Tuning SGA

Hi experts,
Can anyone give me some basic tuning script for tuning SGA.?

Take a look at Oracle ebook:
Oracle® Database Performance Tuning Guide
10g Release 2 (10.2)
Part Number B14211-01
Chapter 7 Memory Configuration and Use
Greetings...
Sim

Similar Messages

Tuning SGA & its Sizing in 9i

Hi,
Please let me know how to tune SGA in oracle 9i.
Approximately, 7 Oracle instances are running in same unix box.
OS Version :
XXXXXXXX:/oradb01> uname -a
SunOS XXXXXXXX 5.8 Generic_117350-59 sun4u sparc SUNW,Netra-T12
RAM Size :
XXXXXXXX:/oradb01> prtconf|grep -i mem
Memory size: 49152 Megabytes
memory (driver not attached)
virtual-memory (driver not attached)
memory-controller, instance #0
memory-controller, instance #1
memory-controller, instance #2
memory-controller, instance #3
memory-controller, instance #4
memory-controller, instance #5
memory-controller, instance #6
memory-controller, instance #7
Oracle Version :
BANNER
Oracle9i Enterprise Edition Release 9.2.0.3.0 - 64bit Production
PL/SQL Release 9.2.0.3.0 - Production
CORE 9.2.0.3.0 Production
TNS for Solaris: Version 9.2.0.3.0 - Production
NLSRTL Version 9.2.0.3.0 - Production
SGA Size :
SQL> show sga
Total System Global Area 3937131360 bytes
Fixed Size 736096 bytes
Variable Size 1778384896 bytes
Database Buffers 2147483648 bytes
Redo Buffers 10526720 bytes
Thanks in advance!!
Edited by: Gowin_dba on Jan 27, 2010 11:26 PM

post formated results from vmstat 5 5 as shown below
bcm@bcm-laptop:~$ vmstat 5 5
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b   swpd   free   buff cache   si   so    bi    bo   in   cs us sy id wa
3 0      0 95036 57396 573856    0    0    37     8 243 367 9 4 86 1
1 0      0 95152 57396 573880    0    0     0    19 398 594 4 3 93 0
0 0      0 96896 57404 573880    0    0     0    16 401 578 5 3 92 0
1 0      0 71468 57412 597472    0    0    18    28 685 1070 12 7 80 0
1 0      0 94408 57420 574108    0    0     0    33 615 1009 12 6 82 0
bcm@bcm-laptop:~$

5 GB SGA on 8GB RAM HP Server 64Bit

Hi all
Recently three months we installed Oracle 10g Database on HP Server (having 4 XEON Processors) with Windows 2003 (64 Bit) OS and we have 8GB RAM.
We wished to have 5500M as the SGA Target but we could not configure more that 3800M on that machine as after that it would error and the database would not get start.
error messages would be like - Out of memory
OR
???? (not recollecting)
Now we are running with only 3500M as sga_target and not utilizing the full available RAM with us. Of course we are using in addition 1500M for pga_aggregate_target without any problem. Even if we increase pga_aggregate_target to 3000M there is no problem but that is not desired to us. We wish to increase sga_target.
We are getting excellent response timings on 3500M sga_target but as human nature would be , we wish to be more greedy and use the full available RAM with us i.e 8GB out of which we can safely use 7GB for Oracle instance. While deducting 1500M for pga_aggregate_target we would like to use 5500M for sga_target.
Any help is appreciated.
Suresh Bansal

