Book Image

Advanced Oracle PL/SQL Developer's Guide (Second Edition) - Second Edition

By : Saurabh K. Gupta
Book Image

Advanced Oracle PL/SQL Developer's Guide (Second Edition) - Second Edition

By: Saurabh K. Gupta

Overview of this book

Oracle Database is one of the most popular databases and allows users to make efficient use of their resources and to enhance service levels while reducing the IT costs incurred. Oracle Database is sometimes compared with Microsoft SQL Server, however, Oracle Database clearly supersedes SQL server in terms of high availability and addressing planned and unplanned downtime. Oracle PL/SQL provides a rich platform for application developers to code and build scalable database applications and introduces multiple new features and enhancements to improve development experience. Advanced Oracle PL/SQL Developer's Guide, Second Edition is a handy technical reference for seasoned professionals in the database development space. This book starts with a refresher of fundamental concepts of PL/SQL, such as anonymous block, subprograms, and exceptions, and prepares you for the upcoming advanced concepts. The next chapter introduces you to the new features of Oracle Database 12c, not limited to PL/SQL. In this chapter, you will understand some of the most talked about features such as Multitenant and Database In-Memory. Moving forward, each chapter introduces advanced concepts with the help of demonstrations, and provides you with the latest update from Oracle Database 12c context. This helps you to visualize the pre- and post-applications of a feature over the database releases. By the end of this book, you will have become an expert in PL/SQL programming and will be able to implement advanced concepts of PL/SQL for efficient management of Oracle Database.
Table of Contents (19 chapters)
Advanced Oracle PL/SQL Developer's Guide Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Result cache in Real Application Clusters


The Oracle Database Real Application Cluster (RAC) option allows the sharing of a cluster database across multiple database instances. It enhances the scalability and availability of database applications.

The Result cache, being the native component of database instance memory, is supported on RAC environments. The behavior and handling of result caching on RAC is the same as that of a single instance database. Here are the salient features of result caching in RAC:

  • Each RAC instance maintains a local version of the Server Result Cache in the shared pool of the SGA

  • A result is added to the instance result cache when a user executes a SQL query or a PL/SQL function on a database instance

  • If the same user executes the same query from another instance, the cached result is copied to that instance's result cache over RAC interconnect

  • The dynamic view GV$RESULT_CACHE_OBJECTS will show duplicate entries with the same cache ID, but for different instances ...