Increase SGA Size

HI,
EBS- 12.0.6
DB- 10.2.0.3
I found this in the ADDM Report ---
FINDING 1: 100% impact (18551 seconds)
The SGA was inadequately sized, causing additional I/O or hard parses.
RECOMMENDATION 1: DB Configuration, 100% benefit (18551 seconds)
ACTION: Increase the size of the SGA by setting the parameter
"sga_target" to 3140 M.
ADDITIONAL INFORMATION:
The value of parameter "sga_target" was "2512 M" during the analysis
period.
SYMPTOMS THAT LED TO THE FINDING:
SYMPTOM: Wait class "User I/O" was consuming significant database time.
(43% impact [7964 seconds])
SYMPTOM: Hard parsing of SQL statements was consuming significant
database time. (3.1% impact [577 seconds])
Workarround :
1. Make the entry in the pfile as sga_max_size=3500M.
2. Shutdown the DB
3. Startup the DB with the pfile
4. SQL>CREATE SPFILE='path of the spfile' FROM PFILE"
5. Shutdown Immediate
6. Startup the DB with the newly created spfile " SQL>STARTUP SPFILE='path of the spfile' "
7 sql> show parameter sga to make sure your changes takes effect
Please correct me if am wrong ..
Thanks

you have to tune the application layer , check top ten query in AWR within perfromance tab , run SQL tuning advisor for each query and see the recommendations , implemnet recommendations , as i have expericence it alls due to huge IO occuring at database (i.e Full Table Scan) due to missing index , if index is not being used then check if any function is used on index coulm (it inhabit skip index usage) then try to avoid function over index column or create function based index. You may need to run explain plan of that query or tkprof tool to identify what optimizer is taking route to fetch data.Check also stats are gathered on tables and index properly.
I have got eliminated function over indexed column by giving alternate to our techno functional consultant.

Similar Messages

How can i increase sga size in oracle 10g

Hello friends
how can i increase my sga size in oracle 10g
Regards
Vicky
Edited by: Vignesh Chinnasamy on 31-Jul-2012 02:28

HI
**SQL> Show parameter sga ;**
NAME                                 TYPE        VALUE
lock_sga                             boolean     FALSE
pre_page_sga                         boolean     FALSE
sga_max_size                         big integer 2G
sga_target                           big integer 2G
**SQL> show parameter memory;**
NAME                                 TYPE        VALUE
hi_shared_memory_address             integer     0
shared_memory_address                integer     0
**[root@mte ~]# ulimit -a**
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
pending signals                 (-i) 1024
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 278528
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited
*[root@mte ~]#*

How to increase SGA size in Oracle 9i release 9.0.1.1.1

Hi,
We have Oracle 2000 server on a intel machine (2.8GHz processor and 2 GB RAM). Virtual memory is :- 3GB.
We have a Oracle 9.0.1.1.1 running on this machine. What are the parameters that I need to set to increase the SGA size. We want a large SGA size with enough space for shared pool.
Thanks in advance.
--Malay

Malay,
First Check out the RAM utilization for the OS Kernel and remaining to the applications and then to SGA.
We have Oracle 2000 server on a intel machine (2.8GHz processor and 2 GB RAM). Virtual memory is :- 3GB.I suppose its Windows 2000 Server!!!
& What's the size of the Database?
all these things allow you to decide how "large" you can increase the SGA

Need to Increase SGA Size

Hi,
RDBMS : 11.1.0.7.0
OS : RHEL 5 (X86_64)
EBS : 12.1.3
My Database Server RAM size is 128 gb
Currently my Parameters are
SGA_Target = 2g
SGA_max = 2g
Shared_pool_size = 600m
Kernel Parameters are :
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.sem = 256 32000 100 142
kernel.shmmni = 4096
kernel.msgmni = 2878
fs.file-max = 6553600
net.ipv4.ip_local_port_range = 1000 65000
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 262144
My question is...
As My project manager is asking to increase the SGA Size as i have 128gb RAM of server.
Maximum how much i can increase the SGA Size
It is PRODUCTION Server... Now it's running with out any issue... but so much RAM is there y can't we use....?
Please advice..
Thanks,

As per the Note
Maximum SHMMAX values for Linux x86 and x86-64 [ID 567506.1]
=======================================================================
QUESTION 2
===========
What is the maximum value of SHMMAX for a 64-bit (x86-64) Linux system?
ANSWER 2
===========
Oracle Global Customer Support officially recommends a " maximum" for SHMMAX of "1/2 of physical RAM".
The maximum size of a shared memory segment is limited by the size of the available user address space. On 64-bit systems, this is a theoretical 2^64bytes. So the "theoretical limit" for SHMMAX is the amount of physical RAM that you have. However, to actually attempt to use such a value could potentially lead to a situation where no system memory is available for anything else. Therefore a more realistic "physical limit" for SHMMAX would probably be "physical RAM - 2Gb".
In an Oracle RDBMS application, this "physical limit" still leaves inadequate system memory for other necessary functions. Therefore, the common "Oracle maximum" for SHMMAX that you will often see is "1/2 of physical RAM". Many Oracle customers chose a higher fraction, at their discretion.
Occasionally, Customers may erroneously think that that setting the SHMMAX as recommended in this NOTE limits the total SGA. That is not true. Setting the SHMMAX as recommended only causes a few more âshared memory segmentsâ to be used for whatever total SGA that you subsequently configure in Oracle. For additional detail, please see Document 15566.1, "SGA, SHMMAX, Semaphores and Shared Memory Explained"
==========================================================================
Our server RAM is 128 gb.... as per the note 1/2 of the physical RAM we can assign for SHMMAX parameter... (apprx 60gb)
How can i understood this answer for my configuration......
Please advice...
Thanks,