Excerpt from oracle docs.
Benefits of Automatic Shared Memory Management
Automatic Shared Memory Management simplifies the configuration of the SGA. Before Oracle Database 10G, buffer cache, shared pool, java pool, and large pool need to be manually specified for the database. Under sizing can lead to poor performance and out-of-memory errors (ORA-4031), while over sizing can waste memory. This feature enables you to specify a total memory amount to be used for all SGA Components (buffer cache, shared pool, java pool, and large pool). The Oracle database periodically redistributes memory between these components according to workload requirements. Before Oracle Database 10G, the user did not have exact control over the total size of the SGA since memory was allocated by Oracle for the fixed SGA, and for other internal metadata allocations over and above the total size of the user specified SGA parameters. The new SGA size parameter SGA_TARGET now includes all the memory in the SGA, including all the automatically sized components, manually sized components, and any internal allocations during startup.
Configuring Automatic Shared Memory Management
Automatic Shared Memory Management can be configured by using the SGA_TARGET initialization parameter. If you specify a non-zero value for SGA_TARGET, the following four memory pools are automatically sized:
* Database buffer cache (Default pool)
* Shared pool
* Large pool
* Java pool
If you set SGA_TARGET to 0, Automatic Shared Memory Management is disabled. The default value of SGA_TARGET is 0.
The individual parameters used before Oracle 10G releases to specify the sizes of the automatically sized components have not been made obsolete. The initialization parameters that size these pools (DB_CACHE_SIZE, SHARED_POOL_SIZE, LARGE_POOL_SIZE, and JAVA_POOL_SIZE) are now referred to as auto-tuned SGA parameters.
The following buffers are now referred to as manually sized components:
* Log buffer
* Other buffer caches (KEEP/RECYCLE, other block sizes)
* Streams pool (new in Oracle Database 10g)
* Fixed SGA and other internal allocations
Note: STATISTICS_LEVEL must be set to TYPICAL (default) or ALL to use Automatic Shared Memory Management.
Jaffar

SGA Sizing

Dear Experts
is there any formula to size SGA in 32bit and 64bit. with 4GB or 16GB RAM.
regards
saima

user2108660 wrote:
Dear Experts
is there any formula to size SGA in 32bit and 64bit. with 4GB or 16GB RAM.
regards
saimaThere is no such formula and do not need AFAIK.But there is main matter is supporting memory like 32bit systems can be support maximum 4G(possible).But in your case you mean is tuning SGA.So its depend your system activities.You have to use Memory Advisor through Enterprise Manager or dynamic performance views(like v$SGA_TARGET_ADVICE).

ORA-00830: cannot set statistics_level to BASIC with auto-tune SGA enabled

Hi Experts
I get this error message when I try to set statictics_level parameter to basic.
Solution says to disable auto-tuning SGA. Fine, but how can I disable it? I cannot fine any system parameter similar to it.
thanks
Attila

It means you need to remove SGA* parameters from your pfile and start tuning the instance manually with SHARED_POOL_SIZE and DB_CACHE_SIZE and other parameters.

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

RAC/Standby enviornment configuration---database wise

Hi, Our final migration is getting very close. I have implemented/configured everything according to oracle MAA, and hopefully after migration, the system will be more stable than previous enviornment.
However, I have some questions here regarding memory parameter, and others.
Our OS is redhat linux 5. DB are 11.2.0.3
Primary are 2 nodes RAC, standby are 2 nodes RAC, plus one standalone standby.
/proc/meminfo shows below:
nfo
MemTotal: 98989076 kB
MemFree: 369244 kB
Buffers: 881572 kB
Cached: 94279628 kB
SwapCached: 2436 kB
Active: 14723460 kB
Inactive: 82602444 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 98989076 kB
LowFree: 369244 kB
SwapTotal: 101032776 kB
SwapFree: 100839952 kB
Dirty: 2640 kB
Writeback: 0 kB
AnonPages: 2161964 kB
Mapped: 6253148 kB
Slab: 733628 kB
PageTables: 216548 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
CommitLimit: 150527312 kB
Committed_AS: 25108780 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 476800 kB
VmallocChunk: 34359261519 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
Hugepagesize: 2048 kB
/proc/cpuinfo shows 15 processors.
I have setup the memory target=43904M, hugepage not configured (SA not sure how and I am not sure if it will benefit). Our application is a busy ticketing enviornment. I want to be sure the parameters I setup can handle the load, no node evicitons , etc.
Here are some of my parameters:
lock_sga boolean FALSEbuffer_pool_keep string
buffer_pool_recycle string
global_context_pool_size string
java_pool_size big integer 0
large_pool_size big integer 0
olap_page_pool_size big integer 0
shared_pool_reserved_size big integer 192M
shared_pool_size big integer 0
streams_pool_size big integer 0
pre_page_sga boolean FALSE
sga_max_size big integer 43904M
sga_target big integer 0
memory_max_target big integer 43904M
memory_target big integer 43904M
shared_memory_address integer 0
I would your guys good opinion are those good enough? OUr previous environments are AIX db 11gr1. Our two node Primary RAC kept having node evicitons every other month seems like(previous DBA configured it). and I want to avoid that in my new environment.
Thank you in advance.

