dbms_scheduler replaces cron for shell scripts Oracle Tips by Burleson Consulting

Question:  I hear that in Oracle 10g I can bypass crontab jobs for scheduling UNIX/Linux shell scripts.  Why is this better?

Answer: Yes, there are serious limitations to Linux crons, especially when the server is down when a shell script is set to execute, the job will be "missed".  The dbms_scheduler remembers missed jobs.

Here is a sample shell script invoked from dbms_scheduler. Note the use of program_type='EXECUTABLE':

BEGIN
-- Shell Script (OS executable file).
DBMS_SCHEDULER.create_program (
   program_name => 'test_executable_prog',
   program_type => 'EXECUTABLE',
   program_action => '/u01/app/oracle/dba/MyJob.ksh',
   number_of_arguments => 0,
   enabled => TRUE,
   comments => 'CREATE_PROGRAM test using a schell script.');
END;
/

Also, note that the user ID executing the script must have execute authority on the script (chmod 700), and these shell scripts normally run as the Oracle user who participates in the Linux DBA group.

For this and more details with dbms_scheduler, see Dr. Hall's book "Oracle Job Scheduling":

http://www.rampant-books.com/book_2005_1_scheduling.htm

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