Sunday, May 22, 2016

Ensuring Data Protection Using Oracle Flashback Features - Part 5

Introduction

In the previous article we have reviewed Oracle 11g and 12c Flashback new features and enhancements.
In this part (last one in this articles series) we will review the Oracle Flashback licensing. In addition, we will also summarize everything and we will see which Oracle Flashback feature should be used in various human errors use cases.

Oracle Flashback - Licensing 

Most of the powerful Flashback features require having a license for the Enterprise Edition. This includes the following features:
  • Flashback Table
  • Flashback Drop
  • Flashback Transaction Query
  • Flashback Transaction
  • Flashback Database
Flashback Query and Flashback Version Query are available for all Oracle Editions. As for Flashback Data Archive, starting from 11.2.0.4, it is supported for all of the Oracle Editions, but for versions earlier than 11.2.0.4, it requires having a license for the Enterprise Edition + Oracle Advanced Compression option (extra cost option).

Figure 1: Oracle Flashback Features Licensing

Summary
Oracle Flashback technology provides a set of tools which can be used by the DBA in order to recover from various human errors that caused undesired data loss or data modifications. The following table summarizes this article by explaining which Oracle Flashback feature is most suitable per each scenario:

Figure 2: Various Use Cases for using Oracle Flashback Features

The great thing about Oracle Flashback technology is that it allows recovering from various human errors with the minimum effort and time, which results in a reduced RTO (Recovery Time Objective). Having said that, Oracle Flashback technology should never be used as a replacement of the traditional backups, but rather as a complementary solution that provides a very effective way to recover from various human errors and does not require restoring and recovering data using backup (either RMAN or user-managed backups). For example, Oracle Flashback technology will not protect against the following scenarios:
  • Loss of data file or control file
  • Block corruptions (either physical or logical)
  • Site disaster 


The article reviewed the Oracle Flashback technology from Oracle version 9i – where the first flashback feature named “Flashback Query” was introduced, up to the most recent Oracle Database version (12.1.0.2). Oracle Flashback technology can definitely empower the DBAs by making their lives easier when it comes to protecting the data from various human errors.

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