bool recursing, List **readyRels,
+				 LOCKMODE lockmode)
 {
 	HeapTuple	tuple;
+	Relation	constr_rel;
+	ScanKeyData skey;
+	SysScanDesc conscan;
 	AttrNumber	attnum;
-	Relation	attr_rel;
 	ObjectAddress address;
+	Constraint *constraint;
+	CookedConstraint *ccon;
+	List	   *cooked;
+	List	   *ready = NIL;
 
 	/*
-	 * lookup the attribute
+	 * In cases of multiple inheritance, we might visit the same child more
+	 * than once.  In the topmost call, set up a list that we fill with all
+	 * visited relations, to skip those.
 	 */
-	attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
+	if (readyRels == NULL)
+		readyRels = &ready;
+	if (list_member_oid(*readyRels, RelationGetRelid(rel)))
+		return InvalidObjectAddress;
+	*readyRels = lappend_oid(*readyRels, RelationGetRelid(rel));
 
-	tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+	/* At top level, permission check was done in ATPrepCmd, else do it */
+	if (recursing)
+	{
+		ATSimplePermissions(AT_AddConstraint, rel, ATT_TABLE | ATT_FOREIGN_TABLE);
+		Assert(conName != NULL);
+	}
 
-	if (!HeapTupleIsValid(tuple))
+	attnum = get_attnum(RelationGetRelid(rel), colName);
+	if (attnum == InvalidAttrNumber)
 		ereport(ERROR,
 				(errcode(ERRCODE_UNDEFINED_COLUMN),
 				 errmsg("column \"%s\" of relation \"%s\" does not exist",
 						colName, RelationGetRelationName(rel))));
 
-	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
-
 	/* Prevent them from altering a system attribute */
 	if (attnum <= 0)
 		ereport(ERROR,
@@ -7554,42 +7774,167 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	/*
-	 * Okay, actually perform the catalog change ... if needed
-	 */
-	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
-	{
-		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = true;
+	/* See if there's already a constraint */
+	constr_rel = table_open(ConstraintRelationId, RowExclusiveLock);
+	ScanKeyInit(&skey,
+				Anum_pg_constraint_conrelid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(RelationGetRelid(rel)));
+	conscan = systable_beginscan(constr_rel, ConstraintRelidTypidNameIndexId, true,
+								 NULL, 1, &skey);
 
-		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+	while (HeapTupleIsValid(tuple = systable_getnext(conscan)))
+	{
+		Form_pg_constraint conForm = (Form_pg_constraint) GETSTRUCT(tuple);
+		bool		changed = false;
+		HeapTuple	copytup;
+
+		if (conForm->contype != CONSTRAINT_NOTNULL)
+			continue;
+
+		if (extractNotNullColumn(tuple) != attnum)
+			continue;
+
+		copytup = heap_copytuple(tuple);
+		conForm = (Form_pg_constraint) GETSTRUCT(copytup);
 
 		/*
-		 * Ordinarily phase 3 must ensure that no NULLs exist in columns that
-		 * are set NOT NULL; however, if we can find a constraint which proves
-		 * this then we can skip that.  We needn't bother looking if we've
-		 * already found that we must verify some other NOT NULL constraint.
+		 * If we find an appropriate constraint, we're almost done, but just
+		 * need to change some properties on it: if we're recursing, increment
+		 * coninhcount; if not, set conislocal if not already set.
 		 */
-		if (!tab->verify_new_notnull &&
-			!NotNullImpliedByRelConstraints(rel, (Form_pg_attribute) GETSTRUCT(tuple)))
+		if (recursing)
 		{
-			/* Tell Phase 3 it needs to test the constraint */
-			tab->verify_new_notnull = true;
+			conForm->coninhcount++;
+			changed = true;
+		}
+		else if (!conForm->conislocal)
+		{
+			conForm->conislocal = true;
+			changed = true;
 		}
 
-		ObjectAddressSubSet(address, RelationRelationId,
-							RelationGetRelid(rel), attnum);
+		if (changed)
+		{
+			CatalogTupleUpdate(constr_rel, &copytup->t_self, copytup);
+			ObjectAddressSet(address, ConstraintRelationId, conForm->oid);
+		}
+
+		systable_endscan(conscan);
+		table_close(constr_rel, RowExclusiveLock);
+
+		if (changed)
+			return address;
+		else
+			return InvalidObjectAddress;
 	}
-	else
-		address = InvalidObjectAddress;
 
-	InvokeObjectPostAlterHook(RelationRelationId,
-							  RelationGetRelid(rel), attnum);
+	systable_endscan(conscan);
+	table_close(constr_rel, RowExclusiveLock);
 
-	table_close(attr_rel, RowExclusiveLock);
+	/*
+	 * If we're asked not to recurse, and children exist, raise an error.
+	 */
+	if (!recurse &&
+		find_inheritance_children(RelationGetRelid(rel),
+								  NoLock) != NIL)
+	{
+		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("cannot add constraint to only the partitioned table when partitions exist"),
+					errhint("Do not specify the ONLY keyword."));
+		else
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("cannot add constraint only to table with inheritance children"),
+					errhint("Do not specify the ONLY keyword."));
+	}
+
+	/*
+	 * No constraint exists; we must add one.  First determine a name to use,
+	 * if we haven't already.
+	 */
+	if (!recursing)
+	{
+		Assert(conName == NULL);
+		conName = ChooseConstraintName(RelationGetRelationName(rel),
+									   colName, "not_null",
+									   RelationGetNamespace(rel),
+									   NIL);
+	}
+	constraint = makeNode(Constraint);
+	constraint->contype = CONSTR_NOTNULL;
+	constraint->conname = conName;
+	constraint->deferrable = false;
+	constraint->initdeferred = false;
+	constraint->location = -1;
+	constraint->colname = colName;
+	constraint->skip_validation = false;
+	constraint->initially_valid = true;
+
+	/* and do it */
+	cooked = AddRelationNewConstraints(rel, NIL, list_make1(constraint),
+									   false, !recursing, false, NULL);
+	ccon = linitial(cooked);
+	ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
+
+	/*
+	 * Mark pg_attribute.attnotnull for the column. Tell that function not to
+	 * recurse, because we're going to do it here.
+	 */
+	set_attnotnull(wqueue, rel, attnum, false, lockmode);
+
+	/*
+	 * Recurse to propagate the constraint to children that don't have one.
+	 */
+	if (recurse)
+	{
+		List	   *children;
+		ListCell   *lc;
+
+		children = find_inheritance_children(RelationGetRelid(rel),
+											 lockmode);
+
+		foreach(lc, children)
+		{
+			Relation	childrel;
+
+			childrel = table_open(lfirst_oid(lc), NoLock);
+
+			ATExecSetNotNull(wqueue, childrel,
+							 conName, colName, recurse, true,
+							 readyRels, lockmode);
+
+			table_close(childrel, NoLock);
+		}
+	}
 
 	return address;
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET ATTNOTNULL
+ *
+ * This doesn't exist in the grammar; it's used when creating a
+ * primary key and the column is not already marked attnotnull.
+ */
+static void
+ATExecSetAttNotNull(List **wqueue, Relation rel,
+					const char *colName, LOCKMODE lockmode)
+{
+	AttrNumber	attnum;
+
+	attnum = get_attnum(RelationGetRelid(rel), colName);
+	if (attnum == InvalidAttrNumber)	/* XXX should not happen .. elog? */
+		ereport(ERROR,
+				errcode(ERRCODE_UNDEFINED_COLUMN),
+				errmsg("column \"%s\" of relation \"%s\" does not exist",
+					   colName, RelationGetRelationName(rel)));
+
+	set_attnotnull(wqueue, rel, attnum, false, lockmode);
+}
+
 /*
  * ALTER TABLE ALTER COLUMN CHECK NOT NULL
  *
@@ -8872,13 +9217,14 @@ ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Assert(IsA(newConstraint, Constraint));
 
 	/*
-	 * Currently, we only expect to see CONSTR_CHECK and CONSTR_FOREIGN nodes
-	 * arriving here (see the preprocessing done in parse_utilcmd.c).  Use a
-	 * switch anyway to make it easier to add more code later.
+	 * Currently, we only expect to see CONSTR_CHECK, CONSTR_NOTNULL and
+	 * CONSTR_FOREIGN nodes arriving here (see the preprocessing done in
+	 * parse_utilcmd.c).
 	 */
 	switch (newConstraint->contype)
 	{
 		case CONSTR_CHECK:
+		case CONSTR_NOTNULL:
 			address =
 				ATAddCheckConstraint(wqueue, tab, rel,
 									 newConstraint, recurse, false, is_readd,
@@ -8963,9 +9309,9 @@ ChooseForeignKeyConstraintNameAddition(List *colnames)
 }
 
 /*
- * Add a check constraint to a single table and its children.  Returns the
- * address of the constraint added to the parent relation, if one gets added,
- * or InvalidObjectAddress otherwise.
+ * Add a check or NOT NULL constraint to a single table and its children.
+ * Returns the address of the constraint added to the parent relation,
+ * if one gets added, or InvalidObjectAddress otherwise.
  *
  * Subroutine for ATExecAddConstraint.
  *
@@ -9023,6 +9369,7 @@ ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			NewConstraint *newcon;
 
 			newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
+			newcon->attnum = ccon->attnum;
 			newcon->name = ccon->name;
 			newcon->contype = ccon->contype;
 			newcon->qual = ccon->expr;
@@ -9034,6 +9381,14 @@ ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		if (constr->conname == NULL)
 			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 (constr->contype == CONSTR_NOTNULL)
+			set_attnotnull(wqueue, rel, ccon->attnum,
+						   !ccon->is_no_inherit, lockmode);
+
 		ObjectAddressSet(address, ConstraintRelationId, ccon->conoid);
 	}
 
@@ -11958,16 +12313,11 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 					 bool recurse, bool recursing,
 					 bool missing_ok, LOCKMODE lockmode)
 {
-	List	   *children;
-	ListCell   *child;
 	Relation	conrel;
-	Form_pg_constraint con;
 	SysScanDesc scan;
 	ScanKeyData skey[3];
 	HeapTuple	tuple;
 	bool		found = false;
-	bool		is_no_inherit_constraint = false;
-	char		contype;
 
 	/* At top level, permission check was done in ATPrepCmd, else do it */
 	if (recursing)
@@ -11996,47 +12346,8 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 	/* There can be at most one matching row */
 	if (HeapTupleIsValid(tuple = systable_getnext(scan)))
 	{
-		ObjectAddress conobj;
-
-		con = (Form_pg_constraint) GETSTRUCT(tuple);
-
-		/* Don't drop inherited constraints */
-		if (con->coninhcount > 0 && !recursing)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
-					 errmsg("cannot drop inherited constraint \"%s\" of relation \"%s\"",
-							constrName, RelationGetRelationName(rel))));
-
-		is_no_inherit_constraint = con->connoinherit;
-		contype = con->contype;
-
-		/*
-		 * If it's a foreign-key constraint, we'd better lock the referenced
-		 * table and check that that's not in use, just as we've already done
-		 * for the constrained table (else we might, eg, be dropping a trigger
-		 * that has unfired events).  But we can/must skip that in the
-		 * self-referential case.
-		 */
-		if (contype == CONSTRAINT_FOREIGN &&
-			con->confrelid != RelationGetRelid(rel))
-		{
-			Relation	frel;
-
-			/* Must match lock taken by RemoveTriggerById: */
-			frel = table_open(con->confrelid, AccessExclusiveLock);
-			CheckTableNotInUse(frel, "ALTER TABLE");
-			table_close(frel, NoLock);
-		}
-
-		/*
-		 * Perform the actual constraint deletion
-		 */
-		conobj.classId = ConstraintRelationId;
-		conobj.objectId = con->oid;
-		conobj.objectSubId = 0;
-
-		performDeletion(&conobj, behavior, 0);
-
+		dropconstraint_internal(rel, tuple, behavior, recurse, recursing,
+								missing_ok, NULL, lockmode);
 		found = true;
 	}
 
@@ -12045,31 +12356,248 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 	if (!found)
 	{
 		if (!missing_ok)
-		{
 			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
-					 errmsg("constraint \"%s\" of relation \"%s\" does not exist",
-							constrName, RelationGetRelationName(rel))));
-		}
+					errcode(ERRCODE_UNDEFINED_OBJECT),
+					errmsg("constraint \"%s\" of relation \"%s\" does not exist",
+						   constrName, RelationGetRelationName(rel)));
 		else
-		{
 			ereport(NOTICE,
-					(errmsg("constraint \"%s\" of relation \"%s\" does not exist, skipping",
-							constrName, RelationGetRelationName(rel))));
-			table_close(conrel, RowExclusiveLock);
-			return;
+					errmsg("constraint \"%s\" of relation \"%s\" does not exist, skipping",
+						   constrName, RelationGetRelationName(rel)));
+	}
+
+	table_close(conrel, RowExclusiveLock);
+}
+
+/*
+ * Remove a constraint, using its pg_constraint tuple
+ *
+ * Implementation for ALTER TABLE DROP CONSTRAINT and ALTER TABLE ALTER COLUMN
+ * DROP NOT NULL.
+ *
+ * Returns the address of the constraint being removed.
+ */
+static ObjectAddress
+dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior behavior,
+						bool recurse, bool recursing, bool missing_ok, List **readyRels,
+						LOCKMODE lockmode)
+{
+	Relation	conrel;
+	Form_pg_constraint con;
+	ObjectAddress conobj;
+	List	   *children;
+	ListCell   *child;
+	bool		is_no_inherit_constraint = false;
+	bool		dropping_pk = false;
+	char	   *constrName;
+	List	   *unconstrained_cols = NIL;
+	char	   *colname;	/* to match NOT NULL constraints when recursing */
+	List	   *ready = NIL;
+
+	if (readyRels == NULL)
+		readyRels = &ready;
+	if (list_member_oid(*readyRels, RelationGetRelid(rel)))
+		return InvalidObjectAddress;
+	*readyRels = lappend_oid(*readyRels, RelationGetRelid(rel));
+
+	conrel = table_open(ConstraintRelationId, RowExclusiveLock);
+
+	con = (Form_pg_constraint) GETSTRUCT(constraintTup);
+	constrName = NameStr(con->conname);
+
+	/*
+	 * If the constraint is marked conislocal and is also inherited, then we
+	 * just set conislocal false and we're done.  The constraint doesn't go
+	 * away, and we don't modify any children.
+	 */
+	if (con->conislocal && con->coninhcount > 0)
+	{
+		HeapTuple	copytup;
+
+		/* make a copy we can scribble on */
+		copytup = heap_copytuple(constraintTup);
+		con = (Form_pg_constraint) GETSTRUCT(copytup);
+		con->conislocal = false;
+		CatalogTupleUpdate(conrel, &copytup->t_self, copytup);
+
+		table_close(conrel, RowExclusiveLock);
+
+		ObjectAddressSet(conobj, ConstraintRelationId, con->oid);
+		return conobj;
+	}
+
+	/* Don't drop inherited constraints */
+	if (con->coninhcount > 0 && !recursing)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+				 errmsg("cannot drop inherited constraint \"%s\" of relation \"%s\"",
+						constrName, RelationGetRelationName(rel))));
+
+	/*
+	 * See if we have a NOT NULL constraint or a PRIMARY KEY.  If so, we have
+	 * more checks and actions below, so obtain the list of columns that are
+	 * constrained by the constraint being dropped.
+	 */
+	if (con->contype == CONSTRAINT_NOTNULL)
+	{
+		AttrNumber	colnum = extractNotNullColumn(constraintTup);
+
+		if (colnum != InvalidAttrNumber)
+			unconstrained_cols = list_make1_int(colnum);
+	}
+	else if (con->contype == CONSTRAINT_PRIMARY)
+	{
+		Datum		adatum;
+		ArrayType  *arr;
+		int			numkeys;
+		bool		isNull;
+		int16	   *attnums;
+
+		dropping_pk = true;
+
+		adatum = heap_getattr(constraintTup, Anum_pg_constraint_conkey,
+							  RelationGetDescr(conrel), &isNull);
+		if (isNull)
+			elog(ERROR, "null conkey for constraint %u", con->oid);
+		arr = DatumGetArrayTypeP(adatum);	/* ensure not toasted */
+		numkeys = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			numkeys < 0 ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != INT2OID)
+			elog(ERROR, "conkey is not a 1-D smallint array");
+		attnums = (int16 *) ARR_DATA_PTR(arr);
+
+		for (int i = 0; i < numkeys; i++)
+			unconstrained_cols = lappend_int(unconstrained_cols, attnums[i]);
+	}
+
+	is_no_inherit_constraint = con->connoinherit;
+
+	/*
+	 * If it's a foreign-key constraint, we'd better lock the referenced table
+	 * and check that that's not in use, just as we've already done for the
+	 * constrained table (else we might, eg, be dropping a trigger that has
+	 * unfired events).  But we can/must skip that in the self-referential
+	 * case.
+	 */
+	if (con->contype == CONSTRAINT_FOREIGN &&
+		con->confrelid != RelationGetRelid(rel))
+	{
+		Relation	frel;
+
+		/* Must match lock taken by RemoveTriggerById: */
+		frel = table_open(con->confrelid, AccessExclusiveLock);
+		CheckTableNotInUse(frel, "ALTER TABLE");
+		table_close(frel, NoLock);
+	}
+
+	/*
+	 * Perform the actual constraint deletion
+	 */
+	ObjectAddressSet(conobj, ConstraintRelationId, con->oid);
+	performDeletion(&conobj, behavior, 0);
+
+	/*
+	 * If this was a NOT NULL or the primary key, the constrained columns must
+	 * have had pg_attribute.attnotnull set.  See if we need to reset it, and
+	 * do so.
+	 */
+	if (unconstrained_cols)
+	{
+		Relation	attrel;
+		Bitmapset  *pkcols;
+		Bitmapset  *ircols;
+		ListCell   *lc;
+
+		/* Make the above deletion visible */
+		CommandCounterIncrement();
+
+		attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+		/*
+		 * We want to test columns for their presence in the primary key, but
+		 * only if we're not dropping it.
+		 */
+		pkcols = dropping_pk ? NULL :
+			RelationGetIndexAttrBitmap(rel,
+									   INDEX_ATTR_BITMAP_PRIMARY_KEY);
+		ircols = RelationGetIndexAttrBitmap(rel, INDEX_ATTR_BITMAP_IDENTITY_KEY);
+
+		foreach(lc, unconstrained_cols)
+		{
+			AttrNumber	attnum = lfirst_int(lc);
+			HeapTuple	atttup;
+			HeapTuple	contup;
+			Form_pg_attribute attForm;
+
+			/*
+			 * Obtain pg_attribute tuple and verify conditions on it.  We use
+			 * a copy we can scribble on.
+			 */
+			atttup = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum);
+			if (!HeapTupleIsValid(atttup))
+				elog(ERROR, "cache lookup failed for column %d", attnum);
+			attForm = (Form_pg_attribute) GETSTRUCT(atttup);
+
+			/*
+			 * Since the above deletion has been made visible, we can now
+			 * search for any remaining constraints on this column (or these
+			 * columns, in the case we're dropping a multicol primary key.)
+			 * Then, verify whether any further NOT NULL or primary key
+			 * exists, and reset attnotnull if none.
+			 *
+			 * However, if this is a generated identity column, abort the
+			 * whole thing with a specific error message, because the
+			 * constraint is required in that case.
+			 */
+			contup = findNotNullConstraintAttnum(rel, attnum);
+			if (contup ||
+				bms_is_member(attnum - FirstLowInvalidHeapAttributeNumber,
+							  pkcols))
+				continue;
+
+			/*
+			 * It's not valid to drop the last NOT NULL constraint for a
+			 * GENERATED AS IDENTITY column.
+			 */
+			if (attForm->attidentity)
+				ereport(ERROR,
+						errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						errmsg("column \"%s\" of relation \"%s\" is an identity column",
+							   get_attname(RelationGetRelid(rel), attnum,
+										   false),
+							   RelationGetRelationName(rel)));
+
+			/*
+			 * It's not valid to drop the last NOT NULL constraint for the
+			 * replica identity either.  XXX make exception for FULL?
+			 */
+			if (bms_is_member(lfirst_int(lc) - FirstLowInvalidHeapAttributeNumber, ircols))
+				ereport(ERROR,
+						errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						errmsg("column \"%s\" is in index used as replica identity",
+							   get_attname(RelationGetRelid(rel), lfirst_int(lc), false)));
+
+			/* Reset attnotnull */
+			if (attForm->attnotnull)
+			{
+				attForm->attnotnull = false;
+				CatalogTupleUpdate(attrel, &atttup->t_self, atttup);
+			}
 		}
+		table_close(attrel, RowExclusiveLock);
 	}
 
