Setting sga_max_size

what is the maximum value upto which we may increase the sga_max_size. I have already increased it to 2.8 GB.
Oracle 10gR2 (64 bit)
RHEL3
physical RAM 5GB

On what factors the size of sga depends?SGA depends on the load, type of DB...
For example Datwarehouse will have enormous SGA because of long running queries but the user requests are minimal so it will be more
If we increase SGA ,we decrease overall RAM No ..SGA is a part of RAM when a DB is running so memory is relased when the db is down..If you physically add more RAM then you can assign more SGA thats all
But performance has so may other parameter
Jonathan hinted s few days back
Because of the huge SGA and the type of thransactions(Inserts) the dirty buffers are very high so it needs tobe written first before allocating for future requests so I/O contention may happen resulting in bad performance
These are based on my experience may or may not suit your case

Similar Messages

Setting sga_max_size and memory_target

what happens when i set
sga_max_size = 4500
memory_target = 5000M
memory_max_target=5000M
sga_target=0
can / will oracle use more than 4.5GB for sga ?
can pga grow more than 500M ?
startup;
ORACLE instance started.
Total System Global Area 4710043648 bytes
Fixed Size 2234376 bytes
Variable Size 3925870584 bytes
Database Buffers 771751936 bytes
Redo Buffers 10186752 byt

user9198889 wrote:
g777 wrote:
hi
DB and OS version would be nice to see...
look here
http://www.dba-oracle.com/oracle11g/oracle_11g_memory_target_parameter.htm
SGA_MAX_SIZE & SGA_TARGET
linux 5.5
db 11.2.0.2 rac GI 11.2.0.2thanks for the links,
"When using AMM (by setting memory_target, and/or sga_target, the values for the “traditional” pool parameters (db_cache_size, shared_pool_size, &c) are not ignored. Rather, they will specify the minimum size that Oracle will always maintain for each sub-area in the SGA.
so that means PGA wont grow more than 500MB and SGA be set to minimum of 4.5GB?
actually if you carefully read the above comment it doesnt mentiond sga_max_size it only says traditional pools such as db_cache_size etc...
does this also include sga_max_size?
I had a look at the other link to a thread but the question is slightly diffrent, they are discussing relation of sga_target to memory_target, I am intrested to know about sga_nax_size inrelation to memory_target

Unable to set sga_max_size parameter through spfile

My 10g db running in spfile. I am trying to decrease sga_max_size to 1024M where i have 1504 now ...
Do i am not doing in a right way ? Please suggest me
i am trying like this .....
SQL> sho parameter sga
NAME TYPE VALUE
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 1504M
sga_target big integer 0
alter system set sga_max_size =1020M scope= spfile;
SQL>system altered
SQL> sho parameter sga
NAME TYPE VALUE
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 1504M
sga_target big integer 0

SCOPE=SPFILE would not change the in-memory value. So a SHOW PARAMETER would still show the previous value.
You must compare the SPFILE before and after the ALTER SYSTEM. (Don't copy the spfile in a text editor but make a copy of the spfile to view OR use the "strings" command on Unix/Linux . If you accidentally write to the spfile with a text editor you will corrupt it. So, the best way to check the value is to run a CREATE PFILE FROM SPFILE and view the pfile which would be the initSID.ora file.

Setting SGA_MAX_SIZE without setting SGA_TARGET

RDBMS Version: 10.2.0.4
OS : Solart 5.10
We are currently facing some performance issues in one of our DBs.
This DB has SGA Components individually set. For eg: DB_CACHE_SIZE is set to 2gb.
I've noticed that
SGA_MAX_SIZE = 6GB
SGA_TARGET = Not setShould we set both SGA_TARGET, SGA_MAX_SIZE to take advantage of 10gR2's Automatice shared Memory Management?

sga_max_size sets the maximum value for sga_target.see MOSC Notes 295626.1, 396940.1, 270065.1 and 256913.1.
SGA_TARGET parameter is new with Oracle 10g. It specifies the total amaount of SGA memory available to an instance. Setting this parameter makes Oracle distribute the available memory among various components - such as shared pool (for SQL and PL/SQL), Java pool, large_pool and buffer cache - as required. This new feature is called Automatic Shared Memory Management. With ASMM, the parameters java_pool_size, shared_pool_size, large_pool_size and db_cache_size need not be specified explicitely anymore. sga_target cannot be higher than sga_max_size.
SGA_MAX_SIZE != SGA_TARGET when?
http://www.orafaq.com/wiki/Sga_target
Thanks

