diff --git a/src/test/isolation/expected/nowait-2.out b/src/test/isolation/expected/nowait-2.out
new file mode 100644
index 0000000000000000000000000000000000000000..6e24bbbf2682b2099bcec5d9af45a360025f29f0
--- /dev/null
+++ b/src/test/isolation/expected/nowait-2.out
@@ -0,0 +1,43 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1a s2a s2b s1b s2c
+step s1a: SELECT * FROM foo FOR SHARE NOWAIT;
+id             data           
+
+1              x              
+step s2a: SELECT * FROM foo FOR SHARE NOWAIT;
+id             data           
+
+1              x              
+step s2b: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s1b: COMMIT;
+step s2c: COMMIT;
+
+starting permutation: s2a s1a s2b s1b s2c
+step s2a: SELECT * FROM foo FOR SHARE NOWAIT;
+id             data           
+
+1              x              
+step s1a: SELECT * FROM foo FOR SHARE NOWAIT;
+id             data           
+
+1              x              
+step s2b: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s1b: COMMIT;
+step s2c: COMMIT;
+
+starting permutation: s2a s2b s1a s1b s2c
+step s2a: SELECT * FROM foo FOR SHARE NOWAIT;
+id             data           
+
+1              x              
+step s2b: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s1a: SELECT * FROM foo FOR SHARE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s1b: COMMIT;
+step s2c: COMMIT;
diff --git a/src/test/isolation/expected/nowait-3.out b/src/test/isolation/expected/nowait-3.out
new file mode 100644
index 0000000000000000000000000000000000000000..844464654a6fe394400f790165ab4465df3e5c01
--- /dev/null
+++ b/src/test/isolation/expected/nowait-3.out
@@ -0,0 +1,17 @@
+Parsed test spec with 3 sessions
+
+starting permutation: s1a s2a s3a s1b s2b s3b
+step s1a: SELECT * FROM foo FOR UPDATE;
+id             data           
+
+1              x              
+step s2a: SELECT * FROM foo FOR UPDATE; <waiting ...>
+step s3a: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s1b: COMMIT;
+step s2a: <... completed>
+id             data           
+
+1              x              
+step s2b: COMMIT;
+step s3b: COMMIT;
diff --git a/src/test/isolation/expected/nowait.out b/src/test/isolation/expected/nowait.out
new file mode 100644
index 0000000000000000000000000000000000000000..a6343b4afa17059e92f7213a2d7b396d25cc87b0
--- /dev/null
+++ b/src/test/isolation/expected/nowait.out
@@ -0,0 +1,65 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1a s1b s2a s2b
+step s1a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s1b: COMMIT;
+step s2a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s2b: COMMIT;
+
+starting permutation: s1a s2a s1b s2b
+step s1a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s2a: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s1b: COMMIT;
+step s2b: COMMIT;
+
+starting permutation: s1a s2a s2b s1b
+step s1a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s2a: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s2b: COMMIT;
+step s1b: COMMIT;
+
+starting permutation: s2a s1a s1b s2b
+step s2a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s1a: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s1b: COMMIT;
+step s2b: COMMIT;
+
+starting permutation: s2a s1a s2b s1b
+step s2a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s1a: SELECT * FROM foo FOR UPDATE NOWAIT;
+ERROR:  could not obtain lock on row in relation "foo"
+step s2b: COMMIT;
+step s1b: COMMIT;
+
+starting permutation: s2a s2b s1a s1b
+step s2a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s2b: COMMIT;
+step s1a: SELECT * FROM foo FOR UPDATE NOWAIT;
+id             data           
+
+1              x              
+step s1b: COMMIT;
diff --git a/src/test/isolation/isolation_schedule b/src/test/isolation/isolation_schedule
index 36acec1ca8e2a7a7f1045db29673696775b8f8c6..10c89ff1269d130238b0c6e8c6b4b682e16d9889 100644
--- a/src/test/isolation/isolation_schedule
+++ b/src/test/isolation/isolation_schedule
@@ -25,3 +25,6 @@ test: propagate-lock-delete
 test: drop-index-concurrently-1
 test: alter-table-1
 test: timeouts
+test: nowait
+test: nowait-2
+test: nowait-3
diff --git a/src/test/isolation/specs/nowait-2.spec b/src/test/isolation/specs/nowait-2.spec
new file mode 100644
index 0000000000000000000000000000000000000000..007d0237c2ba86ecfe0dd9120d35a17f32914808
--- /dev/null
+++ b/src/test/isolation/specs/nowait-2.spec
@@ -0,0 +1,37 @@
+# Test NOWAIT with multixact locks.