 	/*
 	 * For partitioned tables, non-CHECK inherited constraints are dropped via
 	 * the dependency mechanism, so we're done here.
 	 */
-	if (contype != CONSTRAINT_CHECK &&
+	if (con->contype != CONSTRAINT_CHECK &&
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		table_close(conrel, RowExclusiveLock);
-		return;
+		return conobj;
 	}
 
 	/*
@@ -12094,50 +12622,104 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 				 errmsg("cannot remove constraint from only the partitioned table when partitions exist"),
 				 errhint("Do not specify the ONLY keyword.")));
 
+	/* For NOT NULL constraints we recurse by column name */
+	if (con->contype == CONSTRAINT_NOTNULL)
+		colname = NameStr(TupleDescAttr(RelationGetDescr(rel),
+										linitial_int(unconstrained_cols) - 1)->attname);
+	else
+		colname = NULL;		/* keep compiler quiet */
+
 	foreach(child, children)
 	{
 		Oid			childrelid = lfirst_oid(child);
 		Relation	childrel;
+		HeapTuple	tuple;
+		Form_pg_constraint childcon;
 		HeapTuple	copy_tuple;
+		SysScanDesc scan;
+		ScanKeyData skey[3];
+
+		if (list_member_oid(*readyRels, childrelid))
+			continue;		/* child already processed */
 
 		/* find_inheritance_children already got lock */
 		childrel = table_open(childrelid, NoLock);
 		CheckTableNotInUse(childrel, "ALTER TABLE");
 
-		ScanKeyInit(&skey[0],
-					Anum_pg_constraint_conrelid,
-					BTEqualStrategyNumber, F_OIDEQ,
-					ObjectIdGetDatum(childrelid));
-		ScanKeyInit(&skey[1],
-					Anum_pg_constraint_contypid,
-					BTEqualStrategyNumber, F_OIDEQ,
-					ObjectIdGetDatum(InvalidOid));
-		ScanKeyInit(&skey[2],
-					Anum_pg_constraint_conname,
-					BTEqualStrategyNumber, F_NAMEEQ,
-					CStringGetDatum(constrName));
-		scan = systable_beginscan(conrel, ConstraintRelidTypidNameIndexId,
-								  true, NULL, 3, skey);
+		/*
+		 * We search for NOT NULL constraint by column number, and other
+		 * constraints by name.
+		 */
+		if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			bool	found = false;
+			AttrNumber child_colnum;
+			HeapTuple	child_tup;
 
-		/* There can be at most one matching row */
-		if (!HeapTupleIsValid(tuple = systable_getnext(scan)))
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
-					 errmsg("constraint \"%s\" of relation \"%s\" does not exist",
-							constrName,
-							RelationGetRelationName(childrel))));
+			child_colnum = get_attnum(RelationGetRelid(childrel), colname);
+			ScanKeyInit(&skey[0],
+						Anum_pg_constraint_conrelid,
+						BTEqualStrategyNumber, F_OIDEQ,
+						ObjectIdGetDatum(childrelid));
+			scan = systable_beginscan(conrel, ConstraintRelidTypidNameIndexId,
+									  true, NULL, 1, skey);
+			while (HeapTupleIsValid(child_tup = systable_getnext(scan)))
+			{
+				Form_pg_constraint constr = (Form_pg_constraint) GETSTRUCT(child_tup);
+				AttrNumber	constr_colnum;
 
-		copy_tuple = heap_copytuple(tuple);
+				if (constr->contype != CONSTRAINT_NOTNULL)
+					continue;
+				constr_colnum = extractNotNullColumn(child_tup);
+				if (constr_colnum != child_colnum)
+					continue;
 
-		systable_endscan(scan);
+				found = true;
+				break;	/* found it */
+			}
+			if (!found)	/* shouldn't happen? */
+				elog(ERROR, "failed to find NOT NULL constraint for column \"%s\" in table \"%s\"",
+					 colname, RelationGetRelationName(childrel));
 
-		con = (Form_pg_constraint) GETSTRUCT(copy_tuple);
+			copy_tuple = heap_copytuple(child_tup);
+			systable_endscan(scan);
+		}
+		else
+		{
+			ScanKeyInit(&skey[0],
+						Anum_pg_constraint_conrelid,
+						BTEqualStrategyNumber, F_OIDEQ,
+						ObjectIdGetDatum(childrelid));
+			ScanKeyInit(&skey[1],
+						Anum_pg_constraint_contypid,
+						BTEqualStrategyNumber, F_OIDEQ,
+						ObjectIdGetDatum(InvalidOid));
+			ScanKeyInit(&skey[2],
+						Anum_pg_constraint_conname,
+						BTEqualStrategyNumber, F_NAMEEQ,
+						CStringGetDatum(constrName));
+			scan = systable_beginscan(conrel, ConstraintRelidTypidNameIndexId,
+									  true, NULL, 3, skey);
+			/* There can only be one, so no need to loop */
+			tuple = systable_getnext(scan);
+			if (!HeapTupleIsValid(tuple))
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_OBJECT),
+						 errmsg("constraint \"%s\" of relation \"%s\" does not exist",
+								constrName,
+								RelationGetRelationName(childrel))));
+			copy_tuple = heap_copytuple(tuple);
+			systable_endscan(scan);
+		}
 
-		/* Right now only CHECK constraints can be inherited */
-		if (con->contype != CONSTRAINT_CHECK)
-			elog(ERROR, "inherited constraint is not a CHECK constraint");
+		childcon = (Form_pg_constraint) GETSTRUCT(copy_tuple);
 
-		if (con->coninhcount <= 0)	/* shouldn't happen */
+		/* Right now only CHECK and NOT NULL constraints can be inherited */
+		if (childcon->contype != CONSTRAINT_CHECK &&
+			childcon->contype != CONSTRAINT_NOTNULL)
+			elog(ERROR, "inherited constraint is not a CHECK or NOT NULL constraint");
+
+		if (childcon->coninhcount <= 0)	/* shouldn't happen */
 			elog(ERROR, "relation %u has non-inherited constraint \"%s\"",
 				 childrelid, constrName);
 
@@ -12147,17 +12729,17 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 			 * If the child constraint has other definition sources, just
 			 * decrement its inheritance count; if not, recurse to delete it.
 			 */
-			if (con->coninhcount == 1 && !con->conislocal)
+			if (childcon->coninhcount == 1 && !childcon->conislocal)
 			{
 				/* Time to delete this child constraint, too */
-				ATExecDropConstraint(childrel, constrName, behavior,
-									 true, true,
-									 false, lockmode);
+				dropconstraint_internal(childrel, copy_tuple, behavior,
+										recurse, true, missing_ok, readyRels,
+										lockmode);
 			}
 			else
 			{
 				/* Child constraint must survive my deletion */
-				con->coninhcount--;
+				childcon->coninhcount--;
 				CatalogTupleUpdate(conrel, &copy_tuple->t_self, copy_tuple);
 
 				/* Make update visible */
@@ -12171,8 +12753,8 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 			 * need to mark the inheritors' constraints as locally defined
 			 * rather than inherited.
 			 */
-			con->coninhcount--;
-			con->conislocal = true;
+			childcon->coninhcount--;
+			childcon->conislocal = true;
 
 			CatalogTupleUpdate(conrel, &copy_tuple->t_self, copy_tuple);
 
@@ -12186,6 +12768,8 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 	}
 
 	table_close(conrel, RowExclusiveLock);
+
+	return conobj;
 }
 
 /*
@@ -13511,10 +14095,10 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
 											 NIL,
 											 con->conname);
 				}
-				else if (cmd->subtype == AT_SetNotNull)
+				else if (cmd->subtype == AT_SetAttNotNull)
 				{
 					/*
-					 * The parser will create AT_SetNotNull subcommands for
+					 * The parser will create AT_AttSetNotNull subcommands for
 					 * columns of PRIMARY KEY indexes/constraints, but we need
 					 * not do anything with them here, because the columns'
 					 * NOT NULL marks will already have been propagated into
@@ -15258,6 +15842,7 @@ MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
 	SysScanDesc parent_scan;
 	ScanKeyData parent_key;
 	HeapTuple	parent_tuple;
+	Oid			parent_relid = RelationGetRelid(parent_rel);
 	bool		child_is_partition = false;
 
 	catalog_relation = table_open(ConstraintRelationId, RowExclusiveLock);
@@ -15271,7 +15856,7 @@ MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
 	ScanKeyInit(&parent_key,
 				Anum_pg_constraint_conrelid,
 				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(RelationGetRelid(parent_rel)));
+				ObjectIdGetDatum(parent_relid));
 	parent_scan = systable_beginscan(catalog_relation, ConstraintRelidTypidNameIndexId,
 									 true, NULL, 1, &parent_key);
 
@@ -15283,7 +15868,8 @@ MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
 		HeapTuple	child_tuple;
 		bool		found = false;
 
-		if (parent_con->contype != CONSTRAINT_CHECK)
+		if (parent_con->contype != CONSTRAINT_CHECK &&
+			parent_con->contype != CONSTRAINT_NOTNULL)
 			continue;
 
 		/* if the parent's constraint is marked NO INHERIT, it's not inherited */
@@ -15303,14 +15889,30 @@ MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
 			Form_pg_constraint child_con = (Form_pg_constraint) GETSTRUCT(child_tuple);
 			HeapTuple	child_copy;
 
-			if (child_con->contype != CONSTRAINT_CHECK)
+			if (child_con->contype != parent_con->contype)
 				continue;
 
-			if (strcmp(NameStr(parent_con->conname),
+			/*
+			 * CHECK constraint are matched by name, NOT NULL ones by
+			 * attribute number
+			 */
+			if (child_con->contype == CONSTRAINT_CHECK &&
+				strcmp(NameStr(parent_con->conname),
 					   NameStr(child_con->conname)) != 0)
 				continue;
+			else if (child_con->contype == CONSTRAINT_NOTNULL)
+			{
+				AttrNumber	parent_attno = extractNotNullColumn(parent_tuple);
+				AttrNumber	child_attno = extractNotNullColumn(child_tuple);
 
-			if (!constraints_equivalent(parent_tuple, child_tuple, tuple_desc))
+				if (strcmp(get_attname(parent_relid, parent_attno, false),
+						   get_attname(RelationGetRelid(child_rel), child_attno,
+									   false)) != 0)
+					continue;
+			}
+
+			if (child_con->contype == CONSTRAINT_CHECK &&
+				!constraints_equivalent(parent_tuple, child_tuple, tuple_desc))
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("child table \"%s\" has different definition for check constraint \"%s\"",
@@ -15518,6 +16120,7 @@ RemoveInheritance(Relation child_rel, Relation parent_rel, bool expect_detached)
 	HeapTuple	attributeTuple,
 				constraintTuple;
 	List	   *connames;
+	List	   *nncolumns;
 	bool		found;
 	bool		child_is_partition = false;
 
@@ -15588,6 +16191,8 @@ RemoveInheritance(Relation child_rel, Relation parent_rel, bool expect_detached)
 	 * this, we first need a list of the names of the parent's check
 	 * constraints.  (We cheat a bit by only checking for name matches,
 	 * assuming that the expressions will match.)
+	 *
+	 * For NOT NULL columns, we store column numbers to match.
 	 */
 	catalogRelation = table_open(ConstraintRelationId, RowExclusiveLock);
 	ScanKeyInit(&key[0],
@@ -15598,6 +16203,7 @@ RemoveInheritance(Relation child_rel, Relation parent_rel, bool expect_detached)
 							  true, NULL, 1, key);
 
 	connames = NIL;
+	nncolumns = NIL;
 
 	while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
 	{
@@ -15605,6 +16211,8 @@ RemoveInheritance(Relation child_rel, Relation parent_rel, bool expect_detached)
 
 		if (con->contype == CONSTRAINT_CHECK)
 			connames = lappend(connames, pstrdup(NameStr(con->conname)));
+		if (con->contype == CONSTRAINT_NOTNULL)
+			nncolumns = lappend_int(nncolumns, extractNotNullColumn(constraintTuple));
 	}
 
 	systable_endscan(scan);
@@ -15620,21 +16228,40 @@ RemoveInheritance(Relation child_rel, Relation parent_rel, bool expect_detached)
 	while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
 	{
 		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
-		bool		match;
+		bool		match = false;
 		ListCell   *lc;
 
-		if (con->contype != CONSTRAINT_CHECK)
-			continue;
-
-		match = false;
-		foreach(lc, connames)
+		/*
+		 * Match CHECK constraints by name, NOT NULL constraints by column
+		 * number, and ignore all others.
+		 */
+		if (con->contype == CONSTRAINT_CHECK)
 		{
-			if (strcmp(NameStr(con->conname), (char *) lfirst(lc)) == 0)
+			foreach(lc, connames)
 			{
-				match = true;
-				break;
+				if (con->contype == CONSTRAINT_CHECK &&
+					strcmp(NameStr(con->conname), (char *) lfirst(lc)) == 0)
+				{
+					match = true;
+					break;
+				}
 			}
 		}
+		else if (con->contype == CONSTRAINT_NOTNULL)
+		{
+			AttrNumber	child_attno = extractNotNullColumn(constraintTuple);
+
+			foreach(lc, nncolumns)
+			{
+				if (lfirst_int(lc) == child_attno)
+				{
+					match = true;
+					break;
+				}
+			}
+		}
+		else
+			continue;
 
 		if (match)
 		{
@@ -17925,7 +18552,7 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd,
 	StorePartitionBound(attachrel, rel, cmd->bound);
 
 	/* Ensure there exists a correct set of indexes in the partition. */
-	AttachPartitionEnsureIndexes(rel, attachrel);
+	AttachPartitionEnsureIndexes(wqueue, rel, attachrel);
 
 	/* and triggers */
 	CloneRowTriggersToPartition(rel, attachrel);
@@ -18038,13 +18665,12 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd,
  * partitioned table.
  */
 static void
-AttachPartitionEnsureIndexes(Relation rel, Relation attachrel)
+AttachPartitionEnsureIndexes(List **wqueue, Relation rel, Relation attachrel)
 {
 	List	   *idxes;
 	List	   *attachRelIdxs;
 	Relation   *attachrelIdxRels;
 	IndexInfo **attachInfos;
-	int			i;
 	ListCell   *cell;
 	MemoryContext cxt;
 	MemoryContext oldcxt;
@@ -18060,14 +18686,13 @@ AttachPartitionEnsureIndexes(Relation rel, Relation attachrel)
 	attachInfos = palloc(sizeof(IndexInfo *) * list_length(attachRelIdxs));
 
 	/* Build arrays of all existing indexes and their IndexInfos */
-	i = 0;
 	foreach(cell, attachRelIdxs)
 	{
 		Oid			cldIdxId = lfirst_oid(cell);
+		int			i = foreach_current_index(cell);
 
 		attachrelIdxRels[i] = index_open(cldIdxId, AccessShareLock);
 		attachInfos[i] = BuildIndexInfo(attachrelIdxRels[i]);
-		i++;
 	}
 
