Re: [PATCH] Add support for ON UPDATE/DELETE actions on ALTER CONSTRAINT - Mailing list pgsql-hackers

Matheus de Oliveira <matioli.matheus@gmail.com> writes:
> [ postgresql-alter-constraint.v5.patch ]

Somebody seems to have marked this Ready For Committer without posting
any review, which is not very kosher, but I took a quick look at it
anyway.

* It's failing to apply, as noted by the cfbot, because somebody added
an unrelated test to the same spot in foreign_key.sql.  I fixed that
in the attached rebase.

* It also doesn't pass "git diff --check" whitespace checks, so
I ran it through pgindent.

* Grepping around for other references to struct Constraint,
I noticed that you'd missed updating equalfuncs.c.  I did not
fix that.

The main issue I've got though is a definitional one --- I'm not at all
sold on your premise that constraint deferrability syntax should mean
different things depending on the previous state of the constraint.
We don't generally act that way in other ALTER commands and I don't see
a strong argument to start doing so here.  If you didn't do this then
you wouldn't (I think) need the extra struct Constraint fields in the
first place, which is why I didn't run off and change equalfuncs.c.

In short, I'm inclined to argue that this variant of ALTER TABLE
should replace *all* the fields of the constraint with the same
properties it'd have if you'd created it fresh using the same syntax.
This is by analogy to CREATE OR REPLACE commands, which don't
preserve any of the old properties of the replaced object.  Given
the interactions between these fields, I think you're going to end up
with a surprising mess of ad-hoc choices if you do differently.
Indeed, you already have, but I think it'll get worse if anyone
tries to extend the feature set further.

Perhaps the right way to attack it, given that, is to go ahead and
invent "ALTER TABLE t ADD OR REPLACE CONSTRAINT c ...".  At least
in the case at hand with FK constraints, we could apply suitable
optimizations (ie skip revalidation) when the new definition shares
the right properties with the old, and otherwise treat it like a
drop-and-add.

            regards, tom lane

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 90bf195..198c640 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -55,7 +55,9 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL |
EXTENDED| MAIN } 
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
-    ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [
INITIALLYDEFERRED | INITIALLY IMMEDIATE ] 
+    ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable>
+      [ ON DELETE <replaceable class="parameter">action</replaceable> ] [ ON UPDATE <replaceable
class="parameter">action</replaceable>] 
+      [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
     VALIDATE CONSTRAINT <replaceable class="parameter">constraint_name</replaceable>
     DROP CONSTRAINT [ IF EXISTS ]  <replaceable class="parameter">constraint_name</replaceable> [ RESTRICT | CASCADE ]
     DISABLE TRIGGER [ <replaceable class="parameter">trigger_name</replaceable> | ALL | USER ]
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index fb2be10..f897986 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -9012,8 +9012,43 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
                  errmsg("constraint \"%s\" of relation \"%s\" is not a foreign key constraint",
                         cmdcon->conname, RelationGetRelationName(rel))));

+    /*
+     * Verify for FKCONSTR_ACTION_UNKNOWN, if found, replace by current
+     * action. We could handle FKCONSTR_ACTION_UNKNOWN bellow, but since we
+     * already have to handle the case of changing to the same action, seems
+     * simpler to simple replace FKCONSTR_ACTION_UNKNOWN by the current action
+     * here.
+     */
+    if (cmdcon->fk_del_action == FKCONSTR_ACTION_UNKNOWN)
+        cmdcon->fk_del_action = currcon->confdeltype;
+
+    if (cmdcon->fk_upd_action == FKCONSTR_ACTION_UNKNOWN)
+        cmdcon->fk_upd_action = currcon->confupdtype;
+
+    /*
+     * Do the same for deferrable attributes. But consider that if changed
+     * only initdeferred attribute and to true, force deferrable to be also
+     * true. On the other hand, if changed only deferrable attribute and to
+     * false, force initdeferred to be also false.
+     */
+    if (!cmdcon->was_deferrable_set)
+        cmdcon->deferrable = cmdcon->initdeferred ? true : currcon->condeferrable;
+
+    if (!cmdcon->was_initdeferred_set)
+        cmdcon->initdeferred = !cmdcon->deferrable ? false : currcon->condeferred;
+
+    /*
+     * This is a safe check only, should never happen here.
+     */
+    if (cmdcon->initdeferred && !cmdcon->deferrable)
+        ereport(ERROR,
+                (errcode(ERRCODE_SYNTAX_ERROR),
+                 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
+
     if (currcon->condeferrable != cmdcon->deferrable ||
-        currcon->condeferred != cmdcon->initdeferred)
+        currcon->condeferred != cmdcon->initdeferred ||
+        currcon->confdeltype != cmdcon->fk_del_action ||
+        currcon->confupdtype != cmdcon->fk_upd_action)
     {
         HeapTuple    copyTuple;
         HeapTuple    tgtuple;
@@ -9031,6 +9066,8 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
         copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
         copy_con->condeferrable = cmdcon->deferrable;
         copy_con->condeferred = cmdcon->initdeferred;
+        copy_con->confdeltype = cmdcon->fk_del_action;
+        copy_con->confupdtype = cmdcon->fk_upd_action;
         CatalogTupleUpdate(conrel, ©Tuple->t_self, copyTuple);