Increase SGA size with ORA-02095.

Hi Experts,
I want to increase SGA for oracle 10G in window 2003 . however, I got error as
SQL> alter system set sga_max_size=1700M,scope=spfile;
alter system set sga_max_size=1700M,scope=spfile
ERROR at line 1:
ORA-02095: specified initialization parameter cannot be modified
SQL> alter system set SGA_TARGET=1700M scope=SPFILE;
System altered.
SQL> alter system set sga_max_size=1700M,scope=spfile;
alter system set sga_max_size=1700M,scope=spfile
ERROR at line 1:
ORA-02095: specified initialization parameter cannot be modified
Now I just increase SGA_target as 1700M How to increase SGA_MAX_SIZE?
Thanks
JIM
Edited by: user589812 on Mar 23, 2009 8:42 AM

SQL> alter system set sga_max_size=1700M,scope=spfile;
alter system set sga_max_size=1700M,scope=spfile
ERROR at line 1:
ORA-02095: specified initialization parameter cannot be modified
take out comma,
alter system set sga_max_size=1700M scope=spfile;

How to Increase the SGA Size.

Hi Guru's
I want to Know
How to Increase the SGA Size in Database 8.1.7.4.1
My Ram Size is 6 GB
When I query the Below Script
select name, value
from v$parameter
where name in ('shared_pool_size', 'java_pool_size', 'streams_pool_size',
'log_buffer', 'db_cache_size', 'db_2k_cache_size', 'db_4k_cache_size',
'db_8k_cache_size', 'db_16k_cache_size', 'db_32k_cache_size',
'db_keep_cache_size', 'db_recycle_cache_size', 'large_pool_size');
Result
shared_pool_size     300000000
large_pool_size     0
java_pool_size     50000000
log_buffer     10485760
Please Suggest Me the How Much Value also to increase the SGA
My RAM SIZE is 6 GB
Regards
***SBJ***

SGA size on 8i is static , and for increasing the size you have to make the changes in the pfile and bounce the database
First thumb rule is that your SGA should not exceed more than 40% of your PHYSICAL RAM in oracle <= 8i version. You can go around 80% from oracle 9i onwards
http://mohamedazar.wordpress.com/2010/08/30/can-i-increase-sga-target-size-greater-than-sga-max-size/
Edited by: Amigo on Dec 18, 2010 1:31 AM

Couldn't increase the size of SGA

Hi,
I have RedHat linux 3.4, oracle 10.2.0.2, when I try to increase the sga size over 5GB its not accepting it. Can any one tell me what needs to be done to increasea the SGA ? I'm running on 64-bit OS and 64-bit oracle

Hi,
I have RedHat linux 3.4, oracle 10.2.0.2, when I tryIs linux 3.4 a partial RHEL 4 kernel version?
to increase the sga size over 5GB its not accepting it.What happens? Any errors, does the instance crash?

Increasing the size of the SGA

I'm using the Oracle Enterprise Manager Database Control on a 10.2.0.4 instance running on Redhat Enterprise Linux. One of the recommendations that the AWR\ADDM always seems to give is: "Increase the size of the SGA by setting the parameter SGA_TARGET to N". I've gone through the process twice already by upping the SGA_MAX_SIZE and SGA_TARGET parameters. It's currently recommending to up it to 6176M, I have not done this yet.
(1) Is this one of the recommendations that you would ignore within the DBCA if performance of the database seemed acceptable?
(2) Why does it always come back from the AWR\ADDM as a recommendation?
(3) What SQL or performance statistics does it do to determine whether the SGA is undersized and how does Oracle determine the SGA recommended size that shows up in the ADDM feedback?
Thanks in advance...

Truely new questions do deserve new threads. Questions that are a direct result of responses to the initial question should be asked on the same thread.
If there has been a time gap between the last post on the initial thread and the new question coming to mind then a new thread is probably the better choice.
To answer the question asked if the database is not suffering ORA-04031 errors and performance is OK then I would ignore the recommendation to increase the size of the SGA yet again.
What you might want to do first is reivew how the sga is being used (v$sgastat) and look for bad code technique that leads to needing memory, i.e., the use of SQL that passes constants to Oracle in what would otherwise be the same SQL statement if a bind variable was used and excessive use of Dynamic SQL when again bind variables could have been used in the SQL.
IMHO -- Mark D Powell --

Increase the SGA size!