 	/*
@@ -18133,7 +18758,7 @@ AttachPartitionEnsureIndexes(Relation rel, Relation attachrel)
 		 * the first matching, unattached one we find, if any, as partition of
 		 * the parent index.  If we find one, we're done.
 		 */
-		for (i = 0; i < list_length(attachRelIdxs); i++)
+		for (int i = 0; i < list_length(attachRelIdxs); i++)
 		{
 			Oid			cldIdxId = RelationGetRelid(attachrelIdxRels[i]);
 			Oid			cldConstrOid = InvalidOid;
@@ -18189,6 +18814,28 @@ AttachPartitionEnsureIndexes(Relation rel, Relation attachrel)
 			stmt = generateClonedIndexStmt(NULL,
 										   idxRel, attmap,
 										   &conOid);
+
+			/*
+			 * If the index is a primary key, mark all columns as NOT NULL if
+			 * they aren't already.
+			 */
+			if (stmt->primary)
+			{
+				MemoryContextSwitchTo(oldcxt);
+				for (int j = 0; j < info->ii_NumIndexKeyAttrs; j++)
+				{
+					AttrNumber	childattno;
+
+					childattno = get_attnum(RelationGetRelid(attachrel),
+											get_attname(RelationGetRelid(rel),
+														info->ii_IndexAttrNumbers[j],
+														false));
+					set_attnotnull(wqueue, attachrel, childattno,
+								   true, AccessExclusiveLock);
+				}
+				MemoryContextSwitchTo(cxt);
+			}
+
 			DefineIndex(RelationGetRelid(attachrel), stmt, InvalidOid,
 						RelationGetRelid(idxRel),
 						conOid,
@@ -18201,7 +18848,7 @@ AttachPartitionEnsureIndexes(Relation rel, Relation attachrel)
 
 out:
 	/* Clean up. */
-	for (i = 0; i < list_length(attachRelIdxs); i++)
+	for (int i = 0; i < list_length(attachRelIdxs); i++)
 		index_close(attachrelIdxRels[i], AccessShareLock);
 	MemoryContextSwitchTo(oldcxt);
 	MemoryContextDelete(cxt);
@@ -19102,6 +19749,13 @@ ATExecAttachPartitionIdx(List **wqueue, Relation parentIdx, RangeVar *name)
 								   RelationGetRelationName(partIdx))));
 		}
 
+		/*
+		 * If it's a primary key, make sure the columns in the partition are
+		 * NOT NULL.
+		 */
+		if (parentIdx->rd_index->indisprimary)
+			verifyPartitionIndexNotNull(childInfo, partTbl);
+
 		/* All good -- do it */
 		IndexSetParentIndex(partIdx, RelationGetRelid(parentIdx));
 		if (OidIsValid(constraintOid))
@@ -19238,6 +19892,29 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 	}
 }
 
+/*
+ * When attaching an index as a partition of a partitioned index which is a
+ * primary key, verify that all the columns in the partition are marked NOT
+ * NULL.
+ */
+static void
+verifyPartitionIndexNotNull(IndexInfo *iinfo, Relation partition)
+{
+	for (int i = 0; i < iinfo->ii_NumIndexKeyAttrs; i++)
+	{
+		Form_pg_attribute att = TupleDescAttr(RelationGetDescr(partition),
+											  iinfo->ii_IndexAttrNumbers[i] - 1);
+
+		if (!att->attnotnull)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					errmsg("invalid primary key definition"),
+					errdetail("Column \"%s\" of relation \"%s\" is not marked NOT NULL.",
+							  NameStr(att->attname),
+							  RelationGetRelationName(partition)));
+	}
+}
+
 /*
  * Return an OID list of constraints that reference the given relation
  * that are marked as having a parent constraints.
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index ba00b99249..d6d67c9083 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -717,6 +717,10 @@ _outConstraint(StringInfo str, const Constraint *node)
 
 		case CONSTR_NOTNULL:
 			appendStringInfoString(str, "NOT_NULL");
+			WRITE_BOOL_FIELD(is_no_inherit);
+			WRITE_STRING_FIELD(colname);
+			WRITE_BOOL_FIELD(skip_validation);
+			WRITE_BOOL_FIELD(initially_valid);
 			break;
 
 		case CONSTR_DEFAULT:
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 597e5b3ea8..4c200485f3 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -390,10 +390,16 @@ _readConstraint(void)
 	switch (local_node->contype)
 	{
 		case CONSTR_NULL:
-		case CONSTR_NOTNULL:
 			/* no extra fields */
 			break;
 
+		case CONSTR_NOTNULL:
+			READ_BOOL_FIELD(is_no_inherit);
+			READ_STRING_FIELD(colname);
+			READ_BOOL_FIELD(skip_validation);
+			READ_BOOL_FIELD(initially_valid);
+			break;
+
 		case CONSTR_DEFAULT:
 			READ_NODE_FIELD(raw_expr);
 			READ_STRING_FIELD(cooked_expr);
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index e3824efe9b..75d8445914 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -1644,6 +1644,8 @@ relation_excluded_by_constraints(PlannerInfo *root,
 	 * Currently, attnotnull constraints must be treated as NO INHERIT unless
 	 * this is a partitioned table.  In future we might track their
 	 * inheritance status more accurately, allowing this to be refined.
+	 *
+	 * XXX do we need/want to change this?
 	 */
 	include_notnull = (!rte->inh || rte->relkind == RELKIND_PARTITIONED_TABLE);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index acf6cf4866..86692bf395 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -4099,6 +4099,19 @@ ConstraintElem:
 					n->initially_valid = !n->skip_validation;
 					$$ = (Node *) n;
 				}
+			| NOT NULL_P ColId ConstraintAttributeSpec
+				{
+					Constraint *n = makeNode(Constraint);
+
+					n->contype = CONSTR_NOTNULL;
+					n->location = @1;
+					n->colname = $3;
+					processCASbits($4, @4, "NOT NULL",
+								   NULL, NULL, NULL,
+								   &n->is_no_inherit, yyscanner);
+					n->initially_valid = !n->skip_validation;
+					$$ = (Node *) n;
+				}
 			| UNIQUE opt_unique_null_treatment '(' columnList ')' opt_c_include opt_definition OptConsTableSpace
 				ConstraintAttributeSpec
 				{
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index b0f6fe4fa6..5a420aef1c 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -80,9 +80,10 @@ typedef struct
 	bool		isforeign;		/* true if CREATE/ALTER FOREIGN TABLE */
 	bool		isalter;		/* true if altering existing table */
 	List	   *columns;		/* ColumnDef items */
-	List	   *ckconstraints;	/* CHECK constraints */
+	List	   *ckconstraints;	/* CHECK and NOT NULL constraints */
 	List	   *fkconstraints;	/* FOREIGN KEY constraints */
 	List	   *ixconstraints;	/* index-creating constraints */
+	List	   *nnconstraints;	/* NOT NULL constraints */
 	List	   *likeclauses;	/* LIKE clauses that need post-processing */
 	List	   *extstats;		/* cloned extended statistics */
 	List	   *blist;			/* "before list" of things to do before
@@ -244,6 +245,7 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 	cxt.ckconstraints = NIL;
 	cxt.fkconstraints = NIL;
 	cxt.ixconstraints = NIL;
+	cxt.nnconstraints = NIL;
 	cxt.likeclauses = NIL;
 	cxt.extstats = NIL;
 	cxt.blist = NIL;
@@ -348,6 +350,7 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 	 */
 	stmt->tableElts = cxt.columns;
 	stmt->constraints = cxt.ckconstraints;
+	stmt->nnconstraints = cxt.nnconstraints;
 
 	result = lappend(cxt.blist, stmt);
 	result = list_concat(result, cxt.alist);
@@ -533,10 +536,11 @@ static void
 transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 {
 	bool		is_serial;
-	bool		saw_nullable;
 	bool		saw_default;
+	bool		saw_nullable;
 	bool		saw_identity;
 	bool		saw_generated;
+	bool		need_notnull = false;
 	ListCell   *clist;
 
 	cxt->columns = lappend(cxt->columns, column);
@@ -634,10 +638,8 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		constraint->cooked_expr = NULL;
 		column->constraints = lappend(column->constraints, constraint);
 
-		constraint = makeNode(Constraint);
-		constraint->contype = CONSTR_NOTNULL;
-		constraint->location = -1;
-		column->constraints = lappend(column->constraints, constraint);
+		/* have a NOT NULL constraint added later */
+		need_notnull = true;
 	}
 
 	/* Process column constraints, if any... */
@@ -655,7 +657,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		switch (constraint->contype)
 		{
 			case CONSTR_NULL:
-				if (saw_nullable && column->is_not_null)
+				if ((saw_nullable && column->is_not_null) || need_notnull)
 					ereport(ERROR,
 							(errcode(ERRCODE_SYNTAX_ERROR),
 							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
@@ -667,15 +669,58 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 				break;
 
 			case CONSTR_NOTNULL:
-				if (saw_nullable && !column->is_not_null)
-					ereport(ERROR,
-							(errcode(ERRCODE_SYNTAX_ERROR),
-							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
-									column->colname, cxt->relation->relname),
-							 parser_errposition(cxt->pstate,
-												constraint->location)));
-				column->is_not_null = true;
-				saw_nullable = true;
+
+				/*
+				 * For NOT NULL declarations, we need to mark the column as
+				 * not nullable, and set things up to have a CHECK constraint
+				 * created.  Also, duplicate NOT NULL declarations are not
+				 * allowed.
+				 */
+				if (saw_nullable)
+				{
+					if (!column->is_not_null)
+						ereport(ERROR,
+								(errcode(ERRCODE_SYNTAX_ERROR),
+								 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
+										column->colname, cxt->relation->relname),
+								 parser_errposition(cxt->pstate,
+													constraint->location)));
+					else
+						ereport(ERROR,
+								errcode(ERRCODE_SYNTAX_ERROR),
+								errmsg("redundant NOT NULL declarations for column \"%s\" of table \"%s\"",
+									   column->colname, cxt->relation->relname),
+								parser_errposition(cxt->pstate,
+												   constraint->location));
+				}
+
+				/*
+				 * If this is the first time we see this column being marked
+				 * not null, keep track to later add a NOT NULL constraint.
+				 */
+				if (!column->is_not_null)
+				{
+					Constraint *notnull;
+
+					column->is_not_null = true;
+					saw_nullable = true;
+
+					notnull = makeNode(Constraint);
+					notnull->contype = CONSTR_NOTNULL;
+					notnull->conname = constraint->conname;
+					notnull->deferrable = false;
+					notnull->initdeferred = false;
+					notnull->location = -1;
+					notnull->colname = column->colname;
+					notnull->skip_validation = false;
+					notnull->initially_valid = true;
+
+					cxt->nnconstraints = lappend(cxt->nnconstraints, notnull);
+
+					/* Don't need this anymore, if we had it */
+					need_notnull = false;
+				}
+
 				break;
 
 			case CONSTR_DEFAULT:
@@ -725,16 +770,19 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 					column->identity = constraint->generated_when;
 					saw_identity = true;
 
-					/* An identity column is implicitly NOT NULL */
-					if (saw_nullable && !column->is_not_null)
+					/*
+					 * Identity columns are always NOT NULL, but we may have a
+					 * constraint already.
+					 */
+					if (!saw_nullable)
+						need_notnull = true;
+					else if (!column->is_not_null)
 						ereport(ERROR,
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
 										column->colname, cxt->relation->relname),
 								 parser_errposition(cxt->pstate,
 													constraint->location)));
-					column->is_not_null = true;
-					saw_nullable = true;
 					break;
 				}
 
@@ -758,6 +806,11 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 
 			case CONSTR_CHECK:
 				cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
+
+				/*
+				 * XXX If the user says CHECK (IS NOT NULL), should we turn
+				 * that into a regular NOT NULL constraint?
+				 */
 				break;
 
 			case CONSTR_PRIMARY:
@@ -840,6 +893,29 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 										constraint->location)));
 	}
 
+	/*
+	 * If we need a NOT NULL constraint for SERIAL or IDENTITY, and one was
+	 * not explicitly specified, add one now.
+	 */
+	if (need_notnull && !(saw_nullable && column->is_not_null))
+	{
+		Constraint *notnull;
+
+		column->is_not_null = true;
+
+		notnull = makeNode(Constraint);
+		notnull->contype = CONSTR_NOTNULL;
+		notnull->conname = NULL;
+		notnull->deferrable = false;
+		notnull->initdeferred = false;
+		notnull->location = -1;
+		notnull->colname = column->colname;
+		notnull->skip_validation = false;
+		notnull->initially_valid = true;
+
+		cxt->nnconstraints = lappend(cxt->nnconstraints, notnull);
+	}
+
 	/*
 	 * If needed, generate ALTER FOREIGN TABLE ALTER COLUMN statement to add
 	 * per-column foreign data wrapper options to this column after creation.
@@ -915,6 +991,10 @@ transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
 			cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
 			break;
 
+		case CONSTR_NOTNULL:
+			cxt->nnconstraints = lappend(cxt->nnconstraints, constraint);
+			break;
+
 		case CONSTR_FOREIGN:
 			if (cxt->isforeign)
 				ereport(ERROR,
@@ -926,7 +1006,6 @@ transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
 			break;
 
 		case CONSTR_NULL:
-		case CONSTR_NOTNULL:
 		case CONSTR_DEFAULT:
 		case CONSTR_ATTR_DEFERRABLE:
 		case CONSTR_ATTR_NOT_DEFERRABLE:
@@ -962,6 +1041,7 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 	AclResult	aclresult;
 	char	   *comment;
 	ParseCallbackState pcbstate;
+	bool		process_notnull_constraints;
 
 	setup_parser_errposition_callback(&pcbstate, cxt->pstate,
 									  table_like_clause->relation->location);
@@ -1043,6 +1123,8 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 		def->inhcount = 0;
 		def->is_local = true;
 		def->is_not_null = attribute->attnotnull;
+		if (attribute->attnotnull)
+			process_notnull_constraints = true;
 		def->is_from_type = false;
 		def->storage = 0;
 		def->raw_default = NULL;
@@ -1124,14 +1206,19 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 	 * we don't yet know what column numbers the copied columns will have in
 	 * the finished table.  If any of those options are specified, add the
 	 * LIKE clause to cxt->likeclauses so that expandTableLikeClause will be
-	 * called after we do know that.  Also, remember the relation OID so that
+	 * called after we do know that; in addition, do that if there are any NOT
+	 * NULL constraints, because those must be propagated even if not
+	 * explicitly requested.
+	 *
+	 * In order for this to work, we remember the relation OID so that
 	 * expandTableLikeClause is certain to open the same table.
 	 */
-	if (table_like_clause->options &
+	if ((table_like_clause->options &
 		(CREATE_TABLE_LIKE_DEFAULTS |
 		 CREATE_TABLE_LIKE_GENERATED |
 		 CREATE_TABLE_LIKE_CONSTRAINTS |
-		 CREATE_TABLE_LIKE_INDEXES))
+		 CREATE_TABLE_LIKE_INDEXES)) ||
+		process_notnull_constraints)
 	{
 		table_like_clause->relationOid = RelationGetRelid(relation);
 		cxt->likeclauses = lappend(cxt->likeclauses, table_like_clause);
@@ -1203,6 +1290,7 @@ expandTableLikeClause(RangeVar *heapRel, TableLikeClause *table_like_clause)
 	TupleConstr *constr;
 	AttrMap    *attmap;
 	char	   *comment;
+	ListCell   *lc;
 
 	/*
 	 * Open the relation referenced by the LIKE clause.  We should still have
@@ -1382,6 +1470,20 @@ expandTableLikeClause(RangeVar *heapRel, TableLikeClause *table_like_clause)
 		}
 	}
 
+	/*
+	 * Copy NOT NULL constraints, too (these do not require any option to have
+	 * been given).
+	 */
+	foreach(lc, RelationGetNotNullConstraints(relation, false))
+	{
+		AlterTableCmd *atsubcmd;
+
+		atsubcmd = makeNode(AlterTableCmd);
+		atsubcmd->subtype = AT_AddConstraint;
+		atsubcmd->def = (Node *) lfirst_node(Constraint, lc);
+		atsubcmds = lappend(atsubcmds, atsubcmd);
+	}
+
 	/*
 	 * If we generated any ALTER TABLE actions above, wrap them into a single
 	 * ALTER TABLE command.  Stick it at the front of the result, so it runs
@@ -2059,10 +2161,12 @@ transformIndexConstraints(CreateStmtContext *cxt)
 	ListCell   *lc;
 
 	/*
-	 * Run through the constraints that need to generate an index. For PRIMARY
-	 * KEY, mark each column as NOT NULL and create an index. For UNIQUE or
-	 * EXCLUDE, create an index as for PRIMARY KEY, but do not insist on NOT
-	 * NULL.
+	 * Run through the constraints that need to generate an index, and do so.
+	 *
+	 * For PRIMARY KEY, in addition we set each column's attnotnull flag true.
+	 * We do not create a separate CHECK (IS NOT NULL) constraint, as that
+	 * would be redundant: the PRIMARY KEY constraint itself fulfills that
+	 * role.  Other constraint types don't need any NOT NULL markings.
 	 */
 	foreach(lc, cxt->ixconstraints)
 	{
@@ -2136,9 +2240,7 @@ transformIndexConstraints(CreateStmtContext *cxt)
 	}
 