SGA_MAX_SIZE=high

Hi All,
os:HP unix
Db:oracle 10g
db size 20gb
load:normal
i have 32Gb of memeory...if i set sga_max_size=16g...any impact in future?
what will be the impact if i set sga_max_size set to high value....
can any one suggets me for the best values....
thanks,
dbc

dbc001 wrote:
Hi All,
os:HP unix
Db:oracle 10g
db size 20gb
load:normal
i have 32Gb of memeory...if i set sga_max_size=16g...any impact in future?
what will be the impact if i set sga_max_size set to high value....
can any one suggets me for the best values....
thanks,
dbc General thumb rule for setting the oracle memory againt RAM is oracle should get 60-70% of total memory. But this may differ in many conditions.
So first you need to check whats 'sga target advisory','db cache advisory','shared pool cache advisor' and pga advisor are saying about the cahce sizes? Take a report from AWR, so that you will get the idea if increasing SGA would help. Also you can check from v$sga_target_advice
Also read super post from below;
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:488583600346559562
Now coming to impact if SGA set to very high - well in that case your OS wont get enough memory for its processing and can bring down whole database performance. Then also there would be lots of swapping of pages from disk to memory and viceversa.Also there can be high CPU utilization because oracle has to keep large part of buffers in cahce and its processing will take cpu

Sga_target vs sga_max_size

Hi,
I'm using ASMM and sga_target is set to 1000M.
the sga_max_size parameter should be have the same value as sga_target?
For example: what's happen if i set sga_max_size to 1200M ?
Thank's

Hi,
I think, that if you set sga_max_size to 1200M and you have SGA_target=1000M, then you could dynamicaly (without restarting instance) increase sga up to 1200M. SGA_MAX_SIZE is only about possibility to increase your sga and oracle DOESN'T allocate whole SGA_MAX_SIZE - it allocate only your sga_target.
You can test it by decreasing SGA_TARGET by command ALTER SYSTEM SET SGA_TARGET=800M SCOPE=MEMORY; and you can see that memory will be released. You can test it in other direction too - increase sga_target to 1200M and aditional memory will be allocated from free memory.
Pavel

Sga_max_size & memory_max_target

Hi All,
Could you please tell me ...
In oracle 11.1 If I want to set Memory Parameter
alter system set memory_max_target=2000M scope=spfile;
alter system set memory_target=2000M scope=spfile;
Do I need to set sga_max_size value ? or it will set automatically
As Per my knowledge
We need to Set following sga parameter to 0, if ASMM, or AMM set to ON.(By default oracle 11g using ASMM, or AMM set to ON)
alter system set sga_target=0 scope=spfile;
alter system set pga_aggregate_target=0 scope=spfile;
I am not sure about sga_max_size
Thanking in Advance
Dev

Dev wrote:
I tested setting of SGA_MAX_SIZE=0 it is not setting to 0 after restart but not setting to 0
alter system set SGA_MAX_SIZE =0 scope=spfile
and bounced the instance
ALTER SYSTEM SET SGA_TARGET = 0 scope=spfile; not working
Have you allocated manually for each Memory parameters? DB Buffer cache, shared pool & so on?
If you are setting to ZERO means, you are configuring remaining all parameter manually.
Set those values and then try to set SGA_MAX to 0 then bounce it.

Sga_max_size in 9i

Hi
Sorry about this simple question but little bit confused.
If I set "sga_max_size" parameter in 9i, Does the sga compenents change (increase/decrease) dynamically while the database is up?
or
This is parameter only necessary if I want to increase the sga components manuelly while the database is up?

so, option2.
Is that right?
In oracle 9i,
this parameter is only necessary if I want to increase the sga components manuelly while the database is up.
The sga compenents doesnt increase automatically while the db is up.

