diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 10e18b9fe3..35fc9f0548 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -6710,16 +6710,34 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
 
 		while (HeapTupleIsValid(tgtuple = systable_getnext(tgscan)))
 		{
+			Form_pg_trigger tgform = (Form_pg_trigger) GETSTRUCT(tgtuple);
 			Form_pg_trigger copy_tg;
 
+			/*
+			 * Remember OIDs of other relation(s) involved in FK constraint.
+			 * (Note: it's likely that we could skip forcing a relcache inval
+			 * for other rels that don't have a trigger whose properties
+			 * change, but let's be conservative.)
+			 */
+			if (tgform->tgrelid != RelationGetRelid(rel))
+				otherrelids = list_append_unique_oid(otherrelids,
+													 tgform->tgrelid);
+
+			/*
+			 * Update deferrability of RI_FKey_noaction_del,
+			 * RI_FKey_noaction_upd, RI_FKey_check_ins and RI_FKey_check_upd
+			 * triggers, but not others; see createForeignKeyTriggers and
+			 * CreateFKCheckTrigger.
+			 */
+			if (tgform->tgfoid != F_RI_FKEY_NOACTION_DEL &&
+				tgform->tgfoid != F_RI_FKEY_NOACTION_UPD &&
+				tgform->tgfoid != F_RI_FKEY_CHECK_INS &&
+				tgform->tgfoid != F_RI_FKEY_CHECK_UPD)
+				continue;
+
 			copyTuple = heap_copytuple(tgtuple);
 			copy_tg = (Form_pg_trigger) GETSTRUCT(copyTuple);
 
-			/* Remember OIDs of other relation(s) involved in FK constraint */
-			if (copy_tg->tgrelid != RelationGetRelid(rel))
-				otherrelids = list_append_unique_oid(otherrelids,
-													 copy_tg->tgrelid);
-
 			copy_tg->tgdeferrable = cmdcon->deferrable;
 			copy_tg->tginitdeferred = cmdcon->initdeferred;
 			simple_heap_update(tgrel, &copyTuple->t_self, copyTuple);
@@ -7481,6 +7499,9 @@ CreateFKCheckTrigger(Oid myRelOid, Oid refRelOid, Constraint *fkconstraint,
 
