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
Credits
About the Author
About the Reviewers
Preface

Scheduler management


Managing the Scheduler in the database is a little vague. Most things are defined very clearly, but there is no such thing as the ability to stop or start the Scheduler in a supported way. In the Oracle RDBMS, there is the system privilege MANAGE SCHEDULER that enables you to define job classes, windows, and window groups. Setting and reading Scheduler attributes is controlled by this privilege, as is purging the Scheduler logs. The Scheduler attributes are listed in the ALL_SCHEDULER_GLOBAL_ATTRIBUTE view. Not all attributes listed here can be modified, and not all Scheduler attributes are listed. The current_open_window, for example, is a read-only and changes when the next window opens or the current window closes.

max_job_slave_processes can be used to limit the number of processes the Scheduler is allowed to use. The max_job_slave_processes parameter cannot be set to 0. In the earlier versions of Oracle, we could prevent the dbms_jobs jobs from running by setting...