Edition-based Redefinition The Key to Zero-Downtime Application Patching and Upgrade (Bryn Llewellyn)
In general, patching or upgrading the artifacts in an Oracle Database that implement an applications back end involves changing two or more functionally dependent objects. Because each DDL autocommits, such changes inevitably imply that the system is mutually inconsistent once the patching begins and that its integrity is regained only when patching completes. Before EBR, your only option, therefore, was to take downtime. EBR allows you to create a semantic copy of the live system within the same database so that you can make your changes to that while the live system remains in interruped use. Of course, the quota-consuming data nust be mutually synchronized, transactionally. EBR supports this too. This workshop explains how it all works.
At the end of this workshop, you will appreciate the conceptual and practical challenges that any technology that aims to support zero-downtime application patching must meet. You will understand how EBR meets these challenges. And you will realize that no other conceivable approach could meet these. You will gain a deep understanding of EBRs key features: the edition, the editioning view, and the crossedition trigger. The workshop will prioritize giving you a robust mental model so that you will be able confidently to design how you will adopt EBR in your database and then implement EBR exercises to meet your zero-downtime patching requirements. You will be shown the SQL statements and PL/SQL subprogram calls that you need in sufficient detail to make your new understanding concrete and immediately usable.