Altering SGA_MAX_SIZE

i have a Oracle 10g in a server XEON with two processores and 4 Gb RAM. My SGA_MAX_SIZE have 900 Mg, but i think that this is very little. How can i do for resize mi SGA_MAX_SIZE?

If you use spfile
SQL> show parameter spfile
SQL> alter system set SGA_MAX_SIZE=xxx scope=spfile;If not use spfile, you must modify pfile ... init<SID>.ora
and then
SQL> shutdown immediate;
SQL> startup;Anyway you should increase SGA_TARGET initialization parameter as well...
If you use spfile , SGA_TARGET(dynamic) ... can change.. (not more SGA_MAX_SIZE) no shutdown database
SQL> alter system set sga_target=xxx;So, your Step ... if you use spfile
SQL> show parameter sga
SQL> alter system set SGA_MAX_SIZE=xxxx scope=spfile;
SQL> alter system set SGA_TARGET=xxxx scope=spfile;
SQL> shutdown immediate;
SQL> startup;good Luck

Similar Messages

Increasing SGA_MAX_SIZE in Oracle 10.2.0.1

Hi,
we have successfully upgrade our database from 8.1.7.0 to 10.2.0.1
now in the database control, SGA max size is 524MB
i want to increase it, as to increase the size of SHARED_POOL_SIZE and DATBASE_BUFFER size
i have checked the init.ora file, in that there is no parameter mentioned as sga_max_size
from where and how to increase the SGA_MAX_SIZE in 10g version ?
with regards

Hi,
Database is using init.ora file in the pfile folder
In the init.ora file i have increased the SGA_MAX_SIZE parameter to 1024Mb from 524Mb
Now, from dbcontrol screen, Automatic Shared Memory Managment is Disabled and i want to make it ENABLE
now when i click on ENABLE button, on the next page it shows total SGa size i.e 332 Mb
and further wheni click on "OK" button for ASSM configuration, it shows the error as below :-
1.) SGATargetSize - ORA-02097 : parameter cannot be modified because specified vale is invalid ORA : cannot set sga_target due to existing internal settings, see alert log for information
in the alert log , it mentions
Cannot set sga_target with db_block_buffers set
and
Alter system set java_pool_size='0' SCOPE=MEMORY;
2) sharedPoolsize - ORA-02097 parameter cannot be modified because specified value is invalid ORA-04034: unable to shrink pool to specified size
now i just mentioned the memory component details for reference :
shared pool : 104 Mb
buffer cache : 169 Mb
large pool : 0
java pool : 4 Mb
other : 54 Mb
total SGA -- 332 Mb
Maximum SGA Size -- 1024 Mb
how to make ASSM Enable ???
With Regards

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 vs sga_target

Whats the difference between SGA_MAX_SIZE and SGA_TARGET? I am bit confused.
As per Oracle® Database Reference 10g Release 1 (10.1)
SGA_MAX_SIZE specifies the maximum size of the SGA for the lifetime of the instance
Then why SGA_TARGET is used.
I am missing something here. Kindly clarify.
Thanks in Advance
SID.

Max_size is what the SGA can grow to if it has to.
SGA_Target is what you'd like the SGA to be.
Then why SGA_TARGET is used.
Because you might want to dynamically grow your SGA, above the target. Suppose someone gives you a transportable tablespace and it comes from a 4K-blocksize database, and you're using 8K blocks. You have to 'alter system set db_4k_cache_size=something', but if you try that when your TARGET already equals your MAX_SIZE, you'll be told there's no room to grow the SGA, so the only way to achieve what you want is to shrink some other part of the SGA or to set the parameter in your init.ora and bounce. Either could be problematic on a production box. That's just one example: remember that 'SGA_TARGET' is indeed only a target: Oracle is allowed to exceed the target if thinks the workload makes it necessary to do so.
So the difference between MAX_SIZE and TARGET is 'slack space': memory that's not in use, but could be if you (or Oracle) determined a need for it.
On a lot of operating systems, this difference is paged out and thus doesn't mean you're wasting real, physical memory.
But on others (and I think this is true of Windows and Linux), you would indeed be 'consuming' that memory difference -which would thus amount to wasted physical memory.

