Change PROCEDURE to FUNCTION in CREATE TRIGGER syntax

Since procedures are now a different thing from functions, change the
CREATE TRIGGER and CREATE EVENT TRIGGER syntax to use FUNCTION in the
clause that specifies the function.  PROCEDURE is still accepted for
compatibility.

pg_dump and ruleutils.c output is not changed yet, because that would
require a change in information_schema.sql and thus a catversion change.

Reported-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Jonathan S. Katz <jonathan.katz@excoventures.com>

doc/src/sgml/ddl.sgml

@@ -3580,7 +3580,7 @@ LANGUAGE plpgsql;
 <programlisting>
 CREATE TRIGGER insert_measurement_trigger
     BEFORE INSERT ON measurement
-    FOR EACH ROW EXECUTE PROCEDURE measurement_insert_trigger();
+    FOR EACH ROW EXECUTE FUNCTION measurement_insert_trigger();
 </programlisting>
 
          We must redefine the trigger function each month so that it always

doc/src/sgml/event-trigger.sgml

@@ -1044,7 +1044,7 @@ CREATE FUNCTION noddl() RETURNS event_trigger
     AS 'noddl' LANGUAGE C;
 
 CREATE EVENT TRIGGER noddl ON ddl_command_start
-    EXECUTE PROCEDURE noddl();
+    EXECUTE FUNCTION noddl();
 </programlisting>
    </para>
 
@@ -1129,7 +1129,7 @@ $$;
 
 CREATE EVENT TRIGGER no_rewrite_allowed
                   ON table_rewrite
-   EXECUTE PROCEDURE no_rewrite();
+   EXECUTE FUNCTION no_rewrite();
 </programlisting>
    </para>
  </sect1>

doc/src/sgml/func.sgml

@@ -20594,7 +20594,7 @@ SELECT (pg_stat_file('filename')).modification;
 <programlisting>
 CREATE TRIGGER z_min_update
 BEFORE UPDATE ON tablename
-FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger();
+FOR EACH ROW EXECUTE FUNCTION suppress_redundant_updates_trigger();
 </programlisting>
       In most cases, you would want to fire this trigger last for each row.
       Bearing in mind that triggers fire in name order, you would then
@@ -20846,7 +20846,7 @@ END
 $$;
 CREATE EVENT TRIGGER test_event_trigger_for_drops
    ON sql_drop
-   EXECUTE PROCEDURE test_event_trigger_for_drops();
+   EXECUTE FUNCTION test_event_trigger_for_drops();
 </programlisting>
     </para>
   </sect2>
@@ -20911,7 +20911,7 @@ $$;
 
 CREATE EVENT TRIGGER test_table_rewrite_oid
                   ON table_rewrite
-   EXECUTE PROCEDURE test_event_trigger_table_rewrite_oid();
+   EXECUTE FUNCTION test_event_trigger_table_rewrite_oid();
 </programlisting>
     </para>
   </sect2>

doc/src/sgml/information_schema.sgml

@@ -5793,7 +5793,7 @@ ORDER BY c.ordinal_position;
       <entry><type>character_data</type></entry>
       <entry>
        Statement that is executed by the trigger (currently always
-       <literal>EXECUTE PROCEDURE
+       <literal>EXECUTE FUNCTION
        <replaceable>function</replaceable>(...)</literal>)
       </entry>
      </row>

doc/src/sgml/lo.sgml

@@ -70,7 +70,7 @@
 CREATE TABLE image (title text, raster lo);
 
 CREATE TRIGGER t_raster BEFORE UPDATE OR DELETE ON image
-    FOR EACH ROW EXECUTE PROCEDURE lo_manage(raster);
+    FOR EACH ROW EXECUTE FUNCTION lo_manage(raster);
 </programlisting>
 
   <para>

doc/src/sgml/plperl.sgml

@@ -1300,7 +1300,7 @@ $$ LANGUAGE plperl;
 