 	/*
-	 * Now append all the IndexStmts to cxt->alist.  If we generated an ALTER
-	 * TABLE SET NOT NULL statement to support a primary key, it's already in
-	 * cxt->alist.
+	 * Now append all the IndexStmts to cxt->alist.
 	 */
 	cxt->alist = list_concat(cxt->alist, finalindexlist);
 }
@@ -2146,12 +2248,10 @@ transformIndexConstraints(CreateStmtContext *cxt)
 /*
  * transformIndexConstraint
  *		Transform one UNIQUE, PRIMARY KEY, or EXCLUDE constraint for
- *		transformIndexConstraints.
+ *		transformIndexConstraints. An IndexStmt is returned.
  *
- * We return an IndexStmt.  For a PRIMARY KEY constraint, we additionally
- * produce NOT NULL constraints, either by marking ColumnDefs in cxt->columns
- * as is_not_null or by adding an ALTER TABLE SET NOT NULL command to
- * cxt->alist.
+ * For a PRIMARY KEY constraint, we additionally force the columns to be
+ * marked as NOT NULL, without producing a CHECK (IS NOT NULL) constraint.
  */
 static IndexStmt *
 transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
@@ -2417,7 +2517,6 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 		{
 			char	   *key = strVal(lfirst(lc));
 			bool		found = false;
-			bool		forced_not_null = false;
 			ColumnDef  *column = NULL;
 			ListCell   *columns;
 			IndexElem  *iparam;
@@ -2438,13 +2537,14 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 				 * column is defined in the new table.  For PRIMARY KEY, we
 				 * can apply the NOT NULL constraint cheaply here ... unless
 				 * the column is marked is_from_type, in which case marking it
-				 * here would be ineffective (see MergeAttributes).
+				 * here would be ineffective (see MergeAttributes).  Note that
+				 * this isn't effective in ALTER TABLE either, unless the
+				 * column is being added in the same command.
 				 */
 				if (constraint->contype == CONSTR_PRIMARY &&
 					!column->is_from_type)
 				{
 					column->is_not_null = true;
-					forced_not_null = true;
 				}
 			}
 			else if (SystemAttributeByName(key) != NULL)
@@ -2487,14 +2587,6 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 						if (strcmp(key, inhname) == 0)
 						{
 							found = true;
-
-							/*
-							 * It's tempting to set forced_not_null if the
-							 * parent column is already NOT NULL, but that
-							 * seems unsafe because the column's NOT NULL
-							 * marking might disappear between now and
-							 * execution.  Do the runtime check to be safe.
-							 */
 							break;
 						}
 					}
@@ -2548,15 +2640,11 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 			iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;
 			index->indexParams = lappend(index->indexParams, iparam);
 
-			/*
-			 * For a primary-key column, also create an item for ALTER TABLE
-			 * SET NOT NULL if we couldn't ensure it via is_not_null above.
-			 */
-			if (constraint->contype == CONSTR_PRIMARY && !forced_not_null)
+			if (constraint->contype == CONSTR_PRIMARY)
 			{
 				AlterTableCmd *notnullcmd = makeNode(AlterTableCmd);
 
-				notnullcmd->subtype = AT_SetNotNull;
+				notnullcmd->subtype = AT_SetAttNotNull;
 				notnullcmd->name = pstrdup(key);
 				notnullcmds = lappend(notnullcmds, notnullcmd);
 			}
@@ -3328,6 +3416,7 @@ transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
 	cxt.isalter = true;
 	cxt.columns = NIL;
 	cxt.ckconstraints = NIL;
+	cxt.nnconstraints = NIL;
 	cxt.fkconstraints = NIL;
 	cxt.ixconstraints = NIL;
 	cxt.likeclauses = NIL;
@@ -3571,8 +3660,8 @@ transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
 
 		/*
 		 * We assume here that cxt.alist contains only IndexStmts and possibly
-		 * ALTER TABLE SET NOT NULL statements generated from primary key
-		 * constraints.  We absorb the subcommands of the latter directly.
+		 * AT_SetAttNotNull statements generated from primary key constraints.
+		 * We absorb the subcommands of the latter directly.
 		 */
 		if (IsA(istmt, IndexStmt))
 		{
@@ -3600,14 +3689,21 @@ transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
 	{
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
-		newcmd->def = (Node *) lfirst(l);
+		newcmd->def = (Node *) lfirst_node(Constraint, l);
 		newcmds = lappend(newcmds, newcmd);
 	}
 	foreach(l, cxt.fkconstraints)
 	{
 		newcmd = makeNode(AlterTableCmd);
 		newcmd->subtype = AT_AddConstraint;
-		newcmd->def = (Node *) lfirst(l);
+		newcmd->def = (Node *) lfirst_node(Constraint, l);
+		newcmds = lappend(newcmds, newcmd);
+	}
+	foreach(l, cxt.nnconstraints)
+	{
+		newcmd = makeNode(AlterTableCmd);
+		newcmd->subtype = AT_AddConstraint;
+		newcmd->def = (Node *) lfirst_node(Constraint, l);
 		newcmds = lappend(newcmds, newcmd);
 	}
 
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 461735e84f..0242cf24b4 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -2472,6 +2472,20 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 								 conForm->connoinherit ? " NO INHERIT" : "");
 				break;
 			}
+		case CONSTRAINT_NOTNULL:
+			{
+				AttrNumber	attnum;
+
+				attnum = extractNotNullColumn(tup);
+
+				appendStringInfo(&buf, "NOT NULL %s",
+								 quote_identifier(get_attname(conForm->conrelid,
+															  attnum, false)));
+				if (((Form_pg_constraint) GETSTRUCT(tup))->connoinherit)
+					appendStringInfoString(&buf, " NO INHERIT");
+				break;
+			}
+
 		case CONSTRAINT_TRIGGER:
 
 			/*
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 5d988986ed..ed95dc8dc6 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -82,7 +82,8 @@ static catalogid_hash *catalogIdHash = NULL;
 static void flagInhTables(Archive *fout, TableInfo *tblinfo, int numTables,
 						  InhInfo *inhinfo, int numInherits);
 static void flagInhIndexes(Archive *fout, TableInfo *tblinfo, int numTables);
-static void flagInhAttrs(DumpOptions *dopt, TableInfo *tblinfo, int numTables);
+static void flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo,
+						 int numTables);
 static int	strInArray(const char *pattern, char **arr, int arr_size);
 static IndxInfo *findIndexByOid(Oid oid);
 
@@ -226,7 +227,7 @@ getSchemaData(Archive *fout, int *numTablesPtr)
 	getTableAttrs(fout, tblinfo, numTables);
 
 	pg_log_info("flagging inherited columns in subtables");
-	flagInhAttrs(fout->dopt, tblinfo, numTables);
+	flagInhAttrs(fout, fout->dopt, tblinfo, numTables);
 
 	pg_log_info("reading partitioning data");
 	getPartitioningInfo(fout);
@@ -471,7 +472,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
  * What we need to do here is:
  *
  * - Detect child columns that inherit NOT NULL bits from their parents, so
- *   that we needn't specify that again for the child.
+ *   that we needn't specify that again for the child. (Versions >= 16 no
+ *   longer need this.)
  *
  * - Detect child columns that have DEFAULT NULL when their parents had some
  *   non-null default.  In this case, we make up a dummy AttrDefInfo object so
@@ -491,7 +493,7 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
  * modifies tblinfo
  */
 static void
-flagInhAttrs(DumpOptions *dopt, TableInfo *tblinfo, int numTables)
+flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables)
 {
 	int			i,
 				j,
@@ -572,8 +574,9 @@ flagInhAttrs(DumpOptions *dopt, TableInfo *tblinfo, int numTables)
 				}
 			}
 
-			/* Remember if we found inherited NOT NULL */
-			tbinfo->inhNotNull[j] = foundNotNull;
+			/* In versions < 16, remember if we found inherited NOT NULL */
+			if (fout->remoteVersion < 160000)
+				tbinfo->localNotNull[j] = !foundNotNull;
 
 			/*
 			 * Manufacture a DEFAULT NULL clause if necessary.  This breaks
diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index d518349e10..5b858b2348 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -601,6 +601,7 @@ RestoreArchive(Archive *AHX)
 
 								if (strcmp(te->desc, "CONSTRAINT") == 0 ||
 									strcmp(te->desc, "CHECK CONSTRAINT") == 0 ||
+									strcmp(te->desc, "NOT NULL CONSTRAINT") == 0 ||
 									strcmp(te->desc, "FK CONSTRAINT") == 0)
 									strcpy(buffer, "DROP CONSTRAINT");
 								else
@@ -3511,6 +3512,7 @@ _getObjectDescription(PQExpBuffer buf, const TocEntry *te)
 	/* these object types don't have separate owners */
 	else if (strcmp(type, "CAST") == 0 ||
 			 strcmp(type, "CHECK CONSTRAINT") == 0 ||
+			 strcmp(type, "NOT NULL CONSTRAINT") == 0 ||
 			 strcmp(type, "CONSTRAINT") == 0 ||
 			 strcmp(type, "DATABASE PROPERTIES") == 0 ||
 			 strcmp(type, "DEFAULT") == 0 ||
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 7a504dfe25..229c4ab316 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -8372,6 +8372,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	PQExpBuffer q = createPQExpBuffer();
 	PQExpBuffer tbloids = createPQExpBuffer();
 	PQExpBuffer checkoids = createPQExpBuffer();
+	PQExpBuffer defaultoids = createPQExpBuffer();
 	PGresult   *res;
 	int			ntups;
 	int			curtblindx;
@@ -8389,6 +8390,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_attalign;
 	int			i_attislocal;
 	int			i_attnotnull;
+	int			i_localnotnull;
 	int			i_attoptions;
 	int			i_attcollation;
 	int			i_attcompression;
@@ -8398,16 +8400,17 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 
 	/*
 	 * We want to perform just one query against pg_attribute, and then just
-	 * one against pg_attrdef (for DEFAULTs) and one against pg_constraint
-	 * (for CHECK constraints).  However, we mustn't try to select every row
-	 * of those catalogs and then sort it out on the client side, because some
-	 * of the server-side functions we need would be unsafe to apply to tables
-	 * we don't have lock on.  Hence, we build an array of the OIDs of tables
-	 * we care about (and now have lock on!), and use a WHERE clause to
-	 * constrain which rows are selected.
+	 * one against pg_attrdef (for DEFAULTs) and two against pg_constraint
+	 * (for CHECK constraints and for NOT NULL constraints).  However, we
+	 * mustn't try to select every row of those catalogs and then sort it out
+	 * on the client side, because some of the server-side functions we need
+	 * would be unsafe to apply to tables we don't have lock on.  Hence, we
+	 * build an array of the OIDs of tables we care about (and now have lock
+	 * on!), and use a WHERE clause to constrain which rows are selected.
 	 */
 	appendPQExpBufferChar(tbloids, '{');
 	appendPQExpBufferChar(checkoids, '{');
+	appendPQExpBufferChar(defaultoids, '{');
 	for (int i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -8451,7 +8454,6 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 						 "a.attstattarget,\n"
 						 "a.attstorage,\n"
 						 "t.typstorage,\n"
-						 "a.attnotnull,\n"
 						 "a.atthasdef,\n"
 						 "a.attisdropped,\n"
 						 "a.attlen,\n"
@@ -8468,6 +8470,17 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 						 "ORDER BY option_name"
 						 "), E',\n    ') AS attfdwoptions,\n");
 
+	/*
+	 * Write out NOT NULL, except if it's marked connoinherit.
+	 */
+	if (fout->remoteVersion >= 160000)
+		appendPQExpBufferStr(q,
+							 "co.conname IS NOT NULL AS attnotnull,\n"
+							 "co.conislocal AS local_notnull,\n");
+	else
+		appendPQExpBufferStr(q,
+							 "a.attnotnull, false AS local_notnull,\n");
+
 	if (fout->remoteVersion >= 140000)
 		appendPQExpBufferStr(q,
 							 "a.attcompression AS attcompression,\n");
@@ -8502,10 +8515,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 					  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
 					  "JOIN pg_catalog.pg_attribute a ON (src.tbloid = a.attrelid) "
 					  "LEFT JOIN pg_catalog.pg_type t "
-					  "ON (a.atttypid = t.oid)\n"
-					  "WHERE a.attnum > 0::pg_catalog.int2\n"
-					  "ORDER BY a.attrelid, a.attnum",
+					  "ON (a.atttypid = t.oid)\n",
 					  tbloids->data);
+	if (fout->remoteVersion >= 160000)
+		appendPQExpBufferStr(q,
+							 " LEFT JOIN pg_catalog.pg_constraint co ON (a.attrelid = co.conrelid\n"
+							 "   AND co.contype = 'n' AND co.conkey = array[a.attnum])\n"
+							 "WHERE a.attnum > 0::pg_catalog.int2\n"
+							 "ORDER BY a.attrelid, a.attnum");
 
 	res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
 
@@ -8525,6 +8542,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_attalign = PQfnumber(res, "attalign");
 	i_attislocal = PQfnumber(res, "attislocal");
 	i_attnotnull = PQfnumber(res, "attnotnull");
+	i_localnotnull = PQfnumber(res, "local_notnull");
 	i_attoptions = PQfnumber(res, "attoptions");
 	i_attcollation = PQfnumber(res, "attcollation");
 	i_attcompression = PQfnumber(res, "attcompression");
@@ -8533,8 +8551,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	i_atthasdef = PQfnumber(res, "atthasdef");
 
 	/* Within the next loop, we'll accumulate OIDs of tables with defaults */
-	resetPQExpBuffer(tbloids);
-	appendPQExpBufferChar(tbloids, '{');
+	resetPQExpBuffer(defaultoids);
+	appendPQExpBufferChar(defaultoids, '{');
 
 	/*
 	 * Outer loop iterates once per table, not once per row.  Incrementing of
@@ -8590,7 +8608,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull = (bool *) pg_malloc(numatts * sizeof(bool));
-		tbinfo->inhNotNull = (bool *) pg_malloc(numatts * sizeof(bool));
+		tbinfo->localNotNull = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
 		hasdefaults = false;
 
@@ -8612,6 +8630,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attalign[j] = *(PQgetvalue(res, r, i_attalign));
 			tbinfo->attislocal[j] = (PQgetvalue(res, r, i_attislocal)[0] == 't');
 			tbinfo->notnull[j] = (PQgetvalue(res, r, i_attnotnull)[0] == 't');
+			tbinfo->localNotNull[j] = (PQgetvalue(res, r, i_localnotnull)[0] == 't');
 			tbinfo->attoptions[j] = pg_strdup(PQgetvalue(res, r, i_attoptions));
 			tbinfo->attcollation[j] = atooid(PQgetvalue(res, r, i_attcollation));
 			tbinfo->attcompression[j] = *(PQgetvalue(res, r, i_attcompression));
@@ -8620,16 +8639,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attrdefs[j] = NULL; /* fix below */
 			if (PQgetvalue(res, r, i_atthasdef)[0] == 't')
 				hasdefaults = true;
-			/* these flags will be set in flagInhAttrs() */
-			tbinfo->inhNotNull[j] = false;
 		}
 
 		if (hasdefaults)
 		{
 			/* Collect OIDs of interesting tables that have defaults */
-			if (tbloids->len > 1)	/* do we have more than the '{'? */
-				appendPQExpBufferChar(tbloids, ',');
-			appendPQExpBuffer(tbloids, "%u", tbinfo->dobj.catId.oid);
+			if (defaultoids->len > 1)	/* do we have more than the '{'? */
+				appendPQExpBufferChar(defaultoids, ',');
+			appendPQExpBuffer(defaultoids, "%u", tbinfo->dobj.catId.oid);
 		}
 	}
 
@@ -8639,7 +8656,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 * Now get info about column defaults.  This is skipped for a data-only
 	 * dump, as it is only needed for table schemas.
 	 */
-	if (!dopt->dataOnly && tbloids->len > 1)
+	if (!dopt->dataOnly && defaultoids->len > 1)
 	{
 		AttrDefInfo *attrdefs;
 		int			numDefaults;
@@ -8647,14 +8664,14 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 
 		pg_log_info("finding table default expressions");
 
-		appendPQExpBufferChar(tbloids, '}');
+		appendPQExpBufferChar(defaultoids, '}');
 
 		printfPQExpBuffer(q, "SELECT a.tableoid, a.oid, adrelid, adnum, "
 						  "pg_catalog.pg_get_expr(adbin, adrelid) AS adsrc\n"
 						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
 						  "JOIN pg_catalog.pg_attrdef a ON (src.tbloid = a.adrelid)\n"
 						  "ORDER BY a.adrelid, a.adnum",
-						  tbloids->data);
+						  defaultoids->data);
 
 		res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
 
@@ -8897,9 +8914,111 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		PQclear(res);
 	}
 
+	/*
+	 * Get info about table NOT NULL constraints.  This is skipped for a
+	 * data-only dump, as it is only needed for table schemas.
+	 *
+	 * Optimizing for tables that have no NOT NULL constraint seems
+	 * pointless, so we don't try.
+	 */
+	if (!dopt->dataOnly)
+	{
+		ConstraintInfo *constrs;
+		int			numConstrs;
+		int			i_tableoid;
+		int			i_oid;
+		int			i_conrelid;
+		int			i_conname;
+		int			i_condef;
+		int			i_conislocal;
+
+		pg_log_info("finding table not null constraints");
+
+		/*
+		 * Only constraints marked connoinherit need to be handled here;
+		 * most of them are instead handled when columns are defined.
+		 */
+		resetPQExpBuffer(q);
+		appendPQExpBuffer(q,
+						  "SELECT co.tableoid, co.oid, conrelid, conname, "
+						  "pg_catalog.pg_get_constraintdef(co.oid) AS condef,\n"
+						  "  conislocal, coninhcount, connoinherit "
+						  "FROM unnest('%s'::pg_catalog.oid[]) AS src(tbloid)\n"
+						  "JOIN pg_catalog.pg_constraint co ON (src.tbloid = co.conrelid)\n"
+						  "JOIN pg_catalog.pg_class c ON (conrelid = c.oid)\n"
+						  "WHERE contype = 'n' AND (connoinherit OR relispartition)\n"
+						  "ORDER BY co.conrelid, co.conname",
+						  tbloids->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_condef = PQfnumber(res, "condef");
+		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_condef));
+				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');
+
+				constrs[j].separate = true;
+
+				constrs[j].dobj.dump = tbinfo->dobj.dump;
+			}
+		}
+
+		PQclear(res);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(tbloids);
 	destroyPQExpBuffer(checkoids);
+	destroyPQExpBuffer(defaultoids);
 }
 
