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).

Similar Messages

Oracle SGA sizing

Hi,
I have an oracle rac 10g with 4 nodes on linux and each node has 12G RAM memory. my current SGA sizing from pfile looks like this, I need suggestions to change values to have better performance...
racdb2.__db_cache_size=2080374784
racdb3.__db_cache_size=2214592512
racdb4.__db_cache_size=5620367360
racdb1.__db_cache_size=2818572288
racdb2.__java_pool_size=16777216
racdb3.__java_pool_size=16777216
racdb1.__java_pool_size=67108864
racdb4.__java_pool_size=67108864
racdb1.__large_pool_size=16777216
racdb2.__large_pool_size=16777216
racdb3.__large_pool_size=16777216
racdb4.__large_pool_size=16777216
racdb2.__shared_pool_size=5737807872
racdb3.__shared_pool_size=5603590144
racdb4.__shared_pool_size=2147483648
racdb1.__shared_pool_size=4932501504
racdb1.__streams_pool_size=16777216
racdb2.__streams_pool_size=0
racdb3.__streams_pool_size=0
racdb4.__streams_pool_size=0

SQL> select * from v$sga_target_advice;
SGA_SIZE SGA_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR ESTD_PHYSICAL_READS
       268           1         471             1            37727
       134          .5       10732          22.7856            54293
       201            .75         498           1.0573            43363
       536           2         435            .9236            29420
       402            1.5         435            .9236            29420
       469           1.75         435            .9236            29420
       335           1.25         442            .9384            31046
7 rows selected.

Thump rule for SGA sizing depends on TOTAL DB SIZE

Is there any thump rule for sizing SGA depends on TOTAL database size for OLTP system?

Please dont do that. There was a thumb rule that if you are using oracle >=9i, you can go upto 80% of your physical RAM. But, I will not advice you so.
Start your SGA with an optimal value, keep on eye on your performance, take statspack report and if further increase required in the SGA, go ahed.
Because, setting over size SGA cause problems as well setting below par sga also provide poor performance. It should be sized optimially.
There are few good notes available in metalink.
Jaffar

Needing to add keep pool to SGA, sizing and checking for room?

Hi all,
I'm needing to experiment with pinning a table and index (recommended by COTS product vendor) to see if it helps performance.
I'm trying to set up a keep pool...and put the objects in it
I've gone into the database, and found that I will need to set up a keep pool:
SQL> show parameter keep
NAME TYPE VALUE
buffer_pool_keep string
control_file_record_keep_time integer 7
db_keep_cache_size big integer 0
That being said, and I'm having a HUGE senior moment right now...how
do I go about making sure I have enough room to make a little keep
pool?
I've looked at my objects I want to put in there, and one is about
.675 MB, and the other is about .370 MB. So, roughly a little more
than 1MB
Looking at my SGA parameters:
SQL> show parameter sga
NAME TYPE VALUE
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 572M
sga_target big integer 572M
Now...how do I find out what is being used in SGA, to make sure I have room?
I've been searching around, and trying to come up with some queries. I
came up with this one:
SQL> select name, value / (1024*1024) size_mb from v$sga;
NAME SIZE_MB
Fixed Size 1.97846222
Variable Size 232.002007
Database Buffers 332
Redo Buffers 6.01953125
From this, it appears everything is being used....so, not sure what to
do from here.
Suggestions and links greatly appreciated!
cayenne

SELECT SIZE_FOR_ESTIMATE, BUFFERS_FOR_ESTIMATE, ESTD_PHYSICAL_READ_FACTOR, ESTD_PHYSICAL_READS
FROM V$DB_CACHE_ADVICE
    WHERE NAME          = 'KEEP'
     AND BLOCK_SIZE    = (SELECT VALUE FROM V$PARAMETER WHERE NAME = 'db_block_size')
     AND ADVICE_STATUS = 'ON';
SELECT   ds.BUFFER_POOL,
         Substr(do.object_name,1,9) object_name,
         ds.blocks                  object_blocks,
         Count(* )                  cached_blocks
FROM     dba_objects do,
         dba_segments ds,
         v$bh v
WHERE    do.data_object_id = v.objd
         AND do.owner = ds.owner (+)
         AND do.object_name = ds.segment_name (+)
         AND do.object_type = ds.segment_type (+)
         AND ds.BUFFER_POOL IN ('KEEP','RECYCLE')
GROUP BY ds.BUFFER_POOL,
         do.object_name,
         ds.blocks
ORDER BY do.object_name,
         ds.BUFFER_POOL; Edited by: sb92075 on Jul 9, 2009 2:48 PM

