Simulating ORA-errors or How to write custom message to Oracle alert log file

To test monitoring script or monitoring tool: Simulating ORA-errors

Writes to alert log:

SQL> exec dbms_system.ksdwrt(2, 'ORA-600: TEST :Check alert log');

PL/SQL procedure successfully completed.

Writes to trace file:

SQL> exec dbms_system.ksdwrt(1, 'ORA-600: TEST :Check udump');

PL/SQL procedure successfully completed.

Writes to alert log and trace file:

SQL> exec dbms_system.ksdwrt(3, 'ORA-600: TEST :Check alert log and udump');

PL/SQL procedure successfully completed.

Your alert log should look something like this:

Mon May 23 10:36:03 2014
ORA-600: TEST :Check alert log
Mon May 23 10:36:13 2014
ORA-600: TEST :Check alert log and udump

Your trace file should look something like this:

*** 2014-05-23 10:21:11.096

*** SERVICE NAME:(SYS$USERS) 2014-05-23 10:21:11.080

*** SESSION ID:(317.26206) 2014-05-23 10:21:11.080

*** 2014-05-23 10:35:53.782

ORA-600: TEST :Check udump

*** 2014-05-23 10:36:13.704

ORA-600: TEST :Check alert log and udump