14 copyright © 2004, oracle. all rights reserved. performance monitoring
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14Copyright © 2004, Oracle. All rights reserved.
Performance Monitoring
14-2 Copyright © 2004, Oracle. All rights reserved.
Objectives
After completing this lesson you should be able to do the following:
• Troubleshoot invalid and unusable objects
• Gather optimizer statistics
• View performance metrics
• React to performance issues
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Performance Monitoring
Memory allocation
issues
Memory allocation
issues
Input/outputdevice
contention
Input/outputdevice
contention
Application code
problems
Application code
problems
Resourcecontention
Resourcecontention
Network bottlenecks
Network bottlenecks
?DBA
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Monitoring Methodologies
• Reactive
• Proactive– Server-generated alerts– Automated Database Diagnostic Monitor (ADDM)
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Database and Instance Metrics
Several hundred different performance statistics are available through:
• Data dictionary
• Dynamic performance views
• Optimizer statistics
DBA
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Data Dictionary Metrics
Object status:
• PL/SQL code objects
• Indexes
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Invalid and Unusable Objects
• PL/SQL code objects are recompiled.
• Indexes are rebuilt.
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Optimizer Statistics
Optimizer statistics are:
• Not real-time
• Persistent across instance restarts
SQL> SELECT COUNT(*) FROM hr.employees;
COUNT(*)
----------
214
SQL> SELECT num_rows FROM dba_tables
2 WHERE owner='HR' AND table_name = 'EMPLOYEES';
NUM_ROWS
----------
107
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Manually Gather Optimizer Statistics
• If database was not created with the DBCA
• If tables are extremely volatile
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Automate Optimizer Statistics Collection
Use the Oracle Scheduler to automate customized statistics collection.
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Schedule Optimizer Statistics Collection
Statistics should be gathered as needed to ensure the optimizer can make appropriatedecisions.
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Dynamic Performance Views
Dynamic Performance views are:
• Real-time
• Non-persistent across instance restarts
SQL> SELECT name, value FROM v$sysstat
2 WHERE name='sorts (memory)' ORDER BY name;
NAME VALUE
--------------- ----------
sorts (memory) 1979183
SQL> /
NAME VALUE
--------------- ----------
sorts (memory) 1979184
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Viewing Metric Information
• Use the All Metrics link in the Related Links region.
• Drill-down for in-depth analysis.
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Reacting to Performance Issues
Use Enterprise Manager to:
• Find key performance issues
• Drill down to the root cause
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Reacting to Performance Issues
Drill down into performance measurements to identify bottlenecks
• Key bottleneck: log buffer space
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Summary
In this lesson you should have learned how to:
• Troubleshoot invalid and unusable objects
• Gather optimizer statistics
• View performance metrics
• React to performance issues
14-20 Copyright © 2004, Oracle. All rights reserved.
Practice 14: Monitoring Performance
This practice covers the following:
• Viewing performance metrics
• Repairing unusable indexes
• Manually collecting optimizer statistics
• Automating statistics collection