Increase the SGA_MAX_SIZE and SGA_TARGET parameters

HI ,
I am using oracle 10g R2 and windows server 2003 .
My server is having 8 GB RAM .
I want to increase the SGA_MAX_SIZE and SGA_TARGET parameters .
I am using the below command , but getting the error
SQL> alter system set sga_max_size=2000M scope=spfile ;
alter system set sga_max_size=2000M scope=spfile
ERROR at line 1:
ORA-32001: write to SPFILE requested but no SPFILE specified at startup
Can someone please help ..

hi
connect as sys user and then try...
first make folder as backup and then copy the old SPFILEorcl to the same folder(backup)
now you can easily modify the files otherwise you will get error..
you will find here..
C:\ORACLE_HOME\database
SQL> alter system set sga_max_size=2000M scope=spfile ;
System altered.OR.
connect as sys user.
and do the following...
1).SQL>create pfile from spfile;
2).modify the pfile and decrease\increase the size of pools.
3).shutdown database.
4). Startup database using created pfile.
if it start ok then.
5.) Recreate the Spfile with the created Pfile.
SQL>create spfile from pfile;sarah

Increase SGA_MAX_SIZE and SGA_TARGET

Hi all,
I want to increase SGA_MAX_SIZE and SGA_TARGET in 10g. Currently we have
SQL> sho parameter sga
NAME TYPE VALUE
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 2384M
sga_target big integer 2384M
And we have 16GB RAM in redhat linux 4(32 bit).Oracle 10.2.0.3 DB.
Because of 32 bit OS, I was not able to increase shmmax more than 4GB.
In this situation how and how much SGA_MAX_SIZE and SGA_TARGET I can increase?
Thanks in Advance,
Sunil

Hi sunilgln,
Given the present state of things, you have to take a meassure of how many RAM is used with nothing running but the OS, that will give you the Linux footprint.
Take note of the amount of physical free memory (using top command)
Later you have to estimate how much swapping are you willing to accept, the SGA you define may be within the ranges of
FREE MEM*90% and FREE MEM*90+(OS FOOTPRINT*%SWAP MEMORY WILLING TO USE)
This is a proposal for setting this up, you need to tune and balance load depending on usage.
Another recommendation, SGA_TARGET is dynamic, SGA_MAX_SIZE is not...but you may set SGA_MAX_SIZE to a full allocation and set SGA_TARGET to a percentage that allocation and gradually use it.
What happens is: the OS will "allocate" a chunk(or chunks) the size given by SGA_MAX_SIZE, but the real usage by the database will be determined by SGA_TARGET.
Hope this helps you
Ignacio
Regards
http://oracledisect.blogspot.com

SGA_MAX_SIZE and AMM

Hi, all,
I've been testing using AMM in our newly-upgraded 11gR2 databases. All databases (Prod and non-Prod) are running 11.2.0.3 on AIX 5.3 (64-bit).
I noticed that despite me explicitly setting the following to 0:
alter system set db_cache_size = 0 scope=spfile;
alter system set log_buffer = 0 scope=spfile;
alter system set pga_aggregate_target = 0 scope=spfile;
alter system set sga_max_size = 0 scope=spfile;
alter system set sga_target = 0 scope=spfile;
alter system set shared_pool_size = 0 scope=spfile;
alter system set shared_pool_reserved_size = 0 scope=spfile;
And allowing Oracle 'full control' how it manages all parts of the memory (SGA and PGA)
-- The 'big' database
alter system set memory_max_target = 24G scope=spfile;
alter system set memory_target = 24G scope=spfile;
-- The 'small' database
alter system set memory_max_target = 3G scope=spfile;
alter system set memory_target = 3G scope=spfile;
I bounce both databases and things seem to come up OK. The only exception is that sga_max_size seems to be set to a specific value:
For the 'big' database, it's 16Gb (2/3rds of the total memory_target)
For the 'small' database, it's 1536Mb (1/2 of the total memory_target)
I don't really understand why this is happening. I've double-checked my SPFILE, I've queried v$spparameter and I've read MOS 443746.1
+"If MEMORY_TARGET is set to a non-zero value:+
+If neither is set, they will be auto-tuned without any minimum or default values. We will have a policy of distributing the total memory set by MEMORY_TARGET parameter in a fixed ratio to the the SGA and PGA during initialization. The policy is to give 60% to the SGA and 40% to the PGA at startup."+
BUT I presume that sga_max_size works in the same way that it did when we weren't using AMM - it's the upper limit of the SGA. Not ideal, to be honest, as I can definitely see times when the SGA needs a LOT of buffer cache in Production (and, therefore, lots of SGA)
I do see this in the alert.logs whenever I restart the system:
Using parameter settings in server-side spfile /opt/oracle/product/11.2.0.3/db/dbs/spfilebigdb.ora
System parameters with non-default values:
processes                = 600
sessions                 = 928
timed_statistics         = TRUE
resource_limit           = TRUE
event                    = "10262 trace name context forever, level 160000"
sga_max_size             = 16G
So it's suggesting that it's querying the SPFILE and determining that sga_max_size should be set. But I've double-double-checked and that isn't the case.
Now, I know I can get around this by explicitly setting sga_max_size at memory_target. But I was wondering if anyone else had seen this before too?
Mark

Another workaround is to remove the memory components entirely from the SPFILE (instead of having them set to 0, don't have them in the file at all). This seems to also set the sga_max_size to the memory_target - which is expected behaviour given the MOS note.

