Dml error logging

Dml error loggin is around since Oracle version 10.2.0.1
What is it.
One time datawarehouse was running a job that was inserting more then 10 milion rows.
Almost at the end the bacth job failed with ORA-00001: unique constraint violated
That let to some frustration because of the error message no rows where inserted.
As so many time Oracle has a soltion for this.

Here is a little example

CREATE TABLE t1 (col1 NUMBER PRIMARY KEY);

CREATE TABLE t2 (col1 NUMBER PRIMARY KEY);

INSERT INTO t1 VALUES(1);

INSERT INTO t1 VALUES(2);

INSERT INTO t1 VALUES(3);

INSERT INTO t1 VALUES(4);

INSERT INTO t2 VALUES(1);

INSERT INTO t2 VALUES(2);

INSERT INTO t2 VALUES(3);

INSERT INTO t2 VALUES(8);

INSERT INTO t2 VALUES(9);

COMMIT;

and here is the trick
SQL>EXECUTE DBMS_ERRLOG.CREATE_ERROR_LOG('t1',error_log_t1')

this means we put errorlogging on for table t1.and created the errorlog table error_log_t1
Now we going to insert rows into table t1 from table t2
SQL>insert into t1 select * from t2 log errors reject limit unlimited

2 rows created

That should have been 5 rows created.
Why where te rows rejected
select * from error_log_t1

ORA_ERR_NUMBER$ ORA_ERR_MESG$                                                COL

--------------- ------------------------------------------------------------ ---

              1 ORA-00001: unique constraint (GDA001.SYS_C0040470) violated  1

              1 ORA-00001: unique constraint (GDA001.SYS_C0040470) violated  2

              1 ORA-00001: unique constraint (GDA001.SYS_C0040470) violated  3

You see the error message and the value in the colomn under COL.

Which is correct because value 1,2,3 already exist in T1.

but al the other rows are inserted instead of when you not using dml error logging.

Thats it