Katharina Römer Principal Sales Consultant STCC Stuttgart ORACLE Deutschland GmbH

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3 Katharina Römer Principal Sales Consultant STCC Stuttgart ORACLE Deutschland GmbH

4 Performance Diagnosis Demystified: Best Practices for Oracle Database 10g

5 Agenda Oracle Database 10g Performance Monitoring & Diagnostics: Architecture Automatic Database Diagnostic Monitor (ADDM) Performance Diagnosis: Usage Model Best Practices

6 Oracle Database 10g Performance Monitoring & Diagnostics: Architecture

7 Performance Monitoring Architecture SGA In-memory statistics MMON Snapshots DBA Reactive monitoring Alerts ADDM Proactive monitoring ADDM results AWR

8 Automatic Workload Repository External clients EM SQL*Plus SGA Efficient in-memory statistics collection V$ DBA_% MMON AWR snapshots Internal clients ADDM Self-tuning component Self-tuning component

9 AWR In-Memory Statistics AWR statistics ASH In-memory statistics SGA V$SYSSTAT V$SQL V$SEGMENT_STATISTICS V$SYS_TIME_MODEL V$SYSMETRIC_HISTORY V$ACTIVE_SESSION_HISTORY...

10 Active Session History (ASH) Statistics ASH Rolling buffer V$SESSION SGA MMON MMNL Recent history V$ACTIVE_SESSION_HISTORY AWR snapshots

11 Base Statistics and Metrics Metrics are derived from base statistics Client 1 Client 2 Client 3 V$SYSMETRIC Metric 1 Metric 2 Base statistic MMON V$SESSMETRIC V$SERVICEMETRIC V$METRICNAME V$FILEMETRIC V$EVENTMETRIC V$WAITCLASSMETRIC Dynamic performance views

12 AWR Snapshots MMON ADDM finds top problems SGA In-memory statistics SYSAUX 6:00am 7:00am 8:00am 9:00am Snapshot 1 Snapshot 2 Snapshot 3 Snapshot 4 9:00 am

13 Statistics Levels STATISTICS_LEVEL BASIC TYPICAL ALL Disable all self-tuning capabilities Recommended default value Additional statistics for manual SQL diagnostics

14 Oracle Database 10g Automatic Database Diagnostic Monitor (ADDM)

15 ADDM Performance Monitoring MMON 60 minutes In-memory statistics SGA Snapshots ADDM ADDM results EM AWR ADDM results

16 Problem Classification System System wait RAC waits Concurrency Buffer busy Parse latches Buf cache latches Symptoms I/O waits Nonproblem areas Root causes

17 Advisory Framework ADDM SQL Tuning Advisor Memory SQL Access Advisor PGA SGA PGA Advisor Buffer Cache Advisor Library Cache Advisor Space Segment Advisor Undo Advisor

18 Oracle Database 10g Performance Diagnosis: Usage Model

19 Performance Monitoring Solutions SGA In-memory statistics MMON Snapshots DBA Reactive monitoring Alerts ADDM Proactive monitoring ADDM results AWR

20 Proactive Performance Diagnosis Database performs Proactive Diagnosis periodically Automatic Database Diagnostic Monitor (ADDM) findings are stored in Advisory Framework Enable historical performance analysis Can be invoked manually Oracle Enterprise Manager 10g provides guided problem resolution

21 Grid Control and ADDM Findings

22 ADDM Analysis Results 1 2 3

23 ADDM Recommendations

24 ADDM Recommendations

25 Grid Control and ADDM Task

26 Reactive Performance Diagnosis Perform General Manual Analysis React to an alert or validate tuning action Use Oracle Enterprise Manager 10g Performance Page drill-downs Diagnosing Targeted ploblems Transient or Transient performance analysis (few minutes) Targeted Analysis: Time,session,module,SQL, etc. or their combination Use ASH report Diagnosing problems due to Database workload or configuration changes Compare Performance to Baseline Use Compare Periods Report Diagnosing Slow Moving / Hung Databases Use Oracle Enterprise Manager 10g Memory Access Mode and Hang Analysis

27 Database Home Page

28 Database Performance Page

29 Database Performance Page

30 Active Sessions Waiting

31 Active Sessions Working: CPU Used

32 SQL Details

33 SQL Explain Plans: Topology Viewer

34 Session Details

35 Generate ASH Reports

36 Generate AWR Reports

37 Compare Periods: Results

38 Diagnosing Hung or Extremely Slow Databases Oracle Database 10g Release 2 enhances problem analysis when the database is performing very slowly, or is hung, with the following functionality: Direct attach to SGA for performance monitoring Referred to as Memory Access Mode Hang analysis using Oracle Enterprise Manager 10g

39 Monitoring in Memory Access Mode

40 Hang Analysis Using Enterprise Manager Real-time evaluation of waiting and blocked sessions Graphical view of blocked sessions and root blockers Drill down to details Quick root cause analysis of blocking problems

41 Hang Analysis Using Enterprise Manager

42 Oracle Database 10g Performance Diagnosis: Best Practices from Real-World Deployments

43 Performance Diagnosis: Best Practices Proactive Diagnosis Automatic Database Diagnostic Monitor (ADDM) Automatic Database Diagnostic Monitor (ADDM): Run ADDM Now Reactive Diagnosis General Manual Analysis: Oracle Enterprise Manager 10g Page Drill-Downs Transient or Targeted Analysis: ASH Report Workload Change Comparison: AWR Compare Periods Report Database Hung/Slow Moving: Oracle Enterprise Manager 10g Hang Analysis, Memory Access

44 Performance Diagnosis: Best Practices If licensed for Database Diagnostic and Tuning Packs, disable Statspack AWR is a super set of Statspack Running both at same time may impact Performance Do not change STATISTICS_LEVEL from default setting of TYPICAL TYPICAL: Recommended, Minimal Performance Overhead BASIC: Disables Self-Management, Not Recommended ALL: Advanced Diagnosis, Consult Support

45 Best Practices: Implementing Advisor Recommendations When to implement ADDM or other Advisor recommendations? Look for persistent problems rather than one-off scenarios Gauge trends by running AWR/ADDM reports for longer time periods SQL Tuning Sets (STS) for tracking and tuning SQL statements STS can be used for capturing workload Can be transported to another system for testing

46 Best Practices: Implementing Advisor Recommendations Use rigorous change control mechanism when implementing recommendations Preserve interesting Advisory Task data Give meaningful Task Name and Description Change Task Expiration Date appropriately Preserve AWR raw data beyond retention using Preserved Snapshot Sets Support Purposes Future Compare Periods Analysis

47 Best Practices: Use ASH Data Sifting through the ASHes: Performance Analysis with the Oracle 10g Active Session History by Graham Wood, on OTN Make best use of ASH data Use ASH Report to get footprint of a target (session,sql_id) Always on, almost no overhead!! Avoids workload replay in most cases!! ASH simulation is available for even pre-10g Databases

48 D E M O N S T R A T I O N Performance Management

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