(9I) DYNAMIC SGA : SGA_MAX_SIZE, DB_CACHE_SIZE, DB_KEEP_CACHE_SIZE

제품 : ORACLE SERVER
작성날짜 : 2005-01-05
(9I) DYNAMIC SGA : SGA_MAX_SIZE, DB_CACHE_SIZE, DB_KEEP_CACHE_SIZE
==================================================================
PURPOSE
Oracle 9i의 새 기능인 동적으로 SGA 파라미터들을 변경하는 방법에
대하여 알아보기로 한다.
Explanation
Oracle 8i까지는 Buffer Cache, Shared Pool, Large Pool 등과 같은 SGA
파라미터들에 대해 그 크기를 동적으로, db가 운영 중인 상태에서는 변경할
수가 없었다.
즉, 이러한 파라미터들을 변경하려면 db를 shutdown하고 initSID.ora 화일에
서 그 크기를 다시 설정하고, 이 파라미터를 이용해서 db 인스턴스를 restart
해야만 했었다.
Oracle 9i에서는 DBA가 ALTER SYSTEM 명령을 이용해서 SGA 파라미터의 크기
를 동적으로 변경할 수 있게 되었다. 이 특정을 'Dynamic SGA'라고 부른다.
SGA 전체의 최대 크기(SGA_MAX_SIZE)를 정의하고 그 한도 내에서 파라미터의
크기를 변경할 수 있는 것이다. 데이타베이스를 shutdown/startup 없이 작업
이 가능하기 때문에 'Planned Downtime'을 줄이는 한 방법으로도 이해할 수
있다.
이 글에서는 SGA에 할당할 수 있는 최소 단위인 'Granule'의 개념을 살펴보
고, 이 granule이 어떠한 방법에 의해 동적으로 할당되는지에 대해 알아보고
자 한다.
또한 Buffer Cache 파라미터 중 새로운 것과 이전 버전에 비해 달라진 내용
을 소개하기로 한다.
1. Granule
Granule은 가상 메모리 상의 연속된 공간으로, dynamic SGA 모델에서 할당할
수 있는 최소 단위이다. 이 granule의 크기는 SGA 전체의 추정값
(SGA_MAX_SIZE)에 따라 다음과 같이 구분된다.
4MB if estimated SGA size is < 128M
16MB otherwise
SGA의 Buffer Cache, Shared Pool, Large Pool 등의 파라미터는 이 granule
단위로 늘어나거나 줄어들 수 있다. (현재 dynamic SGA를 사용할 수 있는
SGA 관련 파라미터는 Buffer Cache, Shared Pool, Large Pool 세 가지이다.)
2. Dynamic SGA(DB_CACHE_SIZE, SHARED_POOL_SIZE)
DBA는 ALTER SYSTEM 명령을 통해 initSID.ora 화일에 정의된 SGA 관련 파라미
터 값을 동적으로 변경할 수 있다. SGA 파라미터의 크기를 늘려주기 위해서
는 필요한 만큼의 free granule이 존재해야만 하며, 현재 사용하고 있는 SGA
의 크기가 SGA_MAX_SIZE보다 작아야 한다. Free granule이 없다고 해서 다른
파라미터로부터 granule을 free시켜서 그 granule을 이용할 수 있는 것은 아
니다.
반드시 DBA가 명시적으로 free/allocate해야 한다.
다음의 예를 살펴보자. 설명을 단순화하기 위해 이 경우는 SGA가 Buffer
Cache와 Shared Pool로만 구성되었다고만 하자.
예) initSID.ora
SGA_MAX_SIZE = 128M
DB_CACHE_SIZE = 96M
SHARED_POOL_SIZE = 32M
Note : DB_CACHE_SIZE는 Oracle 9i에 새롭게 도입된 파라미터이다.
위와 같은 상태일 때 동적으로 SHARED_POOL_SIZE를 64M로 늘리면 에러가 발생
한다.
SQL> ALTER SYSTEM SET SHARED_POOL_SIZE=64M;
(insufficient memory error message)
이 에러는 SHARED_POOL_SIZE를 늘림으로써 전체 SGA의 크기가 SGA_MAX_SIZE
보다 커지기 때문에 발생한다. (96M + 64M > 128M)
이를 해결하기 위해서는 DB_CACHE_SIZE를 줄인 후, SHARED_POOL_SIZE를 늘린다.
SQL> ALTER SYSTEM SET DB_CACHE_SIZE=64M;
SQL> ALTER SYSTEM SET SHARED_POOL_SIZE=64M;
Note : DB_CACHE_SIZE가 shrink되는 동안에
ALTER SYSTEM SET SHARED_POOL_SIZE=64M;
를 하면 insufficient error가 발생할 수도 있다.
이 경우는 DB_CACHE_SIZE가 shrink된 후 다시 수행하면 정상적으로
수행이 된다.
Note : 위 예제의 경우 estimated SGA 크기가 128M 이상이므로, granule의
단위는 16M이다. 따라서 SGA 파라미터의 크기를 16M의 정수배로 했다.