Hi,
Most evictions happen due to lost of network connectivity between nodes , resource consumption on the nodes which prevents processes like ocssd , oprocd and cssdmonitor.
or unable to read voting disk, unexpected failures or hangs...
Also if there is any inconsistency of patches across nodes also can cause node eviction. so ensure whatever patches should apply on all the nodes and try to apply latest security patches also. Node eviction is not the only reason for improper SGA settings.
I have setup the memory target=43904M, hugepage not configured (SA not sure how and I am not sure if it will benefit). Our application is a busy ticketing enviornment. I want to be sure the parameters I setup can handle the load, no node evicitons , etc.There are some benefits with hugepages, the page size value can be set 2MB instead of 4kb also whatever memory used by hugepages will be dedicated.
I suggest you to go through with below links.
Very Large Memory and HugePages - http://docs.oracle.com/cd/B28359_01/server.111/b32009/appi_vlm.htm+
Tuning SGA With HugePages - http://docs.oracle.com/cd/B28359_01/server.111/b32009/appi_vlm.htm#CACIBJBB+
*HugePages on Oracle Linux 64-bit [ID 361468.1]*+
And coming to SGA size settings. This should be analyzed once it goes Live , We cannot predict now.
It purely depends on how much buffer hit ratio, physical reads and so on... Once its live then you can use advisors or AWR reports to see for any changes in SGA/memory..
Sorry may be provided information not much helpful. These days am not in touch with RAC. :)

Confusion about Automatic Shared Memory Management

Hi,
Oracle Database 10g includes the Automatic Shared Memory Management feature which simplifies the SGA memory management significantly. To use Automatic Shared Memory Management, we have to set the SGA_TARGET initialization parameter to a nonzero value and the STATISTICS_LEVEL initialization parameter to TYPICAL or ALL.
Oracle Database 10g Rel. 2 documentation, in some places, says that:
If SGA_TARGET is specified, then the following FIVE memory pools are automatically sized:
* Buffer cache (DB_CACHE_SIZE)
* Shared pool (SHARED_POOL_SIZE)
* Large pool (LARGE_POOL_SIZE)
* Java pool (JAVA_POOL_SIZE)
* Streams pool (STREAMS_POOL_SIZE)
Ref.:
1. http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14237/initparams192.htm
2. http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14220/memory.htm
3. Oracle Database 10g: New Features for Administrators - Student Guide
But in some places I found the following:
If SGA_TARGET is specified, then the buffer cache (DB_CACHE_SIZE), Java pool (JAVA_POOL_SIZE), large pool (LARGE_POOL_SIZE), and shared pool (SHARED_POOL_SIZE) memory pools are automatically sized.
Here you can see that Streams Pool is not included in the automatically sized pools.
Ref.:
1. http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14211/build_db.htm#sthref252
Also, according to Oracle Press' Book "OCP Oracle Database 10g: New Features for Administrators Exam Guide:
Under Automatic Shared Memory Management, the database manages the
following FOUR major components of the SGA, also known as the auto-tuned SGA
parameters:
■ Buffer cache (DB_CACHE_SIZE)
■ Shared pool (SHARED_POOL_SIZE)
■ Large pool (LARGE_POOL_SIZE)
■ Java pool (JAVA_POOL_SIZE)
It is important to understand that even under Automatic Shared Memory
Management, you still need to configure any SGA component other than the four
auto-tuned components. Following are the manually sized components of the SGA:
■ Redo Log Buffer
■ The KEEP and RECYCLE buffer caches (if specified)
■ The nonstandard block size buffer caches (if specified)
■ The new Streams pool SGA component
■ The new Oracle Storage Management (OSM) buffer cache, which is meant
for the optional ASM instance
Now my question is "IS Streams Pool an auto-tuned SGA parameter?"
Thanks in advance.
--Khan.

