diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 04a3dc632a5..cd36c7c0355 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.174.2.4 2007/02/02 00:07:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.174.2.5 2008/04/24 20:18:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3138,6 +3138,11 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
 		tab->newvals = lappend(tab->newvals, newval);
 	}
 
+	/*
+	 * If the new column is NOT NULL, tell Phase 3 it needs to test that.
+	 */
+	tab->new_notnull |= colDef->is_not_null;
+
 	/*
 	 * Add needed dependency entries for the new column.
 	 */
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index b6e46393b4d..b408205aca9 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -433,6 +433,18 @@ create table atacc1 ( test int );
 alter table atacc1 add constraint atacc_test1 primary key (test1);
 ERROR:  column "test1" named in key does not exist
 drop table atacc1;
+-- adding a new column as primary key to a non-empty table.
+-- should fail unless the column has a non-null default value.
+create table atacc1 ( test int );
+insert into atacc1 (test) values (0);
+-- add a primary key column without a default (fails).
+alter table atacc1 add column test2 int primary key;
+NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "atacc1_pkey" for table "atacc1"
+ERROR:  column "test2" contains null values
+-- now add a primary key column with a default (succeeds).
+alter table atacc1 add column test2 int default 0 primary key;
+NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "atacc1_pkey" for table "atacc1"
+drop table atacc1;
 -- something a little more complicated
 create table atacc1 ( test int, test2 int);
 -- add a primary key constraint
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 8690f61dbed..cc899a8bef9 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -453,6 +453,16 @@ create table atacc1 ( test int );
 alter table atacc1 add constraint atacc_test1 primary key (test1);
 drop table atacc1;
 
+-- adding a new column as primary key to a non-empty table.
+-- should fail unless the column has a non-null default value.
+create table atacc1 ( test int );
+insert into atacc1 (test) values (0);
+-- add a primary key column without a default (fails).
+alter table atacc1 add column test2 int primary key;
+-- now add a primary key column with a default (succeeds).
+alter table atacc1 add column test2 int default 0 primary key;
+drop table atacc1;
+
 -- something a little more complicated
 create table atacc1 ( test int, test2 int);
 -- add a primary key constraint