         InvokeObjectPostAlterHook(ConstraintRelationId,
@@ -9067,23 +9104,106 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
                 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 createForeignKeyActionTriggers
-             * 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);

+            /*
+             * Set deferrability here, but note that it may be overridden
+             * bellow if the pg_trigger entry is on the referencing table and
+             * depending on the action used for ON UPDATE/DELETE. But for
+             * check triggers (in the referenced table) it is kept as is
+             * (since ON UPDATE/DELETE actions makes no difference for the
+             * check triggers).
+             */
             copy_tg->tgdeferrable = cmdcon->deferrable;
             copy_tg->tginitdeferred = cmdcon->initdeferred;
+
+            /*
+             * Set ON DELETE action
+             */
+            if (tgform->tgfoid == F_RI_FKEY_NOACTION_DEL ||
+                tgform->tgfoid == F_RI_FKEY_RESTRICT_DEL ||
+                tgform->tgfoid == F_RI_FKEY_CASCADE_DEL ||
+                tgform->tgfoid == F_RI_FKEY_SETNULL_DEL ||
+                tgform->tgfoid == F_RI_FKEY_SETDEFAULT_DEL)
+            {
+                switch (cmdcon->fk_del_action)
+                {
+                    case FKCONSTR_ACTION_NOACTION:
+                        copy_tg->tgdeferrable = cmdcon->deferrable;
+                        copy_tg->tginitdeferred = cmdcon->initdeferred;
+                        copy_tg->tgfoid = F_RI_FKEY_NOACTION_DEL;
+                        break;
+                    case FKCONSTR_ACTION_RESTRICT:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_RESTRICT_DEL;
+                        break;
+                    case FKCONSTR_ACTION_CASCADE:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_CASCADE_DEL;
+                        break;
+                    case FKCONSTR_ACTION_SETNULL:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_SETNULL_DEL;
+                        break;
+                    case FKCONSTR_ACTION_SETDEFAULT:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_SETDEFAULT_DEL;
+                        break;
+                    default:
+                        elog(ERROR, "unrecognized FK action type: %d",
+                             (int) cmdcon->fk_del_action);
+                        break;
+                }
+            }
+
+            /*
+             * Set ON UPDATE action
+             */
+            if (tgform->tgfoid == F_RI_FKEY_NOACTION_UPD ||
+                tgform->tgfoid == F_RI_FKEY_RESTRICT_UPD ||
+                tgform->tgfoid == F_RI_FKEY_CASCADE_UPD ||
+                tgform->tgfoid == F_RI_FKEY_SETNULL_UPD ||
+                tgform->tgfoid == F_RI_FKEY_SETDEFAULT_UPD)
+            {
+                switch (cmdcon->fk_upd_action)
+                {
+                    case FKCONSTR_ACTION_NOACTION:
+                        copy_tg->tgdeferrable = cmdcon->deferrable;
+                        copy_tg->tginitdeferred = cmdcon->initdeferred;
+                        copy_tg->tgfoid = F_RI_FKEY_NOACTION_UPD;
+                        break;
+                    case FKCONSTR_ACTION_RESTRICT:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_RESTRICT_UPD;
+                        break;
+                    case FKCONSTR_ACTION_CASCADE:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_CASCADE_UPD;
+                        break;
+                    case FKCONSTR_ACTION_SETNULL:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_SETNULL_UPD;
+                        break;
+                    case FKCONSTR_ACTION_SETDEFAULT:
+                        copy_tg->tgdeferrable = false;
+                        copy_tg->tginitdeferred = false;
+                        copy_tg->tgfoid = F_RI_FKEY_SETDEFAULT_UPD;
+                        break;
+                    default:
+                        elog(ERROR, "unrecognized FK action type: %d",
+                             (int) cmdcon->fk_upd_action);
+                        break;
+                }
+            }
+
             CatalogTupleUpdate(tgrel, ©Tuple->t_self, copyTuple);

