Who inserts data in snapshot log

The Book tells:


Snapshot Log Creation

If you create a snapshot log, Oracle does the following:

A table MLOG$_master_table is created. The table stores the ROWID and timestamp of rows inserted, updated and deleted in the master table.

Oracle creates an AFTER ROW trigger on the master table to insert the ROWIDs and timestamps of inserted, updated, and deleted rows into the master snapshot log. The trigger is named TLOG$_master_table_name. Oracle8 does not have a trigger. The code that was contained in the trigger in Oracle7 is contained in the Oracle8 kernel. If we create a snapshot log on the EMP table using the CREATE SNAPSHOT LOG command, the following trigger is created automatically by Oracle.

CREATE OR REPLACE TRIGGER "SCOTT"."TLOG$_EMP"
AFTER INSERT OR UPDATE OR DELETE
ON "SCOTT"."EMP"
REFERENCING OLD AS OLD
FOR EACH ROW
DECLARE
dmltype CHAR;
BEGIN
IF INSERTING
THEN
dmltype := 'I';
ELSIF UPDATING
THEN
dmltype := 'U';
ELSIF DELETING
THEN
dmltype := 'D';
END IF;

INSERT INTO "SCOTT"."MLOG$_EMP" (m_row$$,dmltype$$)
VALUES (:old.ROWID, dmltype);
END;

But I can not found any triggers for this table ?
Anyway the snapshot log works very fine and I can see the data is recorded in it if I change the data in master table .
So who is inserting data in snapshot log ?


I am using oracle9i , maybe 9i did something special in this case ?

The trigger is "internalized" -- you can't see it.