16M의 정수배가 아닌 경우는 지정한 값보다 큰 값에 대해 16M의
정수배 중 가장 가까운 값을 택하게 된다.
즉, 아래 두 문장의 결과는 똑같다.
SQL> ALTER SYSTEM SET SHARED_POOL_SIZE=64M;
SQL> ALTER SYSTEM SET SHARED_POOL_SIZE=49M;
Note : LARGE_POOL_SIZE 와 JAVA_POOL_SIZE 파라미터는 동적으로 변경하는
것이 불가능하다.
1) Dynamic Shared Pool
인스턴스 start 후, Shared Pool의 크기는 다음과 같은 명령에 의해 동적으
로 변경(grow or shrink)될 수 있다.
ALTER SYSTEM SET SHARED_POOL_SIZE=64M;
다음과 같은 제약 사항이 있다.
- 실제 할당되는 크기는 16M의 정수배가 된다.
- 전체 SGA의 크기는 SGA_MAX_SIZE를 초과할 수는 없다.
2) Dynamic Buffer Cache
인스턴스 start 후, Buffer Cache의 크기는 다음과 같은 명령에 의해 동적으
로 변경(grow or shrink)될 수 있다.
ALTER SYSTEM SET DB_CACHE_SIZE=96M;
다음과 같은 제약 사항이 있다.
- 실제 할당되는 크기는 16M의 정수배가 된다.
- 전체 SGA의 크기는 SGA_MAX_SIZE를 초과할 수는 없다.
- DB_CACHE_SIZE는 0이 될 수 없다.
3. Buffer Cache 파라미터의 변경된 내용
여기서는 Buffer Cache 파라미터와 관련하여 Oracle 9i에 의미가 없어진 파라
미터와 새롭게 추가된 파라미터, 그리고 dynamic SGA 중 Buffer Cache와 관련
이 있는 부분에 대해 기술하고자 한다.
1) Deprecated Buffer Cache Parameters
다음의 세 가지 파라미터는 backward compatibility를 위해 존재하는 것으
로, 차후 의미가 없어진다.
- DB_BLOCK_BUFFERS
- BUFFER_POOL_KEEP
- BUFFER_POOL_RECYCLE
위의 파라미터들이 정의되어 있으면 이 값들을 사용하게 될 것이다. 하지만,
다음에 나올 새로운 파라미터들을 사용하는 것이 좋으며, 만일 위 파라미터
(DB_BLOCK_BUFFERS, BUFFER_POOL_KEEP, BUFFER_POOL_RECYCLE) 값들을 사용
한다면 이 글에서 설명한 dynamic SGA 특징을 사용할 수는 없다. 또한
initSID.ora 화일에 위 파라미터들과 새로운 파라미터를 동시에 기술한다면
에러가 발생한다.
2) New Buffer Cache Sizing Parameters
다음의 세 파라미터가 추가되었다. 이 파라미터들은 primary block size에
대한 buffer cache 정보를 다루고 있다.
- DB_CACHE_SIZE
- DB_KEEP_CACHE_SIZE
- DB_RECYCLE_CACHE_SIZE
DB_CACHE_SIZE 파라미터에 지정된 값은 primary block size에 대한 default
Buffer Pool의 크기를 의미한다. 또한 이전 버전과 마찬가지로 KEEP과
RECYCLE buffer pool을 둘 수 있는데, 이는 DB_KEEP_CACHE_SIZE,
DB_RECYCLE_CACHE_SIZE 라는 파라미터를 이용한다.
이전 버전과 다른 점은 이전 버전의 경우 각각의 파라미터
(DB_BLOCK_BUFFERS, BUFFER_POOL_KEEP,BUFFER_POOL_RECYCLE)에 정의된 값들
이 buffer 갯수(즉, 실제 메모리 크기를 구하려면 db_block_size를 곱했어야
했다. )였는데 반해 이제는 구체적인 메모리 크기이다.
또한 이전에는 DB_BLOCK_BUFFERS가 BUFFER_POOL_KEEP, BUFFER_POOL_RECYCLE
의 값을 포함하고 있었지만, 이제는 DB_CACHE_SIZE가 DB_KEEP_CACHE_SIZE,
DB_RECYCLE_CACHE_SIZE를 포함하고 있지 않다.
즉, 각각의 파라미터들은 독립적이다.
Note : Oracle 9i부터는 multiple block size(2K, 4K, 8K, 16K, 32K)를 지원한다.
위에서 언급한 primary block size는 DB_BLOCK_SIZE에 의해 정해진 block
size를 의미한다. (SYSTEM tablespace는 이 block size를 이용한다.)
3) Dynamic Buffer Cache Size Parameters
바로 위에서 언급한 세 파라미터는 아래와 같이 ALTER SYSTEM 명령에 의해
동적으로 변경 가능하다.
SQL> ALTER SYSTEM SET DB_CACHE_SIZE=96M;
SQL> ALTER SYSTEM SET DB_KEEP_CACHE_SIZE=16M;
SQL> ALTER SYSTEM SET DB_RECYCLE_CACHE_SIZE=16M;
Example
none
Reference Documents
<Note:148495.1>