 /*
@@ -15572,12 +15691,12 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 									 !tbinfo->attrdefs[j]->separate);
 
 					/*
-					 * Not Null constraint --- suppress if inherited, except
-					 * if partition, or in binary-upgrade case where that
-					 * won't work.
+					 * Not Null constraint --- suppress unless it is locally
+					 * defined, except if partition, or in binary-upgrade case
+					 * where that won't work.
 					 */
 					print_notnull = (tbinfo->notnull[j] &&
-									 (!tbinfo->inhNotNull[j] ||
+									 (tbinfo->localNotNull[j] ||
 									  tbinfo->ispartition || dopt->binary_upgrade));
 
 					/*
@@ -15970,7 +16089,7 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 			 * we have to mark it separately.
 			 */
 			if (!shouldPrintColumn(dopt, tbinfo, j) &&
-				tbinfo->notnull[j] && !tbinfo->inhNotNull[j])
+				tbinfo->notnull[j] && tbinfo->localNotNull[j])
 				appendPQExpBuffer(q,
 								  "ALTER %sTABLE ONLY %s ALTER COLUMN %s SET NOT NULL;\n",
 								  foreign, qualrelname,
@@ -16795,6 +16914,31 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 									  .createStmt = q->data,
 									  .dropStmt = delq->data));
 	}
+	else if (coninfo->contype == 'n')
+	{
+		appendPQExpBuffer(q, "ALTER %sTABLE %s\n", foreign,
+						  fmtQualifiedDumpable(tbinfo));
+		appendPQExpBuffer(q, "    ADD CONSTRAINT %s %s;\n",
+						  fmtId(coninfo->dobj.name),
+						  coninfo->condef);
+
+		appendPQExpBuffer(delq, "ALTER %sTABLE %s\n", foreign,
+						  fmtQualifiedDumpable(tbinfo));
+		appendPQExpBuffer(delq, "DROP CONSTRAINT %s;\n",
+						  fmtId(coninfo->dobj.name));
+
+		tag = psprintf("%s %s", tbinfo->dobj.name, coninfo->dobj.name);
+
+		if (coninfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+			ArchiveEntry(fout, coninfo->dobj.catId, coninfo->dobj.dumpId,
+						 ARCHIVE_OPTS(.tag = tag,
+									  .namespace = tbinfo->dobj.namespace->dobj.name,
+									  .owner = tbinfo->rolname,
+									  .description = "NOT NULL CONSTRAINT",
+									  .section = SECTION_POST_DATA,
+									  .createStmt = q->data,
+									  .dropStmt = delq->data));
+	}
 	else if (coninfo->contype == 'c' && tbinfo)
 	{
 		/* CHECK constraint on a table */
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index ed6ce41ad7..765fe6399a 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -345,7 +345,7 @@ typedef struct _tableInfo
 	char	  **attfdwoptions;	/* per-attribute fdw options */
 	char	  **attmissingval;	/* per attribute missing value */
 	bool	   *notnull;		/* NOT NULL constraints on attributes */
-	bool	   *inhNotNull;		/* true if NOT NULL is inherited */
+	bool	   *localNotNull;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
 	struct _constraintInfo *checkexprs; /* CHECK constraints */
 	bool		needs_override; /* has GENERATED ALWAYS AS IDENTITY */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 93e24d5145..afd1bb2e9a 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3115,7 +3115,7 @@ my %tests = (
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.fk_reference_test_table (\E
-			\n\s+\Qcol1 integer NOT NULL\E
+			\n\s+\Qcol1 integer\E
 			\n\);
 			/xm,
 		like =>
@@ -3507,7 +3507,7 @@ my %tests = (
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
-			\s+\Qcol1 integer NOT NULL,\E\n
+			\s+\Qcol1 integer,\E\n
 			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
 			\);
 			/xms,
@@ -3621,7 +3621,7 @@ my %tests = (
 						) INHERITS (dump_test.test_inheritance_parent);',
 		regexp => qr/^
 		\QCREATE TABLE dump_test.test_inheritance_child (\E\n
-		\s+\Qcol1 integer,\E\n
+		\s+\Qcol1 integer NOT NULL,\E\n
 		\s+\QCONSTRAINT test_inheritance_child CHECK ((col2 >= 142857))\E\n
 		\)\n
 		\QINHERITS (dump_test.test_inheritance_parent);\E\n
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index d01ab504b6..e774124c27 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -37,7 +37,7 @@ typedef struct CookedConstraint
 	ConstrType	contype;		/* CONSTR_DEFAULT or CONSTR_CHECK */
 	Oid			conoid;			/* constr OID if created, otherwise Invalid */
 	char	   *name;			/* name, or NULL if none */
-	AttrNumber	attnum;			/* which attr (only for DEFAULT) */
+	AttrNumber	attnum;			/* which attr (only for NOTNULL, DEFAULT) */
 	Node	   *expr;			/* transformed default or check expr */
 	bool		skip_validation;	/* skip validation? (only for CHECK) */
 	bool		is_local;		/* constraint has local (non-inherited) def */
@@ -113,6 +113,9 @@ extern List *AddRelationNewConstraints(Relation rel,
 									   bool is_local,
 									   bool is_internal,
 									   const char *queryString);
+extern List *AddRelationNotNullConstraints(Relation rel,
+										   List *constraints,
+										   List *additional_notnulls);
 
 extern void RelationClearMissing(Relation rel);
 extern void SetAttrMissing(Oid relid, char *attname, char *value);
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index 16bf5f5576..13573a3cf1 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -181,6 +181,7 @@ DECLARE_ARRAY_FOREIGN_KEY((confrelid, confkey), pg_attribute, (attrelid, attnum)
 /* Valid values for contype */
 #define CONSTRAINT_CHECK			'c'
 #define CONSTRAINT_FOREIGN			'f'
+#define CONSTRAINT_NOTNULL			'n'
 #define CONSTRAINT_PRIMARY			'p'
 #define CONSTRAINT_UNIQUE			'u'
 #define CONSTRAINT_TRIGGER			't'
@@ -237,9 +238,6 @@ extern Oid	CreateConstraintEntry(const char *constraintName,
 								  bool conNoInherit,
 								  bool is_internal);
 
-extern void RemoveConstraintById(Oid conId);
-extern void RenameConstraintById(Oid conId, const char *newname);
-
 extern bool ConstraintNameIsUsed(ConstraintCategory conCat, Oid objId,
 								 const char *conname);
 extern bool ConstraintNameExists(const char *conname, Oid namespaceid);
@@ -247,6 +245,13 @@ extern char *ChooseConstraintName(const char *name1, const char *name2,
 								  const char *label, Oid namespaceid,
 								  List *others);
 
+extern HeapTuple findNotNullConstraintAttnum(Relation rel, AttrNumber attnum);
+extern HeapTuple findNotNullConstraint(Relation rel, const char *colname);
+extern AttrNumber extractNotNullColumn(HeapTuple constrTup);
+
+extern void RemoveConstraintById(Oid conId);
+extern void RenameConstraintById(Oid conId, const char *newname);
+
 extern void AlterConstraintNamespaces(Oid ownerId, Oid oldNspId,
 									  Oid newNspId, bool isType, ObjectAddresses *objsMoved);
 extern void ConstraintSetParentConstraint(Oid childConstrId,
diff --git a/src/include/commands/tablecmds.h b/src/include/commands/tablecmds.h
index 17b9404937..8f7ce96651 100644
--- a/src/include/commands/tablecmds.h
+++ b/src/include/commands/tablecmds.h
@@ -73,6 +73,8 @@ extern ObjectAddress renameatt(RenameStmt *stmt);
 
 extern ObjectAddress RenameConstraint(RenameStmt *stmt);
 
+extern List *RelationGetNotNullConstraints(Relation relation, bool cooked);
+
 extern ObjectAddress RenameRelation(RenameStmt *stmt);
 
 extern void RenameRelationInternal(Oid myrelid,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index cc7b32b279..46bf610764 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2177,6 +2177,7 @@ typedef enum AlterTableType
 	AT_CookedColumnDefault,		/* add a pre-cooked column default */
 	AT_DropNotNull,				/* alter column drop not null */
 	AT_SetNotNull,				/* alter column set not null */
+	AT_SetAttNotNull,			/* set attnotnull w/o a constraint */
 	AT_DropExpression,			/* alter column drop expression */
 	AT_CheckNotNull,			/* check column is already marked not null */
 	AT_SetStatistics,			/* alter column set statistics */
@@ -2462,10 +2463,11 @@ typedef struct VariableShowStmt
  *		Create Table Statement
  *
  * NOTE: in the raw gram.y output, ColumnDef and Constraint nodes are
- * intermixed in tableElts, and constraints is NIL.  After parse analysis,
- * tableElts contains just ColumnDefs, and constraints contains just
- * Constraint nodes (in fact, only CONSTR_CHECK nodes, in the present
- * implementation).
+ * intermixed in tableElts, and constraints and notnullcols are NIL.  After
+ * parse analysis, tableElts contains just ColumnDefs, notnullcols has been
+ * filled with not-nullable column names from various sources, and constraints
+ * contains just Constraint nodes (in fact, only CONSTR_CHECK nodes, in the
+ * present implementation).
  * ----------------------
  */
 
@@ -2480,6 +2482,7 @@ typedef struct CreateStmt
 	PartitionSpec *partspec;	/* PARTITION BY clause */
 	TypeName   *ofTypename;		/* OF typename */
 	List	   *constraints;	/* constraints (list of Constraint nodes) */
+	List	   *nnconstraints;	/* NOT NULL constraints (ditto) */
 	List	   *options;		/* options from WITH clause */
 	OnCommitAction oncommit;	/* what do we do at COMMIT? */
 	char	   *tablespacename; /* table space to use, or NULL */
@@ -2568,6 +2571,9 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* expr, as nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
 
+	/* Fields used for "raw" NOT NULL constraints: */
+	char	   *colname;		/* column it applies to */
+
 	/* Fields used for unique constraints (UNIQUE and PRIMARY KEY): */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
diff --git a/src/test/modules/test_ddl_deparse/expected/alter_table.out b/src/test/modules/test_ddl_deparse/expected/alter_table.out
index 87a1ab7aab..4d8e3abfed 100644
--- a/src/test/modules/test_ddl_deparse/expected/alter_table.out
+++ b/src/test/modules/test_ddl_deparse/expected/alter_table.out
@@ -28,6 +28,7 @@ ALTER TABLE parent ADD COLUMN b serial;
 NOTICE:  DDL test: type simple, tag CREATE SEQUENCE
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
 NOTICE:    subcommand: type ADD COLUMN (and recurse) desc column b of table parent
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint parent_b_not_null on table parent
 NOTICE:  DDL test: type simple, tag ALTER SEQUENCE
 ALTER TABLE parent RENAME COLUMN b TO c;
 NOTICE:  DDL test: type simple, tag ALTER TABLE
@@ -57,24 +58,18 @@ NOTICE:    subcommand: type DETACH PARTITION desc table part2
 DROP TABLE part2;
 ALTER TABLE part ADD PRIMARY KEY (a);
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
-NOTICE:    subcommand: type SET NOT NULL desc column a of table part
-NOTICE:    subcommand: type SET NOT NULL desc column a of table part1
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:    subcommand: type ADD INDEX desc index part_pkey
 ALTER TABLE parent ALTER COLUMN a SET NOT NULL;
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
-NOTICE:    subcommand: type SET NOT NULL desc column a of table parent
-NOTICE:    subcommand: type SET NOT NULL desc column a of table child
-NOTICE:    subcommand: type SET NOT NULL desc column a of table grandchild
+NOTICE:    subcommand: type SET NOT NULL (and recurse) desc constraint parent_a_not_null on table parent
 ALTER TABLE parent ALTER COLUMN a DROP NOT NULL;
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
-NOTICE:    subcommand: type DROP NOT NULL desc column a of table parent
-NOTICE:    subcommand: type DROP NOT NULL desc column a of table child
-NOTICE:    subcommand: type DROP NOT NULL desc column a of table grandchild
+NOTICE:    subcommand: type DROP NOT NULL (and recurse) desc column a of table parent
 ALTER TABLE parent ALTER COLUMN a SET NOT NULL;
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
-NOTICE:    subcommand: type SET NOT NULL desc column a of table parent
-NOTICE:    subcommand: type SET NOT NULL desc column a of table child
-NOTICE:    subcommand: type SET NOT NULL desc column a of table grandchild
+NOTICE:    subcommand: type SET NOT NULL (and recurse) desc constraint parent_a_not_null on table parent
 ALTER TABLE parent ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
 NOTICE:  DDL test: type simple, tag CREATE SEQUENCE
 NOTICE:  DDL test: type simple, tag ALTER SEQUENCE
@@ -116,6 +111,7 @@ NOTICE:  DDL test: type alter table, tag ALTER TABLE
 NOTICE:    subcommand: type ALTER COLUMN SET TYPE desc column c of table parent
 NOTICE:    subcommand: type ALTER COLUMN SET TYPE desc column c of table child
 NOTICE:    subcommand: type ALTER COLUMN SET TYPE desc column c of table grandchild
+NOTICE:    subcommand: type (re) ADD CONSTRAINT desc constraint parent_b_not_null on table parent
 NOTICE:    subcommand: type (re) ADD STATS desc statistics object parent_stat
 ALTER TABLE parent ALTER COLUMN c SET DEFAULT 0;
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
diff --git a/src/test/modules/test_ddl_deparse/expected/create_table.out b/src/test/modules/test_ddl_deparse/expected/create_table.out
index 2178ce83e9..dc9175bf77 100644
--- a/src/test/modules/test_ddl_deparse/expected/create_table.out
+++ b/src/test/modules/test_ddl_deparse/expected/create_table.out
@@ -54,6 +54,8 @@ NOTICE:  DDL test: type simple, tag CREATE SEQUENCE
 NOTICE:  DDL test: type simple, tag CREATE SEQUENCE
 NOTICE:  DDL test: type simple, tag CREATE SEQUENCE
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 NOTICE:  DDL test: type simple, tag ALTER SEQUENCE
@@ -74,6 +76,8 @@ CREATE TABLE IF NOT EXISTS fkey_table (
     EXCLUDE USING btree (check_col_2 WITH =)
 );
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
@@ -86,7 +90,7 @@ CREATE TABLE employees OF employee_type (
 );
 NOTICE:  DDL test: type simple, tag CREATE TABLE
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
-NOTICE:    subcommand: type SET NOT NULL desc column name of table employees
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 -- Inheritance
 CREATE TABLE person (
@@ -96,6 +100,8 @@ CREATE TABLE person (
 	location 	point
 );
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 CREATE TABLE emp (
 	salary 		int4,
@@ -128,6 +134,10 @@ CREATE TABLE like_datatype_table (
   EXCLUDING ALL
 );
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint datatype_table_id_big_not_null on table like_datatype_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint datatype_table_id_not_null on table like_datatype_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint datatype_table_is_small_not_null on table like_datatype_table
 CREATE TABLE like_fkey_table (
   LIKE fkey_table
   INCLUDING DEFAULTS
@@ -137,6 +147,11 @@ CREATE TABLE like_fkey_table (
 NOTICE:  DDL test: type simple, tag CREATE TABLE
 NOTICE:  DDL test: type alter table, tag ALTER TABLE
 NOTICE:    subcommand: type ALTER COLUMN SET DEFAULT (precooked) desc column id of table like_fkey_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint fkey_table_big_id_not_null on table like_fkey_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint fkey_table_check_col_1_not_null on table like_fkey_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint fkey_table_check_col_2_not_null on table like_fkey_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint fkey_table_datatype_id_not_null on table like_fkey_table
+NOTICE:    subcommand: type ADD CONSTRAINT (and recurse) desc constraint fkey_table_id_not_null on table like_fkey_table
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 -- Volatile table types
@@ -144,21 +159,29 @@ CREATE UNLOGGED TABLE unlogged_table (
     id INT PRIMARY KEY
 );
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 CREATE TEMP TABLE temp_table (
     id INT PRIMARY KEY
 );
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 CREATE TEMP TABLE temp_table_commit_delete (
     id INT PRIMARY KEY
 )
 ON COMMIT DELETE ROWS;
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
 CREATE TEMP TABLE temp_table_commit_drop (
     id INT PRIMARY KEY
 )
 ON COMMIT DROP;
 NOTICE:  DDL test: type simple, tag CREATE TABLE
+NOTICE:  DDL test: type alter table, tag ALTER TABLE
+NOTICE:    subcommand: type SET ATTNOTNULL desc <NULL>
 NOTICE:  DDL test: type simple, tag CREATE INDEX
diff --git a/src/test/modules/test_ddl_deparse/test_ddl_deparse.c b/src/test/modules/test_ddl_deparse/test_ddl_deparse.c
index b7c6f98577..88977bf2c7 100644
--- a/src/test/modules/test_ddl_deparse/test_ddl_deparse.c
+++ b/src/test/modules/test_ddl_deparse/test_ddl_deparse.c
@@ -129,6 +129,9 @@ get_altertable_subcmdinfo(PG_FUNCTION_ARGS)
 			case AT_SetNotNull:
 				strtype = "SET NOT NULL";
 				break;
+			case AT_SetAttNotNull:
+				strtype = "SET ATTNOTNULL";
+				break;
 			case AT_DropExpression:
 				strtype = "DROP EXPRESSION";
 				break;
@@ -318,6 +321,7 @@ get_altertable_subcmdinfo(PG_FUNCTION_ARGS)
 		if (OidIsValid(sub->address.objectId))
 		{
 			char	   *objdesc;
+
 			objdesc = getObjectDescription((const ObjectAddress *) &sub->address, false);
 			values[1] = CStringGetTextDatum(objdesc);
 		}
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 3b708c7976..010a215cb4 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1119,9 +1119,13 @@ ERROR:  relation "non_existent" does not exist
 create table atacc1 (test int not null);
 alter table atacc1 add constraint "atacc1_pkey" primary key (test);
 alter table atacc1 alter column test drop not null;
-ERROR:  column "test" is in a primary key
 alter table atacc1 drop constraint "atacc1_pkey";
-alter table atacc1 alter column test drop not null;
+\d atacc1
+               Table "public.atacc1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ test   | integer |           |          | 
+
 insert into atacc1 values (null);
 alter table atacc1 alter test set not null;
 ERROR:  column "test" of relation "atacc1" contains null values
@@ -1191,23 +1195,10 @@ alter table parent alter a drop not null;
 insert into parent values (NULL);
 insert into child (a, b) values (NULL, 'foo');
 alter table only parent alter a set not null;
-ERROR:  column "a" of relation "parent" contains null values
+ERROR:  cannot add constraint to table with inheritance children
+HINT:  Do not specify the ONLY keyword.
 alter table child alter a set not null;
 ERROR:  column "a" of relation "child" contains null values
-delete from parent;
-alter table only parent alter a set not null;
-insert into parent values (NULL);
-ERROR:  null value in column "a" of relation "parent" violates not-null constraint
-DETAIL:  Failing row contains (null).
-alter table child alter a set not null;
-insert into child (a, b) values (NULL, 'foo');
-ERROR:  null value in column "a" of relation "child" violates not-null constraint
-DETAIL:  Failing row contains (null, foo).
-delete from child;
-alter table child alter a set not null;
-insert into child (a, b) values (NULL, 'foo');
-ERROR:  null value in column "a" of relation "child" violates not-null constraint
-DETAIL:  Failing row contains (null, foo).
 drop table child;
 drop table parent;
 -- test setting and removing default values
@@ -3834,6 +3825,28 @@ Referenced by:
     TABLE "ataddindex" CONSTRAINT "ataddindex_ref_id_fkey" FOREIGN KEY (ref_id) REFERENCES ataddindex(id)
 