Hi,
I would advise you to read Document I.D. Note:295626.1 on Oracle Metalink.
It states that
When enabled, it lets Oracle decide of the right size for some components of the SGA:
SHARED POOL
LARGE POOL
JAVA POOL
DB CACHE (using the DB_BLOCK_SIZE value)
The SGA_TARGET value will therefore define the memory size sharable between auto-tuned and manual parameters.
The manual parameters are:
DB_<KEEP/RECYCLE>CACHESIZE
DB_nK_CACHE_SIZE (non default block size)
LOG_BUFFER
FIXED SGA
STREAMS_POOL_SIZE
Adith

SGA Tuning

Oracle version: 10g and 11g
How to monitor SGA size for tuning whether we need to increase the SGA size or not

Hi;
Please mention db versions.
Also Please see our previous discussion:
Estimating SGA Size
Re: Estimating SGA Size
SGA and PGA size
SGA and PGA size
Also see:
http://www.oracle-base.com/articles/11g/AutomaticMemoryManagement_11gR1.php
http://orafaq.com/wiki/SGA
Regard
Helios

Guidelines for SGA and PGA tuning for 10gR2 RAC and ASM ?

I am looking for tuning information on SGA and PGA tuning for Oracle 10g (10.2) RAC and ASM for a 4TB OLTP and DSS mixed environment on Solaris 10 platform.

We are running Solaris 10 SPARC 64 bit with Oracle 10gR2 RAC Enterprise Edition and ASM on Sun servers with 32GB of RAM for memory for a 4TB OLTP database.
It is in design phase so I do not have an existing AWR or Statspack report yet. Is there a best practices guideline on how to size parameters for the SGA (ie: shared_pool_size, etc) and PGA for this environment from Oracle?

NT 의 SGA TUNING

제품 : ORACLE SERVER
작성날짜 : 2002-04-25
NT의 SGA TUNING
================
PURPOSE
NT에서의 SGA TUNING하는 법을 알아본다.
Explanations
<Library cache tuning>
SELECT gethitratio, reloads/pins "Reload Ratio"
FROM V$librarycache
where namespace='SQL AREA'
1) 90% 이상 :app program 의 효율성 향상 노력
2) 1 %초과 : shared_pool_size 증가
<Library cache 크기 조정>
SELCT SUM(sharable_mem) "DB Object Size"
FROM v$db_object_cache;
SELECT SUM(sharable_mem) "SQL SIZE"
FROM v$sqlarea
WHERE executions>5;
SELCT SUM(250*users_opening) "Cursor Size"
FROM v$sqlarea;
이들의 합 이상으로 할당
<Dictionary Cache tuning>
SELECT SUM(gets) "Dictionary Cache Gets",
SUM(getmisses) "Misses"     ,
SUM(getmisses)/SUM(gets) *100 ||'%' "Miss Ratio"
FROM v$rowcache;
15% 초과이면 shared_pool_size 를 증가 고려
<Database Buffer Cache tuning>
SELECT (1-phy.value/(cur.value + con.value))*100 ||’%’
"Cache Hit Ratio"
FROM v$sysstat phy,v$sysstat cur v$sysstat con
WHERE phy.name ='physical reads'
AND cur.name ='db block gets'
AND con.name='consistent gets';
80% 미만이면 DB_BLOCK_BUFFERS 증가
(RAW device 는 90% 미만)
Reference Documents
--------------------

제품 : ORACLE SERVER
작성날짜 : 2002-04-25
NT의 SGA TUNING
================
PURPOSE
NT에서의 SGA TUNING하는 법을 알아본다.
Explanations
<Library cache tuning>
SELECT gethitratio, reloads/pins "Reload Ratio"
FROM V$librarycache
where namespace='SQL AREA'
1) 90% 이상 :app program 의 효율성 향상 노력
2) 1 %초과 : shared_pool_size 증가
<Library cache 크기 조정>
SELCT SUM(sharable_mem) "DB Object Size"
FROM v$db_object_cache;
SELECT SUM(sharable_mem) "SQL SIZE"
FROM v$sqlarea
WHERE executions>5;
SELCT SUM(250*users_opening) "Cursor Size"
FROM v$sqlarea;
이들의 합 이상으로 할당
<Dictionary Cache tuning>
SELECT SUM(gets) "Dictionary Cache Gets",
SUM(getmisses) "Misses"     ,
SUM(getmisses)/SUM(gets) *100 ||'%' "Miss Ratio"
FROM v$rowcache;
15% 초과이면 shared_pool_size 를 증가 고려
<Database Buffer Cache tuning>
SELECT (1-phy.value/(cur.value + con.value))*100 ||’%’
"Cache Hit Ratio"
FROM v$sysstat phy,v$sysstat cur v$sysstat con
WHERE phy.name ='physical reads'
AND cur.name ='db block gets'
AND con.name='consistent gets';
80% 미만이면 DB_BLOCK_BUFFERS 증가
(RAW device 는 90% 미만)
Reference Documents
--------------------

