pg_event_trigger_dropped_objects: Add name/args output columns

These columns can be passed to pg_get_object_address() and used to
reconstruct the dropped objects identities in a remote server containing
similar objects, so that the drop can be replicated.

Reviewed by Stephen Frost, Heikki Linnakangas, Abhijit Menon-Sen, Andres
Freund.

Author: alvherre

doc/src/sgml/func.sgml

@@ -17835,6 +17835,24 @@ FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger();
          identifier present in the identity is quoted if necessary.
         </entry>
        </row>
+       <row>
+        <entry><literal>address_names</literal></entry>
+        <entry><type>text[]</type></entry>
+        <entry>
+         An array that, together with <literal>object_type</literal> and
+         <literal>address_args</literal>,
+         can be used by the <function>pg_get_object_address()</function> to
+         recreate the object address in a remote server containing an
+         identically named object of the same kind.
+        </entry>
+       </row>
+       <row>
+        <entry><literal>address_args</literal></entry>
+        <entry><type>text[]</type></entry>
+        <entry>
+         Complement for <literal>address_names</literal> above.
+        </entry>
+       </row>
       </tbody>
      </tgroup>
     </informaltable>

src/backend/commands/event_trigger.c

@@ -117,6 +117,8 @@ typedef struct SQLDropObject
 	const char *objname;
 	const char *objidentity;
 	const char *objecttype;
+	List	   *addrnames;
+	List	   *addrargs;
 	bool		original;
 	bool		normal;
 	slist_node	next;
@@ -1324,10 +1326,11 @@ EventTriggerSQLDropAddObject(const ObjectAddress *object, bool original, bool no
 		heap_close(catalog, AccessShareLock);
 	}
 
-	/* object identity */
-	obj->objidentity = getObjectIdentity(&obj->address);
+	/* object identity, objname and objargs */
+	obj->objidentity =
+		getObjectIdentityParts(&obj->address, &obj->addrnames, &obj->addrargs);
 
-	/* and object type, too */
+	/* object type */
 	obj->objecttype = getObjectTypeDescription(&obj->address);
 
 	slist_push_head(&(currentEventTriggerState->SQLDropList), &obj->next);
@@ -1390,8 +1393,8 @@ pg_event_trigger_dropped_objects(PG_FUNCTION_ARGS)
 	{
 		SQLDropObject *obj;
 		int			i = 0;
-		Datum		values[9];
-		bool		nulls[9];
+		Datum		values[11];
+		bool		nulls[11];
 
 		obj = slist_container(SQLDropObject, next, iter.cur);
 
@@ -1434,6 +1437,22 @@ pg_event_trigger_dropped_objects(PG_FUNCTION_ARGS)
 		else
 			nulls[i++] = true;
 
+		/* address_names and address_args */
+		if (obj->addrnames)
+		{
+			values[i++] = PointerGetDatum(strlist_to_textarray(obj->addrnames));
+
+			if (obj->addrargs)
+				values[i++] = PointerGetDatum(strlist_to_textarray(obj->addrargs));
+			else
+				values[i++] = PointerGetDatum(construct_empty_array(TEXTOID));
+		}
+		else
+		{
+			nulls[i++] = true;
+			nulls[i++] = true;
+		}
+
 		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
 	}
 

src/include/catalog/pg_proc.h

@@ -5081,7 +5081,8 @@ DATA(insert OID = 3785 (  pg_logical_slot_peek_binary_changes PGNSP PGUID 12 100
 DESCR("peek at binary changes from replication slot");
 
 /* event triggers */
-DATA(insert OID = 3566 (  pg_event_trigger_dropped_objects		PGNSP PGUID 12 10 100 0 0 f f f f t t s 0 0 2249 "" "{26,26,23,16,16,25,25,25,25}" "{o,o,o,o,o,o,o,o,o}" "{classid, objid, objsubid, original, normal, object_type, schema_name, object_name, object_identity}" _null_ pg_event_trigger_dropped_objects _null_ _null_ _null_ ));
+DATA(insert OID = 3566 (  pg_event_trigger_dropped_objects		PGNSP PGUID 12 10 100 0 0 f f f f t t s 0 0 2249 "" "{26,26,23,16,16,25,25,25,25,1009,1009}" "{o,o,o,o,o,o,o,o,o,o,o}" "{classid, objid, objsubid, original, normal, object_type, schema_name, object_name, object_identity, address_names, address_args}" _null_ pg_event_trigger_dropped_objects _null_ _null_ _null_ ));
+
 DESCR("list objects dropped by the current command");
 DATA(insert OID = 4566 (  pg_event_trigger_table_rewrite_oid	PGNSP PGUID 12 1 0 0 0 f f f f t f s 0 0 26 "" "{26}" "{o}" "{oid}" _null_ pg_event_trigger_table_rewrite_oid _null_ _null_ _null_ ));
 DESCR("return Oid of the table getting rewritten");

