Book Image

Mastering Oracle Scheduler in Oracle 11g Databases

By : Ronald Rood
Book Image

Mastering Oracle Scheduler in Oracle 11g Databases

By: Ronald Rood

Overview of this book

Scheduler (DBMS_SCHEDULER) is included in Oracle Database and is a tool for the automation, management, and control of jobs. It enables users to schedule jobs running inside the database such as PL/SQL procedures or PL/SQL blocks, as well as jobs running outside the database like shell scripts. Scheduler ensures that jobs are run on time, automates business processes, and optimizes the use of available resources. You just need to specify a fixed date and time and Scheduler will do the rest. What if you don't know the precise time to execute your job? Nothing to worry about, you can specify an event upon which you want your job to be done and Scheduler will execute your job at the appropriate time. Although scheduling sounds quite easy, it requires programming skills and knowledge to set up such a powerful, intelligent scheduler for your project. This book is your practical guide to DBMS_SCHEDULER for setting up platform-independent schedules that automate the execution of time-based or event-based job processes. It will show you how to automate business processes, and help you manage and monitor those jobs efficiently and effectively. It explains how Scheduler can be used to achieve the tasks you need to make happen in the real world. With a little understanding of how the Scheduler can be used and what kind of control it gives, you will be able to recognize the real power that many known enterprise-class schedulers ñ with serious price tags ñ cannot compete with. You will see how running a specific program can be made dependent on the successful running of certain other programs, and how to separate various tasks using the built-in security mechanisms. You will learn to manage resources to balance the load on your system, and gain increased database performance.
Table of Contents (15 chapters)
Mastering Oracle Scheduler in Oracle 11g Databases
About the Author
About the Reviewers


In addition to the permissions on these files, there also happen to be bugs in the Scheduler. If you ever plan to use chains, apply the patch for bug 5705385. It should be fixed in and, and is available as one-off patch for and This bug causes the situation in which a running chain exists without a running job. If you don't have this patch and you start a job that is running a chain, it ends successfully. The next run terminates upon startup. The third start will have the chain running again and the fourth run will again terminate upon startup.

By definition, no running chain can exist when there is no running job that runs the chain. Without this fix, the situation is a little different; a chain can exist in *_SCHEDULER_RUNNING_CHAINS without a job in *_SCHEDULER_RUNNING_JOBS.

Starting the job again cleans this situation up. In case you cannot apply this patch, it is possible to use the job event queue to trigger the detection of this situation...