 CREATE TRIGGER test_valid_id_trig
     BEFORE INSERT OR UPDATE ON test
-    FOR EACH ROW EXECUTE PROCEDURE valid_id();
+    FOR EACH ROW EXECUTE FUNCTION valid_id();
 </programlisting>
   </para>
  </sect1>
@@ -1350,7 +1350,7 @@ $$ LANGUAGE plperl;
 
 CREATE EVENT TRIGGER perl_a_snitch
     ON ddl_command_start
-    EXECUTE PROCEDURE perlsnitch();
+    EXECUTE FUNCTION perlsnitch();
 </programlisting>
   </para>
  </sect1>

doc/src/sgml/plpgsql.sgml

@@ -4069,7 +4069,7 @@ CREATE FUNCTION emp_stamp() RETURNS trigger AS $emp_stamp$
 $emp_stamp$ LANGUAGE plpgsql;
 
 CREATE TRIGGER emp_stamp BEFORE INSERT OR UPDATE ON emp
-    FOR EACH ROW EXECUTE PROCEDURE emp_stamp();
+    FOR EACH ROW EXECUTE FUNCTION emp_stamp();
 </programlisting>
    </example>
 
@@ -4124,7 +4124,7 @@ $emp_audit$ LANGUAGE plpgsql;
 
 CREATE TRIGGER emp_audit
 AFTER INSERT OR UPDATE OR DELETE ON emp
-    FOR EACH ROW EXECUTE PROCEDURE process_emp_audit();
+    FOR EACH ROW EXECUTE FUNCTION process_emp_audit();
 </programlisting>
    </example>
 
@@ -4203,7 +4203,7 @@ $$ LANGUAGE plpgsql;
 
 CREATE TRIGGER emp_audit
 INSTEAD OF INSERT OR UPDATE OR DELETE ON emp_view
-    FOR EACH ROW EXECUTE PROCEDURE update_emp_view();
+    FOR EACH ROW EXECUTE FUNCTION update_emp_view();
 </programlisting>
    </example>
 
@@ -4348,7 +4348,7 @@ $maint_sales_summary_bytime$ LANGUAGE plpgsql;
 
 CREATE TRIGGER maint_sales_summary_bytime
 AFTER INSERT OR UPDATE OR DELETE ON sales_fact
-    FOR EACH ROW EXECUTE PROCEDURE maint_sales_summary_bytime();
+    FOR EACH ROW EXECUTE FUNCTION maint_sales_summary_bytime();
 
 INSERT INTO sales_fact VALUES(1,1,1,10,3,15);
 INSERT INTO sales_fact VALUES(1,2,1,20,5,35);
@@ -4425,15 +4425,15 @@ $emp_audit$ LANGUAGE plpgsql;
 CREATE TRIGGER emp_audit_ins
     AFTER INSERT ON emp
     REFERENCING NEW TABLE AS new_table
-    FOR EACH STATEMENT EXECUTE PROCEDURE process_emp_audit();
+    FOR EACH STATEMENT EXECUTE FUNCTION process_emp_audit();
 CREATE TRIGGER emp_audit_upd
     AFTER UPDATE ON emp
     REFERENCING OLD TABLE AS old_table NEW TABLE AS new_table
-    FOR EACH STATEMENT EXECUTE PROCEDURE process_emp_audit();
+    FOR EACH STATEMENT EXECUTE FUNCTION process_emp_audit();
 CREATE TRIGGER emp_audit_del
     AFTER DELETE ON emp
     REFERENCING OLD TABLE AS old_table
-    FOR EACH STATEMENT EXECUTE PROCEDURE process_emp_audit();
+    FOR EACH STATEMENT EXECUTE FUNCTION process_emp_audit();
 </programlisting>
    </example>
 
@@ -4498,7 +4498,7 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql;
 
-CREATE EVENT TRIGGER snitch ON ddl_command_start EXECUTE PROCEDURE snitch();
+CREATE EVENT TRIGGER snitch ON ddl_command_start EXECUTE FUNCTION snitch();
 </programlisting>
    </example>
   </sect2>

doc/src/sgml/pltcl.sgml

@@ -789,7 +789,7 @@ $$ LANGUAGE pltcl;
 CREATE TABLE mytab (num integer, description text, modcnt integer);
 