             InvokeObjectPostAlterHook(TriggerRelationId, currcon->oid, 0);
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 6414ade..5c524e3 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2906,6 +2906,8 @@ _copyConstraint(const Constraint *from)
     COPY_SCALAR_FIELD(deferrable);
     COPY_SCALAR_FIELD(initdeferred);
     COPY_LOCATION_FIELD(location);
+    COPY_SCALAR_FIELD(was_deferrable_set);
+    COPY_SCALAR_FIELD(was_initdeferred_set);
     COPY_SCALAR_FIELD(is_no_inherit);
     COPY_NODE_FIELD(raw_expr);
     COPY_STRING_FIELD(cooked_expr);
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 86c31a4..7e4ec65 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -3445,6 +3445,8 @@ _outConstraint(StringInfo str, const Constraint *node)
     WRITE_BOOL_FIELD(deferrable);
     WRITE_BOOL_FIELD(initdeferred);
     WRITE_LOCATION_FIELD(location);
+    WRITE_BOOL_FIELD(was_deferrable_set);
+    WRITE_BOOL_FIELD(was_initdeferred_set);

     appendStringInfoString(str, " :contype ");
     switch (node->contype)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index c97bb36..690f94f 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -185,7 +185,8 @@ static void SplitColQualList(List *qualList,
                              List **constraintList, CollateClause **collClause,
                              core_yyscan_t yyscanner);
 static void processCASbits(int cas_bits, int location, const char *constrType,
-               bool *deferrable, bool *initdeferred, bool *not_valid,
+               bool *deferrable, bool *was_deferrable_set,
+               bool *initdeferred, bool *was_initdeferred_set, bool *not_valid,
                bool *no_inherit, core_yyscan_t yyscanner);
 static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);

@@ -543,7 +544,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <ival>    TableLikeOptionList TableLikeOption
 %type <list>    ColQualList
 %type <node>    ColConstraint ColConstraintElem ConstraintAttr
-%type <ival>    key_actions key_delete key_match key_update key_action
+%type <ival>    key_actions opt_key_actions
+%type <ival>    key_delete key_match key_update key_action
 %type <ival>    ConstraintAttributeSpec ConstraintAttributeElem
 %type <str>        ExistingIndex

