For some reasons Oracle DBAs needs to write custom messages to the alert log for better commenting or readability. This can be achieved by dbms_system.ksdwrt package.
Here is the syntax:
execute sys.dbms_system.ksdwrt(<argument>,to_char(sysdate)|| ' -- ');
where the argument values can be
- 1 to write to trace file
- 2 to write to alert log file
- 3 to write both trace and alert logfile.
SQL> exec dbms_system.ksdwrt(2,'Database bounced for increasing the value of distributed_lock_timeout');
PL/SQL procedure successfully completed.
$ tail alert_prod9.log
Mon Aug 08 03:32:23 2011
Incremental checkpoint up to RBA [0x4a.107ae1.0], current log tail at RBA [0x4a.1084ae.0]
Mon Aug 08 04:02:29 2011
Incremental checkpoint up to RBA [0x4a.109252.0], current log tail at RBA [0x4a.109d5e.0]
Mon Aug 08 04:06:39 2011
Database bounced for increasing the value of distributed_lock_timeout