 CREATE TRIGGER trig_mytab_modcount BEFORE INSERT OR UPDATE ON mytab
-    FOR EACH ROW EXECUTE PROCEDURE trigfunc_modcount('modcnt');
+    FOR EACH ROW EXECUTE FUNCTION trigfunc_modcount('modcnt');
 </programlisting>
 
      Notice that the trigger function itself does not know the column
@@ -852,7 +852,7 @@ CREATE OR REPLACE FUNCTION tclsnitch() RETURNS event_trigger AS $$
   elog NOTICE "tclsnitch: $TG_event $TG_tag"
 $$ LANGUAGE pltcl;
 
-CREATE EVENT TRIGGER tcl_a_snitch ON ddl_command_start EXECUTE PROCEDURE tclsnitch();
+CREATE EVENT TRIGGER tcl_a_snitch ON ddl_command_start EXECUTE FUNCTION tclsnitch();
 </programlisting>
     </para>
    </sect1>

doc/src/sgml/ref/create_event_trigger.sgml

@@ -24,7 +24,7 @@ PostgreSQL documentation
 CREATE EVENT TRIGGER <replaceable class="parameter">name</replaceable>
     ON <replaceable class="parameter">event</replaceable>
     [ WHEN <replaceable class="parameter">filter_variable</replaceable> IN (filter_value [, ... ]) [ AND ... ] ]
-    EXECUTE PROCEDURE <replaceable class="parameter">function_name</replaceable>()
+    EXECUTE { FUNCTION | PROCEDURE } <replaceable class="parameter">function_name</replaceable>()
 </synopsis>
  </refsynopsisdiv>
 
@@ -98,6 +98,14 @@ CREATE EVENT TRIGGER <replaceable class="parameter">name</replaceable>
       A user-supplied function that is declared as taking no argument and
       returning type <literal>event_trigger</literal>.
      </para>
+
+     <para>
+      In the syntax of <literal>CREATE EVENT TRIGGER</literal>, the keywords
+      <literal>FUNCTION</literal> and <literal>PROCEDURE</literal> are
+      equivalent, but the referenced function must in any case be a function,
+      not a procedure.  The use of the keyword <literal>PROCEDURE</literal>
+      here is historical and deprecated.
+     </para>
     </listitem>
    </varlistentry>
 
@@ -136,7 +144,7 @@ END;
 $$;
 
 CREATE EVENT TRIGGER abort_ddl ON ddl_command_start
-   EXECUTE PROCEDURE abort_any_command();
+   EXECUTE FUNCTION abort_any_command();
 </programlisting></para>
  </refsect1>
 

doc/src/sgml/ref/create_trigger.sgml

@@ -33,7 +33,7 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
     [ REFERENCING { { OLD | NEW } TABLE [ AS ] <replaceable class="parameter">transition_relation_name</replaceable> } [ ... ] ]
     [ FOR [ EACH ] { ROW | STATEMENT } ]
     [ WHEN ( <replaceable class="parameter">condition</replaceable> ) ]
-    EXECUTE PROCEDURE <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">arguments</replaceable> )
+    EXECUTE { FUNCTION | PROCEDURE } <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">arguments</replaceable> )
 
 <phrase>where <replaceable class="parameter">event</replaceable> can be one of:</phrase>
 
@@ -401,6 +401,14 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
       and returning type <literal>trigger</literal>, which is executed when
       the trigger fires.
      </para>
+
+     <para>
+      In the syntax of <literal>CREATE TRIGGER</literal>, the keywords
+      <literal>FUNCTION</literal> and <literal>PROCEDURE</literal> are
+      equivalent, but the referenced function must in any case be a function,
+      not a procedure.  The use of the keyword <literal>PROCEDURE</literal>
+      here is historical and deprecated.
+     </para>
     </listitem>
    </varlistentry>
 