 DROP TABLE ataddindex;
+CREATE TABLE atnotnull1 ();
+ALTER TABLE atnotnull1
+  ADD COLUMN a INT,
+  ALTER a SET NOT NULL;
+ALTER TABLE atnotnull1
+  ADD COLUMN b INT,
+  ADD NOT NULL b;
+ALTER TABLE atnotnull1
+  ADD COLUMN c INT,
+  ADD PRIMARY KEY (c);
+SELECT conrelid::regclass, conname, contype, conkey,
+ (SELECT attname FROM pg_attribute WHERE attrelid = conrelid AND attnum = conkey[1]),
+ coninhcount, conislocal
+ FROM pg_constraint WHERE contype IN ('n','p') AND
+ conrelid IN ('atnotnull1'::regclass);
+  conrelid  |        conname        | contype | conkey | attname | coninhcount | conislocal 
+------------+-----------------------+---------+--------+---------+-------------+------------
+ atnotnull1 | atnotnull1_a_not_null | n       | {1}    | a       |           0 | t
+ atnotnull1 | atnotnull1_b_not_null | n       | {2}    | b       |           0 | t
+ atnotnull1 | atnotnull1_pkey       | p       | {3}    | c       |           0 | t
+(3 rows)
+
 -- unsupported constraint types for partitioned tables
 CREATE TABLE partitioned (
 	a int,
@@ -4355,8 +4368,7 @@ ERROR:  cannot alter inherited column "b"
 -- cannot add/drop NOT NULL or check constraints to *only* the parent, when
 -- partitions exist
 ALTER TABLE ONLY list_parted2 ALTER b SET NOT NULL;
-ERROR:  constraint must be added to child tables too
-DETAIL:  Column "b" of relation "part_2" is not already NOT NULL.
+ERROR:  cannot add constraint to only the partitioned table when partitions exist
 HINT:  Do not specify the ONLY keyword.
 ALTER TABLE ONLY list_parted2 ADD CONSTRAINT check_b CHECK (b <> 'zz');
 ERROR:  constraint must be added to child tables too
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 2eec483eaa..14bc2f1cc3 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -247,11 +247,12 @@ ERROR:  insert or update on table "clstr_tst" violates foreign key constraint "c
 DETAIL:  Key (b)=(1111) is not present in table "clstr_tst_s".
 SELECT conname FROM pg_constraint WHERE conrelid = 'clstr_tst'::regclass
 ORDER BY 1;
-    conname     
-----------------
+       conname        
+----------------------
+ clstr_tst_a_not_null
  clstr_tst_con
  clstr_tst_pkey
-(2 rows)
+(3 rows)
 
 SELECT relname, relkind,
     EXISTS(SELECT 1 FROM pg_class WHERE oid = c.reltoastrelid) AS hastoast
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index e6f6602d95..014205b6bf 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -288,6 +288,28 @@ ERROR:  new row for relation "atacc1" violates check constraint "atacc1_test2_ch
 DETAIL:  Failing row contains (null, 3).
 DROP TABLE ATACC1 CASCADE;
 NOTICE:  drop cascades to table atacc2
+-- NOT NULL NO INHERIT
+CREATE TABLE ATACC1 (a int, not null a no inherit);
+CREATE TABLE ATACC2 () INHERITS (ATACC1);
+\d ATACC2
+               Table "public.atacc2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Inherits: atacc1
+
+DROP TABLE ATACC1, ATACC2;
+CREATE TABLE ATACC1 (a int);
+ALTER TABLE ATACC1 ADD NOT NULL a NO INHERIT;
+CREATE TABLE ATACC2 () INHERITS (ATACC1);
+\d ATACC2
+               Table "public.atacc2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Inherits: atacc1
+
+DROP TABLE ATACC1, ATACC2;
 --
 -- Check constraints on INSERT INTO
 --
@@ -754,6 +776,98 @@ ALTER TABLE deferred_excl ADD EXCLUDE (f1 WITH =);
 ERROR:  could not create exclusion constraint "deferred_excl_f1_excl"
 DETAIL:  Key (f1)=(3) conflicts with key (f1)=(3).
 DROP TABLE deferred_excl;
+-- verify constraints created for NOT NULL clauses
+CREATE TABLE notnull_tbl1 (a INTEGER NOT NULL);
+\d notnull_tbl1
+            Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+         conname         | contype | conkey 
+-------------------------+---------+--------
+ notnull_tbl1_a_not_null | n       | {1}
+(1 row)
+
+-- DROP NOT NULL gets rid of both the attnotnull flag and the constraint itself
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+\d notnull_tbl1
+            Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+ conname | contype | conkey 
+---------+---------+--------
+(0 rows)
+
+-- SET NOT NULL puts both back
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+\d notnull_tbl1
+            Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+         conname         | contype | conkey 
+-------------------------+---------+--------
+ notnull_tbl1_a_not_null | n       | {1}
+(1 row)
+
+-- Doing it twice doesn't create a redundant constraint
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+         conname         | contype | conkey 
+-------------------------+---------+--------
+ notnull_tbl1_a_not_null | n       | {1}
+(1 row)
+
+-- Using the "table constraint" syntax also works
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
+\d notnull_tbl1
+            Table "public.notnull_tbl1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+ conname | contype | conkey 
+---------+---------+--------
+ foobar  | n       | {1}
+(1 row)
+
+DROP TABLE notnull_tbl1;
+CREATE TABLE notnull_tbl2 (a INTEGER PRIMARY KEY);
+ALTER TABLE notnull_tbl2 ALTER a DROP NOT NULL;
+ERROR:  column "a" is in a primary key
+CREATE TABLE notnull_tbl3 (a INTEGER NOT NULL, CHECK (a IS NOT NULL));
+ALTER TABLE notnull_tbl3 ALTER A DROP NOT NULL;
+ALTER TABLE notnull_tbl3 ADD b int, ADD CONSTRAINT pk PRIMARY KEY (a, b);
+\d notnull_tbl3
+            Table "public.notnull_tbl3"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+ b      | integer |           | not null | 
+Indexes:
+    "pk" PRIMARY KEY, btree (a, b)
+Check constraints:
+    "notnull_tbl3_a_check" CHECK (a IS NOT NULL)
+
+ALTER TABLE notnull_tbl3 DROP CONSTRAINT pk;
+\d notnull_tbl3
+            Table "public.notnull_tbl3"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+Check constraints:
+    "notnull_tbl3_a_check" CHECK (a IS NOT NULL)
+
 -- Comments
 -- Setup a low-level role to enforce non-superuser checks.
 CREATE ROLE regress_constraint_comments;
diff --git a/src/test/regress/expected/create_table.out b/src/test/regress/expected/create_table.out
index 5eace915a7..32102204a1 100644
--- a/src/test/regress/expected/create_table.out
+++ b/src/test/regress/expected/create_table.out
@@ -766,22 +766,24 @@ CREATE TABLE part_b PARTITION OF parted (
 ) FOR VALUES IN ('b');
 NOTICE:  merging constraint "check_a" with inherited definition
 -- conislocal should be false for any merged constraints, true otherwise
-SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY conislocal, coninhcount;
- conislocal | coninhcount 
-------------+-------------
- f          |           1
- t          |           0
-(2 rows)
+SELECT conname, conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY coninhcount DESC, conname;
+      conname      | conislocal | coninhcount 
+-------------------+------------+-------------
+ check_a           | f          |           1
+ part_b_b_not_null | t          |           1
+ check_b           | t          |           0
+(3 rows)
 
 -- Once check_b is added to the parent, it should be made non-local for part_b
 ALTER TABLE parted ADD CONSTRAINT check_b CHECK (b >= 0);
 NOTICE:  merging constraint "check_b" with inherited definition
-SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass;
+SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY coninhcount DESC, conname;
  conislocal | coninhcount 
 ------------+-------------
  f          |           1
  f          |           1
-(2 rows)
+ t          |           1
+(3 rows)
 
 -- Neither check_a nor check_b are droppable from part_b
 ALTER TABLE part_b DROP CONSTRAINT check_a;
@@ -792,10 +794,11 @@ ERROR:  cannot drop inherited constraint "check_b" of relation "part_b"
 -- traditional inheritance where they will be left behind, because they would
 -- be local constraints.
 ALTER TABLE parted DROP CONSTRAINT check_a, DROP CONSTRAINT check_b;
-SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass;
- conislocal | coninhcount 
-------------+-------------
-(0 rows)
+SELECT conname, conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY coninhcount;
+      conname      | conislocal | coninhcount 
+-------------------+------------+-------------
+ part_b_b_not_null | t          |           1
+(1 row)
 
 -- specify PARTITION BY for a partition
 CREATE TABLE fail_part_col_not_found PARTITION OF parted FOR VALUES IN ('c') PARTITION BY RANGE (c);
diff --git a/src/test/regress/expected/event_trigger.out b/src/test/regress/expected/event_trigger.out
index 5a10958df5..2c8a6b2212 100644
--- a/src/test/regress/expected/event_trigger.out
+++ b/src/test/regress/expected/event_trigger.out
@@ -408,6 +408,7 @@ NOTICE:  END: command_tag=CREATE SCHEMA type=schema identity=evttrig
 NOTICE:  END: command_tag=CREATE SEQUENCE type=sequence identity=evttrig.one_col_a_seq
 NOTICE:  END: command_tag=CREATE SEQUENCE type=sequence identity=evttrig.one_col_c_seq
 NOTICE:  END: command_tag=CREATE TABLE type=table identity=evttrig.one
+NOTICE:  END: command_tag=ALTER TABLE type=table identity=evttrig.one
 NOTICE:  END: command_tag=CREATE INDEX type=index identity=evttrig.one_pkey
 NOTICE:  END: command_tag=ALTER SEQUENCE type=sequence identity=evttrig.one_col_a_seq
 NOTICE:  END: command_tag=ALTER SEQUENCE type=sequence identity=evttrig.one_col_c_seq
@@ -422,6 +423,7 @@ CREATE TABLE evttrig.parted (
     id int PRIMARY KEY)
     PARTITION BY RANGE (id);
 NOTICE:  END: command_tag=CREATE TABLE type=table identity=evttrig.parted
+NOTICE:  END: command_tag=ALTER TABLE type=table identity=evttrig.parted
 NOTICE:  END: command_tag=CREATE INDEX type=index identity=evttrig.parted_pkey
 CREATE TABLE evttrig.part_1_10 PARTITION OF evttrig.parted (id)
   FOR VALUES FROM (1) TO (10);
diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out
index 5b30ee49f3..e90f4f846b 100644
--- a/src/test/regress/expected/foreign_data.out
+++ b/src/test/regress/expected/foreign_data.out
@@ -1652,11 +1652,12 @@ SELECT relname, conname, contype, conislocal, coninhcount, connoinherit
   FROM pg_class AS pc JOIN pg_constraint AS pgc ON (conrelid = pc.oid)
   WHERE pc.relname = 'fd_pt1'
   ORDER BY 1,2;
- relname |  conname   | contype | conislocal | coninhcount | connoinherit 
----------+------------+---------+------------+-------------+--------------
- fd_pt1  | fd_pt1chk1 | c       | t          |           0 | t
- fd_pt1  | fd_pt1chk2 | c       | t          |           0 | f
-(2 rows)
+ relname |      conname       | contype | conislocal | coninhcount | connoinherit 
+---------+--------------------+---------+------------+-------------+--------------
+ fd_pt1  | fd_pt1_c1_not_null | n       | t          |           0 | f
+ fd_pt1  | fd_pt1chk1         | c       | t          |           0 | t
+ fd_pt1  | fd_pt1chk2         | c       | t          |           0 | f
+(3 rows)
 
 -- child does not inherit NO INHERIT constraints
 \d+ fd_pt1
diff --git a/src/test/regress/expected/foreign_key.out b/src/test/regress/expected/foreign_key.out
index 55f7158c1a..a601f33268 100644
--- a/src/test/regress/expected/foreign_key.out
+++ b/src/test/regress/expected/foreign_key.out
@@ -2036,13 +2036,19 @@ ORDER BY co.contype, cr.relname, co.conname, p.conname;
  part33_self_fk | parted_self_fk_id_abc_fkey | f       | t            | parted_self_fk_id_abc_fkey | t            | parted_self_fk
  part3_self_fk  | parted_self_fk_id_abc_fkey | f       | t            | parted_self_fk_id_abc_fkey | t            | parted_self_fk
  parted_self_fk | parted_self_fk_id_abc_fkey | f       | t            |                            |              | parted_self_fk
+ part1_self_fk  | part1_self_fk_id_not_null  | n       | t            |                            |              | 
+ part2_self_fk  | parted_self_fk_id_not_null | n       | t            |                            |              | 
+ part32_self_fk | part3_self_fk_id_not_null  | n       | t            |                            |              | 
+ part33_self_fk | part33_self_fk_id_not_null | n       | t            |                            |              | 
+ part3_self_fk  | part3_self_fk_id_not_null  | n       | t            |                            |              | 
+ parted_self_fk | parted_self_fk_id_not_null | n       | t            |                            |              | 
  part1_self_fk  | part1_self_fk_pkey         | p       | t            | parted_self_fk_pkey        | t            | 
  part2_self_fk  | part2_self_fk_pkey         | p       | t            | parted_self_fk_pkey        | t            | 
  part32_self_fk | part32_self_fk_pkey        | p       | t            | part3_self_fk_pkey         | t            | 
  part33_self_fk | part33_self_fk_pkey        | p       | t            | part3_self_fk_pkey         | t            | 
  part3_self_fk  | part3_self_fk_pkey         | p       | t            | parted_self_fk_pkey        | t            | 
  parted_self_fk | parted_self_fk_pkey        | p       | t            |                            |              | 
-(12 rows)
+(18 rows)
 
 -- detach and re-attach multiple times just to ensure everything is kosher
 ALTER TABLE parted_self_fk DETACH PARTITION part2_self_fk;
@@ -2065,13 +2071,19 @@ ORDER BY co.contype, cr.relname, co.conname, p.conname;
  part33_self_fk | parted_self_fk_id_abc_fkey | f       | t            | parted_self_fk_id_abc_fkey | t            | parted_self_fk
  part3_self_fk  | parted_self_fk_id_abc_fkey | f       | t            | parted_self_fk_id_abc_fkey | t            | parted_self_fk
  parted_self_fk | parted_self_fk_id_abc_fkey | f       | t            |                            |              | parted_self_fk
+ part1_self_fk  | part1_self_fk_id_not_null  | n       | t            |                            |              | 
+ part2_self_fk  | parted_self_fk_id_not_null | n       | t            |                            |              | 
+ part32_self_fk | part3_self_fk_id_not_null  | n       | t            |                            |              | 
+ part33_self_fk | part33_self_fk_id_not_null | n       | t            |                            |              | 
+ part3_self_fk  | part3_self_fk_id_not_null  | n       | t            |                            |              | 
+ parted_self_fk | parted_self_fk_id_not_null | n       | t            |                            |              | 
  part1_self_fk  | part1_self_fk_pkey         | p       | t            | parted_self_fk_pkey        | t            | 
  part2_self_fk  | part2_self_fk_pkey         | p       | t            | parted_self_fk_pkey        | t            | 
  part32_self_fk | part32_self_fk_pkey        | p       | t            | part3_self_fk_pkey         | t            | 
  part33_self_fk | part33_self_fk_pkey        | p       | t            | part3_self_fk_pkey         | t            | 
  part3_self_fk  | part3_self_fk_pkey         | p       | t            | parted_self_fk_pkey        | t            | 
  parted_self_fk | parted_self_fk_pkey        | p       | t            |                            |              | 
-(12 rows)
+(18 rows)
 