Hello Martin,
Can I execute by ORA-27102 the following commandos in order to set and use the values of sga_max_size immediately?
Variant 1)
>sqlplus /nolog
>connect / as sysdba
> startup nomout
> ALTER SYSTEM SET SGA_MAX_SIZE= value SCOPE=pfile;
> shutdown immediate
> startup
Variant 2)
Changing the values of sga_max_size, etc. in init<DBSID>.ora
>sqlplus /nolog
>connect / as sysdba
> startup from pfile = /oracle/<SID>/dbs/ init<DBSID>.ora;
Thank you very much!
regards
Thom

Setting AWE_WINDOW_SIZE

Hi All,
I have edited the boot.ini file and added the
/3GB /PAE entry into the it.
Following are the entries that are pending to be done which i can do.
USE_INDIRECT_BUFFERS=TRUE,
Using DB_BLOCK_BUFFERS parameter in the initialization file instead of the DB_CACHE parameter.
The point where I am stuck is how to set the AWE_WINDOW_SIZE, i tried searching for this key in the registry and did not find it.
Since it is told that that default value would be 1 GB, it's an indication that the registry already should have that parameter, but i am not able to find it.
Request if i can get instructions as to how to set the AWE_WINDOW_SIZE.
Thanks in advance
Regards
Karthik..

Hi Karthik,
I have some notes on setting awe_windows_size that may help:
http://www.dba-oracle.com/t_awe_window_size.htm
MetaLink Note:225349.1 gives these recommendations for setting manual SGA for AWE as follows:
alter system set sga_target = 0;
alter system set sga_max_size = 0;
alter system set shared_pool_size = 500;
alter system set large_pool_size = 100;
alter system set java_pool_size = 16;
pga_target =256m;
USE_INDIRECT_DATA_BUFFERS=TRUE
Hope this helps. . .
Donald K. Burleson
Oracle Press author
Author of "Oracle Tuning: The Definitive Reference":
http://www.dba-oracle.com/bp/s_oracle_tuning_book.htm

Is there a limit for SGA_MAX_SIZE on windows Server 2003 Standard Edition

I have a 9.2.0.8 Standard Edition running on windows Server 2003 Standard Edition. I cannot set SGA_MAX_SIZE to more than 1.7G. I have total of 3G RAM on that machine.

