Oracle DB Tunning

Aloha!
one of the DB that were using, experienced 100% CPU usage once it is accessed by a client and sometimes it stays at 100% even no one is using that said DB.
Also, the viewing response accessing a datasheet, using toad, is very poor. It takes 40 to 50 mins just to view a datasheet.
I believe it is just a simple tunning issue. Hope you could help me on this.
Thanks

TheHades0210 wrote:
Aloha!
one of the DB that were using, experienced 100% CPU usage once it is accessed by a client and sometimes it stays at 100% even no one is using that said DB.
Also, the viewing response accessing a datasheet, using toad, is very poor. It takes 40 to 50 mins just to view a datasheet.
I believe it is just a simple tunning issue. Hope you could help me on this.
ThanksIf a virus scanner is installed on the server, make certain that it does not scan the data, index, redo, control, or other files used by the database. I would also suggest excluding the Oracle binary files from the virus scanner checks.
While AWR/ASH might be helpful, a Diagnostic Pack license is required to use those features. Start simple. From a command line window (cmd.exe) on the server, execute the following command:
TASKLIST /S . /V /FO TABLE > C:\Running_Processes.txtIf the CPU is not yet at 100% utilization, start your report or whatever normally drives the CPU to 100% utilization. Run the following command when the CPU is heavily loaded:
TASKLIST /S . /V /FO TABLE > C:\Running_Processes2.txtThe above commands create two text files named C:\Running_Processes.txt and C:\Running_Processes2.txt. Open both of those files and see which process (image name) had the most significant increase in CPU Time by comparing that column in the two reports.
You might take a look at the following blog article that was scheduled for release about 7 hours ago:
http://hoopercharles.wordpress.com/2010/02/22/cpu-usage-monitoring-what-are-the-statistics-and-when-are-the-statistics-updated/
If the CPU consumption problem is caused by Oracle, you might try one of these utility scripts to find the cause of the performance problem within the database:
http://hoopercharles.wordpress.com/2010/02/09/working-with-oracle%e2%80%99s-time-model-data-3/
http://hoopercharles.wordpress.com/2010/01/09/drilling-into-session-detail-from-the-operating-system-on-the-windows-platform-2/
Charles Hooper
Co-author of "Expert Oracle Practices: Oracle Database Administration from the Oak Table"
http://hoopercharles.wordpress.com/
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.

Similar Messages

Oracle Performance tunning genral question

Hi,
Below is the list of Areas of Oracle db for which tunning activities are done. You are invited to comment to it weather this is complete list or need some addition or deletion. As I'm learning PT for Oracle now a days, therefore I want to expand my knowledge by sharing what I'm learning and what I need to learn.
So comment with Open hearts on it. Espically from experts and Gurus.
Here is the List
1-Planning for Performance, include Storage consideration( Weather it is SAN, NAS, DAS), Network planning and host OS planning with proper configuration for running Oracle.
2-Database desining (Not under-Normalized and not Over-Normalized with proper usage of Indexes, views and Stored Procedures)
3- Instance tunning (Memory structure + B.g Processes)
4- Session tunning.
5- Segment Space tunning.
6- SQL tunning.
This is what uptill what I've learned. If it needs addition kindly tell me what are these. Please also provide me links(good and precise one) for PT tutorials on web.Also note that I'm discussing this w.r.t Single instance non-rac db.
Looking for Good sugessions
Regards,
Abbasi

