EBR a new feature in 11gR2 Database which plays vital role in R12.2 Online Patching
Edition-Based Redefinition enables you to upgrade an application’s database objects while the application is in use, thus minimizing or eliminating down time. This is accomplished by changing (redefining) database objects in a private environment known as an edition.
Only when all changes have been made and tested then it make the new version of the application objects available to users.
Editioned Database Objects
• All code type objects support editioning
• The Database automatically manages multiple copies of these objects during patching
• All code type objects support editioning
• The Database automatically manages multiple copies of these objects during patching
As shown above, Patch and Run Edition of Application File system sees different Projection of the table.
Code in RUN edition will treat description as 30 Characters whereas Code in Patch edition will see the new expanded 80 Characters.
A new edition is created as a child of an existing edition. The changes are made in the child edition, while the parent edition remains available for use. Changes to data (such as when a patch is applied) are made by writing only to new columns or new tables not seen by the old edition.
EBR allows an application’s database objects to be changed without interrupting the application’s availability. For example, an Oracle E-Business Suite patch can be applied while users are logged in and active. This is accomplished by making the changes in the privacy of a new edition.
Key objects used by EBR include:
• Editioning views expose a different projection of a changed table to each edition, allowing each to see only its own columns.
• Cross-edition triggers propagate data changes made by the old edition into the columns of the new edition, which subsequently replaces the old edition.
Key objects used by EBR include:
• Editioning views expose a different projection of a changed table to each edition, allowing each to see only its own columns.
• Cross-edition triggers propagate data changes made by the old edition into the columns of the new edition, which subsequently replaces the old edition.
Creating a copy of the database part of the running system has been accomplished by taking advantage of the Oracle Database 11g R2 Edition-Based Redefinition (EBR) feature. This allows an application to efficiently store multiple copies of its application definition in the same database, and thereby enables online upgrade of the database tier.
The term edition refers to the isolation mechanism that allows pre-upgrade and post-upgrade schemas to co-exist. The simplest way to think of an edition is as a separate (isolated) copy of all database code objects that are changed by a patch.
The three types of database edition are:
• Run: Online users connect to this edition, which is always the default database edition. The run edition will always exist.
• Patch: Patching tools connect to this edition. A child of the run edition, the patch edition exists only while a patching cycle is in progress.
• Old: When a patch edition is promoted to be the run edition, the previous run edition is now regarded as an old edition. There may be zero or more old editions at a given time. They are discarded when full cleanup is performed. You cannot connect to an old edition.
• Run: Online users connect to this edition, which is always the default database edition. The run edition will always exist.
• Patch: Patching tools connect to this edition. A child of the run edition, the patch edition exists only while a patching cycle is in progress.
• Old: When a patch edition is promoted to be the run edition, the previous run edition is now regarded as an old edition. There may be zero or more old editions at a given time. They are discarded when full cleanup is performed. You cannot connect to an old edition.
No comments:
Post a Comment