@@ -2275,7 +2277,7 @@ alter_table_cmd:
                     $$ = (Node *)n;
                 }
             /* ALTER TABLE <name> ALTER CONSTRAINT ... */
-            | ALTER CONSTRAINT name ConstraintAttributeSpec
+            | ALTER CONSTRAINT name opt_key_actions ConstraintAttributeSpec
                 {
                     AlterTableCmd *n = makeNode(AlterTableCmd);
                     Constraint *c = makeNode(Constraint);
@@ -2283,9 +2285,11 @@ alter_table_cmd:
                     n->def = (Node *) c;
                     c->contype = CONSTR_FOREIGN; /* others not supported, yet */
                     c->conname = $3;
-                    processCASbits($4, @4, "ALTER CONSTRAINT statement",
-                                    &c->deferrable,
-                                    &c->initdeferred,
+                    c->fk_upd_action = (char) ($4 >> 8);
+                    c->fk_del_action = (char) ($4 & 0xFF);
+                    processCASbits($5, @4, "ALTER CONSTRAINT statement",
+                                    &c->deferrable, &c->was_deferrable_set,
+                                    &c->initdeferred, &c->was_initdeferred_set,
                                     NULL, NULL, yyscanner);
                     $$ = (Node *)n;
                 }
@@ -3642,7 +3646,7 @@ ConstraintElem:
                     n->raw_expr = $3;
                     n->cooked_expr = NULL;
                     processCASbits($5, @5, "CHECK",
-                                   NULL, NULL, &n->skip_validation,
+                                   NULL, NULL, NULL, NULL, &n->skip_validation,
                                    &n->is_no_inherit, yyscanner);
                     n->initially_valid = !n->skip_validation;
                     $$ = (Node *)n;
@@ -3659,8 +3663,8 @@ ConstraintElem:
                     n->indexname = NULL;
                     n->indexspace = $7;
                     processCASbits($8, @8, "UNIQUE",
-                                   &n->deferrable, &n->initdeferred, NULL,
-                                   NULL, yyscanner);
+                                   &n->deferrable, NULL, &n->initdeferred, NULL,
+                                   NULL, NULL, yyscanner);
                     $$ = (Node *)n;
                 }
             | UNIQUE ExistingIndex ConstraintAttributeSpec
@@ -3674,8 +3678,8 @@ ConstraintElem:
                     n->indexname = $2;
                     n->indexspace = NULL;
                     processCASbits($3, @3, "UNIQUE",
-                                   &n->deferrable, &n->initdeferred, NULL,
-                                   NULL, yyscanner);
+                                   &n->deferrable, NULL, &n->initdeferred, NULL,
+                                   NULL, NULL, yyscanner);
                     $$ = (Node *)n;
                 }
             | PRIMARY KEY '(' columnList ')' opt_c_include opt_definition OptConsTableSpace
@@ -3690,8 +3694,8 @@ ConstraintElem:
                     n->indexname = NULL;
                     n->indexspace = $8;
                     processCASbits($9, @9, "PRIMARY KEY",
-                                   &n->deferrable, &n->initdeferred, NULL,
-                                   NULL, yyscanner);
+                                   &n->deferrable, NULL, &n->initdeferred, NULL,
+                                   NULL, NULL, yyscanner);
                     $$ = (Node *)n;
                 }
             | PRIMARY KEY ExistingIndex ConstraintAttributeSpec
@@ -3705,8 +3709,8 @@ ConstraintElem:
                     n->indexname = $3;
                     n->indexspace = NULL;
                     processCASbits($4, @4, "PRIMARY KEY",
-                                   &n->deferrable, &n->initdeferred, NULL,
-                                   NULL, yyscanner);
+                                   &n->deferrable, NULL, &n->initdeferred, NULL,
+                                   NULL, NULL, yyscanner);
                     $$ = (Node *)n;
                 }
             | EXCLUDE access_method_clause '(' ExclusionConstraintList ')'
@@ -3724,8 +3728,8 @@ ConstraintElem:
                     n->indexspace        = $8;
                     n->where_clause        = $9;
                     processCASbits($10, @10, "EXCLUDE",
-                                   &n->deferrable, &n->initdeferred, NULL,
-                                   NULL, yyscanner);
+                                   &n->deferrable, NULL, &n->initdeferred, NULL,
+                                   NULL, NULL, yyscanner);
                     $$ = (Node *)n;
                 }
             | FOREIGN KEY '(' columnList ')' REFERENCES qualified_name
@@ -3741,7 +3745,8 @@ ConstraintElem:
                     n->fk_upd_action    = (char) ($10 >> 8);
                     n->fk_del_action    = (char) ($10 & 0xFF);
                     processCASbits($11, @11, "FOREIGN KEY",
-                                   &n->deferrable, &n->initdeferred,
+                                   &n->deferrable, NULL,
+                                   &n->initdeferred, NULL,
                                    &n->skip_validation, NULL,
                                    yyscanner);
                     n->initially_valid = !n->skip_validation;
@@ -3821,7 +3826,7 @@ ExclusionWhereClause:
  * We combine the update and delete actions into one value temporarily
  * for simplicity of parsing, and then break them down again in the
  * calling production.  update is in the left 8 bits, delete in the right.
- * Note that NOACTION is the default.
+ * Note that NOACTION is the default. See also opt_key_actions.
  */
 key_actions:
             key_update
@@ -3836,6 +3841,23 @@ key_actions:
                 { $$ = (FKCONSTR_ACTION_NOACTION << 8) | (FKCONSTR_ACTION_NOACTION & 0xFF); }
         ;

+/*
+ * Basically the same as key_actions, but using FKCONSTR_ACTION_UNKNOWN
+ * as the default one instead of NOACTION.
+ */
+opt_key_actions:
+            key_update
+                { $$ = ($1 << 8) | (FKCONSTR_ACTION_UNKNOWN & 0xFF); }
+            | key_delete
+                { $$ = (FKCONSTR_ACTION_UNKNOWN << 8) | ($1 & 0xFF); }
+            | key_update key_delete
+                { $$ = ($1 << 8) | ($2 & 0xFF); }
+            | key_delete key_update
+                { $$ = ($2 << 8) | ($1 & 0xFF); }
+            | /*EMPTY*/
+                { $$ = (FKCONSTR_ACTION_UNKNOWN << 8) | (FKCONSTR_ACTION_UNKNOWN & 0xFF); }
+        ;
+
 key_update: ON UPDATE key_action        { $$ = $3; }
         ;

