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12Copyright 2005, Oracle. All rights reserved.

Proactive Maintenance


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12-2 Copyright 2005, Oracle. All rights reserved.

Objectives

After completing this lesson, you should be able to do

the following:

Set warning and critical alert thresholds

Use server-generated alerts Collect and use baseline metrics

Manage the Automatic Workload Repository

(AWR)

Use the Automatic Database Diagnostic Monitor Describe the advisory framework


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Automatic

Workload

Repository

Server

alerts

Automated

tasks

Advisory

framework

Data warehouse

of the databaseAutomatic collection

of important statistics

Direct memory

access

Automatic Proactive

Efficient


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Introduction of Concepts and Related

Tasks

Thresholds and metric baselines

Enabling metric baselining

Server-generated alerts

Creating and testing an alert Automatic Workload Repository (AWR)

Managing the AWR

Automatic Database Diagnostic Monitor (ADDM)

Advisory framework Automated maintenance tasks

> Baseline

Alert

AWRADDM

Advisors

AutoTasks


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Introducing Terminology

Baseline: Data gathered of a normal running

database for performance comparison

Metric: Rate of change in a cumulative statistic

Threshold: A boundary value against which metricvalues are compared


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Cyclic Nature of Workloads

End of day 1

OLTP DW

Metric

Time

ValueEnd of day 2 End of day 3


7/3812-7 Copyright 2005, Oracle. All rights reserved.

Overview of Thresholds and Metric

Baselines: Fixed Thresholds

Fixed

thresholds

OLTP DW

Metric

Time

Value

Deviations missed

Critical

Warning

End of day 1 End of day 2 End of day 3



Overview of Thresholds and Metric

Baselines: Adaptive Thresholds

Adaptive thresholdsEnd ofbaseline

Metric

Time

Value

Deviations captured

Critical

Warning

Normal

Grouping



Metric Baselines and Thresholds:

Concepts

Baseline period

Static

baseline

Moving

window

Metric threshold

FixedAdaptive

Time

grouped

Percent of

MAX

Significance

level

Automaticallycomputed

baseline

statistics



Metric Baseline and Threshold

Full Notes Page



Editing Thresholds



Enabling Metric Baselining



Creating Static Metric Baselines



Server-Generated Alerts

Server

alerts

queue.

Metric exceeds

threshold.

AWR

Enterprise Manager

Oracle

instance

Baseline

> Alert

AWR

ADDM

Advisors

AutoTasks



Server-Generated Alert Types

MMON

85% Warning

97% Critical Cleared

Cleared

Alert

SnapshotToo Old

Resumable

SessionSuspended

Recovery Area

Low OnFree Space

Metric based

Event based

Threshold

(stateful)

alerts

Nonthreshold

(stateless)

alerts

DBA_OUTSTANDING_ALERTS DBA_ALERT_HISTORY



Default Server-Generated Alerts

Resumable

Session

Suspended

Snapshot

Too Old

Recovery Area

Low On

Free Space

85% Warning

97% Critical

Tablespace

space usage

Database Control:

SYSTEMmetrics

Tablespace



Creating and Testing an Alert

1. Specify a threshold.

2. Create a test case.

3. Check for an alert.

2 1

3



Where We Are

Thresholds and metric baselines

Enabling metric baselining

Server-generated alerts

Creating and testing an alert Automatic Workload Repository (AWR)

Managing the AWR

Automatic Database Diagnostic Monitor (ADDM)

Advisory framework Automated maintenance tasks



Automatic Workload Repository (AWR)

Built-in repository of performance

information

Snapshots of database metrics taken every

60 minutes and retained for 7 days

Foundation for all self-management

functions

MMONIn-memorystatistics Snapshots

AWRSGA

60 minutes

Baseline

Alert

> AWRADDM

Advisors

AutoTasks



AWR Infrastructure

SGA

V$ DBA_*

ADDMSelf-tuning

component

Self-tuning

component

Internal clients

External clients

EM SQL*Plus

Efficient

in-memory

statistics

collection

AWR

snapshotsMMON



AWR Snapshot Sets

DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE ( - start_snap_idIN NUMBER ,

end_snap_id IN NUMBER ,

baseline_name IN VARCHAR2);

Relevant periodin the past



Enterprise Manager and AWR



Managing the AWR

Retention period:

The default is 7 days.

Consider storage needs.

Collection interval: The default is

60 minutes.

Consider storage needs and performance impact.

Collection level:

Basic (disables most of ADDM functionality)

Typical (recommended)

All (adds additional SQL tuning information to

snapshots)



Automatic Database Diagnostic Monitor

(ADDM)

Runs after each AWR snapshot

Monitors the instance; detects bottlenecks

Stores results within the AWR

Snapshots

ADDM

AWR

EM

ADDM results

BaselineAlert

AWR> ADDMAdvisorsAutoTasks



ADDM Findings

1

2

3


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ADDM Recommendations


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Advisory Framework

ADDM

SQL Tuning

Advisor

SQL Access

Advisor

Memory

Space

PGA Advisor

SGA

Segment Advisor

Undo Advisor

Buffer Cache

Advisor

Library Cache

Advisor

PGA

Backup MTTR Advisor

Baseline

Alert

AWR

ADDM

> AdvisorsAutoTasks


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Advisors

Full Notes Page


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SQL Tuning and Access Advisors

DBA

Poorly performing

SQL statement

SQL Tuning

Advisor

Restructured

SQL statement

Correct setup flaws.

Rewrite the SQL

statement.

Add indexes or

materialized views.

How can I

make it run

faster?


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Memory Advisors

Shared pool

Database buffer cache

Program Global Area (PGA)

Tip: Enable ASMM.


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Segment Advisor

Entire

tablespace

Individual

schema

objects


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Enterprise Manager and Advisors


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The DBMS_ADVISORPackage

Creates a script of all the recommendations

that are acceptedGET_TASK_SCRIPT

Marks one or more recommendations as

accepted, rejected, or ignoredMARK_RECOMMENDATION

Modifies a task parameterSET_TASK_PARAMETER

Updates task attributesUPDATE_TASK_ATTRIBUTE

S

Causes a suspended task to resumeRESUME_TASK

Creates and returns a text report for the

specified taskGET_TASK_REPORT

Suspends a task that is currently executingINTERRUPT_TASK

Initiates execution of the taskEXECUTE_TASK

Deletes a task from the repositoryDELETE_TASK

Creates a new task in the repositoryCREATE_TASKDescriptionProcedure


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Automated Maintenance Tasks

Scheduler initiates jobs.

Jobs run in default maintenance window.

Limit maintenance impact on normal

operation by using Resource Manager.Maintenance examples:

Gathering optimizer statistics

Gathering segment information

Backing up database

Baseline

Alert

AWR

ADDM

Advisors

> AutoTasks


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A review of major elements working together:

AutomaticWorkload

Repository

Server

alerts

Automated

tasks

Advisory

framework

Automatic Proactive

Efficient


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Summary

In this lesson, you should have learned how to:

Set warning and critical alert thresholds

Use server-generated alerts

Collect and use baseline metrics Manage the Automatic Workload Repository

(AWR)

Use the Automatic Database Diagnostic Monitor

Describe the advisory framework


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Practice Overview:


This practice covers configuring your database for

proactive maintenance by:

Configuring an alert and testing it

Enabling metric baselines Creating a static metric baseline to compute

statistics

Deleting the baseline


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