+
+setup
+{
+  CREATE TABLE foo (
+	id int PRIMARY KEY,
+	data text NOT NULL
+  );
+  INSERT INTO foo VALUES (1, 'x');
+}
+
+teardown
+{
+  DROP TABLE foo;
+}
+
+session "s1"
+setup		{ BEGIN; }
+step "s1a"	{ SELECT * FROM foo FOR SHARE NOWAIT; }
+step "s1b"	{ COMMIT; }
+
+session "s2"
+setup		{ BEGIN; }
+step "s2a"	{ SELECT * FROM foo FOR SHARE NOWAIT; }
+step "s2b"	{ SELECT * FROM foo FOR UPDATE NOWAIT; }
+step "s2c"	{ COMMIT; }
+
+# s1 and s2 both get SHARE lock, creating a multixact lock, then s2
+# tries to upgrade to UPDATE but aborts because it cannot acquire a
+# multi-xact lock
+permutation "s1a" "s2a" "s2b" "s1b" "s2c"
+# the same but with the SHARE locks acquired in a different order, so
+# s2 again aborts because it can't acquired a multi-xact lock
+permutation "s2a" "s1a" "s2b" "s1b" "s2c"
+# s2 acquires SHARE then UPDATE, then s1 tries to acquire SHARE but
+# can't so aborts because it can't acquire a regular lock
+permutation "s2a" "s2b" "s1a" "s1b" "s2c"
\ No newline at end of file
diff --git a/src/test/isolation/specs/nowait-3.spec b/src/test/isolation/specs/nowait-3.spec
new file mode 100644
index 0000000000000000000000000000000000000000..58dec7fa44bd6048a36fa3eb3ed7f6bfa9304352
--- /dev/null
+++ b/src/test/isolation/specs/nowait-3.spec
@@ -0,0 +1,33 @@
+# Test NOWAIT with tuple locks.
+
+setup
+{
+  CREATE TABLE foo (
+	id int PRIMARY KEY,
+	data text NOT NULL
+  );
+  INSERT INTO foo VALUES (1, 'x');
+}
+
+teardown
+{
+  DROP TABLE foo;
+}
+
+session "s1"
+setup		{ BEGIN; }
+step "s1a"	{ SELECT * FROM foo FOR UPDATE; }
+step "s1b"	{ COMMIT; }
+
+session "s2"
+setup		{ BEGIN; }
+step "s2a"	{ SELECT * FROM foo FOR UPDATE; }
+step "s2b"	{ COMMIT; }
+
+session "s3"
+setup		{ BEGIN; }
+step "s3a"	{ SELECT * FROM foo FOR UPDATE NOWAIT; }
+step "s3b"	{ COMMIT; }
+
+# s3 skips to second record due to tuple lock held by s2
+permutation "s1a" "s2a" "s3a" "s1b" "s2b" "s3b"
\ No newline at end of file
diff --git a/src/test/isolation/specs/nowait.spec b/src/test/isolation/specs/nowait.spec
new file mode 100644
index 0000000000000000000000000000000000000000..73580cd1b2a28863c46e4726e0c18680e2ac4299
--- /dev/null
+++ b/src/test/isolation/specs/nowait.spec
@@ -0,0 +1,25 @@
+# Test NOWAIT when regular row locks can't be acquired.
+
+setup
+{
+  CREATE TABLE foo (
+	id int PRIMARY KEY,
+	data text NOT NULL
+  );
+  INSERT INTO foo VALUES (1, 'x');
+}
+
+teardown
+{
+  DROP TABLE foo;
+}
+
+session "s1"
+setup		{ BEGIN; }
+step "s1a"	{ SELECT * FROM foo FOR UPDATE NOWAIT; }
+step "s1b"	{ COMMIT; }
+
+session "s2"
+setup		{ BEGIN; }
+step "s2a"	{ SELECT * FROM foo FOR UPDATE NOWAIT; }
+step "s2b"	{ COMMIT; }