@@ -5361,8 +5383,8 @@ CreateTrigStmt:
                     n->transitionRels = NIL;
                     n->isconstraint  = true;
                     processCASbits($10, @10, "TRIGGER",
-                                   &n->deferrable, &n->initdeferred, NULL,
-                                   NULL, yyscanner);
+                                   &n->deferrable, NULL, &n->initdeferred, NULL,
+                                   NULL, NULL, yyscanner);
                     n->constrrel = $9;
                     $$ = (Node *)n;
                 }
@@ -16218,7 +16240,8 @@ SplitColQualList(List *qualList,
  */
 static void
 processCASbits(int cas_bits, int location, const char *constrType,
-               bool *deferrable, bool *initdeferred, bool *not_valid,
+               bool *deferrable, bool *was_deferrable_set,
+               bool *initdeferred, bool *was_initdeferred_set, bool *not_valid,
                bool *no_inherit, core_yyscan_t yyscanner)
 {
     /* defaults */
@@ -16229,6 +16252,14 @@ processCASbits(int cas_bits, int location, const char *constrType,
     if (not_valid)
         *not_valid = false;

+    if (was_deferrable_set)
+        *was_deferrable_set = cas_bits & (CAS_DEFERRABLE
+                                          | CAS_NOT_DEFERRABLE) ? true : false;
+
+    if (was_initdeferred_set)
+        *was_initdeferred_set = cas_bits & (CAS_INITIALLY_DEFERRED
+                                            | CAS_INITIALLY_IMMEDIATE) ? true : false;
+
     if (cas_bits & (CAS_DEFERRABLE | CAS_INITIALLY_DEFERRED))
     {
         if (deferrable)
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 94ded3c..a6d70d4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2117,6 +2117,8 @@ typedef enum ConstrType            /* types of constraints */
 #define FKCONSTR_ACTION_CASCADE        'c'
 #define FKCONSTR_ACTION_SETNULL        'n'
 #define FKCONSTR_ACTION_SETDEFAULT    'd'
+#define FKCONSTR_ACTION_UNKNOWN        'u' /* unknown is used only for ALTER
+                                         * CONSTRAINT */

 /* Foreign key matchtype codes */
 #define FKCONSTR_MATCH_FULL            'f'
@@ -2134,6 +2136,10 @@ typedef struct Constraint
     bool        initdeferred;    /* INITIALLY DEFERRED? */
     int            location;        /* token location, or -1 if unknown */

+    /* Fields used by ALTER CONSTRAINT to verify if a change was actually made */
+    bool        was_deferrable_set; /* Was DEFERRABLE informed? */
+    bool        was_initdeferred_set;    /* Was INITIALLY DEFERRED informed? */
+
     /* Fields used for constraints with expressions (CHECK and DEFAULT): */
     bool        is_no_inherit;    /* is constraint non-inheritable? */
     Node       *raw_expr;        /* expr, as untransformed parse tree */
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index e5407bb..32ea16c 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -736,6 +736,28 @@ ORDER BY 1,2,3;
  fknd2   | "RI_FKey_check_upd" |     17 | f            | f
 (12 rows)