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

SGA_MAX_SIZE and shmmax values

All,
My environment is
Oralce - 10.2.0.4.0
Two node RAC environment
Red hat Enterprise Linux 5 64 bit operating system
RAM size - 64 GB
shmmax - 4294967295 (one byte less than 4 GB)
SGA_MAX_SIZE = 3808M
SGA_TARGET = 3808M
PGA_AGGREGATE_TARGET=1000M
When I run the ADDM, it is telling that SGA was inadequately sized, increase the sga_target to 4760M. It says that 33% impact.
In my case, I need to increase SGA_MAX_SIZE.
I may be wrong, but from google, i assume that SGA_MAX_ZIZE can't be more than shmmax. Is it true?
If I have to increase the shmax, is it fine to increase to 5 GB based on ADDM recommendataion. Are there any harm to increase the shmmax to 20GB are so for safer side?
Any relation beween shmmax and RAM size?
If I have to alter the SGA_MAX_SIZE in RAC, I need to bounce the database or i can do one instance at a time right. If I am going with one node at a time, since it is a production, what will happen to the connections in that node when i am restarting that particular instance? I have a TAF policy of "Basic".
is it like all the select statements will be moved to survival node whereas insert, update and delete transactions will be broken?
Awaiting your help..

Always it is recommended to keep "shmmax" half the size of physical memory.
First you need to increase shmmax and then increase the SGA_MAX_SIZE as per ADDM.
See the below doc for all your answers answers.
http://download.oracle.com/docs/cd/B19306_01/install.102/b15668/toc.htm#BGBDFIGF
Hope this solves your issue.
Regards,
Satishbabu Gunukula
hthttp://www.oracleracexpert.com
Click here for solution - [ORA-19755 Error during recovery/DB startup|http://www.oracleracexpert.com/2009/09/ora-19755-could-not-open-change.html]
Click here to learn [Block corruption and recovery|http://www.oracleracexpert.com/2009/08/block-corruption-and-recovery.html]
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Edited by: Satishbabu Gunukula on Sep 23, 2009 2:43 PM

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.

Sga_max_size and sga_target values

I have an 11g database on windows with 4GB RAM, I have set the MEMORY_MAX_TARGET and MEMORY_TARGET, what should I do with the pre-existing sga_max_size and sga_target values

memory_target = sga_target + max(pga_aggregate_target, maximum PGA allocated)
MEMORY_MAX_TARGET = sum of the SGA and instance PGA sizes.
For Automatic memory management
set
ALTER SYSTEM SET SGA_TARGET = 0;
ALTER SYSTEM SET PGA_AGGREGATE_TARGET = 0;
Note:
In a text initialization parameter file, if you omit the line for MEMORY_MAX_TARGET and include a value for MEMORY_TARGET, the database automatically sets MEMORY_MAX_TARGET to the value of MEMORY_TARGET. If you omit the line for MEMORY_TARGET and include a value for MEMORY_MAX_TARGET, the MEMORY_TARGET parameter defaults to zero. After startup, you can then dynamically change MEMORY_TARGET to a nonzero value, provided that it does not exceed the value of MEMORY_MAX_TARGET.
Note:
The preceding steps instruct you to set SGA_TARGET and PGA_AGGREGATE_TARGET to zero so that the sizes of the SGA and instance PGA are tuned up and down as required, without restrictions. You can omit the statements that set these parameter values to zero and leave either or both of the values as positive numbers. In this case, the values act as minimum values for the sizes of the SGA or instance PGA.
Reference

(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

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.

Alter system set shared_pool_size extremely slow.

