The Database Common Management Infrastructure

Page 43

V$EVENT_HISTOGRAM

The V$EVENT_HISTOGRAM view provides a number of buckets that contain wait events that are summarized into several time-related buckets for each event, based on the time that they occurred. The amount of time that each bucket represents is found in the WAIT_TIME_MILLI column, thus you can order on that column to display the wait events in the order that they occur.

V$FILE_HISTOGRAM

The V$FILE_HISTOGRAM view provides a number of buckets that contain datafile block read times that are summarized into several time-related buckets for each block read and how long that read occurred. The amount of time (in milliseconds) that each bucket represents is found in the SINGLEBLKRDTIME_MILLI column.

V$TEMP_HISTOGRAM

The V$TEMP_HISTOGRAM view provides a number of buckets that contain tempfile block read times that are summarized into several time-related buckets for each block read and how long that read occurred. The amount of time (in milliseconds) that each bucket represents is found in the SINGLEBLKRDTIME_MILLI column.

It was a challenge to decide whether the new Oracle Database 10g Common Management Infrastructure (CMI) features belong in this chapter or in Chapter 2 on manageability, or even in Chapter 1 with the introduction of the Grid. Since the biggest benefit of these new features ultimately results in performance benefits, I decided to introduce these new features here. The CMI consists of various components, and I will discuss the new architecture first in this section.

CMI Architecture Overview

Oracle Database 10g offers assistance in performance tuning (and monitoring) of the database through the new Oracle Database 10g Common Management Infrastructure. This infrastructure involves several different architectural components that are brought together to make Oracle Database 10g perform better and to make it easier to manage. The following are the main components of the CMI:

The Automatic Workload Repository (AWR) enables Oracle Database 10g to collect and store performance-related statistics. Additionally, the AWR provides services to process and maintain that information.