Tuning of SGA on Oracle 8.0.5 and AIX 4.3.3

Hi folks,
I have an AIX box running AIX 4.3.3 and Oracle 8.0.5.2.0. The original SGA settings are as follows:
shared_pool_size = 150000000
sort_area_size = 1024876
db_block_buffer = 126102
The SGA size then is:
Total System Global Area 1838467232 bytes
Fixed Size 47264 bytes
Variable Size 803287040 bytes
Database Buffers 1033027584 bytes
Redo Buffers 2105344 bytes
I changed the SGA settings to the following:
shared_pool_size = 768000000
sort_area_size = 512000000
The SGA size is now:
Total System Global Area 2227943584 bytes
Fixed Size 47264 bytes
Variable Size 214097920 bytes
Database Buffers 2013265920 bytes
Redo Buffers 532480 bytes
After this change was done, the system ran but the users had some problems running reports in JDEOneWorld.
I then downsize the SGA settings and altered the db_block_buffer to improve buffer cache hits with these settings:
db_block_buffers = 245760
shared_pool_size = 200000000
sort_area_size = 1048576
On restarting the database with the new values, I noted that the SGA size remained unchanged as below:
Total System Global Area 2278475936 bytes
Fixed Size 47264 bytes
Variable Size 264105984 bytes
Database Buffers 2013265920 bytes
Redo Buffers 1056768 bytes
I tried to increase the size of db_block_buffers to 327680 but encountered ORA-27123 when trying to startup the database. I did some searches in metalink and found an article saying that the SGA size cannot exceed 2GB on AIX platforms. (Doc ID: 114934.1). Therefore I resize the db_block_buffers back to 245760.
What puzzles me is why the SGA size does not reflect my latest init.ora settings? Does anyone have any idea on how I can get the SGA to reflect the updated values in the init.ora file?

I did a find and here are the files I got:
278529 12 -rw-r--r-- 1 oracle dba 8332 May 12 1998 /u01/app/oracle/product/805/dbs/init.ora
278531 0 lrwxrwxrwx 1 oracle dba 43 Apr 14 2001 /u01/app/oracle/product/805/dbs/initklb.ora -> /u01/app/oracle/admin/klb/pfile/initklb.ora
278532 0 lrwxrwxrwx 1 oracle dba 45 Apr 14 2001 /u01/app/oracle/product/805/dbs/initklb_0.ora -> /u01/app/oracle/admin/klb/pfile/initklb_0.ora
49154 8 -rw-r--r-- 1 oracle dba 4657 Sep 7 2000 /u01/app/oracle/product/orig_db/initklb.ora
49155 8 -rw-r--r-- 1 oracle dba 4657 Jul 27 2000 /u01/app/oracle/product/orig_db/initklb_0.ora
151553 4 -rw-r--r-- 1 oracle dba 2985 Aug 4 2006 /u01/app/oracle/product/luz/pfile/initklb.ora
49161 8 -rw-r--r-- 1 oracle dba 4118 Oct 11 11:22 /u01/app/oracle/admin/klb/pfile/initklb.ora
135169 4 -rw-r--r-- 1 oracle dba 2896 Aug 4 2006 /u01/app/oracle/admin/klb/pfile/backup/initklb.ora
49168 8 -rw-r--r-- 1 root dba 4687 Jul 21 2001 /u01/app/oracle/admin/klb/pfile/archive/initklb1.ora
49162 8 -rw-r--r-- 1 oracle dba 4657 Dec 23 1999 /u01/app/oracle/admin/klb/pfile/archive/initklb_0.ora
The instance name is KLB so the applicable files are:
278531 0 lrwxrwxrwx 1 oracle dba 43 Apr 14 2001 /u01/app/oracle/product/805/dbs/initklb.ora -> /u01/app/oracle/admin/klb/pfile/initklb.ora
278532 0 lrwxrwxrwx 1 oracle dba 45 Apr 14 2001 /u01/app/oracle/product/805/dbs/initklb_0.ora -> /u01/app/oracle/admin/klb/pfile/initklb_0.ora
49154 8 -rw-r--r-- 1 oracle dba 4657 Sep 7 2000 /u01/app/oracle/product/orig_db/initklb.ora
49155 8 -rw-r--r-- 1 oracle dba 4657 Jul 27 2000 /u01/app/oracle/product/orig_db/initklb_0.ora
151553 4 -rw-r--r-- 1 oracle dba 2985 Aug 4 2006 /u01/app/oracle/product/luz/pfile/initklb.ora
49161 8 -rw-r--r-- 1 oracle dba 4118 Oct 11 11:22 /u01/app/oracle/admin/klb/pfile/initklb.ora
135169 4 -rw-r--r-- 1 oracle dba 2896 Aug 4 2006 /u01/app/oracle/admin/klb/pfile/backup/initklb.ora
49168 8 -rw-r--r-- 1 root dba 4687 Jul 21 2001 /u01/app/oracle/admin/klb/pfile/archive/initklb1.ora
49162 8 -rw-r--r-- 1 oracle dba 4657 Dec 23 1999 /u01/app/oracle/admin/klb/pfile/archive/initklb_0.ora
Now, exclude the files in the product, backup and archive directories (the pfile should be in the pfile directory), and that leaves us with:
49161 8 -rw-r--r-- 1 oracle dba 4118 Oct 11 11:22 /u01/app/oracle/admin/klb/pfile/initklb.ora
(Which is the file that I edited)
As I mentioned previously, my client is not prepared to perform an upgrade on both Oracle and AIX. As much as I would like to have them upgrade to the latest versions, it is just not possible.
Oracle 8.0.5 does not have spfiles, so there is no way for me to edit a spfile unless this is one of those undocumented tricks floating around.

