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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
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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Proactive Maintenance
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
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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
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Overview of Thresholds and Metric
Baselines: Adaptive Thresholds
Adaptive thresholdsEnd ofbaseline
Metric
Time
Value
Deviations captured
Critical
Warning
Normal
Grouping
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Metric Baselines and Thresholds:
Concepts
Baseline period
Static
baseline
Moving
window
Metric threshold
FixedAdaptive
Time
grouped
Percent of
MAX
Significance
level
Automaticallycomputed
baseline
statistics
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Metric Baseline and Threshold
Full Notes Page
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Editing Thresholds
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Enabling Metric Baselining
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Creating Static Metric Baselines
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Server-Generated Alerts
Server
alerts
queue.
Metric exceeds
threshold.
AWR
Enterprise Manager
Oracle
instance
Baseline
> Alert
AWR
ADDM
Advisors
AutoTasks
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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
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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
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Creating and Testing an Alert
1. Specify a threshold.
2. Create a test case.
3. Check for an alert.
2 1
3
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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
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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
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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
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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
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Enterprise Manager and AWR
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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)
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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
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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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Proactive Maintenance
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:
Proactive Maintenance
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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