 /*
  * Create the triggers that implement an FK constraint.
+ *
+ * NB: if you change any trigger properties here, see also
+ * ATExecAlterConstraint.
  */
 static void
 createForeignKeyTriggers(Relation rel, Oid refRelOid, Constraint *fkconstraint,
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index cb07d755a0..de3c69a8e8 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -525,6 +525,66 @@ ALTER TABLE FKTABLE ADD FOREIGN KEY(ftest2, ftest1)
      references pktable(ptest1, ptest2);
 ERROR:  foreign key constraint "fktable_ftest2_fkey" cannot be implemented
 DETAIL:  Key columns "ftest2" and "ptest1" are of incompatible types: inet and integer.
+DROP TABLE FKTABLE;
+DROP TABLE PKTABLE;
+-- Test that ALTER CONSTRAINT updates trigger deferrability properly
+CREATE TEMP TABLE PKTABLE (ptest1 int primary key);
+CREATE TEMP TABLE FKTABLE (ftest1 int);
+ALTER TABLE FKTABLE ADD CONSTRAINT fknd FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION NOT DEFERRABLE;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdd FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdi FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION DEFERRABLE INITIALLY IMMEDIATE;
+ALTER TABLE FKTABLE ADD CONSTRAINT fknd2 FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fknd2 NOT DEFERRABLE;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdd2 FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION NOT DEFERRABLE;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdd2 DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdi2 FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION NOT DEFERRABLE;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 DEFERRABLE INITIALLY IMMEDIATE;
+SELECT conname, tgfoid::regproc, tgtype, tgdeferrable, tginitdeferred
+FROM pg_trigger JOIN pg_constraint con ON con.oid = tgconstraint
+WHERE tgrelid = 'pktable'::regclass
+ORDER BY 1,2,3;
+ conname |         tgfoid         | tgtype | tgdeferrable | tginitdeferred 
+---------+------------------------+--------+--------------+----------------
+ fkdd    | "RI_FKey_cascade_del"  |      9 | f            | f
+ fkdd    | "RI_FKey_noaction_upd" |     17 | t            | t
+ fkdd2   | "RI_FKey_cascade_del"  |      9 | f            | f
+ fkdd2   | "RI_FKey_noaction_upd" |     17 | t            | t
+ fkdi    | "RI_FKey_cascade_del"  |      9 | f            | f
+ fkdi    | "RI_FKey_noaction_upd" |     17 | t            | f
+ fkdi2   | "RI_FKey_cascade_del"  |      9 | f            | f
+ fkdi2   | "RI_FKey_noaction_upd" |     17 | t            | f
+ fknd    | "RI_FKey_cascade_del"  |      9 | f            | f
+ fknd    | "RI_FKey_noaction_upd" |     17 | f            | f
+ fknd2   | "RI_FKey_cascade_del"  |      9 | f            | f
+ fknd2   | "RI_FKey_noaction_upd" |     17 | f            | f
+(12 rows)
+
+SELECT conname, tgfoid::regproc, tgtype, tgdeferrable, tginitdeferred
+FROM pg_trigger JOIN pg_constraint con ON con.oid = tgconstraint
+WHERE tgrelid = 'fktable'::regclass
+ORDER BY 1,2,3;
+ conname |       tgfoid        | tgtype | tgdeferrable | tginitdeferred 
+---------+---------------------+--------+--------------+----------------
+ fkdd    | "RI_FKey_check_ins" |      5 | t            | t
+ fkdd    | "RI_FKey_check_upd" |     17 | t            | t
+ fkdd2   | "RI_FKey_check_ins" |      5 | t            | t
+ fkdd2   | "RI_FKey_check_upd" |     17 | t            | t
+ fkdi    | "RI_FKey_check_ins" |      5 | t            | f
+ fkdi    | "RI_FKey_check_upd" |     17 | t            | f
+ fkdi2   | "RI_FKey_check_ins" |      5 | t            | f
+ fkdi2   | "RI_FKey_check_upd" |     17 | t            | f
+ fknd    | "RI_FKey_check_ins" |      5 | f            | f
+ fknd    | "RI_FKey_check_upd" |     17 | f            | f
+ fknd2   | "RI_FKey_check_ins" |      5 | f            | f
+ fknd2   | "RI_FKey_check_upd" |     17 | f            | f
+(12 rows)
+
 -- temp tables should go away by themselves, need not drop them.
 -- test check constraint adding
 create table atacc1 ( test int );
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 084f8ca782..14593119d3 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -404,6 +404,39 @@ ALTER TABLE FKTABLE ADD FOREIGN KEY(ftest1, ftest2)
 -- As does this...
 ALTER TABLE FKTABLE ADD FOREIGN KEY(ftest2, ftest1)
      references pktable(ptest1, ptest2);
+DROP TABLE FKTABLE;
+DROP TABLE PKTABLE;
+
+-- Test that ALTER CONSTRAINT updates trigger deferrability properly
+
+CREATE TEMP TABLE PKTABLE (ptest1 int primary key);
+CREATE TEMP TABLE FKTABLE (ftest1 int);
+
+ALTER TABLE FKTABLE ADD CONSTRAINT fknd FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION NOT DEFERRABLE;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdd FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdi FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION DEFERRABLE INITIALLY IMMEDIATE;
+
+ALTER TABLE FKTABLE ADD CONSTRAINT fknd2 FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fknd2 NOT DEFERRABLE;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdd2 FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION NOT DEFERRABLE;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdd2 DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ADD CONSTRAINT fkdi2 FOREIGN KEY(ftest1) REFERENCES pktable
+  ON DELETE CASCADE ON UPDATE NO ACTION NOT DEFERRABLE;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 DEFERRABLE INITIALLY IMMEDIATE;
+
+SELECT conname, tgfoid::regproc, tgtype, tgdeferrable, tginitdeferred
+FROM pg_trigger JOIN pg_constraint con ON con.oid = tgconstraint
+WHERE tgrelid = 'pktable'::regclass
+ORDER BY 1,2,3;
+SELECT conname, tgfoid::regproc, tgtype, tgdeferrable, tginitdeferred
+FROM pg_trigger JOIN pg_constraint con ON con.oid = tgconstraint
+WHERE tgrelid = 'fktable'::regclass
+ORDER BY 1,2,3;
 
 -- temp tables should go away by themselves, need not drop them.