Oracle OEM Tuning Oracle Tips by Burleson Consulting

OEM Instance Efficiency Metrics

Oracle 10g OEM also allows the customization of important instance efficiency metrics as shown in Figure 19.6.  These track overall SGA efficacy each time an AWR snapshot is collected.  The AWR snapshot frequency is customizable and OEM displays the last snapshot collection date in the third column of the display.

Instance efficiency metrics are especially valuable when tracked over time.  For example, the DBA can request a customized alert when the following changes occur:

§         PGA cache Hit (%) drops by more than 10%.

§         PGA multi-pass executions increase above 5%.

This custom alert might indicate a change in SQL processing on the server that may be experiencing excessive disk sorting.  By alerting the DBA before the problem is fully manifested, OEM can be used to give the DBA an opportunity to adjust the resources just-in-time to address the issue before the end-users experience a response time delay.

Alerts Notification and Setup

Oracle Enterprise Manager can be used to send alert notifications to the DBA by pager or email. The following is an example of setting up an email notification for critical alerts using OEM.

From the Database Control page, click the Setup link visible in the header as well as footer areas.

Click Notification Methods on the Setup page. See Figure 19.8 below.

Complete the information needed for the Mail Sever portion on this screen. Users should get help from the network administrator or refer online help to know more about the mail server names, as a discussion on it is beyond the scope of this book.

From any Database Control page, click on the Preferences link visible in header or footer areas. See Figure 19.8 above.

Select General and enter an email address in the E-mail Address section.  Select Notification Rules to modify any default notification rules. This page will show how to change the severity settings for receiving notification.

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