SGA sizing recommendation / white paper

Hello,
I am interested in finding a white paper / recommendations on how to best size Oracle database memory SGA. I know it depends on many variables but here is the details that I have so far:
OS - either windows 2003 or HP unix 11i
# of databases - 5
# of schemas per database = 1
size of each schema 40GB
# of sessions 30-50 at any given time
one user defined per schema
most likely will utilize RAC solution with cluster software on either platform. But we could also use standby database technology instead of RAC as a means of failover/switchover issues.

I agree with Justin, better to create one instance with 5 schemas then the other way around. This way, you can devote all available system resources, to one instance, and let the apps/schemas achieve a balance within that.
If you do five instances, you will have to constantly re-balance the system resources manually based on requirements at the time.

SGA Sizing Questions

Hello,
I have a Windows 64-bit server with 16GB of RAM.
Right now, both my sga_max_size and sga_target are set to 4896M.
I've been reading that if I set the SGA too high, it could cause performance issues, but I would still like to increase this a bit.
My database is around 150GB in size, with many reads and writes to the database through HTMLDB applications, also dealing with BLOBS (documents/images stored in our database that are downloaded and uploaded to the system).
I know I can't be told an exact answer, but does anybody have any suggestions on what a safe SGA size would be? I was going to try setting the max_size to 12G and the target to 8G. Does that sound reasonable, or too high/low?
Thanks,
Nora

Check the v$resource_limit to determine if other limits set have been reached.
select * from v$resource_limit;
SQL> /
RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION LIMIT_VALUE
processes 999 1000 1000 1000
sessions 93 149 1105 1105
enqueue_locks 34 70 14134 14134
enqueue_resources 34 65 5904 UNLIMITED
ges_procs 0 0 0 0
ges_ress 0 0 0 UNLIMITED
ges_locks 0 0 0 UNLIMITED
ges_cache_ress 0 0 0 UNLIMITED
ges_reg_msgs 0 0 0 UNLIMITED
ges_big_msgs 0 0 0 UNLIMITED
ges_rsv_msgs 0 0 0 0
gcs_resources 0 0 0 0
gcs_shadows 0 0 0 0
dml_locks 0 55 4860 UNLIMITED
temporary_table_locks 0 3 UNLIMITED UNLIMITED
transactions 0 13 1215 UNLIMITED
branches 0 2 1215 UNLIMITED
cmtcallbk 0 2 1215 UNLIMITED
sort_segment_locks 1 9 UNLIMITED UNLIMITED
max_rollback_segments 13 13 1215 65535
max_shared_servers 0 0 UNLIMITED UNLIMITED
parallel_max_servers 0 17 20 3600
22 rows selected.
Regards,
Jess
Edited by: jjhoup on Sep 9, 2008 1:32 AM

Linux Huge Pages and SGA Sizing

Hello All -
I have a RAC cluster (2 node), with 132GB of total memory on each box.
I am using AMM and have memory_max_target set at 75GB, and memory_target at 70GB.
I am testing the implementation of huge pages in my lab. My lab cluster has 32GB of total memory, so I set my memory_max_target at 24GB, and memory_target at 22GB.
After running my baseline test, I saw the SGA was automatically set at 12.75GB, and PGA at 9.25GB.
My question is as follows:
I set huge pages to have 24GB of memory locked, so would I set my SGA target at 12.75 and pga_aggregate_target at 9.25GB? Then set sga_max at 14.75GB?
Any advice is much appreciated!
Thanks,
Mike

Hi Mike,
little strange, that you can configure huge pages and still use AMM. Normally these features are mutually exclusive.
MOS Note 361468.1: HugePages on 64-bit Linux
The AMM and HugePages are not compatible. One needs to disable AMM on 11g to be able to use HugePages. See <<Note 749851.1>> for further information.
Regards
Sebastian