 -- Leave this table around, for pg_upgrade/pg_dump tests
 -- Test creating a constraint at the parent that already exists in partitions.
diff --git a/src/test/regress/expected/indexing.out b/src/test/regress/expected/indexing.out
index 1bdd430f06..5351a87425 100644
--- a/src/test/regress/expected/indexing.out
+++ b/src/test/regress/expected/indexing.out
@@ -1065,16 +1065,18 @@ create table idxpart3 (b int not null, a int not null);
 alter table idxpart attach partition idxpart3 for values from (20, 20) to (30, 30);
 select conname, contype, conrelid::regclass, conindid::regclass, conkey
   from pg_constraint where conrelid::regclass::text like 'idxpart%'
-  order by conname;
-    conname     | contype | conrelid  |    conindid    | conkey 
-----------------+---------+-----------+----------------+--------
- idxpart1_pkey  | p       | idxpart1  | idxpart1_pkey  | {1,2}
- idxpart21_pkey | p       | idxpart21 | idxpart21_pkey | {1,2}
- idxpart22_pkey | p       | idxpart22 | idxpart22_pkey | {1,2}
- idxpart2_pkey  | p       | idxpart2  | idxpart2_pkey  | {1,2}
- idxpart3_pkey  | p       | idxpart3  | idxpart3_pkey  | {2,1}
- idxpart_pkey   | p       | idxpart   | idxpart_pkey   | {1,2}
-(6 rows)
+  order by conrelid::regclass::text, conname;
+       conname       | contype | conrelid  |    conindid    | conkey 
+---------------------+---------+-----------+----------------+--------
+ idxpart_pkey        | p       | idxpart   | idxpart_pkey   | {1,2}
+ idxpart1_pkey       | p       | idxpart1  | idxpart1_pkey  | {1,2}
+ idxpart2_pkey       | p       | idxpart2  | idxpart2_pkey  | {1,2}
+ idxpart21_pkey      | p       | idxpart21 | idxpart21_pkey | {1,2}
+ idxpart22_pkey      | p       | idxpart22 | idxpart22_pkey | {1,2}
+ idxpart3_a_not_null | n       | idxpart3  | -              | {2}
+ idxpart3_b_not_null | n       | idxpart3  | -              | {1}
+ idxpart3_pkey       | p       | idxpart3  | idxpart3_pkey  | {2,1}
+(8 rows)
 
 drop table idxpart;
 -- Verify that multi-layer partitioning honors the requirement that all
@@ -1207,12 +1209,21 @@ create table idxpart (a int) partition by range (a);
 create table idxpart0 (like idxpart);
 alter table idxpart0 add unique (a);
 alter table idxpart attach partition idxpart0 default;
-alter table only idxpart add primary key (a);  -- fail, no NOT NULL constraint
-ERROR:  constraint must be added to child tables too
-DETAIL:  Column "a" of relation "idxpart0" is not already NOT NULL.
-HINT:  Do not specify the ONLY keyword.
+alter table only idxpart add primary key (a);  -- works, but idxpart0.a is nullable
+\d idxpart0
+              Table "public.idxpart0"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: idxpart DEFAULT
+Indexes:
+    "idxpart0_a_key" UNIQUE CONSTRAINT, btree (a)
+
+alter index idxpart_pkey attach partition idxpart0_a_key; -- fails, lacks NOT NULL
+ERROR:  invalid primary key definition
+DETAIL:  Column "a" of relation "idxpart0" is not marked NOT NULL.
 alter table idxpart0 alter column a set not null;
-alter table only idxpart add primary key (a);  -- now it works
+alter index idxpart_pkey attach partition idxpart0_a_key;
 alter table idxpart0 alter column a drop not null;  -- fail, pkey needs it
 ERROR:  column "a" is marked NOT NULL in parent table
 drop table idxpart;
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index a7fbeed9eb..8fcec04cb5 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -1847,6 +1847,403 @@ select * from cnullparent where f1 = 2;
 drop table cnullparent cascade;
 NOTICE:  drop cascades to table cnullchild
 --
+-- Test inheritance of NOT NULL constraints
+--
+create table pp1 (f1 int);
+create table cc1 (f2 text, f3 int) inherits (pp1);
+\d cc1
+                Table "public.cc1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           |          | 
+ f2     | text    |           |          | 
+ f3     | integer |           |          | 
+Inherits: pp1
+
+create table cc2(f4 float) inherits(pp1,cc1);
+NOTICE:  merging multiple inherited definitions of column "f1"
+\d cc2
+                     Table "public.cc2"
+ Column |       Type       | Collation | Nullable | Default 
+--------+------------------+-----------+----------+---------
+ f1     | integer          |           |          | 
+ f2     | text             |           |          | 
+ f3     | integer          |           |          | 
+ f4     | double precision |           |          | 
+Inherits: pp1,
+          cc1
+
+-- named NOT NULL constraint
+alter table cc1 add column a2 int constraint nn not null;
+\d cc1
+                Table "public.cc1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           |          | 
+ f2     | text    |           |          | 
+ f3     | integer |           |          | 
+ a2     | integer |           | not null | 
+Inherits: pp1
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d cc2
+                     Table "public.cc2"
+ Column |       Type       | Collation | Nullable | Default 
+--------+------------------+-----------+----------+---------
+ f1     | integer          |           |          | 
+ f2     | text             |           |          | 
+ f3     | integer          |           |          | 
+ f4     | double precision |           |          | 
+ a2     | integer          |           | not null | 
+Inherits: pp1,
+          cc1
+
+alter table pp1 alter column f1 set not null;
+\d pp1
+                Table "public.pp1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+Number of child tables: 2 (Use \d+ to list them.)
+
+\d cc1
+                Table "public.cc1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+ f2     | text    |           |          | 
+ f3     | integer |           |          | 
+ a2     | integer |           | not null | 
+Inherits: pp1
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d cc2
+                     Table "public.cc2"
+ Column |       Type       | Collation | Nullable | Default 
+--------+------------------+-----------+----------+---------
+ f1     | integer          |           | not null | 
+ f2     | text             |           |          | 
+ f3     | integer          |           |          | 
+ f4     | double precision |           |          | 
+ a2     | integer          |           | not null | 
+Inherits: pp1,
+          cc1
+
+-- have a look at pg_constraint
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('pp1'::regclass, 'cc1'::regclass, 'cc2'::regclass)
+ order by 2, 1;
+ conrelid |     conname     | contype | conkey | attname | coninhcount | conislocal 
+----------+-----------------+---------+--------+---------+-------------+------------
+ cc1      | nn              | n       | {4}    | a2      |           0 | t
+ cc2      | nn              | n       | {5}    | a2      |           1 | f
+ pp1      | pp1_f1_not_null | n       | {1}    | f1      |           0 | t
+ cc1      | pp1_f1_not_null | n       | {1}    | f1      |           1 | f
+ cc2      | pp1_f1_not_null | n       | {1}    | f1      |           1 | f
+(5 rows)
+
+-- remove constraint from cc2: no dice, it's inherited
+alter table cc2 alter column a2 drop not null;
+ERROR:  cannot drop inherited constraint "nn" of relation "cc2"
+-- remove constraint cc1, should succeed
+alter table cc1 alter column a2 drop not null;
+-- have a look at pg_constraint
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('pp1'::regclass, 'cc1'::regclass, 'cc2'::regclass)
+ order by 2, 1;
+ conrelid |     conname     | contype | conkey | attname | coninhcount | conislocal 
+----------+-----------------+---------+--------+---------+-------------+------------
+ pp1      | pp1_f1_not_null | n       | {1}    | f1      |           0 | t
+ cc1      | pp1_f1_not_null | n       | {1}    | f1      |           1 | f
+ cc2      | pp1_f1_not_null | n       | {1}    | f1      |           1 | f
+(3 rows)
+
+-- same for cc2
+alter table cc2 alter column f1 drop not null;
+ERROR:  cannot drop inherited constraint "pp1_f1_not_null" of relation "cc2"
+-- remove from cc1, should fail again
+alter table cc1 alter column f1 drop not null;
+ERROR:  cannot drop inherited constraint "pp1_f1_not_null" of relation "cc1"
+-- remove from pp1, should succeed
+alter table pp1 alter column f1 drop not null;
+-- have a look at pg_constraint
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('pp1'::regclass, 'cc1'::regclass, 'cc2'::regclass)
+ order by 2, 1;
+ conrelid | conname | contype | conkey | attname | coninhcount | conislocal 
+----------+---------+---------+--------+---------+-------------+------------
+(0 rows)
+
+drop table pp1 cascade;
+NOTICE:  drop cascades to 2 other objects
+DETAIL:  drop cascades to table cc1
+drop cascades to table cc2
+\d cc1
+\d cc2
+-- test "dropping" a not null constraint that's also inherited
+create table inh_parent (a int not null);
+create table inh_child (a int not null) inherits (inh_parent);
+NOTICE:  merging column "a" with inherited definition
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype in ('n','p') and
+ conrelid in ('inh_child'::regclass, 'inh_parent'::regclass);
+  conrelid  |        conname        | contype | conkey | attname | coninhcount | conislocal | connoinherit 
+------------+-----------------------+---------+--------+---------+-------------+------------+--------------
+ inh_parent | inh_parent_a_not_null | n       | {1}    | a       |           0 | t          | f
+ inh_child  | inh_child_a_not_null  | n       | {1}    | a       |           1 | t          | f
+(2 rows)
+
+alter table inh_child alter a drop not null;
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype in ('n','p') and
+ conrelid in ('inh_child'::regclass, 'inh_parent'::regclass);
+  conrelid  |        conname        | contype | conkey | attname | coninhcount | conislocal | connoinherit 
+------------+-----------------------+---------+--------+---------+-------------+------------+--------------
+ inh_parent | inh_parent_a_not_null | n       | {1}    | a       |           0 | t          | f
+ inh_child  | inh_child_a_not_null  | n       | {1}    | a       |           1 | f          | f
+(2 rows)
+
+alter table inh_parent alter a drop not null;
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype in ('n','p') and
+ conrelid in ('inh_child'::regclass, 'inh_parent'::regclass);
+ conrelid | conname | contype | conkey | attname | coninhcount | conislocal | connoinherit 
+----------+---------+---------+--------+---------+-------------+------------+--------------
+(0 rows)
+
+drop table inh_parent, inh_child;
+-- NOT NULL NO INHERIT
+create table inh_parent(a int);
+create table inh_child() inherits (inh_parent);
+alter table inh_parent add not null a no inherit;
+create table inh_child2() inherits (inh_parent);
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_child2'::regclass)
+ order by 2, 1;
+  conrelid  |        conname        | contype | conkey | attname | coninhcount | conislocal | connoinherit 
+------------+-----------------------+---------+--------+---------+-------------+------------+--------------
+ inh_parent | inh_parent_a_not_null | n       | {1}    | a       |           0 | t          | t
+(1 row)
+
+\d inh_parent
+             Table "public.inh_parent"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+Number of child tables: 2 (Use \d+ to list them.)
+
+\d inh_child
+             Table "public.inh_child"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Inherits: inh_parent
+
+\d inh_child2
+             Table "public.inh_child2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Inherits: inh_parent
+
+drop table inh_parent, inh_child, inh_child2;
+--
+-- test inherit/deinherit
+--
+create table inh_parent(f1 int);
+create table inh_child1(f1 int not null);
+create table inh_child2(f1 int);
+-- inh_child1 should have not null constraint
+alter table inh_child1 inherit inh_parent;
+-- should fail, missing NOT NULL constraint
+alter table inh_child2 inherit inh_child1;
+ERROR:  column "f1" in child table must be marked NOT NULL
+alter table inh_child2 alter column f1 set not null;
+alter table inh_child2 inherit inh_child1;
+-- add NOT NULL constraint recursively
+alter table inh_parent alter column f1 set not null;
+\d inh_parent
+             Table "public.inh_parent"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d inh_child1
+             Table "public.inh_child1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+Inherits: inh_parent
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d inh_child2
+             Table "public.inh_child2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+Inherits: inh_child1
+
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'inh_child1'::regclass, 'inh_child2'::regclass)
+ order by 2, 1;
+  conrelid  |        conname         | contype | coninhcount | conislocal 
+------------+------------------------+---------+-------------+------------
+ inh_child1 | inh_child1_f1_not_null | n       |           1 | t
+ inh_child2 | inh_child2_f1_not_null | n       |           1 | t
+ inh_parent | inh_parent_f1_not_null | n       |           0 | t
+(3 rows)
+
+--
+-- test deinherit procedure
+--
+-- deinherit inh_child1
+alter table inh_child1 no inherit inh_parent;
+\d inh_parent
+             Table "public.inh_parent"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+
+\d inh_child1
+             Table "public.inh_child1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d inh_child2
+             Table "public.inh_child2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ f1     | integer |           | not null | 
+Inherits: inh_child1
+
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'inh_child1'::regclass, 'inh_child2'::regclass)
+ order by 2, 1;
+  conrelid  |        conname         | contype | coninhcount | conislocal 
+------------+------------------------+---------+-------------+------------
+ inh_child1 | inh_child1_f1_not_null | n       |           0 | t
+ inh_child2 | inh_child2_f1_not_null | n       |           1 | t
+ inh_parent | inh_parent_f1_not_null | n       |           0 | t
+(3 rows)
+
+-- test inhcount of inh_child2, should fail
+alter table inh_child2 alter f1 drop not null;
+-- should succeed
+drop table inh_parent;
+drop table inh_child1 cascade;
+NOTICE:  drop cascades to table inh_child2
+--
+-- test multi inheritance tree
+--
+create table inh_parent(f1 int not null);
+create table c1() inherits(inh_parent);
+create table c2() inherits(inh_parent);
+create table d1() inherits(c1, c2);
+NOTICE:  merging multiple inherited definitions of column "f1"
+-- show constraint info
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'c1'::regclass, 'c2'::regclass, 'd1'::regclass)
+ order by 2, 1;
+  conrelid  |        conname         | contype | coninhcount | conislocal 
+------------+------------------------+---------+-------------+------------
+ inh_parent | inh_parent_f1_not_null | n       |           0 | t
+ c1         | inh_parent_f1_not_null | n       |           1 | f
+ c2         | inh_parent_f1_not_null | n       |           1 | f
+ d1         | inh_parent_f1_not_null | n       |           1 | f
+(4 rows)
+
+drop table inh_parent cascade;
+NOTICE:  drop cascades to 3 other objects
+DETAIL:  drop cascades to table c1
+drop cascades to table c2
+drop cascades to table d1
+-- test child table with inherited columns and
+-- with explicitly specified not null constraints
+create table inh_parent_1(f1 int);
+create table inh_parent_2(f2 text);
+create table child(f1 int not null, f2 text not null) inherits(inh_parent_1, inh_parent_2);
+NOTICE:  merging column "f1" with inherited definition
+NOTICE:  merging column "f2" with inherited definition
+-- show constraint info
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent_1'::regclass, 'inh_parent_2'::regclass, 'child'::regclass)
+ order by 2, 1;
+ conrelid |      conname      | contype | coninhcount | conislocal 
+----------+-------------------+---------+-------------+------------
+ child    | child_f1_not_null | n       |           0 | t
+ child    | child_f2_not_null | n       |           0 | t
+(2 rows)
+
+-- also drops child table
+drop table inh_parent_1 cascade;
+NOTICE:  drop cascades to table child
+drop table inh_parent_2;
+-- test multi layer inheritance tree
+create table inh_p1(f1 int not null);
+create table inh_p2(f1 int not null);
+create table inh_p3(f2 int);
+create table inh_p4(f1 int not null, f3 text not null);
+create table c() inherits(inh_p1, inh_p2, inh_p3, inh_p4);
+NOTICE:  merging multiple inherited definitions of column "f1"
+NOTICE:  merging multiple inherited definitions of column "f1"
+ERROR:  relation "c" already exists
+-- constraint on f1 should have three parents
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_p1'::regclass, 'inh_p2'::regclass, 'inh_p3'::regclass, 'inh_p4'::regclass, 'c'::regclass)
+ order by 2, 1;
+ conrelid |      conname       | contype | coninhcount | conislocal 
+----------+--------------------+---------+-------------+------------
+ inh_p1   | inh_p1_f1_not_null | n       |           0 | t
+ inh_p2   | inh_p2_f1_not_null | n       |           0 | t
+ inh_p4   | inh_p4_f1_not_null | n       |           0 | t
+ inh_p4   | inh_p4_f3_not_null | n       |           0 | t
+(4 rows)
+
+create table d(a int not null, f1 int) inherits(inh_p3, c);
+ERROR:  relation "d" already exists
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_p1'::regclass, 'inh_p2'::regclass, 'inh_p3'::regclass, 'inh_p4'::regclass, 'c'::regclass, 'd'::regclass)
+ order by 2, 1;
+ conrelid |      conname       | contype | coninhcount | conislocal 
+----------+--------------------+---------+-------------+------------
+ inh_p1   | inh_p1_f1_not_null | n       |           0 | t
+ inh_p2   | inh_p2_f1_not_null | n       |           0 | t
+ inh_p4   | inh_p4_f1_not_null | n       |           0 | t
+ inh_p4   | inh_p4_f3_not_null | n       |           0 | t
+(4 rows)
+
+drop table inh_p1 cascade;
+drop table inh_p2;
+drop table inh_p3;
+drop table inh_p4;
+--
 -- Check use of temporary tables with inheritance trees
 --
 create table inh_perm_parent (a1 int);
diff --git a/src/test/regress/expected/replica_identity.out b/src/test/regress/expected/replica_identity.out
index 7d798ef2a5..9571840d25 100644
--- a/src/test/regress/expected/replica_identity.out
+++ b/src/test/regress/expected/replica_identity.out
@@ -263,8 +263,21 @@ Indexes:
     "test_replica_identity4_pkey" PRIMARY KEY, btree (id) REPLICA IDENTITY
 Partitions: test_replica_identity4_1 FOR VALUES IN (1)
 
