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Proactive Maintenance

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Objectives

After completing this lesson you should be able to do the following:

• Set warning and critical alert thresholds

• Collect and use baseline metrics

• Use tuning and diagnostic advisors

• Use the Automatic Database Diagnostic Monitor (ADDM)

• Manage the Automatic Workload Repository

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Server Generated Alerts

Serveralertsqueue

Metric exceeds

threshold

AWR

Enterprise Manager

Oracle instance

Oracle instance

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Thresholds

Each metric can be assigned two thresholds:• Warning• Critical

When thresholds are reached, alerts are triggered by:• Notifications that appear in the Alerts region of the

Database Control home page• Optional e-mail alerts

ALERT

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Setting Thresholds

Enterprise Manager’s Manage Metrics property page provides access to threshold settings.

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Baseline Measurements

Baseline measurements provide threshold recommendations based on actual performance data.

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Using Baselines

To activate a stored baseline:

1. Click Copy Thresholds

From Baseline.

2. Select the appropriate threshold.

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Tuning and Diagnostic Advisors

Oracle Database 10g provides several tuning and diagnostic advisors:

• Automatic Database Diagnostic Monitor (ADDM)

• SQL Tuning and Access Advisors

• Memory Advisor

• Mean-Time-To-Recover (MTTR) Advisor

• Segment Advisor

• Undo Management Advisor

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SQL Tuning and Access Advisors

DBA

Poorly performingSQL statement

How can I make it run

faster?

SQL TuningAdvisor

RestructuredSQL statement

Add indexes or materialized views

Rewrite the SQL statement

Correct setup flaws

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Memory Advisors

• Shared pool

• Database buffer cache

• Program Global Area (PGA)

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Segment Advisor

• Entire tablespace

• Individual schema objects

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Automatic Workload Repository (AWR)

• Built-in repository of performance information

• Snapshots of database metrics are taken every 60 minutes and retained for 7 days

• Foundation for all self-management functions

SnapshotsMMONIn-memorystatistics

AWRSGA

60 minutes

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Managing the AWR

• Retention period– Default 7 days– Consider storage needs

• Collection interval– Default 30 minutes– Consider storage needs, performance impact

• Collection level– Basic (disables most of ADDM functionality) – Typical (recommended)– All (adds additional SQL tuning information to snapshots)

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Automatic Database Diagnostic Monitor (ADDM)

• Runs after each AWR snapshot

• Monitors the instance and detects bottlenecks

• Results stored within the AWR

Snapshots

ADDM

AWR

EMADDM results

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ADDM Findings

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ADDM Recommendations

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Summary

In this lesson you should have learned how to:

• Set warning and critical alert thresholds

• Collect and use baseline metrics

• Use tuning and diagnostic advisors

• Use the Automatic Database Diagnostic Monitor (ADDM)

• Manage the Automatic Workload Repository

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Practice 15: Proactive Maintenance

This practice covers configuring your database for proactive maintenance.