SGA Sizing + OEM Issue+AWR reports

Hi Techies,
There is small application(Billing Application) running on Laptop. (Windows Vista 32 bit , RDBMS 10.2.0.3.0.)
1- We have increased the SGA_MAX_SIZE. Thought of Increase 700 M. Once we did the changes it has taken effect as 702 MB Allocated to SGA_MAX_SIZE. The same thing happened, while changing the SGA_TARGET Parameter.(After changed the parameter, it has added up 2MB extra).May I know the reason why the 2MB has added while changing the parameter.
2- OEM is not working , When it prompting for the Host User name and password, it won't accept the username and passowrd which I am used to Login into the Laptop.
3- After the generated the AWR reports, how to approach the finding , though it has many more data . Please help
Thanks,
Tippu

Hi
If you're looking to performance tune your database, run the AWR report - preferably starting and ending at snapshots during which times there was a fair amount of activity, then post the section 'Top 5 Timed Events' here and I will point you in the right direction :-)
If OEM is still not working, you can manually take snapshots and generate AWR reports from sqlplus.
Take a manual snapshot:
BEGIN
DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT ();
END;
Produce an AWR report:
@?/rdbms/admin/awrrpt.sql
Cheers,
Andreas

SGA Size Problem

Hi All,
I want to Know that We Have 8 GB RAM in DATABASE Server 10g R2 and 60 GB database Size and 210 users.
So I want to know what would be the Size of SGA Component and others parameters that affect Performance
pls help me its Urgent
Thanks in advance;

Likasz, using shared server reduces PGA requirements at the cost of increasing SGA requirements. The feature does not save much in the way of total Oracle memory requirements nor was it intended to. The feature exists to reduce the number of Oracle processes that the OS has to support which was an issue on many OS's just a few years ago. It does this at the cost of extra session overhead which is a performance cost compared to using persistent dedicated sessions.
If the front-end is web server or transaction monitor based then you have connection pooling in the front-end and are unlikely to need to basically connection pool on the back-end also. I see no reason to complicate the SGA sizing by configuring an unneeded feature before you have measured the performance of the system using dedicated sessions.
HTH -- Mark D Powell --

10g RAC SGA

Are there any guidelines for 10g RAC SGA sizing?

>
if you are asking for new RAC setup, if 10g use ASSM which will automate the sizing for SGA.
if any issues, you can use memory advisors to get the recommendations.
>
Little correction: The acronym here is ASMM (Automatic Shared Memory Management), activated by setting SGA_TARGET > 0
ASSM (Automatic Segment Space Management) is also a good thing but has nothing to do with the sizing of the SGA.
Apart from that, I agree that ASMM is the way to go with a 10g RAC, when it comes to SGA sizing.
btw, if u use 2 many of these acronyms, u r hrdr 2 undrstnd, specially 4 nuBs, c? :-)
Kind regards
Uwe
http://uhesse.wordpress.com

Uniform SGA sizes or not?

Our shop is currently running Oracle Applications 11.5.10.2 on a single node database(10.2.0.2) on Sun Solaris10. We are planning to migrate to RAC(10.2.0.3) and have started work on our development servers. We are planning our production architecture and have a question related to SGA sizing between nodes.
We our trying to get a better understanding of what our SGA sizes on each of our nodes should be if we have one large capacity node and several smaller capacity nodes. By capacity I mean the size of memory and number of CPUs. The biggest concern is the size of memory. On our large box we will have 48G and on each subsequent node we will have 32G. The SGA on the big node is currently about 12G and the PGA 8G. Combined with other memory requirements we can consume 28-30G on our server. My questions are: What is Oracle's recommendation for sizing the SGAs on the smaller nodes? If we size them based on our large node would we run into memory shortages on the smaller nodes? Does RAC require a uniform SGA size across all nodes? Thanks.

Oracle does not require the same SGA on all nodes. All machines that are intended to share the same workload will typically have similar SGA sizing. However, machines that are intended to carry different workloads will typically have different SGA configurations.
The SGA is node specific and is defined by the workload expected on that node. Realize that the SGA has a number of pools, the major ones being 'data buffer' and 'shared pool'.
In very crude terms, the shared pool is used to handle the SQL & PL/SQL, and the buffer is used to handle the data being affected by the SQL and PL/SQL.
If a node is designated to handle specific workload ("this is the batch machine", "this is the backup machine", "these machines are for the customer service team's web screens") the SQL thrown at the node will be potentially different fromn any other node and it should be sized for that workload. This is standard 'performance tuning'.
Workload segregation is typically accomplished using the 'Service' capability of the database and listener.
IOW, RAC does not eliminate the DBA's need to tune based on workload. The tuning is done at the instance level.