+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2;
+SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid = 'fktable'::regclass AND conname = 'fkdi2';
+                                      pg_get_constraintdef
+-------------------------------------------------------------------------------------------------
+ FOREIGN KEY (ftest1) REFERENCES pktable(ptest1) ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED
+(1 row)
+
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 INITIALLY IMMEDIATE;
+SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid = 'fktable'::regclass AND conname = 'fkdi2';
+                             pg_get_constraintdef
+------------------------------------------------------------------------------
+ FOREIGN KEY (ftest1) REFERENCES pktable(ptest1) ON DELETE CASCADE DEFERRABLE
+(1 row)
+
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 NOT DEFERRABLE;
+SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid = 'fktable'::regclass AND conname = 'fkdi2';
+                       pg_get_constraintdef
+-------------------------------------------------------------------
+ FOREIGN KEY (ftest1) REFERENCES pktable(ptest1) ON DELETE CASCADE
+(1 row)
+
 -- 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/expected/foreign_key.out b/src/test/regress/expected/foreign_key.out
index f0ecf4b..4f226aa 100644
--- a/src/test/regress/expected/foreign_key.out
+++ b/src/test/regress/expected/foreign_key.out
@@ -2394,3 +2394,127 @@ DROP SCHEMA fkpart8 CASCADE;
 NOTICE:  drop cascades to 2 other objects
 DETAIL:  drop cascades to table fkpart8.tbl1
 drop cascades to table fkpart8.tbl2
+-- ALTER CONSTRAINT changing ON UPDATE/DELETE.
+-- Try all combinations and validate the diff with a created constraint
+CREATE SCHEMA createtest; -- created constraints with target action, validation
+CREATE SCHEMA altertest;  -- created with source and altered to target, test
+DO
+$test_alter_con$
+DECLARE
+    v_result json;
+    method text;
+    from_action text;
+    to_action text;
+BEGIN
+    FOR method, from_action, to_action IN
+        WITH act(action) AS (
+            SELECT unnest('{NO ACTION,RESTRICT,CASCADE,SET DEFAULT,SET NULL}'::text[])
+        )
+        SELECT
+            m.method, a1.action, a2.action
+        FROM unnest('{UPDATE,DELETE}'::text[]) AS m(method), act a1, act a2
+    LOOP
+        EXECUTE format(
+            $sql$
+                 -- Alter from ON %1$s %2$s to ON %1$s %3$s
+                CREATE TABLE createtest.foo(id integer primary key);
+                CREATE TABLE createtest.bar(foo_id integer DEFAULT 0 REFERENCES createtest.foo ON %1$s %3$s, val
text);
+
+                CREATE TABLE altertest.foo(id integer primary key);
+                INSERT INTO altertest.foo VALUES(0),(1),(2),(3);
+
+                CREATE TABLE altertest.bar(foo_id integer DEFAULT 0 REFERENCES altertest.foo ON %1$s %2$s, val text);
+
+                ALTER TABLE altertest.bar ALTER CONSTRAINT bar_foo_id_fkey ON %1$s %3$s;
+
+            $sql$, method, from_action, to_action);
+
+        SELECT json_agg(t)
+        INTO v_result
+        FROM (
+            -- Do EXCEPT of the "altertest" and "createtest" constraints, if they are equal (as expected), it should
returnempty 
+            SELECT
+                rel.relname, replace(tg.tgname, tg.oid::text, 'OID') AS tgname,
+                tg.tgfoid::regproc, con.conname, con.confupdtype, con.confdeltype, tg.tgdeferrable,
+                regexp_replace(pg_get_constraintdef(con.oid), '(createtest\.|altertest\.)', '') AS condef
+            FROM pg_trigger tg
+                JOIN pg_constraint con ON con.oid = tg.tgconstraint
+                JOIN pg_class rel ON tg.tgrelid = rel.oid
+            WHERE tg.tgrelid IN ('altertest.foo'::regclass, 'altertest.bar'::regclass)
+            EXCEPT