Tuning Oracle Database - SGA Memory

Good morning Gurus,
I have this environment in my company:
SAP ECC 6
Oracle 10g
Aix 6.1
Our hardware resources:
Memory: 16GB Ram
Processor: 4 x 3.2Ghz
IBM Blade JS12
Recently, we migrated SAP 4.6C (Solaris) to SAP ECC (Aix). In this new version, a lot of users feel that the performance had decreased.
I checked SGA Memory in Oracle, and i noticed that this configuration didn't used all hardware resources.
This parameters was like these:
sga_max_size=712M
pga_aggregate_target=292M
db_cache_size=292M
processes=80
sessions=96
I changed for:
pga_aggregate_target = 4096M
sga_max_size = 4096M
sga_target = 4096M
db_cache_size = 600M
   I noticed, after this change the performance was perfect. We reduced the time db execution in 60%, but now it isn't occur.
   We changed this parameters on July 4nd, now the performance decrease in 30%.
   My question is, after this change, do we need to adjust the parameters in profile?
Thanks very much
Denis
Brazil

Gerd Kirchner wrote:
> Note 617416 is pretty old (2006), you should follow note 830576 for 10g and there is no sga_max_size mentioned.
Yes it is old, because there are no significant changes on automatic memory management between 9i and 10g (11g is another history), so it is "valid"
sga_max_size is not mentioned in note 830576 because the memory parameters depend on the available memory. look at the recommendations for the other "memory" parameters:
DB_CACHE_SIZE                    Size depends on the available memory (Notes 789011, 617416)
LOG_BUFFER                       1048576
PGA_AGGREGATE_TARGET             OLTP: 20 % of available memory
                                 OLAP: 40 % of available memory
SHARED_POOL_SIZE                 400 MB or greater, refer to Note 690241
As you see, there is only one "hard coded" recommendation and one minimum recommendation.
It is not possible to give a recommendation for sga_max_size.
If you do not set it, Oracle automatically calculates it.
If it is set to small, Oracle will adjust it.
What it is important is to set up the DB_CACHE_SIZE and SHARED_POOL_SIZE, they will be the MINUMUM sizes if AMM is
used

SGA Tuning - Total, Free, Used Per Node in RAC

Hi,
I am working on Total, Free, Used MB for SGA per instance, similar to a chart in TOAD (AWR Browser). The report from TOAD is combination of all the nodes. I want to per node.
Can someone help me on the script.
Thanks,

