14 Performance Monitoring Copyright 2004 Oracle All rights

















- Slides: 17

14 Performance Monitoring 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 14 -2 Copyright © 2004, Oracle. All rights reserved.

Performance Monitoring Memory allocation issues Resource contention Input/output device contention ? Application code problems 14 -3 DBA Copyright © 2004, Oracle. All rights reserved. Network bottlenecks

Monitoring Methodologies • • Reactive Proactive – Server-generated alerts – Automated Database Diagnostic Monitor (ADDM) 14 -4 Copyright © 2004, Oracle. All rights reserved.

Database and Instance Metrics Several hundred different performance statistics are available through: • Data dictionary • Dynamic performance views • Optimizer statistics DBA 14 -5 Copyright © 2004, Oracle. All rights reserved.

Data Dictionary Metrics Object status: • PL/SQL code objects • Indexes 14 -7 Copyright © 2004, Oracle. All rights reserved.

Invalid and Unusable Objects • • 14 -8 PL/SQL code objects are recompiled. Indexes are rebuilt. Copyright © 2004, Oracle. All rights reserved.

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 14 -10 Copyright © 2004, Oracle. All rights reserved.

Manually Gather Optimizer Statistics • • 14 -12 If database was not created with the DBCA If tables are extremely volatile Copyright © 2004, Oracle. All rights reserved.

Automate Optimizer Statistics Collection Use the Oracle Scheduler to automate customized statistics collection. 14 -13 Copyright © 2004, Oracle. All rights reserved.

Schedule Optimizer Statistics Collection Statistics should be gathered as needed to ensure the optimizer can make appropriate decisions. 14 -14 Copyright © 2004, Oracle. All rights reserved.

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 14 -15 Copyright © 2004, Oracle. All rights reserved.

Viewing Metric Information • • 14 -16 Use the All Metrics link in the Related Links region. Drill-down for in-depth analysis. Copyright © 2004, Oracle. All rights reserved.

Reacting to Performance Issues Use Enterprise Manager to: • Find key performance issues • Drill down to the root cause 14 -17 Copyright © 2004, Oracle. All rights reserved.

Reacting to Performance Issues Drill down into performance measurements to identify bottlenecks • 14 -18 Key bottleneck: log buffer space Copyright © 2004, Oracle. All rights reserved.

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 -19 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 14 -20 Copyright © 2004, Oracle. All rights reserved.