Hello,
This is the oracle course contents:
Contents
Preface
1 Introduction
Course Objectives 1-2
Organization 1-3
Agenda 1-4
What Is Not Included 1-6
Who Tunes? 1-7
What Does the DBA Tune? 1-8
How to Tune 1-10
Tuning Methodology 1-11
Effective Tuning Goals 1-13
General Tuning Session 1-15
Summary 1-17
2 Basic Tuning Tools
Objectives 2-2
Performance Tuning Diagnostics 2-3
Performance Tuning Tools 2-4
Tuning Objectives 2-5
Top Wait Events 2-6
DB Time 2-7
CPU and Wait Time Tuning Dimensions 2-8
Time Model: Overview 2-9
Time Model Statistics Hierarchy 2-10
Time Model Example 2-12
Dynamic Performance Views 2-13
Dynamic Performance Views: Usage Examples 2-14
Dynamic Performance Views: Considerations 2-15
Statistic Levels 2-16
Statistics and Wait Events 2-18
System Statistic Classes 2-19
Displaying Statistics 2-20
Displaying SGA Statistics 2-22
Wait Events 2-23
Using the V$EVENT_NAME View 2-24
Wait Classes 2-25
Displaying Wait Event Statistics 2-26
Oracle Internal & Oracle Academy Use Only
iv
Commonly Observed Wait Events 2-28
Using the V$SESSION_WAIT View 2-29
Precision of System Statistics 2-31
Using Features of the Packs 2-32
Accessing the Database Home Page 2-34
Enterprise Manager Performance Pages 2-35
Viewing the Alert Log 2-37
Using Alert Log Information as an Aid in Tuning 2-38
User Trace Files 2-40
Background Processes Trace Files 2-41
Summary 2-42
Practice 2 Overview: Using Basic Tools 2-43
3 Using Automatic Workload Repository
Objectives 3-2
Automatic Workload Repository: Overview 3-3
Automatic Workload Repository Data 3-4
Workload Repository 3-5
Database Control and AWR 3-6
AWR Snapshot Purging Policy 3-7
AWR Snapshot Settings 3-8
Manual AWR Snapshots 3-9
Managing Snapshots with PL/SQL 3-10
Generating AWR Reports in EM 3-11
Generating AWR Reports in SQL*Plus 3-12
Reading the AWR Report 3-13
Snapshots and Periods Comparisons 3-14
Compare Periods: Benefits 3-15
Compare Periods: Results 3-16
Compare Periods: Report 3-17
Compare Periods: Load Profile 3-18
Compare Periods: Top Events 3-19
Summary 3-20
Practice 3 Overview: Using AWR-Based Tools 3-21
4 Defining Problems
Objectives 4-2
Defining the Problem 4-3
Limit the Scope 4-4
Setting the Priority 4-5
Top Wait Events 4-6
Oracle Internal & Oracle Academy Use Only
v
Setting the Priority: Example 4-7
Top SQL Reports 4-8
Common Tuning Problems 4-9
Tuning Life Cycle Phases 4-11
Tuning During the Life Cycle 4-12
Application Design and Development 4-13
Testing: Database Configuration 4-14
Deployment 4-15
Production 4-16
Migration, Upgrade, and Environment Changes 4-17
ADDM Tuning Session 4-18
Performance Versus Business Requirements 4-19
Performance Tuning Resources 4-20
Filing a Performance Service Request 4-21
RDA Report 4-22
Monitoring and Tuning Tool: Overview 4-23
Summary 4-25
Practice 4 Overview: Identifying the Problem 4-26
5 Using Metrics and Alerts
Objectives 5-2
Metrics, Alerts, and Baselines 5-3
Limitation of Base Statistics 5-4
Typical Delta Tools 5-5
Oracle Database 11g Solution: Metrics 5-6
Benefits of Metrics 5-7
Viewing Metric History Information 5-8
Using EM to View Metric Details 5-9
Statistic Histograms 5-10
Histogram Views 5-11
Server-Generated Alerts 5-12
Database Control Usage Model 5-13
Setting Thresholds 5-14
Creating and Testing an Alert 5-15
Metric and Alert Views 5-16
View User-Defined SQL Metrics 5-17
Create User-Defined SQL Metrics 5-18
View User-Defined Host Metrics 5-19
Create User-Defined Host Metrics 5-20
Summary 5-21
Practice Overview 5: Working with Metrics 5-22
Oracle Internal & Oracle Academy Use Only
vi
6 Baselines
Objectives 6-2
Comparative Performance Analysis with AWR Baselines 6-3
Automatic Workload Repository Baselines 6-4
Moving Window Baseline 6-5
Baselines in Performance Page Settings 6-6
Baseline Templates 6-7
AWR Baselines 6-8
Creating AWR Baselines 6-9
Single AWR Baseline 6-10
Creating a Repeating Baseline Template 6-11
Managing Baselines with PL/SQL 6-12
Generating a Baseline Template for a Single Time Period 6-13
Creating a Repeating Baseline Template 6-14
Baseline Views 6-15
Performance Monitoring and Baselines 6-17
Defining Alert Thresholds Using a Static Baseline 6-19
Using EM to Quickly Configure Adaptive Thresholds 6-20
Changing Adaptive Threshold Settings 6-22
Summary 6-23
Practice 6: Overview Using AWR Baselines 6-24
7 Using AWR-Based Tools
Objectives 7-2
Automatic Maintenance Tasks 7-3
Maintenance Windows 7-4
Default Maintenance Plan 7-5
Automated Maintenance Task Priorities 7-6
Tuning Automatic Maintenance Tasks 7-7
ADDM Performance Monitoring 7-8
ADDM and Database Time 7-9
DBTime-Graph and ADDM Methodology 7-10
Top Performance Issues Detected 7-12
Database Control and ADDM Findings 7-13
ADDM Analysis Results 7-14
ADDM Recommendations 7-15
Database Control and ADDM Task 7-16
Changing ADDM Attributes 7-17
Retrieving ADDM Reports by Using SQL 7-18
Active Session History: Overview 7-19
Active Session History: Mechanics 7-20
Oracle Internal & Oracle Academy Use Only
vii
ASH Sampling: Example 7-21
Accessing ASH Data 7-22
Dump ASH to File 7-23
Analyzing the ASH Data 7-24