893593 wrote:
Hi,
I am working on Total, Free, Used MB for SGA per instance, similar to a chart in TOAD (AWR Browser). The report from TOAD is combination of all the nodes. I want to per node.
Can someone help me on the script.
Thanks,
10:21:07 SQL> select * from gv$sgainfo
10:21:21   2 ;
   INST_ID NAME                      BYTES RES
      1 Fixed SGA Size                 2213656 No
      1 Redo Buffers                  7585792 No
      1 Buffer Cache Size               637534208 Yes
      1 Shared Pool Size               301989888 Yes
      1 Large Pool Size                16777216 Yes
      1 Java Pool Size                16777216 Yes
      1 Streams Pool Size                16777216 Yes
      1 Shared IO Pool Size                    0 Yes
      1 Granule Size                 16777216 No
      1 Maximum SGA Size              1553305600 No
      1 Startup overhead in Shared Pool    83886080 No
   INST_ID NAME                      BYTES RES
      1 Free SGA Memory Available          553648128
12 rows selected.

What is best use of 1400 gb SGA (2 rac nodes 768gb each)

currently using 11.2.0.3.0 on unix sun sever with 2 RAC nodes each 8 UltraSPARC-T1 cpus (came out in 2005) four threads each so oracle sees 32 CPUS very slow(1.2 gb). Database is 4TB in size on regular SAN (10k speed).
8gb SGA.
New boss wants to update system to the max to get best performance possible Money is a concern of course but budget is pretty high, Our use case is 12-16 users at same time, running reports some small others very large (return single row or 10000s or rows). reports take 5 sec to 5 minutes, Our job is get the fastest system possible, We have total of 8 licenses available so we can have 16 cores. We are also getting a 6tb all flash SSD array for database. we can get any CPU we want but we cant use parallel query server due to all kinds of issues we have experienced (too many slaves, RAC interconnect saturation etc, whack-a-mole). sparc has too many threads and without PS oracle runs query in single thread.
we have speced out the following system for each RAC node
HP ProLiant DL380p Gen8 8 SFF server
2 Intel Xeon E5-2637v2 3.5GHz/4-core cpus
768 gb ram
2 HP 300GB 6G SAS 15K drives for database software
this will give us total of 4 Xeon E5-2637v2 cpus 16 cores total (,5 factor for 8 licenses) and 1536 ram (leaving ~1400 for sga). this will guarantee an available core for each user. we intend to create very very large keep pool around 300 gb for each node that will hold all our dimension tables. this we hope will reduce reads from the SSD to just data from fact tables.,
Are we doing a massive overkill here? the budget for this was way less than what our boss expected. will that big an sga be wasted will say a 256gb be fine. or will oracle take advantage of it and be able to keep most blocks in there.
will an sga that big cause oracle problems due to overhead of handling that much ram?

Current System:
===========
a. Version : 11.2.0.3
b. Unix Sun
c. CPU - 8 cpus with 4 threads => 32 logical cpus or cores
d. database 4TB
e. SAN - 10k speed disk drives
f. 8gb SGA
g. 1.2 gb ??
h. Users --> 12-16 concurrent and run reports varying size
i. reports elasped time 5 sec to 5 mins
j. cpu license -->8
Target System
===========
a. Version: 11.2.0.3
b. HP ProLiant DL380p Gen8 8 SFF server
c. RAM --> 768 GB
d. 2 HP 300GB 6G SAS 15K drives for database software
e. large keep pool -->90 gb to hold all dimension tables.
f. SSD to just data from fact tables
g. SGA -->256gb
Reassessment of the performance issues of current system appears to be required.Good performance tuning expert is required to look into tuning issues of current application by analyzing awr performance metrics . If 8GB SGA is not enough,then reason behind so is that queries running in the system are not having good access path to select lesser data to avoid flushing out of recent buffers from different tables involved in the query. Until those issues are identified , wherever you go, performance issue wont be going away as table size increase in future , problem will reappear.Even if the queries are running with more FULL Scan , then re-platforming to Exadata might be right decision as Exadata has smart scan , cell offloading feature which works faster and might be right direction for best performance and best investment for future.Compression (compress for OLTP) could be one of the other feature to exploit to improve further efficiency while reading the lesser block in lesser read time.
Investment in infrastructure will solve a few issue in short term but long term issue will again arise.
Investment in identifying the performance issues of current system would be best investment in current scenario.

Tuning SGA

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