How to establish a single init.ora file for 3 node RAC under ASM

All,
Our environment is a combination of several different memory sized SUN machines (V880, V490 & 250R).
Setting up a single init.ora file that encompasses each of the nodes memory into the SGA sizing is our desired setup.
Though we have established the file, the question is getting each NODE on the RAC to use that single parameter
file to start its database instead of taking the default init.ora file in the default (asm/dbs) directory.
As we have performed fail-over testing, upon the restart of instances they have restarted with wrong memory
definitions that have hung the nodes when it took more memory then what was available and swap space began
to grow.
Steps to configure and enable this process is what I am looking for.
Thanks
Gerry

Gerry,
Here's what we do. Not sure if it is relevant to your situation ...
(on each node)
$ cat $ORACLE_HOME/dbs/initrac11d1.ora
SPFILE='+DATA/rac11d/spfilerac11d.ora'
(in ASM)
$ asmcmd
ASMCMD> ls -la +data/rac11d
Type Redund Striped Time Sys Name
Y CONTROLFILE/
Y DATAFILE/
Y ONLINELOG/
Y PARAMETERFILE/
Y TEMPFILE/
N spfilerac11d.ora => +DATA/RAC11D/PARAMETERFILE/spfile.267.685170285
The spfile has all parameters, qualified by node where applicable. For example :
$ sqlplus / as sysdba
SQL*Plus: Release 11.1.0.7.0 - Production on Wed May 6 19:00:45 2009
Copyright (c) 1982, 2008, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Release 11.1.0.7.0 - 64bit Production
With the Real Application Clusters option
SQL> create pfile='/tmp/sb.ora' from spfile;
File created.
SQL> Disconnected from Oracle Database 11g Release 11.1.0.7.0 - 64bit Production
With the Real Application Clusters option
$ cat /tmp/sb.ora
*.archive_lag_target=1800
*.audit_file_dest='/var/oracle/admin/rac11d/adump'
rac11d1.dispatchers='(address=(protocol=tcp)(host=msdbc11-vip)(port=64000))'
rac11d2.dispatchers='(address=(protocol=tcp)(host=msdbc12-vip)(port=64000))'
*.global_names=TRUE
rac11d1.instance_number=1
rac11d2.instance_number=2
rac11d1.undo_tablespace='UNDOTBS1'
rac11d2.undo_tablespace='UNDOTBS2'
Hope this helps,
Steve

SGA_MAX_SIZE and SGA_TARGET in Oracle 10G

We have the following H/W with Solaris 9
SPARC-IV 16 CPUs
32GB RAM
128GB swap
What is the optimal size of sga_target and sga_max_size that can be configured for a heavy batch processing oracle server. Nothing runs except oracle in the above server.
We have currently 3GB SGA size , however our heavy queries are very slow.
We have huge updates on tables with more than 200Millions rows.
Do we need to have JAVA_POOL if the java stored procedure are NOT used.
However we are connecting to this database using JDBC also.
Moreover ASM is enabled in this server.
You expert suggetions are always welcome.

That's not a question that can be answered easily. It depends very much on where the time is going. Three main targets:
Writing the log file - which is largely about use of disks, not memory.
Reading data - lots of single block reads suggest looking at a bigger cache
Reading and writing temp because of large sorts/hash joins - pga configuration
One difficulty with TEMP is that the I/Os are often asynchronous, so a session can do a lot of TEMP I/O without recording much time - which means it can cause a problem elsewhere without suffering a problem itself.
You didn't mention the pga_aggregate_size - which is an important consideration in 10g and can be more important than the sga sizing in DSS and batch-like processing. Between them, the SGA and PGA_aggregate_target should probably account for a very large fraction of your memory - but (since you are on Solaris) make sure you look into large memory pages and intimate shared memory, otherwise you may need to leave a lot of memory available for the O/S memory management mechanisms.
As far as the java pool is concerned, check v$sgastat for pools which constantly show free memory, and reclaim any large free volumes.
Bottom line - if you've got the memory in the box, you might as well use it in the best possible place; but at the moment we don't have enough information to tell us where it would be most useful.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk

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

How to do performance tuning in EXadata X4 environment?

