DB Time Basics

The concept and measurement of Database Time (DB Time) has been the cornerstone of Oracle performance analysis since RDBMS version 10, and should be well understood by all Oracle DBAs. This talk will present the core fundamentals as originally conceived and instrumented, by a direct participant.

This talk will introduce the fundamental concept of Database Time (DB Time) as the bedrock metric underlying Oracle performance management methods and technologies developed in version 10 of the RDBMS and continuing to this day. It is necessary for beginners to understand and experts to re-contemplate the core meaning of this concept and it’s instantiation in foundational infrastructure components.

We will discuss the following:

  • Definition of DB Time
  • Measurement of DB Time – Time Model
  • ASH Magic
  • Thinking in DB Time – Average Active Sessions
  • Performance Hub

Attendees will learn or be reminded about the fundamental meaning of DB Time as “user/enterprise time”. They will understand the basics of DB Time instrumentation in Time Model, AWR, and ASH. Finally, the usage of these core concepts to analyze and diagnose performance issues will be demonstrated using the Performance Hub.