+-- Dropping the primary key is not allowed if that would leave the replica
+-- identity as nullable
+CREATE TABLE test_replica_identity5 (a int not null, b int, c int,
+	PRIMARY KEY (b, c));
+CREATE UNIQUE INDEX test_replica_identity5_a_b_key ON test_replica_identity5 (a, b);
+ALTER TABLE test_replica_identity5 REPLICA IDENTITY USING INDEX test_replica_identity5_a_b_key;
+ALTER TABLE test_replica_identity5 DROP CONSTRAINT test_replica_identity5_pkey;
+ERROR:  column "b" is in index used as replica identity
+ALTER TABLE test_replica_identity5 ALTER b SET NOT NULL;
+ALTER TABLE test_replica_identity5 DROP CONSTRAINT test_replica_identity5_pkey;
+ALTER TABLE test_replica_identity5 ALTER b DROP NOT NULL;
+ERROR:  column "b" is in index used as replica identity
 DROP TABLE test_replica_identity;
 DROP TABLE test_replica_identity2;
 DROP TABLE test_replica_identity3;
 DROP TABLE test_replica_identity4;
+DROP TABLE test_replica_identity5;
 DROP TABLE test_replica_identity_othertable;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 3624035639..bae480dabf 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,7 +121,8 @@ test: plancache limit plpgsql copy2 temp domain rangefuncs prepare conversion tr
 # ----------
 test: partition_join partition_prune reloptions hash_part indexing partition_aggregate partition_info tuplesort explain compression memoize stats
 
-# event_trigger cannot run concurrently with any test that runs DDL
+# event_trigger depends on create_am and cannot run concurrently with
+# any test that runs DDL
 # oidjoins is read-only, though, and should run late for best coverage
 test: event_trigger oidjoins
 
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 58ea20ac3d..4f7003523a 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -852,7 +852,7 @@ create table atacc1 (test int not null);
 alter table atacc1 add constraint "atacc1_pkey" primary key (test);
 alter table atacc1 alter column test drop not null;
 alter table atacc1 drop constraint "atacc1_pkey";
-alter table atacc1 alter column test drop not null;
+\d atacc1
 insert into atacc1 values (null);
 alter table atacc1 alter test set not null;
 delete from atacc1;
@@ -917,14 +917,6 @@ insert into parent values (NULL);
 insert into child (a, b) values (NULL, 'foo');
 alter table only parent alter a set not null;
 alter table child alter a set not null;
-delete from parent;
-alter table only parent alter a set not null;
-insert into parent values (NULL);
-alter table child alter a set not null;
-insert into child (a, b) values (NULL, 'foo');
-delete from child;
-alter table child alter a set not null;
-insert into child (a, b) values (NULL, 'foo');
 drop table child;
 drop table parent;
 
@@ -2342,6 +2334,22 @@ ALTER TABLE ataddindex
 \d ataddindex
 DROP TABLE ataddindex;
 
+CREATE TABLE atnotnull1 ();
+ALTER TABLE atnotnull1
+  ADD COLUMN a INT,
+  ALTER a SET NOT NULL;
+ALTER TABLE atnotnull1
+  ADD COLUMN b INT,
+  ADD NOT NULL b;
+ALTER TABLE atnotnull1
+  ADD COLUMN c INT,
+  ADD PRIMARY KEY (c);
+SELECT conrelid::regclass, conname, contype, conkey,
+ (SELECT attname FROM pg_attribute WHERE attrelid = conrelid AND attnum = conkey[1]),
+ coninhcount, conislocal
+ FROM pg_constraint WHERE contype IN ('n','p') AND
+ conrelid IN ('atnotnull1'::regclass);
+
 -- unsupported constraint types for partitioned tables
 CREATE TABLE partitioned (
 	a int,
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 5ffcd4ffc7..5a3c904660 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -196,6 +196,17 @@ INSERT INTO ATACC2 (TEST2) VALUES (3);
 INSERT INTO ATACC1 (TEST2) VALUES (3);
 DROP TABLE ATACC1 CASCADE;
 
+-- NOT NULL NO INHERIT
+CREATE TABLE ATACC1 (a int, not null a no inherit);
+CREATE TABLE ATACC2 () INHERITS (ATACC1);
+\d ATACC2
+DROP TABLE ATACC1, ATACC2;
+CREATE TABLE ATACC1 (a int);
+ALTER TABLE ATACC1 ADD NOT NULL a NO INHERIT;
+CREATE TABLE ATACC2 () INHERITS (ATACC1);
+\d ATACC2
+DROP TABLE ATACC1, ATACC2;
+
 --
 -- Check constraints on INSERT INTO
 --
@@ -556,6 +567,38 @@ ALTER TABLE deferred_excl ADD EXCLUDE (f1 WITH =);
 
 DROP TABLE deferred_excl;
 
+-- verify constraints created for NOT NULL clauses
+CREATE TABLE notnull_tbl1 (a INTEGER NOT NULL);
+\d notnull_tbl1
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+-- DROP NOT NULL gets rid of both the attnotnull flag and the constraint itself
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+\d notnull_tbl1
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+-- SET NOT NULL puts both back
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+\d notnull_tbl1
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+-- Doing it twice doesn't create a redundant constraint
+ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+-- Using the "table constraint" syntax also works
+ALTER TABLE notnull_tbl1 ALTER a DROP NOT NULL;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT foobar NOT NULL a;
+\d notnull_tbl1
+select conname, contype, conkey from pg_constraint where conrelid = 'notnull_tbl1'::regclass;
+DROP TABLE notnull_tbl1;
+
+CREATE TABLE notnull_tbl2 (a INTEGER PRIMARY KEY);
+ALTER TABLE notnull_tbl2 ALTER a DROP NOT NULL;
+
+CREATE TABLE notnull_tbl3 (a INTEGER NOT NULL, CHECK (a IS NOT NULL));
+ALTER TABLE notnull_tbl3 ALTER A DROP NOT NULL;
+ALTER TABLE notnull_tbl3 ADD b int, ADD CONSTRAINT pk PRIMARY KEY (a, b);
+\d notnull_tbl3
+ALTER TABLE notnull_tbl3 DROP CONSTRAINT pk;
+\d notnull_tbl3
+
 -- Comments
 -- Setup a low-level role to enforce non-superuser checks.
 CREATE ROLE regress_constraint_comments;
diff --git a/src/test/regress/sql/create_table.sql b/src/test/regress/sql/create_table.sql
index 93ccf77d4a..18f92b73da 100644
--- a/src/test/regress/sql/create_table.sql
+++ b/src/test/regress/sql/create_table.sql
@@ -532,11 +532,11 @@ CREATE TABLE part_b PARTITION OF parted (
 	CONSTRAINT check_b CHECK (b >= 0)
 ) FOR VALUES IN ('b');
 -- conislocal should be false for any merged constraints, true otherwise
-SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY conislocal, coninhcount;
+SELECT conname, conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY coninhcount DESC, conname;
 
 -- Once check_b is added to the parent, it should be made non-local for part_b
 ALTER TABLE parted ADD CONSTRAINT check_b CHECK (b >= 0);
-SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass;
+SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY coninhcount DESC, conname;
 
 -- Neither check_a nor check_b are droppable from part_b
 ALTER TABLE part_b DROP CONSTRAINT check_a;
@@ -546,7 +546,7 @@ ALTER TABLE part_b DROP CONSTRAINT check_b;
 -- traditional inheritance where they will be left behind, because they would
 -- be local constraints.
 ALTER TABLE parted DROP CONSTRAINT check_a, DROP CONSTRAINT check_b;
-SELECT conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass;
+SELECT conname, conislocal, coninhcount FROM pg_constraint WHERE conrelid = 'part_b'::regclass ORDER BY coninhcount;
 
 -- specify PARTITION BY for a partition
 CREATE TABLE fail_part_col_not_found PARTITION OF parted FOR VALUES IN ('c') PARTITION BY RANGE (c);
diff --git a/src/test/regress/sql/indexing.sql b/src/test/regress/sql/indexing.sql
index 429120e710..e60f3fb932 100644
--- a/src/test/regress/sql/indexing.sql
+++ b/src/test/regress/sql/indexing.sql
@@ -522,7 +522,7 @@ create table idxpart3 (b int not null, a int not null);
 alter table idxpart attach partition idxpart3 for values from (20, 20) to (30, 30);
 select conname, contype, conrelid::regclass, conindid::regclass, conkey
   from pg_constraint where conrelid::regclass::text like 'idxpart%'
-  order by conname;
+  order by conrelid::regclass::text, conname;
 drop table idxpart;
 
 -- Verify that multi-layer partitioning honors the requirement that all
@@ -620,9 +620,11 @@ create table idxpart (a int) partition by range (a);
 create table idxpart0 (like idxpart);
 alter table idxpart0 add unique (a);
 alter table idxpart attach partition idxpart0 default;
-alter table only idxpart add primary key (a);  -- fail, no NOT NULL constraint
+alter table only idxpart add primary key (a);  -- works, but idxpart0.a is nullable
+\d idxpart0
+alter index idxpart_pkey attach partition idxpart0_a_key; -- fails, lacks NOT NULL
 alter table idxpart0 alter column a set not null;
-alter table only idxpart add primary key (a);  -- now it works
+alter index idxpart_pkey attach partition idxpart0_a_key;
 alter table idxpart0 alter column a drop not null;  -- fail, pkey needs it
 drop table idxpart;
 
diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
index 215d58e80d..9cb897e1b4 100644
--- a/src/test/regress/sql/inherit.sql
+++ b/src/test/regress/sql/inherit.sql
@@ -679,6 +679,213 @@ select * from cnullparent;
 select * from cnullparent where f1 = 2;
 drop table cnullparent cascade;
 
+--
+-- Test inheritance of NOT NULL constraints
+--
+create table pp1 (f1 int);
+create table cc1 (f2 text, f3 int) inherits (pp1);
+\d cc1
+create table cc2(f4 float) inherits(pp1,cc1);
+\d cc2
+
+-- named NOT NULL constraint
+alter table cc1 add column a2 int constraint nn not null;
+\d cc1
+\d cc2
+alter table pp1 alter column f1 set not null;
+\d pp1
+\d cc1
+\d cc2
+
+-- have a look at pg_constraint
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('pp1'::regclass, 'cc1'::regclass, 'cc2'::regclass)
+ order by 2, 1;
+
+-- remove constraint from cc2: no dice, it's inherited
+alter table cc2 alter column a2 drop not null;
+
+-- remove constraint cc1, should succeed
+alter table cc1 alter column a2 drop not null;
+
+-- have a look at pg_constraint
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('pp1'::regclass, 'cc1'::regclass, 'cc2'::regclass)
+ order by 2, 1;
+
+-- same for cc2
+alter table cc2 alter column f1 drop not null;
+
+-- remove from cc1, should fail again
+alter table cc1 alter column f1 drop not null;
+
+-- remove from pp1, should succeed
+alter table pp1 alter column f1 drop not null;
+
+-- have a look at pg_constraint
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('pp1'::regclass, 'cc1'::regclass, 'cc2'::regclass)
+ order by 2, 1;
+
+drop table pp1 cascade;
+\d cc1
+\d cc2
+
+-- test "dropping" a not null constraint that's also inherited
+create table inh_parent (a int not null);
+create table inh_child (a int not null) inherits (inh_parent);
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype in ('n','p') and
+ conrelid in ('inh_child'::regclass, 'inh_parent'::regclass);
+alter table inh_child alter a drop not null;
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype in ('n','p') and
+ conrelid in ('inh_child'::regclass, 'inh_parent'::regclass);
+alter table inh_parent alter a drop not null;
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype in ('n','p') and
+ conrelid in ('inh_child'::regclass, 'inh_parent'::regclass);
+drop table inh_parent, inh_child;
+
+-- NOT NULL NO INHERIT
+create table inh_parent(a int);
+create table inh_child() inherits (inh_parent);
+alter table inh_parent add not null a no inherit;
+create table inh_child2() inherits (inh_parent);
+select conrelid::regclass, conname, contype, conkey,
+ (select attname from pg_attribute where attrelid = conrelid and attnum = conkey[1]),
+ coninhcount, conislocal, connoinherit
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'inh_child'::regclass, 'inh_child2'::regclass)
+ order by 2, 1;
+\d inh_parent
+\d inh_child
+\d inh_child2
+drop table inh_parent, inh_child, inh_child2;
+
+--
+-- test inherit/deinherit
+--
+create table inh_parent(f1 int);
+create table inh_child1(f1 int not null);
+create table inh_child2(f1 int);
+
+-- inh_child1 should have not null constraint
+alter table inh_child1 inherit inh_parent;
+
+-- should fail, missing NOT NULL constraint
+alter table inh_child2 inherit inh_child1;
+
+alter table inh_child2 alter column f1 set not null;
+alter table inh_child2 inherit inh_child1;
+
+-- add NOT NULL constraint recursively
+alter table inh_parent alter column f1 set not null;
+
+\d inh_parent
+\d inh_child1
+\d inh_child2
+
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'inh_child1'::regclass, 'inh_child2'::regclass)
+ order by 2, 1;
+
+--
+-- test deinherit procedure
+--
+
+-- deinherit inh_child1
+alter table inh_child1 no inherit inh_parent;
+\d inh_parent
+\d inh_child1
+\d inh_child2
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'inh_child1'::regclass, 'inh_child2'::regclass)
+ order by 2, 1;
+
+-- test inhcount of inh_child2, should fail
+alter table inh_child2 alter f1 drop not null;
+
+-- should succeed
+
+drop table inh_parent;
+drop table inh_child1 cascade;
+
+--
+-- test multi inheritance tree
+--
+create table inh_parent(f1 int not null);
+create table c1() inherits(inh_parent);
+create table c2() inherits(inh_parent);
+create table d1() inherits(c1, c2);
+
+-- show constraint info
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent'::regclass, 'c1'::regclass, 'c2'::regclass, 'd1'::regclass)
+ order by 2, 1;
+
+drop table inh_parent cascade;
+
+-- test child table with inherited columns and
+-- with explicitly specified not null constraints
+create table inh_parent_1(f1 int);
+create table inh_parent_2(f2 text);
+create table child(f1 int not null, f2 text not null) inherits(inh_parent_1, inh_parent_2);
+
+-- show constraint info
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_parent_1'::regclass, 'inh_parent_2'::regclass, 'child'::regclass)
+ order by 2, 1;
+
+-- also drops child table
+drop table inh_parent_1 cascade;
+drop table inh_parent_2;
+
+-- test multi layer inheritance tree
+create table inh_p1(f1 int not null);
+create table inh_p2(f1 int not null);
+create table inh_p3(f2 int);
+create table inh_p4(f1 int not null, f3 text not null);
+
+create table c() inherits(inh_p1, inh_p2, inh_p3, inh_p4);
+
+-- constraint on f1 should have three parents
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_p1'::regclass, 'inh_p2'::regclass, 'inh_p3'::regclass, 'inh_p4'::regclass, 'c'::regclass)
+ order by 2, 1;
+
+create table d(a int not null, f1 int) inherits(inh_p3, c);
+
+select conrelid::regclass, conname, contype, coninhcount, conislocal
+ from pg_constraint where contype = 'n' and
+ conrelid in ('inh_p1'::regclass, 'inh_p2'::regclass, 'inh_p3'::regclass, 'inh_p4'::regclass, 'c'::regclass, 'd'::regclass)
+ order by 2, 1;
+
+drop table inh_p1 cascade;
+drop table inh_p2;
+drop table inh_p3;
+drop table inh_p4;
+
 --
 -- Check use of temporary tables with inheritance trees
 --
diff --git a/src/test/regress/sql/replica_identity.sql b/src/test/regress/sql/replica_identity.sql
index 14620b7713..5748b34162 100644
--- a/src/test/regress/sql/replica_identity.sql
+++ b/src/test/regress/sql/replica_identity.sql
@@ -117,8 +117,20 @@ ALTER INDEX test_replica_identity4_pkey
   ATTACH PARTITION test_replica_identity4_1_pkey;
 \d+ test_replica_identity4
 
+-- Dropping the primary key is not allowed if that would leave the replica
+-- identity as nullable
+CREATE TABLE test_replica_identity5 (a int not null, b int, c int,
+	PRIMARY KEY (b, c));
+CREATE UNIQUE INDEX test_replica_identity5_a_b_key ON test_replica_identity5 (a, b);
+ALTER TABLE test_replica_identity5 REPLICA IDENTITY USING INDEX test_replica_identity5_a_b_key;
+ALTER TABLE test_replica_identity5 DROP CONSTRAINT test_replica_identity5_pkey;
+ALTER TABLE test_replica_identity5 ALTER b SET NOT NULL;
+ALTER TABLE test_replica_identity5 DROP CONSTRAINT test_replica_identity5_pkey;
+ALTER TABLE test_replica_identity5 ALTER b DROP NOT NULL;
+
 DROP TABLE test_replica_identity;
 DROP TABLE test_replica_identity2;
 DROP TABLE test_replica_identity3;
 DROP TABLE test_replica_identity4;
+DROP TABLE test_replica_identity5;
 DROP TABLE test_replica_identity_othertable;
-- 
2.39.2