Generating ASH Reports 7-25
ASH Report Script 7-26
ASH Report: General Section 7-27
ASH Report Structure 7-28
ASH Report: Activity Over Time 7-29
Summary 7-30
Practice 7 Overview: Using AWR-Based Tools 7-31
8 Monitoring an Application
Objectives 8-2
What Is a Service? 8-3
Service Attributes 8-4
Service Types 8-5
Creating Services 8-6
Managing Services in a Single-Instance Environment 8-7
Everything Switches to Services 8-8
Using Services with Client Applications 8-9
Using Services with the Resource Manager 8-10
Services and Resource Manager with EM 8-11
Services and the Resource Manager: Example 8-12
Using Services with the Scheduler 8-13
Services and the Scheduler with EM 8-14
Services and the Scheduler: Example 8-16
Using Services with Parallel Operations 8-17
Using Services with Metric Thresholds 8-18
Changing Service Thresholds by Using EM 8-19
Services and Metric Thresholds: Example 8-20
Service Aggregation and Tracing 8-21
Top Services Performance Page 8-22
Service Aggregation Configuration 8-23
Service Aggregation: Example 8-24
Client Identifier Aggregation and Tracing 8-25
trcsess Utility 8-26
Service Performance Views 8-27
Summary 8-29
Practice 8 Overview: Using Services 8-30
Oracle Internal & Oracle Academy Use Only
viii
9 Identifying Problem SQL Statements
Objectives 9-2
SQL Statement Processing Phases 9-3
Parse Phase 9-4
SQL Storage 9-5
Cursor Usage and Parsing 9-6
SQL Statement Processing Phases: Bind 9-8
SQL Statement Processing Phases: Execute and Fetch 9-9
Processing a DML Statement 9-10
COMMIT Processing 9-12
Role of the Oracle Optimizer 9-13
Identifying Bad SQL 9-15
TOP SQL Reports 9-16
What Is an Execution Plan? 9-17
Methods for Viewing Execution Plans 9-18
Uses of Execution Plans 9-19
DBMS_XPLAN Package: Overview 9-20
EXPLAIN PLAN Command 9-22
EXPLAIN PLAN Command: Example 9-23
EXPLAIN PLAN Command: Output 9-24
Reading an Execution Plan 9-25
Using the V$SQL_PLAN View 9-26
V$SQL_PLAN Columns 9-27
Querying V$SQL_PLAN 9-28
V$SQL_PLAN_STATISTICS View 9-29
Querying the AWR 9-30
SQL*Plus AUTOTRACE 9-32
Using SQL*Plus AUTOTRACE 9-33
SQL*Plus AUTOTRACE: Statistics 9-34
SQL Trace Facility 9-35
How to Use the SQL Trace Facility 9-37
Initialization Parameters 9-38
Enabling SQL Trace 9-40
Disabling SQL Trace 9-41
Formatting Your Trace Files 9-42
TKPROF Command Options 9-43
Output of the TKPROF Command 9-45
TKPROF Output with No Index: Example 9-50
TKPROF Output with Index: Example 9-51
Generate an Optimizer Trace 9-52
Oracle Internal & Oracle Academy Use Only
ix
Summary 9-53
Practice Overview 9: Using Execution Plan Utilities 9-54
10 Influencing the Optimizer
Objectives 10-2
Functions of the Query Optimizer 10-3
Selectivity 10-5
Cardinality and Cost 10-6
Changing Optimizer Behavior 10-7
Using Hints 10-8
Optimizer Statistics 10-9
Extended Statistics 10-10
Controlling the Behavior of the Optimizer with Parameters 10-11
Enabling Query Optimizer Features 10-13
Influencing the Optimizer Approach 10-14
Optimizing SQL Statements 10-15
Access Paths 10-16
Choosing an Access Path 10-17
Full Table Scans 10-18
Row ID Scans 10-20
Index Operations 10-21
B*Tree Index Operations 10-22
Bitmap Indexes 10-23
Bitmap Index Access 10-24
Combining Bitmaps 10-25
Bitmap Operations 10-26
Join Operations 10-27
Join Methods 10-28
Nested Loop Joins 10-29
Hash Joins 10-31
Sort-Merge Joins 10-32
Join Performance 10-34
How the Query Optimizer Chooses Execution Plans for Joins 10-35
Sort Operations 10-37
Tuning Sort Performance 10-38
Reducing the Cost 10-39
Index Maintenance 10-40
Dropping Indexes 10-42
Creating Indexes 10-43
SQL Access Advisor 10-44
Table Maintenance for Performance 10-45
Oracle Internal & Oracle Academy Use Only
x
Table Reorganization Methods 10-46
Summary 10-47
Practice 10 Overview: Influencing the Optimizer 10-48
11 Using SQL Performance Analyzer
Objectives 11-2
Real Application Testing: Overview 11-3
Real Application Testing: Use Cases 11-4
SQL Performance Analyzer: Process 11-5
Capturing the SQL Workload 11-7
Creating a SQL Performance Analyzer Task 11-8
SQL Performance Analyzer: Tasks 11-9
Optimizer Upgrade Simulation 11-10
SQL Performance Analyzer Task Page 11-11
Comparison Report 11-12
Comparison Report SQL Detail 11-13
Tuning Regressing Statements 11-14
Preventing Regressions 11-16
Parameter Change Analysis 11-17
Guided Workflow Analysis 11-18
SQL Performance Analyzer: PL/SQL Example 11-19
SQL Performance Analyzer: Data Dictionary Views 11-21
Summary 11-22
Practice 11: Overview 11-23
12 SQL Performance Management
Objectives 12-2
Maintaining SQL Performance 12-3
Maintaining Optimizer Statistics 12-4
Automated Maintenance Tasks 12-5
Statistic Gathering Options 12-6
Setting Statistic Preferences 12-7
Restore Statistics 12-9
Deferred Statistics Publishing: Overview 12-10
Deferred Statistics Publishing: Example 12-12
Automatic SQL Tuning: Overview 12-13
SQL Statement Profiling 12-14
Plan Tuning Flow and SQL Profile Creation 12-15
SQL Tuning Loop 12-16
Using SQL Profiles 12-17
SQL Tuning Advisor: Overview 12-18
Oracle Internal & Oracle Academy Use Only
xi
Using the SQL Tuning Advisor 12-19