+            SELECT
+                rel.relname, replace(tg.tgname, tg.oid::text, 'OID') AS tgname,
+                tg.tgfoid::regproc, con.conname, con.confupdtype, con.confdeltype, tg.tgdeferrable,
+                regexp_replace(pg_get_constraintdef(con.oid), '(createtest\.|altertest\.)', '') AS condef
+            FROM pg_trigger tg
+                JOIN pg_constraint con ON con.oid = tg.tgconstraint
+                JOIN pg_class rel ON tg.tgrelid = rel.oid
+            WHERE tg.tgrelid IN ('createtest.foo'::regclass, 'createtest.bar'::regclass)
+        ) t;
+
+        DROP TABLE createtest.bar;
+        DROP TABLE createtest.foo;
+        DROP TABLE altertest.bar;
+        DROP TABLE altertest.foo;
+
+        IF (v_result IS NULL) THEN
+            RAISE INFO 'ON % from % to %: OK.', method, from_action, to_action;
+        ELSE
+            RAISE EXCEPTION 'ON % from % to %. FAILED! Unmatching rows: %', method, from_action, to_action, v_result;
+        END IF;
+    END LOOP;
+END;
+$test_alter_con$
+;
+INFO:  ON UPDATE from NO ACTION to NO ACTION: OK.
+INFO:  ON UPDATE from RESTRICT to NO ACTION: OK.
+INFO:  ON UPDATE from CASCADE to NO ACTION: OK.
+INFO:  ON UPDATE from SET DEFAULT to NO ACTION: OK.
+INFO:  ON UPDATE from SET NULL to NO ACTION: OK.
+INFO:  ON DELETE from NO ACTION to NO ACTION: OK.
+INFO:  ON DELETE from RESTRICT to NO ACTION: OK.
+INFO:  ON DELETE from CASCADE to NO ACTION: OK.
+INFO:  ON DELETE from SET DEFAULT to NO ACTION: OK.
+INFO:  ON DELETE from SET NULL to NO ACTION: OK.
+INFO:  ON UPDATE from NO ACTION to RESTRICT: OK.
+INFO:  ON UPDATE from RESTRICT to RESTRICT: OK.
+INFO:  ON UPDATE from CASCADE to RESTRICT: OK.
+INFO:  ON UPDATE from SET DEFAULT to RESTRICT: OK.
+INFO:  ON UPDATE from SET NULL to RESTRICT: OK.
+INFO:  ON DELETE from NO ACTION to RESTRICT: OK.
+INFO:  ON DELETE from RESTRICT to RESTRICT: OK.
+INFO:  ON DELETE from CASCADE to RESTRICT: OK.
+INFO:  ON DELETE from SET DEFAULT to RESTRICT: OK.
+INFO:  ON DELETE from SET NULL to RESTRICT: OK.
+INFO:  ON UPDATE from NO ACTION to CASCADE: OK.
+INFO:  ON UPDATE from RESTRICT to CASCADE: OK.
+INFO:  ON UPDATE from CASCADE to CASCADE: OK.
+INFO:  ON UPDATE from SET DEFAULT to CASCADE: OK.
+INFO:  ON UPDATE from SET NULL to CASCADE: OK.
+INFO:  ON DELETE from NO ACTION to CASCADE: OK.
+INFO:  ON DELETE from RESTRICT to CASCADE: OK.
+INFO:  ON DELETE from CASCADE to CASCADE: OK.
+INFO:  ON DELETE from SET DEFAULT to CASCADE: OK.
+INFO:  ON DELETE from SET NULL to CASCADE: OK.
+INFO:  ON UPDATE from NO ACTION to SET DEFAULT: OK.
+INFO:  ON UPDATE from RESTRICT to SET DEFAULT: OK.
+INFO:  ON UPDATE from CASCADE to SET DEFAULT: OK.
+INFO:  ON UPDATE from SET DEFAULT to SET DEFAULT: OK.
+INFO:  ON UPDATE from SET NULL to SET DEFAULT: OK.
+INFO:  ON DELETE from NO ACTION to SET DEFAULT: OK.
+INFO:  ON DELETE from RESTRICT to SET DEFAULT: OK.
+INFO:  ON DELETE from CASCADE to SET DEFAULT: OK.
+INFO:  ON DELETE from SET DEFAULT to SET DEFAULT: OK.
+INFO:  ON DELETE from SET NULL to SET DEFAULT: OK.
+INFO:  ON UPDATE from NO ACTION to SET NULL: OK.
+INFO:  ON UPDATE from RESTRICT to SET NULL: OK.
+INFO:  ON UPDATE from CASCADE to SET NULL: OK.
+INFO:  ON UPDATE from SET DEFAULT to SET NULL: OK.
+INFO:  ON UPDATE from SET NULL to SET NULL: OK.
+INFO:  ON DELETE from NO ACTION to SET NULL: OK.
+INFO:  ON DELETE from RESTRICT to SET NULL: OK.
+INFO:  ON DELETE from CASCADE to SET NULL: OK.
+INFO:  ON DELETE from SET DEFAULT to SET NULL: OK.
+INFO:  ON DELETE from SET NULL to SET NULL: OK.
+DROP SCHEMA createtest;
+DROP SCHEMA altertest;
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 99af0b8..5223142 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -528,6 +528,16 @@ FROM pg_trigger JOIN pg_constraint con ON con.oid = tgconstraint
 WHERE tgrelid = 'fktable'::regclass
 ORDER BY 1,2,3;

