Oracle Cron Jobs
Version 21c

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I can think of few things in our industry more worthless but still in common use than the Oracle cron job. Cron jobs, by essentially any measure, are both obsolete and functionally deficient. In this following rant I am going to publicly make a point that has needed to be made for a very long time.

Characteristic Database Scheduler Job *NIX Cron Job
Operating system support True True
Operating System interchangeable Jobs can be moved, seamlessly, between operating systems Jobs require rewrite between operating systems
Windows Support True False
O/S Access Required False True
DB Access Required True True
Languages Required SQL plus minimal PL/SQL SQL plus a shell scripting language
RAC Load Balance Aware TRUE FALSE
RAC Failover Aware TRUE FALSE
Data Guard Switchover Aware TRUE FALSE
Data Guard Failover Aware TRUE FALSE
Backed up by RMAN TRUE FALSE
Job Chaining Fully supported No support available
Flexibility Jobs may be modifiable while running Jobs cannot be modified while running
File Watching Fully integrated Non-existent
Job Grouping Fully integrated Non-existent
Job Windowing Jobs can be run solely within defined temporal windows Long running jobs have no windowing rules
Exception Handling Fully integrated Non-existent
Metadata Collection Extensive metadata collected for every run or failure Non-existent
Outage Aware Will never try to run if the database is not open Totally unaware of whether the database exists
Reporting Support Full support for SQL and a wide variety of third-party reporting tools None
Messaging Support Fully integrated with JMS through Advanced Queuing False
Bug Support Support available from Oracle Corp ROFLOL
Licensing Cost None None

When I add up the score I see cron capable of doing only one thing well ... running jobs in the O/S. At all but two other criteria cron is a miserable failure.

Still want to write a cron job? Be my guest but don't expect a non-Cretaceous DBA to support or maintain it any more than you should expect to find "VAX" or "PDP 11" on their CV.
Now that you have, I hope, been convinced to abandon the Paleolithic insanity that is cron the following link may help you locate the vermin so you can exterminate them. Linux: List / Display All Cron Jobs

# crontab -u oracle -l

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