I am trying to increase my shared_pool_size from 60m to 200m by simply typing alter system set shared_pool_size=200m;
I did alter system flush shared_pool; before to clear out the current shared_pool.
I'm on 9i and my SGA_MAX_SIZE is 3g and I have plenty room to grow.
show sga
Total System Global Area 3222769016 bytes
Fixed Size 744824 bytes
Variable Size 2382364672 bytes
Database Buffers 838860800 bytes
Redo Buffers 798720 bytes
My event in v$session_wait is background parameter adjustment.
Any help would be appreciated. I know that I can bounce the server and let it read it from the init.ora. However, I'm trying to fix some current 4031s in my shared pool. The flush did fix them temporarily.

Are you sure your instance was in the state you thought it was ? This is what you reported from show sga:
Total System Global Area 3222769016 bytes
Fixed Size                    744824 bytes
Variable Size             2382364672 bytes
Database Buffers           838860800 bytes
Redo Buffers                  798720 bytesYou say your shared_pool_size is 60M and you want to grow it to 200M, but the Variable Size in the output above suggests that your shared pool had already grown to about 2.3 GB, so your command would have been trying to shrink it quite dramatically. (And 9i isn't very good at shrinking the shared pool because of the problems of pinned and "KEEP"ed objects in the library cache.
Things to check (from another session):
v$sga_current_resize_ops to see if your resize operation is still running, and what it's trying to do.
v$sga_resize_ops to see i f your resize operation completed some time ago - leaving your session stuck somewhere else. (There's a convenient query I wrote against this view published here: http://jonathanlewis.wordpress.com/2007/04/16/sga-resizing/ )
v$session_wait (for the resize session) to see if the session is waiting or working
v$sesstat (for the resize session) to see if it gives you any clues about current activity
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk

ALTER SYSTEM SET SGA_TARGET

Hi,
in 10g R2 should I stop/start database when I change sGA_TARGET :
ALTER SYSTEM SET SGA_TARGET=value [SCOPE={SPFILE|MEMORY|BOTH}]
Thank you.

user522961 wrote:
OK.
When I query V$PARAMETER I have the OLD value for SGA_TARGET. It is normal because the value in V$PARAMETER comes from starting and spfile. How can I be sur that now oRACLE uses the new value for SGA_TARGET effectively ?
Thanks again.Not sure I understand your question. If you set SGA_TARGET with SCOPE=MEMORY or BOTH, it should be in effect immediately.
SQL> alter system set sga_target=253M scope=both;
System altered.
SQL> select value bytes, value/1048576 MB from v$parameter where name = 'sga_target';
BYTES              MB
268435456         256
SQL> show parameter sga
NAME                                 TYPE        VALUE
lock_sga                             boolean     FALSE
pre_page_sga                         boolean     FALSE
sga_max_size                         big integer 512M
sga_target                           big integer 256M
SQL> alter system set sga_target=257M scope=both;
System altered.
SQL> select value bytes, value/1048576 MB from v$parameter where name = 'sga_target';
BYTES              MB
272629760         260
SQL> show parameter sga
NAME                                 TYPE        VALUE
lock_sga                             boolean     FALSE
pre_page_sga                         boolean     FALSE
sga_max_size                         big integer 512M
sga_target                           big integer 260M
SQL>

Altering SGA size

Hi,
We are in the process to increase the size of SGA to improve the performance of our Production Database, as its performance have been degraded.
Our database server is having total 2GB of RAM.
SGA_MAX_SIZE is not defined in the init.ora file
The following are the details of database memory structures :
Total System Global Area = 180.63088 (MB)
database buffers = 53.4921875 (MB)
shared_pool_size = 100 (MB)
large_pool_size = 0.5859 (MB)
java_pool_size = 20 (MB)
db_block_buffers = 6847 bytes
db_block_size = 8192 bytes
So how much SGA size can we increase to improve the performance of the database server?
which parameters from above are required to be altered and upto how much size ?
Kind request to provide the guidance.
Regards.

hi
this depends upon organization to organization
well just check this out the link
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/create.htm#ADMIN00207
Hope this helps
CHeers

Cahnge sga_target & sga_max_size ?

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

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

Altering SGA_MAX_SIZE

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