+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 DEFERRABLE INITIALLY DEFERRED;
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2;
+SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid = 'fktable'::regclass AND conname = 'fkdi2';
+
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 INITIALLY IMMEDIATE;
+SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid = 'fktable'::regclass AND conname = 'fkdi2';
+
+ALTER TABLE FKTABLE ALTER CONSTRAINT fkdi2 NOT DEFERRABLE;
+SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid = 'fktable'::regclass AND conname = 'fkdi2';
+
 -- temp tables should go away by themselves, need not drop them.

 -- test check constraint adding
diff --git a/src/test/regress/sql/foreign_key.sql b/src/test/regress/sql/foreign_key.sql
index b67bef0..ae8b235 100644
--- a/src/test/regress/sql/foreign_key.sql
+++ b/src/test/regress/sql/foreign_key.sql
@@ -1679,3 +1679,80 @@ INSERT INTO fkpart8.tbl2 VALUES(1);
 ALTER TABLE fkpart8.tbl2 DROP CONSTRAINT tbl2_f1_fkey;
 COMMIT;
 DROP SCHEMA fkpart8 CASCADE;
+
+-- ALTER CONSTRAINT changing ON UPDATE/DELETE.
+-- Try all combinations and validate the diff with a created constraint
+CREATE SCHEMA createtest; -- created constraints with target action, validation
+CREATE SCHEMA altertest;  -- created with source and altered to target, test
+
+DO
+$test_alter_con$
+DECLARE
+    v_result json;
+    method text;
+    from_action text;
+    to_action text;
+BEGIN
+    FOR method, from_action, to_action IN
+        WITH act(action) AS (
+            SELECT unnest('{NO ACTION,RESTRICT,CASCADE,SET DEFAULT,SET NULL}'::text[])
+        )
+        SELECT
+            m.method, a1.action, a2.action
+        FROM unnest('{UPDATE,DELETE}'::text[]) AS m(method), act a1, act a2
+    LOOP
+        EXECUTE format(
+            $sql$
+                 -- Alter from ON %1$s %2$s to ON %1$s %3$s
+                CREATE TABLE createtest.foo(id integer primary key);
+                CREATE TABLE createtest.bar(foo_id integer DEFAULT 0 REFERENCES createtest.foo ON %1$s %3$s, val
text);
+
+                CREATE TABLE altertest.foo(id integer primary key);
+                INSERT INTO altertest.foo VALUES(0),(1),(2),(3);
+
+                CREATE TABLE altertest.bar(foo_id integer DEFAULT 0 REFERENCES altertest.foo ON %1$s %2$s, val text);
+
+                ALTER TABLE altertest.bar ALTER CONSTRAINT bar_foo_id_fkey ON %1$s %3$s;
+
+            $sql$, method, from_action, to_action);
+
+        SELECT json_agg(t)
+        INTO v_result
+        FROM (
+            -- Do EXCEPT of the "altertest" and "createtest" constraints, if they are equal (as expected), it should
returnempty 
+            SELECT
+                rel.relname, replace(tg.tgname, tg.oid::text, 'OID') AS tgname,
+                tg.tgfoid::regproc, con.conname, con.confupdtype, con.confdeltype, tg.tgdeferrable,
+                regexp_replace(pg_get_constraintdef(con.oid), '(createtest\.|altertest\.)', '') AS condef
+            FROM pg_trigger tg
+                JOIN pg_constraint con ON con.oid = tg.tgconstraint
+                JOIN pg_class rel ON tg.tgrelid = rel.oid
+            WHERE tg.tgrelid IN ('altertest.foo'::regclass, 'altertest.bar'::regclass)
+            EXCEPT
+            SELECT
+                rel.relname, replace(tg.tgname, tg.oid::text, 'OID') AS tgname,
+                tg.tgfoid::regproc, con.conname, con.confupdtype, con.confdeltype, tg.tgdeferrable,
+                regexp_replace(pg_get_constraintdef(con.oid), '(createtest\.|altertest\.)', '') AS condef
+            FROM pg_trigger tg
+                JOIN pg_constraint con ON con.oid = tg.tgconstraint
+                JOIN pg_class rel ON tg.tgrelid = rel.oid
+            WHERE tg.tgrelid IN ('createtest.foo'::regclass, 'createtest.bar'::regclass)
+        ) t;
+
+        DROP TABLE createtest.bar;
+        DROP TABLE createtest.foo;
+        DROP TABLE altertest.bar;
+        DROP TABLE altertest.foo;
+
+        IF (v_result IS NULL) THEN
+            RAISE INFO 'ON % from % to %: OK.', method, from_action, to_action;
+        ELSE
+            RAISE EXCEPTION 'ON % from % to %. FAILED! Unmatching rows: %', method, from_action, to_action, v_result;
+        END IF;
+    END LOOP;
+END;
+$test_alter_con$
+;
+
+DROP SCHEMA createtest;
+DROP SCHEMA altertest;