@@ -555,7 +563,7 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
 CREATE TRIGGER check_update
     BEFORE UPDATE ON accounts
     FOR EACH ROW
-    EXECUTE PROCEDURE check_account_update();
+    EXECUTE FUNCTION check_account_update();
 </programlisting>
 
    The same, but only execute the function if column <literal>balance</literal>
@@ -565,7 +573,7 @@ CREATE TRIGGER check_update
 CREATE TRIGGER check_update
     BEFORE UPDATE OF balance ON accounts
     FOR EACH ROW
-    EXECUTE PROCEDURE check_account_update();
+    EXECUTE FUNCTION check_account_update();
 </programlisting>
 
    This form only executes the function if column <literal>balance</literal>
@@ -576,7 +584,7 @@ CREATE TRIGGER check_update
     BEFORE UPDATE ON accounts
     FOR EACH ROW
     WHEN (OLD.balance IS DISTINCT FROM NEW.balance)
-    EXECUTE PROCEDURE check_account_update();
+    EXECUTE FUNCTION check_account_update();
 </programlisting>
 
    Call a function to log updates of <literal>accounts</literal>, but only if
@@ -587,7 +595,7 @@ CREATE TRIGGER log_update
     AFTER UPDATE ON accounts
     FOR EACH ROW
     WHEN (OLD.* IS DISTINCT FROM NEW.*)
-    EXECUTE PROCEDURE log_account_update();
+    EXECUTE FUNCTION log_account_update();
 </programlisting>
 
    Execute the function <function>view_insert_row</function> for each row to insert
@@ -597,7 +605,7 @@ CREATE TRIGGER log_update
 CREATE TRIGGER view_insert
     INSTEAD OF INSERT ON my_view
     FOR EACH ROW
-    EXECUTE PROCEDURE view_insert_row();
+    EXECUTE FUNCTION view_insert_row();
 </programlisting>
 
    Execute the function <function>check_transfer_balances_to_zero</function> for each
@@ -609,7 +617,7 @@ CREATE TRIGGER transfer_insert
     AFTER INSERT ON transfer
     REFERENCING NEW TABLE AS inserted
     FOR EACH STATEMENT
-    EXECUTE PROCEDURE check_transfer_balances_to_zero();
+    EXECUTE FUNCTION check_transfer_balances_to_zero();
 </programlisting>
 
    Execute the function <function>check_matching_pairs</function> for each row to
@@ -621,7 +629,7 @@ CREATE TRIGGER paired_items_update
     AFTER UPDATE ON paired_items
     REFERENCING NEW TABLE AS newtab OLD TABLE AS oldtab
     FOR EACH ROW
-    EXECUTE PROCEDURE check_matching_pairs();
+    EXECUTE FUNCTION check_matching_pairs();
 </programlisting>
   </para>
 

doc/src/sgml/tcn.sgml

@@ -47,7 +47,7 @@ test(#   );
 CREATE TABLE
 test=# create trigger tcndata_tcn_trigger
 test-#   after insert or update or delete on tcndata
-test-#   for each row execute procedure triggered_change_notification();
+test-#   for each row execute function triggered_change_notification();
 CREATE TRIGGER
 test=# listen tcn;
 LISTEN

doc/src/sgml/textsearch.sgml

@@ -1884,7 +1884,7 @@ CREATE TABLE messages (
 );
 
 CREATE TRIGGER tsvectorupdate BEFORE INSERT OR UPDATE
-ON messages FOR EACH ROW EXECUTE PROCEDURE
+ON messages FOR EACH ROW EXECUTE FUNCTION
 tsvector_update_trigger(tsv, 'pg_catalog.english', title, body);
 
 INSERT INTO messages VALUES('title here', 'the body text is here');
@@ -1940,7 +1940,7 @@ end
 $$ LANGUAGE plpgsql;
 
 CREATE TRIGGER tsvectorupdate BEFORE INSERT OR UPDATE
-    ON messages FOR EACH ROW EXECUTE PROCEDURE messages_trigger();
+    ON messages FOR EACH ROW EXECUTE FUNCTION messages_trigger();
 </programlisting>
    </para>
 

doc/src/sgml/trigger.sgml

@@ -871,10 +871,10 @@ CREATE FUNCTION trigf() RETURNS trigger
     LANGUAGE C;
 