Hi, I am pretty new to exadata X4 and we had a database (oltp /load mixed) created and data loaded.
Now the application is testing against this database on exadata.
However they claimed the test results were slower than current produciton environment. and they send out the explain plan, etc.
I would like advices from pros here what are specific exadata tuning technics I can perform to find out why this is happening.
Thanks a bunch.
db version is 11.2.0.4

Hi 9233598 -
Database tuning on Exadata is still much the same as on any Oracle database - you should just make sure you are incorporating the Exadata specific features and best practice as applicable. Reference MOS note: Oracle Exadata Best Practices (Doc ID 757552.1) to help configuring Exadata according to the Oracle documented best practices.
When comparing test results with you current production system drill down into specific test cases running specific SQL that is identified as running slower on the Exadata than the non-Exadata environment. You need to determine what is it specifically that is running slower on the Exadata environment and why. This may also turn into a review of the Exadata and non-Exadata architecture. How is application connected to the database in the non-Exadata vs Exadata environment - what's the differences, if any, in the network architecture in between and the application layer?
You mention they sent the explain plans. Looking at the actual execution plans, not just the explain plans, is a good place to start... to identify what the difference is in the database execution between the environments. Make sure you have the execution plans of both environments to compare. I recommend using the Real Time SQL Monitor tool - access it through EM GC/CC from the performance page or using the dbms_sql_tune package. Execute the comparison SQL and use the RSM reports on both environments to help verify you have accurate statistics, where the bottlenecks are and help to understand why you are getting the performance you are and what can be done to improve it. Depending on the SQL being performed and what type of workload any specific statement is doing (OLTP vs Batch/DW) you may need to look into tuning to encourage Exadata smart scans and using parallelism to help.
The SGA and PGA need to be sized appropriately... depending on your environment and workload, and how these were sized previously, your SGA may be sized too big. Often the SGA sizes do not usually need to be as big on Exadata - this is especially true on DW type workloads. DW workload should rarely need an SGA sized over 16GB. Alternatively, PGA sizes may need to be increased. But this all depends on evaluating your environment. Use the AWR to understand what's going on... however, be aware that the memory advisors in AWR - specifically for SGA and buffer cache size - are not specific to Exadata and can be misleading as to the recommended size. Too large of SGA will discourage direct path reads and thus, smart scans - and depending on the statement and the data being returned it may be better to smart scan than a mix of data being returned from the buffer_cache and disk.
You also likely need to evaluate your indexes and indexing strategy on Exadata. You still need indexes on Exadata - but many indexes may no longer be needed and may need to be removed. For the most part you only need PK/FK indexes and true "OLTP" based indexes on Exadata. Others may be slowing you down, because they avoid taking advantage of the Exadata storage offloading features.
You also may want evaluate and determine whether to enable other features that can help performance including configuring huge pages at the OS and DB levels (see MOS notes: 401749.1, 361323.1 and 1392497.1) and write-back caching (see MOS note: 1500257.1).
I would also recommend installing the Exadata plugins into your EM CC/GC environment. These can help drill into the Exadata storage cells and see how things are performing at that layer. You can also look up and understand the cellcli interface to do this from command line - but the EM interface does make things easier and more visible. Are you consolidating databases on Exadata? If so, you should look into enabling IORM. You also probably want to at least enable and set an IORM objective - matching your workload - even with just one database on the Exadata.
I don't know your current production environment infrastructure, but I will say that if things are configured correctly OLTP transactions on Exadata should usually be faster or at least comparable - though there are systems that can match and exceed Exadata performance for OLTP operations just by "out powering" it from a hardware perspective. For DW operations Exadata should outperform any "relatively" hardware comparable non-Exadata system. The Exadata storage offloading features should allow you to run these type of workloads faster - usually significantly so.
Hope this helps.
-Kasey

SGA Sizing

Similar Messages

Maybe you are looking for