SQL Tuning Advisor Options 12-20
SQL Tuning Advisor Recommendations 12-21
Using the SQL Tuning Advisor: Example 12-22
Using the SQL Access Advisor 12-23
View Recommendations 12-25
View Recommendation Details 12-26
SQL Plan Management: Overview 12-27
SQL Plan Baseline: Architecture 12-28
Loading SQL Plan Baselines 12-30
Evolving SQL Plan Baselines 12-31
Important Baseline SQL Plan Attributes 12-32
SQL Plan Selection 12-34
Possible SQL Plan Manageability Scenarios 12-36
SQL Performance Analyzer and SQL Plan Baseline Scenario 12-37
Loading a SQL Plan Baseline Automatically 12-38
Purging SQL Management Base Policy 12-39
Enterprise Manager and SQL Plan Baselines 12-40
Summary 12-41
Practice 12: Overview Using SQL Plan Management 12-42
13 Using Database Replay
Objectives 13-2
Using Database Replay 13-3
The Big Picture 13-4
System Architecture: Capture 13-5
System Architecture: Processing the Workload 13-7
System Architecture: Replay 13-8
Capture Considerations 13-9
Replay Considerations: Preparation 13-10
Replay Considerations 13-11
Replay Options 13-12
Replay Analysis 13-13
Database Replay Workflow in Enterprise Manager 13-15
Capturing Workload with Enterprise Manager 13-16
Capture Wizard: Plan Environment 13-17
Capture Wizard: Options 13-18
Capture Wizard: Parameters 13-19
Viewing Capture Progress 13-20
Viewing Capture Report 13-21
Export Capture AWR Data 13-22
Oracle Internal & Oracle Academy Use Only
xii
Viewing Workload Capture History 13-23
Processing Captured Workload 13-24
Using the Preprocess Captured Workload Wizard 13-25
Using the Replay Workload Wizard 13-26
Replay Workload: Prerequisites 13-27
Replay Workload: Choose Initial Options 13-28
Replay Workload: Customize Options 13-29
Replay Workload: Prepare Replay Clients 13-30
Replay Workload: Client Connections 13-31
Replay Workload: Replay Started 13-32
Viewing Workload Replay Progress 13-33
Viewing Workload Replay Statistics 13-34
Packages and Procedures 13-36
Data Dictionary Views: Database Replay 13-37
Database Replay: PL/SQL Example 13-38
Calibrating Replay Clients 13-40
Summary 13-41
Practice 13: Overview 13-42
14 Tuning the Shared Pool
Objectives 14-2
Shared Pool Architecture 14-3
Shared Pool Operation 14-4
The Library Cache 14-5
Latch and Mutex 14-7
Latch and Mutex: Views and Statistics 14-9
Diagnostic Tools for Tuning the Shared Pool 14-11
AWR/Statspack Indicators 14-13
Load Profile 14-14
Instance Efficiencies 14-15
Top Waits 14-16
Time Model 14-17
Library Cache Activity 14-19
Avoid Hard Parses 14-20
Are Cursors Being Shared? 14-21
Sharing Cursors 14-23
Adaptive Cursor Sharing: Example 14-25
Adaptive Cursor Sharing Views 14-27
Interacting with Adaptive Cursor Sharing 14-28
Avoiding Soft Parses 14-29
Sizing the Shared Pool 14-30
Oracle Internal & Oracle Academy Use Only
xiii
Shared Pool Advisory 14-31
Shared Pool Advisor 14-33
Avoiding Fragmentation 14-34
Large Memory Requirements 14-35
Tuning the Shared Pool Reserved Space 14-37
Keeping Large Objects 14-39
Data Dictionary Cache 14-41
Dictionary Cache Misses 14-42
SQL Query Result Cache: Overview 14-43
Managing the SQL Query Result Cache 14-44
Using the RESULT_CACHE Hint 14-46
Using the DBMS_RESULT_CACHE Package 14-47
Viewing SQL Result Cache Dictionary Information 14-48
SQL Query Result Cache: Considerations 14-49
UGA and Oracle Shared Server 14-50
Large Pool 14-51
Tuning the Large Pool 14-52
Summary 14-53
Practice Overview 14: Tuning the Shared Pool 14-54
15 Tuning the Buffer Cache
Objectives 15-2
Oracle Database Architecture 15-3
Buffer Cache: Highlights 15-4
Database Buffers 15-5
Buffer Hash Table for Lookups 15-6
Working Sets 15-7
Tuning Goals and Techniques 15-9
Symptoms 15-11
Cache Buffer Chains Latch Contention 15-12
Finding Hot Segments 15-13
Buffer Busy Waits 15-14
Calculating the Buffer Cache Hit Ratio 15-15
Buffer Cache Hit Ratio Is Not Everything 15-16
Interpreting Buffer Cache Hit Ratio 15-17
Read Waits 15-19
Free Buffer Waits 15-21
Solutions 15-22
Sizing the Buffer Cache 15-23
Buffer Cache Size Parameters 15-24
Dynamic Buffer Cache Advisory Parameter 15-25
Oracle Internal & Oracle Academy Use Only
xiv
Buffer Cache Advisory View 15-26
Using the V$DB_CACHE_ADVICE View 15-27
Using the Buffer Cache Advisory with EM 15-28
Caching Tables 15-29
Multiple Buffer Pools 15-30
Enabling Multiple Buffer Pools 15-32
Calculating the Hit Ratio for Multiple Pools 15-33
Multiple Block Sizes 15-35
Multiple Database Writers 15-36
Multiple I/O Slaves 15-37
Use Multiple Writers or I/O Slaves 15-38
Private Pool for I/O Intensive Operations 15-39
Automatically Tuned Multiblock Reads 15-40
Flushing the Buffer Cache (for Testing Only) 15-41
Summary 15-42
Practice 15: Overview Tuning the Buffer Cache 15-43
16 Tuning PGA and Temporary Space
Objectives 16-2
SQL Memory Usage 16-3
Performance Impact 16-4
Automatic PGA Memory 16-5
SQL Memory Manager 16-6
Configuring Automatic PGA Memory 16-8
Setting PGA_AGGREGATE_TARGET Initially 16-9
Monitoring SQL Memory Usage 16-10
Monitoring SQL Memory Usage: Examples 16-12
Tuning SQL Memory Usage 16-13
PGA Target Advice Statistics 16-14