src/test/regress/expected/event_trigger.out

@@ -305,8 +305,9 @@ BEGIN
     IF NOT r.normal AND NOT r.original THEN
         CONTINUE;
     END IF;
-    RAISE NOTICE 'NORMAL: orig=% normal=% type=% identity=%',
-        r.original, r.normal, r.object_type, r.object_identity;
+    RAISE NOTICE 'NORMAL: orig=% normal=% type=% identity=% name=% args=%',
+        r.original, r.normal, r.object_type, r.object_identity,
+		r.address_names, r.address_args;
     END LOOP;
 END; $$;
 CREATE EVENT TRIGGER regress_event_trigger_report_dropped ON sql_drop
@@ -316,23 +317,23 @@ CREATE SCHEMA evttrig
 	CREATE INDEX one_idx ON one (col_b)
 	CREATE TABLE two (col_c INTEGER CHECK (col_c > 0) REFERENCES one DEFAULT 42);
 ALTER TABLE evttrig.two DROP COLUMN col_c;
-NOTICE:  NORMAL: orig=t normal=f type=table column identity=evttrig.two.col_c
-NOTICE:  NORMAL: orig=f normal=t type=table constraint identity=two_col_c_check on evttrig.two
+NOTICE:  NORMAL: orig=t normal=f type=table column identity=evttrig.two.col_c name={evttrig,two,col_c} args={}
+NOTICE:  NORMAL: orig=f normal=t type=table constraint identity=two_col_c_check on evttrig.two name={evttrig,two,two_col_c_check} args={}
 ALTER TABLE evttrig.one ALTER COLUMN col_b DROP DEFAULT;
-NOTICE:  NORMAL: orig=t normal=f type=default value identity=for evttrig.one.col_b
+NOTICE:  NORMAL: orig=t normal=f type=default value identity=for evttrig.one.col_b name={evttrig,one,col_b} args={}
 ALTER TABLE evttrig.one DROP CONSTRAINT one_pkey;
-NOTICE:  NORMAL: orig=t normal=f type=table constraint identity=one_pkey on evttrig.one
+NOTICE:  NORMAL: orig=t normal=f type=table constraint identity=one_pkey on evttrig.one name={evttrig,one,one_pkey} args={}
 DROP INDEX evttrig.one_idx;
-NOTICE:  NORMAL: orig=t normal=f type=index identity=evttrig.one_idx
+NOTICE:  NORMAL: orig=t normal=f type=index identity=evttrig.one_idx name={evttrig,one_idx} args={}
 DROP SCHEMA evttrig CASCADE;
 NOTICE:  drop cascades to 2 other objects
 DETAIL:  drop cascades to table evttrig.one
 drop cascades to table evttrig.two
-NOTICE:  NORMAL: orig=t normal=f type=schema identity=evttrig
-NOTICE:  NORMAL: orig=f normal=t type=table identity=evttrig.one
-NOTICE:  NORMAL: orig=f normal=t type=sequence identity=evttrig.one_col_a_seq
-NOTICE:  NORMAL: orig=f normal=t type=default value identity=for evttrig.one.col_a
-NOTICE:  NORMAL: orig=f normal=t type=table identity=evttrig.two
+NOTICE:  NORMAL: orig=t normal=f type=schema identity=evttrig name={evttrig} args={}
+NOTICE:  NORMAL: orig=f normal=t type=table identity=evttrig.one name={evttrig,one} args={}
+NOTICE:  NORMAL: orig=f normal=t type=sequence identity=evttrig.one_col_a_seq name={evttrig,one_col_a_seq} args={}
+NOTICE:  NORMAL: orig=f normal=t type=default value identity=for evttrig.one.col_a name={evttrig,one,col_a} args={}
+NOTICE:  NORMAL: orig=f normal=t type=table identity=evttrig.two name={evttrig,two} args={}
 DROP EVENT TRIGGER regress_event_trigger_report_dropped;
 -- only allowed from within an event trigger function, should fail
 select pg_event_trigger_table_rewrite_oid();

src/test/regress/sql/event_trigger.sql

@@ -218,8 +218,9 @@ BEGIN
     IF NOT r.normal AND NOT r.original THEN
         CONTINUE;
     END IF;
-    RAISE NOTICE 'NORMAL: orig=% normal=% type=% identity=%',
-        r.original, r.normal, r.object_type, r.object_identity;
+    RAISE NOTICE 'NORMAL: orig=% normal=% type=% identity=% name=% args=%',
+        r.original, r.normal, r.object_type, r.object_identity,
+		r.address_names, r.address_args;
     END LOOP;
 END; $$;
 CREATE EVENT TRIGGER regress_event_trigger_report_dropped ON sql_drop