In order to use memory over 4 GB the /PAE flag must be set and Oracle must be tuned
accordingly. As mentioned above, for using memory over 4 GB and less than 16 GB, the
/3GB flag can be set as well. Oracle uses memory above 4 GB by taking advantage of
the AWE (Address Windowing Extension) feature built into Windows 2000, Windows
2003 and Windows XP.
In order to use this memory, the Oracle administrator account (either LocalSystem or the
domain user that installed Oracle) must have the “Lock memory pages” privilege set. In
addition the AWE_WINDOW_MEMORY parameter must also be created and set. This
parameter specifies how much of the 3 GB virtual memory space allocated to Oracle
should be used for mapping database buffers. The default value of 1GB should be
sufficient and increasing this value could be detrimental, since you only have 3 GB of
virtual memory to use. The higher the value of AWE_WINDOW_MEMORY that you
have set, the more likely it is that you will experience user memory issues. Start with the
default value of 1 GB and tune upwards only if you need to.
Once these steps have been completed, larger memory can be set by configuring
DB_BLOCK_SIZE and DB_BLOCK_BUFFERS initialization parameters. When using
Very Large Memory (VLM) you should use DB_BLOCK_BUFFERS rather than
DB_CACHE_SIZE in order to configure memory.

Setting sga_target in Oracle10g using spfile in Window OS

Hi all
Previously we used to set the parameter values thru initora
Now we wish to follow the default spfile for parameters as provided by Oracle.
When we give
alter system set pga_aggregate_target = ???M;
it works properly but the same syntex does not work properly for'
processes as well as sga_target
1. Kindly guide the exact syntix to set these parameters
2. Also advise whether setting sga_target would be sufficient or do we need to set sga_max_size also and possible advantage
3. Role of Oracle Processes and what should be the ideal number for Live installation with say 100-150 simultaneous users. RAM available is enough say 8GB.
Suresh Bansal

Suresh Bansal wrote:
Hi all
Previously we used to set the parameter values thru initora
Now we wish to follow the default spfile for parameters as provided by Oracle.
When we give
alter system set pga_aggregate_target = ???M;
it works properly but the same syntex does not work properly for'
processes as well as sga_target
1. Kindly guide the exact syntix to set these parameters
2. Also advise whether setting sga_target would be sufficient or do we need to set sga_max_size also and possible advantage
3. Role of Oracle Processes and what should be the ideal number for Live installation with say 100-150 simultaneous users. RAM available is enough say 8GB.
Suresh BansalBoth SGA_MAX_SIZE and PROCESSES are parameters that cannot be changed dynamically, because you have omitted the SCOPE= clause of ALTER SYSTEM it takes it's default of BOTH. SGA_TARGET is modifiable in memory, but only up to the limit specified by SGA_MAX_SIZE which defaults to whatever you have SGA_TARGET set to, this means in a default setup you can only reduce SGA_TARGET. From my system
SYS @ DB10G >show parameter SGA_
NAME                                 TYPE        VALUE
sga_max_size                         big integer 584M
sga_target                           big integer 584M
SYS @ DB10G >SELECT NAME,ISSYS_MODIFIABLE
2* FROM V$PARAMETER WHERE NAME LIKE 'sga%'
SYS @ DB10G >/
NAME                                                                             ISSYS_MOD
sga_max_size                                                                     FALSE
sga_target                                                                       IMMEDIATESo I have 584m set for both as a result I can reduce the size, but not increase it.
SYS @ DB10G >alter system set SGA_TARGET=600M;
alter system set SGA_TARGET=600M
ERROR at line 1:
ORA-02097: parameter cannot be modified because specified value is invalid
ORA-00823: Specified value of sga_target greater than sga_max_size
SYS @ DB10G >alter system set SGA_TARGET=400M;
System altered.But I can set it in the spfile.
SYS @ DB10G >alter system set SGA_TARGET=600M SCOPE=SPFILE;
System altered.You only need to set SGA_TARGET, but if you set SGA_MAX_SIZE larger you give yourself room for growth later. This should be clear from the demo above.
PROCESSES controls the size of Oracle's internal process table (externalized as v$process) which is why you can't dynamically reset it, you'll need more entries in this process table than you anticipate user sessions, generally about 15-25% more.
Niall Litchfield
http://www.orawin.info/

Setting sga_max_size

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