PGA Target Advice Histograms 16-15
Automatic PGA and Enterprise Manager 16-16
Automatic PGA and AWR Reports 16-17
Temporary Tablespace Management: Overview 16-18
Temporary Tablespace: Best Practice 16-19
Configuring Temporary Tablespace 16-20
Temporary Tablespace Group: Overview 16-22
Temporary Tablespace Group: Benefits 16-23
Creating Temporary Tablespace Groups 16-24
Maintaining Temporary Tablespace Groups 16-25
View Tablespace Groups 16-26
Monitoring Temporary Tablespace 16-27
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Temporary Tablespace Shrink 16-28
Tablespace Option for Creating Temporary Table 16-29
Summary 16-30
Practice Overview 16: Tuning PGA Memory 16-31
17 Automatic Memory Management
Objectives 17-2
Oracle Database Architecture 17-3
Dynamic SGA 17-4
Granule 17-5
Memory Advisories 17-6
Manually Adding Granules to Components 17-7
Increasing the Size of an SGA Component 17-8
Automatic Shared Memory Management: Overview 17-9
SGA Sizing Parameters: Overview 17-10
Dynamic SGA Transfer Modes 17-11
Memory Broker Architecture 17-12
Manually Resizing Dynamic SGA Parameters 17-13
Behavior of Auto-Tuned SGA Parameters 17-14
Behavior of Manually Tuned SGA Parameters 17-15
Using the V$PARAMETER View 17-16
Resizing SGA_TARGET 17-17
Disabling Automatic Shared Memory Management 17-18
Configuring ASMM 17-19
SGA Advisor 17-20
Monitoring ASMM 17-21
Automatic Memory Management: Overview 17-22
Oracle Database Memory Parameters 17-24
Automatic Memory Parameter Dependency 17-25
Enabling Automatic Memory Management 17-26
Monitoring Automatic Memory Management 17-27
DBCA and Automatic Memory Management 17-29
Summary 17-30
Practice 17: Overview Using Automatic Memory Tuning 17-31
Oracle Internal & Oracle Academy Use Only
xvi
18 Tuning Segment Space Usage
Objectives 18-2
Space Management 18-3
Extent Management 18-4
Locally Managed Extents 18-5
Large Extents: Considerations 18-6
How Table Data Is Stored 18-8
Anatomy of a Database Block 18-9
Minimize Block Visits 18-10
The DB_BLOCK_SIZE Parameter 18-11
Small Block Size: Considerations 18-12
Large Block Size: Considerations 18-13
Block Allocation 18-14
Free Lists 18-15
Block Space Management 18-16
Block Space Management with Free Lists 18-17
Automatic Segment Space Management 18-19
Automatic Segment Space Management at Work 18-20
Block Space Management with ASSM 18-22
Creating an Automatic Segment Space Management Segment 18-23
Migration and Chaining 18-24
Guidelines for PCTFREE and PCTUSED 18-26
Detecting Migration and Chaining 18-27
Selecting Migrated Rows 18-28
Eliminating Migrated Rows 18-29
Shrinking Segments: Overview 18-31
Shrinking Segments: Considerations 18-32
Shrinking Segments by Using SQL 18-33
Segment Shrink: Basic Execution 18-34
Segment Shrink: Execution Considerations 18-35
Using EM to Shrink Segments 18-36
Table Compression: Overview 18-37
Table Compression Concepts 18-38
Using Table Compression 18-39
Summary 18-40
19 Tuning I/O
Objectives 19-2
I/O Architecture 19-3
File System Characteristics 19-4
I/O Modes 19-5
Oracle Internal & Oracle Academy Use Only
xvii
Direct I/O 19-6
Bandwidth Versus Size 19-7
Important I/O Metrics for Oracle Databases 19-8
I/O Calibration and Enterprise Manager 19-10
I/O Calibration and the PL/SQL Interface 19-11
I/O Statistics: Overview 19-13
I/O Statistics and Enterprise Manager 19-14
Stripe and Mirror Everything 19-16
Using RAID 19-17
RAID Cost Versus Benefits 19-18
Should I Use RAID 1 or RAID 5? 19-20
Diagnostics 19-21
Database I/O Tuning 19-22
What Is Automatic Storage Management? 19-23
Tuning ASM 19-24
How Many Disk Groups per Database 19-25
Which RAID Configuration for Best Availability? 19-26
ASM Mirroring Guidelines 19-27
ASM Striping Granularity 19-28
What Type of Striping Works Best? 19-29
ASM Striping Only 19-30
Hardware RAID Striped LUNs 19-31
ASM Guidelines 19-32
ASM Instance Initialization Parameters 19-33
Dynamic Performance Views 19-34
Monitoring Long-Running Operations by Using V$ASM_OPERATION 19-36
ASM Instance Performance Diagnostics 19-37
ASM Performance Page 19-38
Database Instance Parameter Changes 19-39
ASM Scalability 19-40
Summary 19-41
20 Performance Tuning Summary
Objectives 20-2
Necessary Initialization Parameters with Little Performance Impact 20-3
Important Initialization Parameters with Performance Impact 20-4
Sizing Memory Initially 20-6
Database High Availability: Best Practices 20-7
Undo Tablespace: Best Practices 20-8
Temporary Tablespace: Best Practices 20-9
General Tablespace: Best Practices 20-11
Internal Fragmentation Considerations 20-12
Oracle Internal & Oracle Academy Use Only
xviii
Block Size: Advantages and Disadvantages 20-13
Automatic Checkpoint Tuning 20-14
Sizing the Redo Log Buffer 20-15
Sizing Redo Log Files 20-16
Increasing the Performance of Archiving 20-17
Automatic Statistics Gathering 20-19
Automatic Statistics Collection: Considerations 20-20
Commonly Observed Wait Events 20-21
Additional Statistics 20-22
Top 10 Mistakes Found in Customer Systems 20-23
Summary 20-25
Appendix A: Practices and Solutions
Appendix B: Using Statspack
Index

Oracle Performance Tunning

Hi All,
Can any one give me a good article explaining performance tuning in oracle,data gurd ,rman and RAC.
Even though I worked on this topics I am unable to answer some interview question like
How do you monitor your database?/how do you tune your DB....etc.
Earliest response would be appreciated.
Thank you.
Regards,
Rajini.

Hi Helios/Satish,
Thank you very much for reply .
One more thing is is there any document differentiating Oracle 10r2 and 11gr2 features for upgrading and understanding myself to 11g.
Rajini,
Edited by: user13355644 on Jul 22, 2011 2:26 AM

Oracle WebLogic Tunning

Dear All
i have WLS installed on Oracle Linux , and i want to make tunning to my WLs, can anyone help how to tune WLS ?
thanks

Some tips concerning operating system tuning can be found here: http://middlewaremagic.com/weblogic/?p=6040 (in particular the installing and configuring sections)
How to tune the JVM (HotSpot and JRockit) can be found here: http://middlewaremagic.com/weblogic/?p=6388
Overall tuning tips on WebLogic Server can be found here: http://middlewaremagic.com/weblogic/?p=6384

Query optimization in Oracle 8i (tunning)

Hi everyone,
The following SQL statement use more than 15% of the CPU of the machine where it is executed. Please if somebody can help me to rewrite or hinting the query.
This is the statement:
SELECT
/*+ INDEX(APD IDX_ABAPLANI_DET_SOL) */
apd.sinonimo,
apd.sinonimo_planificacion,
apd.cod_despensa,
apd.estante_cod,
apd.correlativo_solicitud,
apd.prioridad,
apd.correlativo_det_sol,
apd.insumo_sinonimo,
apd.cantidad_solicitada,
apd.cantidad_despachada,
apd.estado,
apd.sinonimo_usuario,
apd.sinonimo_observacion,
ap.fecha_creacion,
ap.centro_resultado,
aud.nombre,
aud.a_paterno,
aud.rut,
aud.username,
cenres.cod_flex codigocr,
insumo.cod_flex insumocod,
cenres.des_flex despensa_descripcion,
cenres.des_flex crdescripcion,
insumo.des_flex insumodescripcion
FROM
aba_usuario_despachador aud,
cenres,
insumo,
aba_planificacion_detalle apd,
aba_planificacion ap
WHERE ap.sinonimo = apd.sinonimo_planificacion
AND aud.sinonimo = apd.sinonimo_usuario
AND ap.centro_resultado = cenres.sinonimo
AND insumo.sinonimo = apd.insumo_sinonimo
AND apd.sinonimo_usuario = NVL (:b1, apd.sinonimo_usuario)
AND apd.sinonimo_planificacion = NVL (:b2, apd.sinonimo_planificacion)
AND apd.correlativo_solicitud = NVL (:b3, apd.correlativo_solicitud)
AND apd.estante_cod = NVL (UPPER (:b4), apd.estante_cod)
AND apd.cod_despensa = NVL (UPPER (:b5), apd.cod_despensa)
AND apd.estado = NVL (:b6, apd.estado)
AND ap.centro_resultado = NVL (:b7, ap.centro_resultado)
AND TO_DATE (TO_CHAR (ap.fecha_creacion, 'dd/mm/yyyy'), 'dd/mm/yyyy')
BETWEEN TO_DATE (NVL (:b8,TO_CHAR (ap.fecha_creacion, 'dd/mm/yyyy')),'dd/mm/yyyy')
AND TO_DATE (NVL (:b9,TO_CHAR (ap.fecha_creacion, 'dd/mm/yyyy')),'dd/mm/yyyy')
AND apd.estado NOT LIKE :b10
ORDER BY apd.sinonimo;The version of the database is 8.1.7.4.0.
Here is the output of EXPLAIN PLAN:
Plan
SELECT STATEMENT CHOOSECost: 2,907 Bytes: 104,312 Cardinality: 472
     32 SORT ORDER BY Cost: 2,907 Bytes: 104,312 Cardinality: 472
          31 CONCATENATION
               15 FILTER
                    14 NESTED LOOPS Cost: 11 Bytes: 52,156 Cardinality: 236
                         11 NESTED LOOPS Cost: 10 Bytes: 177 Cardinality: 1
                              8 NESTED LOOPS Cost: 9 Bytes: 133 Cardinality: 1
                                   5 NESTED LOOPS Cost: 8 Bytes: 67 Cardinality: 1
                                        2 TABLE ACCESS BY INDEX ROWID ADMABA.ABA_PLANIFICACION_DETALLE Cost: 7 Bytes: 52 Cardinality: 1
                                             1 INDEX FULL SCAN NON-UNIQUE ADMABA.IDX_ABAPLANI_DET_SOL Cost: 3 Cardinality: 1
                                        4 TABLE ACCESS BY INDEX ROWID ADMABA.ABA_PLANIFICACION Cost: 1 Bytes: 15 Cardinality: 1
                                             3 INDEX UNIQUE SCAN UNIQUE ADMABA.PK_ABA_PLANIFICACION Cardinality: 1
                                   7 TABLE ACCESS BY INDEX ROWID ADMABA.ABA_USUARIO_DESPACHADOR Cost: 1 Bytes: 3,498 Cardinality: 53
                                        6 INDEX UNIQUE SCAN UNIQUE ADMABA.ABA_USUARIO_DESPACHADOR_PK Cardinality: 53
                              10 TABLE ACCESS BY INDEX ROWID OPS$NUCLEO.NUC_CODIGOS_FLEXIBLES Cost: 1 Bytes: 14,828 Cardinality: 337
                                   9 INDEX UNIQUE SCAN UNIQUE OPS$NUCLEO.NUC_CODFLEX_PK Cardinality: 337
                         13 TABLE ACCESS BY INDEX ROWID OPS$NUCLEO.NUC_CODIGOS_FLEXIBLES Cost: 1 Bytes: 1.037.828 Cardinality: 23,587
                              12 INDEX UNIQUE SCAN UNIQUE OPS$NUCLEO.NUC_CODFLEX_PK Cardinality: 23,587
               30 FILTER
                    29 NESTED LOOPS Cost: 11 Bytes: 52,156 Cardinality: 236
                         26 NESTED LOOPS Cost: 10 Bytes: 177 Cardinality: 1
                              23 NESTED LOOPS Cost: 9 Bytes: 133 Cardinality: 1
                                   20 NESTED LOOPS Cost: 8 Bytes: 67 Cardinality: 1
                                        17 TABLE ACCESS BY INDEX ROWID ADMABA.ABA_PLANIFICACION_DETALLE Cost: 7 Bytes: 52 Cardinality: 1
                                             16 INDEX RANGE SCAN NON-UNIQUE ADMABA.IDX_ABAPLANI_DET_SOL Cost: 3 Cardinality: 1
                                        19 TABLE ACCESS BY INDEX ROWID ADMABA.ABA_PLANIFICACION Cost: 1 Bytes: 15 Cardinality: 1
                                             18 INDEX UNIQUE SCAN UNIQUE ADMABA.PK_ABA_PLANIFICACION Cardinality: 1
                                   22 TABLE ACCESS BY INDEX ROWID ADMABA.ABA_USUARIO_DESPACHADOR Cost: 1 Bytes: 3,498 Cardinality: 53
                                        21 INDEX UNIQUE SCAN UNIQUE ADMABA.ABA_USUARIO_DESPACHADOR_PK Cardinality: 53
                              25 TABLE ACCESS BY INDEX ROWID OPS$NUCLEO.NUC_CODIGOS_FLEXIBLES Cost: 1 Bytes: 14,828 Cardinality: 337
                                   24 INDEX UNIQUE SCAN UNIQUE OPS$NUCLEO.NUC_CODFLEX_PK Cardinality: 337
                         28 TABLE ACCESS BY INDEX ROWID OPS$NUCLEO.NUC_CODIGOS_FLEXIBLES Cost: 1 Bytes: 1.037.828 Cardinality: 23,587
                              27 INDEX UNIQUE SCAN UNIQUE OPS$NUCLEO.NUC_CODFLEX_PK Cardinality: 23,587                Thanks in advance!
Edited by: user491853 on 21-ago-2012 15:29

A few comments looking at your sql query:
How much time the query is taking?
How many rows are there in the tables?
Make sure the stats are up-to-date.
Please kindly follow the instructions provided by others as well.
>
The version of the database is 8.1.7.4.0
>
Suggestion: Upgrade your version. Oracle Cost Based Optimizer is more smarter now.Upgrading will make your life much more easier as there are so many enhancements.
AND TO_DATE (TO_CHAR (ap.fecha_creacion, 'dd/mm/yyyy'), 'dd/mm/yyyy')
BETWEEN TO_DATE (NVL (:b8,TO_CHAR (ap.fecha_creacion, 'dd/mm/yyyy')),'dd/mm/yyyy')
AND TO_DATE (NVL (:b9,TO_CHAR (ap.fecha_creacion, 'dd/mm/yyyy')),'dd/mm/yyyy')Why are you using TO_DATE/TO_CHAR on a date column?
AND ap.centro_resultado = NVL (:b7, ap.centro_resultado)the same can be rewritten as below:
AND (ap.centro_resultado =:b7 and :b7 is not null) or :b7 is null This applies to other predicates you are using as well.
The table used in the plan is not found in your sql query eg NUC_CODIGOS_FLEXIBLES.
Regards
Biju

Oracle Forms6i Tunning

Hi All,
I am working on a Forms 6i application with Oracle 10gr2.There is a form in the application in the form which is taking too much time in post query.This form consists of so many database blocks and so many master child relationships.
May i know from experts that ,how to identify the time is consume by the form and database objects in the event post query.
I have tried the given below mention command :
1.ifrun60 module=xyz.fmx userid=scott/tiger@test record=performance log=testform.log
2.ifrun60 module=xyz.fmx userid=scott/tiger@test record=collect log=testform.log
I am not able to read the output of those two files.
Waiting for your reply.......
Thanks,

user3351545 wrote:
Hi All,
I am working on a Forms 6i application with Oracle 10gr2.There is a form in the application in the form which is taking too much time in post query.This form consists of so many database blocks and so many master child relationships.
May i know from experts that ,how to identify the time is consume by the form and database objects in the event post query.
I have tried the given below mention command :
1.ifrun60 module=xyz.fmx userid=scott/tiger@test record=performance log=testform.log
2.ifrun60 module=xyz.fmx userid=scott/tiger@test record=collect log=testform.log
I am not able to read the output of those two files.
Waiting for your reply.......
Thanks,As far as I know there is no (automatic) way to determine the way how long form takes for it's stuff, for DB-Objects you could use DBMS_PROFILER, that works pretty well, I personally use the PL/SQL-Developer from allroundautomations to display the results (easy-cheasy with graph) and there is a trial available http://www.allroundautomations.com/. http://docs.oracle.com/cd/B19306_01/appdev.102/b14258/d_profil.htm

Oracle Application 12.1.1 Tunning

Dear All,
Please can any one provide me the Oracle Application Tunning and check list.
Thanks
Raags INDIA.

Hi,
Please see these documents/threads:
Note: 744143.1 - Tuning performance on eBusiness suite
Note: 864226.1 - How Can I Diagnose Poor E-Business Suite Performance?
Note: 69565.1 - A Holistic Approach to Performance Tuning Oracle Applications Systems
EBS, performence issue
Re: EBS, performence issue
Oracle Apps Tuning
Re: Oracle Apps Tuning
how to track down a forms process that is taking 100% CPU
how to track down a forms process that is taking 100% CPU
There are many other threads which should be helpful, please see old threads for details.
Tuning
http://forums.oracle.com/forums/search.jspa?threadID=&q=Tuning&objID=c3&dateRange=all&userID=&numResults=15&rankBy=10001
Thanks,
Hussein

ORACLE 11g AMM

Hellow, my questions concern ORACLE 11g,
First topic
Tell me if i'm right:
if i set server parameters:
memory_max_target to 1.5 GB
memory_target to 1GB
pga_aggregate_target to 100MB
sga_target to 500MB
Q1.That's mean DB will use at least 500MB for all SGA components and at least 100MB for Server Processes?
Q2.And if it's true Oracle will tune SGA szie above sga_target and for PGA above 100MB if necessary?
Second topic:
If I set :
memory_max_target to 1.5 GB
memory_target to 1GB
pga_aggregate_target to 0
sga_target to 0
Q3.That's mean DB wil tune SGA component's size and PGA buffer it self up to 1GB for both elements?
Thanks for replay.

From MOS ID 169706.1
Automatic Memory Management
Starting with Oracle Database 11g, the Automatic Memory Management feature requires more shared memory (/dev/shm) and file descriptors. The shared memory should be sized to be at least the greater of MEMORY_MAX_TARGET and MEMORY_TARGET for each Oracle instance on the computer. To determine the amount of shared memory available, enter the following command: # df -k /dev/shm/
Note: MEMORY_MAX_TARGET and MEMORY_TARGET cannot be used when LOCK_SGA is enabled or with huge pages on Linux

Temporary tablespace

Our temporary tablespace doesn't empty itself after a commit, rollback or end-session. Can't find the reason why not.
Next size is set to 256K but we get error messages that the temp tablespace is unable to extend next size with 128K which is in fact the next size of all rollbacks segs.
1. Does a rollback segment empties itself into the temporary tablespace?
2. How can I change the settings so that the temporary tablespace empties itself?
Thanks Henry

Hi
The first answer of your question is not fully correct. If you
mark your tablespace 'temporary' it is not used for storing
database objects. It is used onle for sort operations. Oracle
recomend to set equal initial and next segments for this
tablespace and pctincrease=0. You can see recomendation for this
in Oracle Server Tunning. A good size for segments is 2 times of
sort area size and some overhead. But if your users execute many
statements needed big sorts and same time you will need big
temporary tablespace.
Regards

Rule based & Cost based optimizer

Hi,
What is the difference Rule based & Cost based optimizer ?
Thanks

Without an optimizer, all SQL statements would simply do block-by-block, row-by-row table scans and table updates.
The optimizer attempts to find a faster way of accessing rows by looking at alternatives, such as indexes.
Joins add a level of complexity - the simplest join is "take an appropriate row in the first table, scan the second table for a match". However, deciding which is the first (or driving) table is also an optimization decision.
As technology improves a lot of different techiques for accessing the rows or joining that tables have been devised, each with it's own optimium data-size:performance:cost curve.
Rule-Based Optimizer:
The optimization process follows specific defined rules, and will always follow those rules. The rules are easily documented and cover things like 'when are indexes used', 'which table is the first to be used in a join' and so on. A number of the rules are based on the form of the SQL statement, such as order of table names in the FROM clause.
In the hands of an expert Oracle SQL tuner, the RBO is a wonderful tool - except that it does not support such advanced as query rewrite and bitmap indexes. In the hands of the typical developer, the RBO is a surefire recipie for slow SQL.
Cost-Based Optimizer:
The optimization process internally sets up multiple execution proposals and extrapolates the cost of each proposal using statistics and knowledge of the disk, CPU and memory usage of each of the propsals. It is not unusual for the optimizer to analyze hundred, or even thousands, of proposals - remember, something as simple as a different order of table names is a proposal. The proposal with the least cost is generally selected to be executed.
The CBO requires accurate statistics to make reasonable decisions.
Even with good statistics, the complexity of the SQL statement may cause the CBO to make a wrong decision, or ignore a specific proposal. To compensate for this, the developer may provide 'hints' or recommendations to the optimizer. (See the 10g SQL Reference manual for a list of hints.)
The CBO has been constantly improving with every release since it's inception in Oracle 7.0.12, but early missteps have given it a bad reputation. Even in Oracle8i and 9i Release 1, there were countless 'opportunities for improvement' <tm> As of Oracle 10g, the CBO is quite decent - sufficiently so that the RBO has been officially deprecated.

Cahnge sga_target & sga_max_size ?

Dear Friends ,
I want to change the value of sga_max_size , sga_target using "ALTER SYSTEM SET .... scope=spfile " command in my production database server .
Now I need the suggestion which one I need to change First , sga_max_size or the sga_target ?
I want to set ,
sga_target = 15000 M and sga_max_size = 18000 M
Can u plz advice me ?
my another query ,
For the 15000 M sga_target size , what is the recommended size for the PGA , i.e., which value I need to set for the PGA for the value of "sga_target = 1500 M " .
advice me plz ...........
Edited by: shipon_97 on Nov 11, 2008 8:09 PM

>
As mentioned, if you only change spfile value, the order doesn't matter. But to be on the safe side, change sga_max_size first.
Because if you forget to change sga_max_size after your increase sga_target beyond it, your instance can't startup nexttime. You will have to recreate a spfile because you can't edit spfile.
>
For the 15000 M sga_target size , what is the recommended size for the PGA , i.e., which value I need to set for the PGA for the value of "sga_target = 1500 M " .
advice me plz ...........
PGA setting is not directly related to SGA size.
Check Oracle performance tunning guide,
Setting PGA_AGGREGATE_TARGET Initially
Monitoring the Performance of the Automatic PGA Memory Management
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/memory.htm#i47856

Consistent Reads & Physical Reads

hi all,
what is Consistent Reads & Physical Reads

There is no absolute value of the buffer cache hit ratio that is good or bad. The ratio value is first dependend on the application DML activity and the resources available and second is easily distorted (in either direction high or low) by poorly performing SQL. You can have a 99.9% hit ratio on a poorly performing database.
The Performance and Tuning Guide contains information on how to tune the db buffer cache and Oracle will tune the cache automatically if set it to do so with version 9.2 and up via automatic SGA memory management. The Guide errs to the old days of small OLTP environments. Significant number of hash joins and hash aggregation can result in a lower average ratio corresponding to a well performing database.
If you are using manual SGA memory management then you need to determine if the buffer pool is too small or if you think the pool size should be adequate then you need to hunt for the bad SQL (or in a non-OLTP environment just the cause of the low ratio value).
HTH -- Mark D Powell --

Multi Block Size

Oracle 10.2.0.4:
We are creating tablespace of 32K block to place BLOB table. I needed some suggestion on the following:
1. Currently our DB_CACHE_SIZE is set to 0. Do I need to set DB_nk_CACHE_SIZE to 0? Would oracle auto tune this parameter if I set to 0? What's preferable?
2. If I enable CACHE on LOB column would it affect other online users? I am assming there will be a separate buffer pool for 32K block size and probably will not affect online users.

1. Say your DB_BLOCK_SIZE (for the LOB Segment Tablespace) is 8KB. Say your CHUNKSIZE is 32KB.
Say you insert a LOB of 10KB. Oracle's write will be 32KB.
Say you insert a LOB of 100KB. Oracle's writes will be 4 32KB chunks.
2. For a normal table, multiple rows will fit into a block. The "free" space is initial reserved based on PCTFREE. However, actual usage will vary based on the pattern of INSERTs and DELETEs. ASSM manages the candidacy of a block for new rows based on the free space.
3. Before you create a 32KB tablespace, you have to allocate a 32K CACHE. That requires a restart !
4. If you use an SPFILE , the parameter can be "unset" by using the
"ALTER SYSTEM RESET 'db_file_multiblock_read_count'; " command.
TEST TEST TEST !!
You must test the impact of 32KB on your LOBs and other issues. Note that this means that you'd be setting up a separate cache. Whatever cache space the LOB was using the DEFAULT cache earlier is now "released" to other tables/indexes etc. However, if the new 32KB CACHE is much lesser than the space it used to take in the DEFAULT, then the LOB operations may be slower !
Also, obviously your I/Os are now larger with a larger CHUNK size
TEST TEST TEST !!
Test for the impact of unsettting db_file_multiblock_read_count and relying on SYSTEM Stats.

DBA Tasks - Industry standard guidelines

Hey :
As a DBA what are the recommended tasks that we should be doing regularly?
- Daily tasks
- Weekly tasks
- Sanitary checks frequency
- Must have documented reports
- What else??
I am looking at putting a system in place for the team. Any industry standard reference and guidelines would be good starting point for me.

Hi,
Any industry standard reference and guidelines would be good starting point for me. Everybody has a differing idea of the DBA job role. I've been a DBA for 25 years, and I would say the main duties include:
Install, patch and maintain all Oracle software
Tune all Oracle instance components including SQL and PL/SQL
Approve all production schema changes
Approve changes to database design
Control all migrations of Oracle schema objects
Design and implement a backup & recovery system
Implement Oracle failover technology
In addition, in some shops the DBA's take-on responsibility for a whole new set of Oracle DBA tasks:
Data modeling and Oracle database design
Data interface protocols
Managing data security
Managing development projects
Predicting future Oracle trends for hardware usage and user load
I have more notes here:
http://www.dba-oracle.com/t_job_duties.htm

Db_file_multiblock_read_count

Hi,
I have a HP-UX 11.31 Itanium system with 16 CPU's
We have more then one database(all 10.2.0.5) on this system and all om them have different values in db_file_multiblock_read_count=
There is a range from 16 - 64 on the db_file_multiblock_read_count parameter.
I read that it's possible to just unset the parameter and Oracle will tune it by it self.
Anyone know what best practises are and on the database with db_file_multiblock_read_count=64 there is an estimate of 50% OLTP and 50% reports.
Regards
933746

Hi;
I suggest please review
Init.ora Parameter "DB_FILE_MULTIBLOCK_READ_COUNT" Reference Note [ID 30712.1]
How To Unset DB_FILE_MULTIBLOCK_READ_COUNT to Default Value? [ID 473740.1]
Health Check Alert: DB_FILE_MULTIBLOCK_READ_COUNT should be set to recommended value (Only applies to data warehousing) [ID 957460.1]
What is the value of SSTIOMAX and DB_FILE_MULTIBLOCK_READ_COUNT in Oracle 8I, 9I,10g? [ID 291239.1]
Regard
Helios

Oracle DB Tunning

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