Fix incorrect trigger-property updating in ALTER CONSTRAINT.

The code to change the deferrability properties of a foreign-key constraint
updated all the associated triggers to match; but a moment's examination of
the code that creates those triggers in the first place shows that only
some of them should track the constraint's deferrability properties.  This
leads to odd failures in subsequent exercise of the foreign key, as the
triggers are fired at the wrong times.  Fix that, and add a regression test
comparing the trigger properties produced by ALTER CONSTRAINT with those
you get by creating the constraint as-intended to begin with.

Per report from James Parks.  Back-patch to 9.4 where this ALTER
functionality was introduced.

Report: <CAJ3Xv+jzJ8iNNUcp4RKW8b6Qp1xVAxHwSXVpjBNygjKxcVuE9w@mail.gmail.com>

src/backend/commands/tablecmds.c

@@ -6740,16 +6740,34 @@ 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);
@@ -7512,6 +7530,9 @@ 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,

src/test/regress/expected/alter_table.out

@@ -534,6 +534,66 @@ 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 );

src/test/regress/sql/alter_table.sql

@@ -407,6 +407,39 @@ 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.