 CREATE TRIGGER tbefore BEFORE INSERT OR UPDATE OR DELETE ON ttest
-    FOR EACH ROW EXECUTE PROCEDURE trigf();
+    FOR EACH ROW EXECUTE FUNCTION trigf();
 
 CREATE TRIGGER tafter AFTER INSERT OR UPDATE OR DELETE ON ttest
-    FOR EACH ROW EXECUTE PROCEDURE trigf();
+    FOR EACH ROW EXECUTE FUNCTION trigf();
 </programlisting>
    </para>
 

src/backend/parser/gram.y

@@ -5344,7 +5344,7 @@ CreateAmStmt: CREATE ACCESS METHOD name TYPE_P INDEX HANDLER handler_name
 CreateTrigStmt:
 			CREATE TRIGGER name TriggerActionTime TriggerEvents ON
 			qualified_name TriggerReferencing TriggerForSpec TriggerWhen
-			EXECUTE PROCEDURE func_name '(' TriggerFuncArgs ')'
+			EXECUTE FUNCTION_or_PROCEDURE func_name '(' TriggerFuncArgs ')'
 				{
 					CreateTrigStmt *n = makeNode(CreateTrigStmt);
 					n->trigname = $3;
@@ -5366,7 +5366,7 @@ CreateTrigStmt:
 			| CREATE CONSTRAINT TRIGGER name AFTER TriggerEvents ON
 			qualified_name OptConstrFromTable ConstraintAttributeSpec
 			FOR EACH ROW TriggerWhen
-			EXECUTE PROCEDURE func_name '(' TriggerFuncArgs ')'
+			EXECUTE FUNCTION_or_PROCEDURE func_name '(' TriggerFuncArgs ')'
 				{
 					CreateTrigStmt *n = makeNode(CreateTrigStmt);
 					n->trigname = $4;
@@ -5504,6 +5504,11 @@ TriggerWhen:
 			| /*EMPTY*/								{ $$ = NULL; }
 		;
 
+FUNCTION_or_PROCEDURE:
+			FUNCTION
+		|	PROCEDURE
+		;
+
 TriggerFuncArgs:
 			TriggerFuncArg							{ $$ = list_make1($1); }
 			| TriggerFuncArgs ',' TriggerFuncArg	{ $$ = lappend($1, $3); }

src/test/regress/expected/triggers.out

@@ -22,12 +22,12 @@ create unique index pkeys_i on pkeys (pkey1, pkey2);
 create trigger check_fkeys_pkey_exist
 	before insert or update on fkeys
 	for each row
-	execute procedure
+	execute function
 	check_primary_key ('fkey1', 'fkey2', 'pkeys', 'pkey1', 'pkey2');
 create trigger check_fkeys_pkey2_exist
 	before insert or update on fkeys
 	for each row
-	execute procedure check_primary_key ('fkey3', 'fkeys2', 'pkey23');
+	execute function check_primary_key ('fkey3', 'fkeys2', 'pkey23');
 --
 -- For fkeys2:
 -- 	(fkey21, fkey22)	--> pkeys (pkey1, pkey2)

src/test/regress/sql/triggers.sql

@@ -26,13 +26,13 @@ create unique index pkeys_i on pkeys (pkey1, pkey2);
 create trigger check_fkeys_pkey_exist
 	before insert or update on fkeys
 	for each row
-	execute procedure
+	execute function
 	check_primary_key ('fkey1', 'fkey2', 'pkeys', 'pkey1', 'pkey2');
 
 create trigger check_fkeys_pkey2_exist
 	before insert or update on fkeys
 	for each row
-	execute procedure check_primary_key ('fkey3', 'fkeys2', 'pkey23');
+	execute function check_primary_key ('fkey3', 'fkeys2', 'pkey23');
 
 --
 -- For fkeys2: