Performance tunning in oracle

Hi friends,
I am himansu, i am facing a problem during performance tunning of query in oracle , please guide me how to tune a query which will give better performance.

907977 wrote:
Hi friends,
I am himansu, i am facing a problem during performance tunning of query in oracle , please guide me how to tune a query which will give better performance.Welcome to OTN
Please post your thread at SQL, PL/SQL. PL/SQL
and provide your sql query.
Hope this will help you.

Similar Messages

Performance tunning with Oracle Expert for 8i

Hi all,
The database is Oracle 8i Enterprise Edition 8.1.7.4.1 .
What should I do to launch Oracle Expert ? Because I want to get performance suggestions from Oracle Expert's report.
Thank you very much indeed

do you have the tuning pack -
http://www.oracle.com/pls/tahiti/tahiti.drilldown?levelnum=2&toplevel=a76992&method=FULL&chapters=0&book=&wildcards=1&preference=&expand_all=&verb=&word=Oracle+Expert#a76992

Performance Tunning in oracle 11g

Hi everybody,
My oracle version is 11.2.0.2 and OS :RHEL 5.5;64 bit each.As far i know,in 11g most tunning issues are handled by oracle itself.But still there are many issues that a dba should consider.Recently my system begin to response slowly,and i need to investigate the reason and come up with the solution as per management instruction.But i am confuse where and how to start...??
So..my request to experience people pls give some guidance what are issues/tools i would start with??
Another think...i m using toad 9.5,32 bit.Is it possioble to get proper message for 11g incase of generating different tunning reports.
Thanks and Regards,

user8983130 wrote:
Hi everybody,
My oracle version is 11.2.0.2 and OS :RHEL 5.5;64 bit each.As far i know,in 11g most tunning issues are handled by oracle itself.But still there are many issues that a dba should consider.Recently my system begin to response slowly,and i need to investigate the reason and come up with the solution as per management instruction.But i am confuse where and how to start...??
So..my request to experience people pls give some guidance what are issues/tools i would start with??
Another think...i m using toad 9.5,32 bit.Is it possioble to get proper message for 11g incase of generating different tunning reports.
Thanks and Regards,what does AWR show as most recourse intensive SQL?
Those are the statements that need examination.

FDM Performance Tunning with Oracle

Hi,
We are using Oracle 10g with FDM.We have scheduled batch jobs but it takes a long time while importing the data.
Are there any performance tunnings we can do at Oracle end?
Thanks.

First you need to isolate where the performance bottleneck is occurring. If batch loads are significantly slower than interactive loads, then I'd look in the batch processes, as you've suggested yourself.
If load performance is a problem in both batch and interactive modes, then something else you might consider is the number of records in a typical load. Have you configured the location with the optimal load type (SQL Insert or Bulk Insert) for your situation?

Oracle apps performance tunning

Hey
could u any one tell me where i will get the Oracle Apps Performance
Tunning on Module wise like OM/AP/AR.
how to verify that my oracle Apps[11.5.10] instance running fine on linux based !!
i need check list Oracle Apps Performance !!

best would be to start with http://docs.oracle.com/cd/E11882_01/server.112/e16638/toc.htm
Regards
Karan

Oracle 11g Performance tunning

Hi Guru's
I am new to Performance tunning, can u please guide me from where to start performance tuning so that i study and do the practical as well.
I know how to run AWR and ADDM but i want to konw what are the sequence i follow to learn and do performance tunning.
Thanks in advance

best would be to start with http://docs.oracle.com/cd/E11882_01/server.112/e16638/toc.htm
Regards
Karan

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
Oracle Internal & Oracle Academy Use Only
xv
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

Need help for performance tunning

Hello,
I have 16K records return by query, it takes long time to proceed for 7K it takes 7.5 sec.
Note: I used all seeded tables only.
If possible please help me to tune it.
SELECT       msi.inventory_item_id,msi.segment1,msi.rimary_uom_code , msi.primary_unit_of_measure
FROM mtl_system_items_b msi, qp_list_lines qpll,qp_pricing_attributes qppr,
          mtl_category_sets_tl mcs,mtl_category_sets_b mcsb,
          mtl_categories_b mc, mtl_item_categories mcb
WHERE     msi.enabled_flag = 'Y'
     AND qpll.list_line_id = qppr.list_line_id
     AND qppr.product_attr_value = TO_CHAR (msi.inventory_item_id(+))
     AND qppr.product_uom_code = msi.primary_uom_code
     AND mc.category_id = mcb.category_id
     AND msi.inventory_item_id = mcb.inventory_item_id
     AND msi.organization_id = mcb.organization_id
     AND TRUNC (SYSDATE) BETWEEN NVL (qpll.start_date_active,TRUNC (SYSDATE)) AND NVL (qpll.end_date_active,TRUNC (SYSDATE))
     AND mcs.category_set_name = 'LSS SALES CATEGORY'
     AND mcs.language = 'US'
     AND mcs.category_set_id = mcsb.category_set_id
     AND mcsb.structure_id = mc.structure_id
     AND msi.organization_id = :p_organization_id
     AND qpll.list_header_id = :p_price_list_id
     AND mcb.category_id = :p_category_id;
Thanks and regards
Akil.

Thanks Helios ,
here is answers
Databse version
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit
PL/SQL Release 11.1.0.7.0
explain plan
| Id | Operation                       | Name                     | Rows | Bytes | Cost (%CPU)|
|
0 | SELECT STATEMENT
|                          |
1 |   149 | 9439
(1)|
|
1 | NESTED LOOPS                   |                          |     1 |
149 | 9439   (1)|
|*
2 |   HASH JOIN OUTER               |                          |     1 |
135 | 9437   (1)|
|*
3 |    HASH JOIN                    |                          |     1 |
71 | 9432   (1)|
|
4 |     NESTED LOOPS                |                          |     2 |
76 |    53   (0)|
|*
5 |      TABLE ACCESS BY INDEX
ROWID| QP_LIST_LINES            |     2 |
44 |    49   (0)|
|*
6 |       INDEX SKIP SCAN           | QP_LIST_LINES_N2         |
702 |       |    20
(0)|
|*
7 |      INDEX RANGE SCAN           | QP_PRICING_ATTRIBUTES_N3 |     1 |
16 |     2   (0)|
|*
8 |     TABLE ACCESS BY INDEX
ROWID | MTL_SYSTEM_ITEMS_B       | 46254
| 1490K|
9378   (1)|
|*
9 |      INDEX RANGE SCAN           | MTL_SYSTEM_ITEMS_B_N9    | 46254 |       |
174   (1)|
|
10 |    TABLE ACCESS FULL            | XX_WEB_ITEM_IMAGE_TBL    |
277 | 17728 |     5   (0)|
|* 11 |   INDEX RANGE SCAN              | MTL_ITEM_CATEGORIES_U1   |
1 |    14 |     2
(0)|
Predicate Information (identified
by operation id):
2 -
access("XWIIT"."IMAGE_CODE"(+)="MSI"."SEGMENT1")
3 -
access("QPPR"."PRODUCT_ATTR_VALUE"=TO_CHAR("MSI"."INVENTORY_ITEM_ID")
AND
"QPPR"."PRODUCT_UOM_CODE"="MSI"."PRIMARY_UOM_CODE")
5 - filter(NVL("QPLL"."START_DATE_ACTIVE",TRUNC(SYSDATE@!))<=TRUNC(SYSDATE@!)
AND
NVL("QPLL"."END_DATE_ACTIVE",TRUNC(SYSDATE@!))>=TRUNC(SYSDATE@!))
6 -
access("QPLL"."LIST_HEADER_ID"=TO_NUMBER(:P_PRICE_LIST_ID))
filter("QPLL"."LIST_HEADER_ID"=TO_NUMBER(:P_PRICE_LIST_ID))
7 -
access("QPLL"."LIST_LINE_ID"="QPPR"."LIST_LINE_ID")
filter("QPPR"."PRODUCT_UOM_CODE" IS NOT NULL)
8 - filter("MSI"."ENABLED_FLAG"='Y')
9 - access("MSI"."ORGANIZATION_ID"=TO_NUMBER(:P_ORGANIZATION_ID))
11 -
access("MCB"."ORGANIZATION_ID"=TO_NUMBER(:P_ORGANIZATION_ID)
AND
"MSI"."INVENTORY_ITEM_ID"="MCB"."INVENTORY_ITEM_ID"
AND
"MCB"."CATEGORY_ID"=TO_NUMBER(:P_CATEGORY_ID))
       filter("MCB"."CATEGORY_ID"=TO_NUMBER(:P_CATEGORY_ID))
Note
- 'PLAN_TABLE' is old version
TKprof Plan
TKPROF: Release 11.1.0.7.0 - Production on Fri Nov 15 06:12:26 2013
Copyright (c) 1982, 2007, Oracle. All rights reserved.
Trace file: LSSD_ora_19760.trc
Sort options: default
count    = number of times OCI procedure was executed
cpu      = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk     = number of physical reads of buffers from disk
query    = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows     = number of rows processed by the fetch or execute call
SELECT msi.inventory_item_id,
       msi.segment1,
       primary_uom_code,
       primary_unit_of_measure,
       xwiit.image_url
FROM mtl_system_items_b msi,
       qp_list_lines qpll,
       qp_pricing_attributes qppr,
       mtl_item_categories mcb,
       xx_web_item_image_tbl xwiit
WHERE     msi.enabled_flag = 'Y'
       AND qpll.list_line_id = qppr.list_line_id
       AND qppr.product_attr_value = TO_CHAR (msi.inventory_item_id)
       AND qppr.product_uom_code = msi.primary_uom_code
       AND msi.inventory_item_id = mcb.inventory_item_id
       AND msi.organization_id = mcb.organization_id
       AND TRUNC (SYSDATE) BETWEEN NVL (qpll.start_date_active,
                                        TRUNC (SYSDATE))
                               AND NVL (qpll.end_date_active,
                                        TRUNC (SYSDATE))
       AND xwiit.image_code(+) = msi.segment1
       AND msi.organization_id = :p_organization_id
       AND qpll.list_header_id = :p_price_list_id
       AND mcb.category_id = :p_category_id
call     count       cpu    elapsed       disk      query    current        rows
Parse        2      0.00       0.00          0          0          0           0
Execute      2      0.00       0.00          0          0          0           0
Fetch        2      3.84       3.85          0     432560          0        1002
total        6      3.84       3.85          0     432560          0        1002
Misses in library cache during parse: 0
Optimizer mode: ALL_ROWS
Parsing user id: 173
Rows     Row Source Operation
    501 NESTED LOOPS (cr=216280 pr=0 pw=0 time=115 us cost=9439 size=149 card=1)
   2616   HASH JOIN OUTER (cr=211012 pr=0 pw=0 time=39 us cost=9437 size=135 card=1)
78568    HASH JOIN (cr=210997 pr=0 pw=0 time=3786 us cost=9432 size=71 card=1)
78571     NESTED LOOPS (cr=29229 pr=0 pw=0 time=35533 us cost=53 size=76 card=2)
78571      TABLE ACCESS BY INDEX ROWID QP_LIST_LINES (cr=9943 pr=0 pw=0 time=27533 us cost=49 size=44 card=2)
226733       INDEX SKIP SCAN QP_LIST_LINES_N2 (cr=865 pr=0 pw=0 time=4122 us cost=20 size=0 card=702)(object id 99730)
78571      INDEX RANGE SCAN QP_PRICING_ATTRIBUTES_N3 (cr=19286 pr=0 pw=0 time=0 us cost=2 size=16 card=1)(object id 99733)
128857     TABLE ACCESS BY INDEX ROWID MTL_SYSTEM_ITEMS_B (cr=181768 pr=0 pw=0 time=9580 us cost=9378 size=1526382 card=46254)
128857      INDEX RANGE SCAN MTL_SYSTEM_ITEMS_B_N9 (cr=450 pr=0 pw=0 time=1657 us cost=174 size=0 card=46254)(object id 199728)
    277    TABLE ACCESS FULL XX_WEB_ITEM_IMAGE_TBL (cr=15 pr=0 pw=0 time=22 us cost=5 size=17728 card=277)
    501   INDEX RANGE SCAN MTL_ITEM_CATEGORIES_U1 (cr=5268 pr=0 pw=0 time=0 us cost=2 size=14 card=1)(object id 99557)
Note: I modified query and it gives good result, now it takes 3 to 4 sec for 16000 records.
If possible can you plz explain what we have to take care while doing performance tunning
I am a fresher so don't have that much idea.
and also Thanks Hussein for your replay

Tools in Performance Tunning

What are the tools in performance Tunning in ABAP/4
Thanks Regards,
Kumar

Hi kumar,
Tools provided for Performance Analysis
Following are the different tools provided by SAP for performance analysis of an ABAP object
Run time analysis transaction SE30
This transaction gives all the analysis of an ABAP program with respect to the database and the non-database processing.
SQL Trace transaction ST05
The trace list has many lines that are not related to the SELECT statement in the ABAP program. This is because the execution of any ABAP program requires additional administrative SQL calls. To restrict the list output, use the filter introducing the trace list.
The trace list contains different SQL statements simultaneously related to the one SELECT statement in the ABAP program. This is because the R/3 Database Interface - a sophisticated component of the R/3 Application Server - maps every Open SQL statement to one or a series of physical database calls and brings it to execution. This mapping, crucial to R/3s performance, depends on the particular call and database system. For example, the SELECT-ENDSELECT loop on the SPFLI table in our test program is mapped to a sequence PREPARE-OPEN-FETCH of physical calls in an Oracle environment.
The WHERE clause in the trace list's SQL statement is different from the WHERE clause in the ABAP statement. This is because in an R/3 system, a client is a self-contained unit with separate master records and its own set of table data (in commercial, organizational, and technical terms). With ABAP, every Open SQL statement automatically executes within the correct client environment. For this reason, a condition with the actual client code is added to every WHERE clause if a client field is a component of the searched table.
To see a statement's execution plan, just position the cursor on the PREPARE statement and choose Explain SQL. A detailed explanation of the execution plan depends on the database system in use.
how to perform sql trace:
Poorly written SQL statements have the greatest impact on application performance. An SQL
statement using which an Oracle database system reads and/or sorts thousands or even millions of
rows of data can bring the database to a standstill. Indexes should be used properly to prevent such
situations from occurring. To analyze such problems you should use the SQL Trace (TCode ST05) to
with database access operations.
CAUTION
Only one person can perform an SQL trace at a time. Remember to turn off the
trace when you are finished. SQL trace slows the system down.
1. Using SQL Trace
1. Open a program that you want to analyze, in the editor, so that it is ready and waiting to be
executed.
2. Open a new session using the menu path System   Create session.
3. Run transaction ST05 (enter /nst05-zero-five, not oh-five in the Command field, or choose
the menu path System Utilities Performance Trace).
4. Then the initial screen of the test tool appears.
The status of the Performance Trace is displayed in the lower part of the screen. This status tells you
three things namely
Whether any of the Performance Traces are switched on
The users for whom Performance Trace is enabled
The user that switched the Performance Trace on
If the trace is switched on you must switch it off before you can proceed. There are two cases in
which the trace needs to be switched off. They are
If the trace was started within the past hour, it is possible that it is still being used. Contact the
indicated user or try again later
If the trace was started hours or days ago, the user probably left it on by mistake and it can be
safely turned off
To turn off the trace, press the Trace Off pushbutton.
5. The initial screen has various trace functions such as SQL Trace, Enqueue Trace, RFC
Trace
6. Select SQL Trace.
7. There are various options under which trace can be switched on. They are
If you want to switch on the trace under your user name, choose Trace on.
If you want to switch on the trace for another user or user group, choose Trace on for user.
To enter a single user, specify the user name.
To enter a user group, specify a search pattern (you can use the normal wildcards).
If you want to change the user or user group, switch off the Performance Trace and then restart it,
entering the new users or user group.
8. Now switch back to the window containing your editor session (the one with your program
waiting to be executed).
9. Press F8 to run your program.
Note Just press F8 and do nothing. Do not even press the Back button.
10. When your program has run and the hourglass is no longer displayed, switch back to the trace
window.
11. Press the Trace Off pushbutton.
12. Once Performance Trace is switched off, you can analyze the data
Using Runtime Analysis Tool (SE30)
1. You can open the Runtime Analysis tool as follows:
To start from Choose
Any screen System   Utilities   Runtime Analysis   Execute
Initial screen of ABAP
Workbench
Test   Runtime Analysis
Initial screen of ABAP Editor Program   Execute Runtime Analysis
ABAP Editor Utilities   More utilities   Runtime Analysis
2. In the simplest case, you would enter a short description and a measurement object
(transaction, program, or function module) to run the analysis in the current session.
3. In the Measurement restrictions group box, you can make more specific restrictions for the
measurement. For example, you may want to include only certain statements or time periods.
(For further information refer section 3. 0).
4. To start the measurement, choose Measure runtime. From the initial screen, you can
specify whether the analysis should run in the same session or in a parallel session using the
Enable/Disable button in the In parallel session group box.
5. Run the transaction, program, or function module as normal.
6. Return to the initial screen of the Runtime Analysis transaction. To do so, either leave
transaction, program, or function module as normal, or start the runtime analysis again.
7. The name of the performance data file that has just been created is displayed at the bottom of
the initial screen. The file created by the system is added to the list of performance data files.
You can now analyze, print, or delete the file, or save it locally. The Performance file group
box contains options for analyzing performance files. (For further information refer sections 4.
0 and 5. 0)
regards,
keerthi

How to do Performance tunning in OBIEE

Hi All,
We are using OBIEE 10.3.4 version on windows envorinment .In our OBIEE project we are using 9 reports my requriment is we need to do performance tunning for OBIEE side.For eace report accessing its taking around 80 sec.We need to decrease these accessing time,is there any possibility to access all the reports with less response time in OBIEE side.
Could you anyone suggest how to do performance tunning in OBIEE side.
Thanks,
Vijay.

Vijay,
Plz refer
http://www.business-intelligence-quotient.com/?p=119
http://prolynxuk.com/blog/?p=173
http://businessdecisionsystems.com/blog/?p=486
Here is the section from the BIEE admin guide:
=======================
Usage Examples
This section provides a few examples of how to use Oracle hints in conjunction with the Oracle BI Server. For more information about Oracle hints, refer to the Oracle SQL Reference documentation for the version of the Oracle server that you use.
Index Hint
The Index hint instructs the optimizer to scan a specified index rather than a table. The following hypothetical example explains how you would use the Index hint. You find queries against the ORDER_ITEMS table to be slow. You review the query optimizer's execution plan and find the FAST_INDEX index is not being used. You create an Index hint to force the optimizer to scan the FAST_INDEX index rather than the ORDER_ITEMS table. The syntax for the Index hint is index(table_name, index_name). To add this hint to the repository, navigate to the Administration Tool's Physical Table dialog box and type the following text in the Hint field:
index(ORDER_ITEMS, FAST_INDEX)
Leading Hint
The Leading hint forces the optimizer to build the join order of a query with a specified table. The syntax for the Leading hint is leading(table_name). If you were creating a foreign key join between the Products table and the Sales Fact table and wanted to force the optimizer to begin the join with the Products table, you would navigate to the Administration Tool's Physical Foreign Key dialog box and type the following text in the Hint field:
leading(Products)
So, the table names "order_items" and "products" in the above documentation will not be the same after BIEE puts aliases on them.
============
Hope this is useful..
Edited by: Deepak Gupta on Aug 1, 2011 7:18 AM

Query Performance Tunning

Dear Experts,
I am executing a query which is build on a Multiprovider. The execution time is approx. 12 mins, again if I enable a dimension to analyze it takes another 15 mins.
The technical details of the query are:
1) The multiprovider fetches data from three different Cubes.
2) It contains three diff characteristics out of which one is having a 10 level hierarchy and one is having a 2 level hierarchy. Both the hierarchies are externally maintained.
3) It contains KPIs which calculate the sales on diff time lines such as CM MTD, LM MTD, CY YTD, LY YTD with the help of a customer exit.
4) It converts the quatities in alt unit of measures through an exit.
Kindly suggest for performance tunning. How shall i achieve min query execution time??
-Kushal

HI Kushal,
effective query on MP can be found
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/b03b7f4c-c270-2910-a8b8-91e0f6d77096
for nw2004s
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/a9ab011a-0e01-0010-02a1-d496b94c9c0f
modeling on multiprovider
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/2f5aa43f-0c01-0010-a990-9641d3d4eef7
docs on performance available in
FAQ - The Future of SAP NetWeaver Business Intelligence in the Light of the NetWeaver BI&Business Objects Roadmap
https://service.sap.com/bi
-> performance
Also,
check the parallel processing setting, your query is non cumulative ...
629541 Multiprovider: Parallel Processing
911939 Optimization hint for logical MultiProvider partitioning
907881 MultiProvider with (too) many part providers
Performance of non-cumulative queries in MultiProviders
903559 MultiProvider optimization is only partially active
942554 Perf when working with BI inp help with multiprov on Oracle
607164 MultiProvider: Sequential processing is faster than parallel
913975 Performance problems for MultiProviders with many partprov.
hope this helps
Best Regards,
VVenkat..

How to do performance tunning

Hi,
Can any one help me how to do performance tunning.I was given two scripts which contains more UNION clauses.

Hi,
What version of Oracle are you on? If you have Oracle 22S (the S is for "Sentient"), there's one way:
SCOTT@ORA22S> set autotrace traceonly explain
SCOTT@ORA22S> ed
Wrote file afiedt.buf
1 select *
2 from test
3* where test_date > date '2001-01-01'
SCOTT@ORA22S> /
Execution Plan
0    SELECT STATEMENT Optimizer=ALL_ROWS (Cost=40656 Card=1071132 Bytes=163883196)
1 0   TABLE ACCESS (BY INDEX ROWID) OF 'TEST' (TABLE) (Cost=40656 Card=1071132 Bytes=163883196)
2 1     INDEX (FULL SCAN) OF 'TST_CUSTOM_03' (INDEX) (Cost=6785 Card=1071132)
SCOTT@ORA22S> alter session set sql_go_fast = true;
Session altered.
SCOTT@ORA22S> /
Execution Plan
0    SELECT STATEMENT Optimizer=ALL_ROWS (Cost=9979 Card=1071132 Bytes=163883196)
1 0   TABLE ACCESS (FULL) OF 'TEST' (TABLE) (Cost=9979 Card=1071132 Bytes=163883196)Unfortunately Oracle 22S may not be available for a while. Until then you may have to listen to Billy ;-)
cheers,
Anthony

Training classes for Administrator and Performance Tunning

Hi All,
I would like to learn more about ORACLE database so do you know any where offering the classes for Administrator and Performance Tunning in California Bay Area.
THanks,
JP

Oracle. :-)
http://education.oracle.com
Alison

How to learn abt performance tunning...

Hi ,
Is there any way so I can learn tunning in a flash,
anyway I know the concept of Oracle architecture,sql,backup and recovery bust still not able to give proper time to performance tunning plz do suggest me thath how to achieve it and plz provide me the link where I can get learn things without going into big 1000 pages book.
very warm regards : Alok Kumar ...

As for as tuning concern, I recommend you to read following books,
1. Cary Milsap's, Oracle Performance.
2. Don Tow's, SQL Tuning
3. Tom Kyte's, Expert one on one.
4. Jonathan Lewis, Buddiling Effective Database.
Apart from the above books, you can also visit their respective site to get more info about performance tuning. http://asktom.oracle.com, www.hotsos.com,http://www.jlcomp.demon.co.uk, www.evdbt.com, www.oraperf.com and etc.
My recommendation would be start learning about:
SQL Tuning
Join Methods
tracing event 10046,10053 and reding execution plan & tkprof.
wait events and how to spot the error.
Jaffar

Performance tunning in oracle

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