Hi,
We are using EBS 12.0.6 and DB 10.2.0.3.
Currentlly My SGA is 2 GB and we have 8 GB of RAM, and Swap area is 10 GB.
Please recommemded us to SGA size and related DOC ID.
thx.

Hi again;
In addition to my previous post also check
Oracle Database 10g Automated SGA Memory Tuning Doc ID: 257643.1
How To Use Automatic Shared Memory Management (ASMM) In Oracle10g Doc ID: 295626.1
Hope it helps
Regard
Helios

How to increase the size of sort_area_size

How to increase the size of sort_area_size and what size should be according to the PROD database
Thanks

user10869960 wrote:
Hi,
Many Thanks Charles
Oracle does not recommend using the SORT_AREA_SIZE parameter unless the instance is configured with the shared server option. Oracle recommends that you enable automatic sizing of SQL working areas by setting PGA_AGGREGATE_TARGET instead. SORT_AREA_SIZE is retained for backward compatibility."
--How can i know the instance is configured with the shared server option or not?This might be a tough question to answer. A shared server configuration may be enabled, but the clients may still connect using dedicated sessions, in which case PGA_AGGREGATE_TARGET would still apply.
From
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/dynviews_2088.htm
V$SESSION includes a column named SERVER which will contain one of the following for each of the sessions: DEDICATED, SHARED, PSEUDO, or NONE. As a quick check, you could query V$SESSION to see if any sessions are connected using a shared server connection.
From:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/manproc.htm
There are several parameters which are used to configure shared server support, as well as several views to monitor shared server.
As Robert mentioned, when the WORKAREA_SIZE_POLICY is set to AUTO, the SORT_AREA_SIZE setting is not used, unless a shared server configuration is in use.
--What default value is WORKAREA_SIZE_POLICY and SORT_AREA_SIZE ?From:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/initparams157.htm
"Setting PGA_AGGREGATE_TARGET to a nonzero value has the effect of automatically setting the WORKAREA_SIZE_POLICY parameter to AUTO. This means that SQL working areas used by memory-intensive SQL operators (such as sort, group-by, hash-join, bitmap merge, and bitmap create) will be automatically sized. A nonzero value for this parameter is the default since, unless you specify otherwise, Oracle sets it to 20% of the SGA or 10 MB, whichever is greater."
Actually I am facing performence issue since long time till now i did not get the solution even i have raised SRs but i could not.When the issue occur system seems hang.what i monitored whenever hdisk0 and hdisk1 use 100% the issue occur.
Regards,
SajidWhen you say that you have had a performance issue for a long time, is it a performance problem faced by a single SQL statement, a single user, a single application, or everything on the server? If you are able to identify a single user, or SQL statement that is experiencing poor performance, I suggest starting with a 10046 trace at level 8 (wait events) or level 12 (wait events and bind variables) to determine why the execution appears to be slow. If you have not yet determined a specific user or SQL statement that is experiencing performance problems, you might start with either a Statspack Report or an AWR Report (AWR requires a separate license).
If you believe that temp tablespace usage may be a contributing factor to the performance problem, you may want to periodically run this query, which will indicate currently in use temp tablespace usage:
{code}
SELECT /*+ ORDERED */
TU.USERNAME,
S.SID,
S.SERIAL#,
S.SQL_ID,
S.SQL_ADDRESS,
TU.SEGTYPE,
TU.EXTENTS,
TU.BLOCKS,
SQL.SQL_TEXT
FROM
V$TEMPSEG_USAGE TU,
V$SESSION S,
V$SQL SQL
WHERE
TU.SESSION_ADDR=S.SADDR
AND TU.SESSION_NUM=S.SERIAL#
AND S.SQL_ID=SQL.SQL_ID
AND S.SQL_ADDRESS=SQL.ADDRESS;
{code}
The SID and SERIAL# returned by the above could then be used to enable a 10046 trace for a session. The SQL_ID (and CHILD_NUMBER from V$SESSION in recent releases) could be used with DBMS_XPLAN.DISPLAY_CURSOR to return the execution plan for the SQL statement.
You could also take a look in V$SQL_WORKAREA_ACTIVE to determine which, if any, SQL statement are resulting in single-pass, or multi-pass executions, which both access the temp tablespace.
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.

SGA Size

I will preface this by saying that this is probably a stupid question. I am pretty much an Oracle newbie, but I'm constantly trying to learn stuff. I have done a lot of reading on this topic, so I definitely have my own opinion, but everybody in my office thinks I'm crazy. So here goes...
We run a data warehouse in my shop on a server that has 6 CPUs and 12 GB of RAM, using Oracle 10.2.0.3. I was perusing our server's settings, and I noticed that the SGA was sized at 528 MB. It was not explicitly set in the parameter file, so I'm guessing that this value is calculated from the underlying pool sizes. Here's my stupid question: Isn't this not a good size for the SGA, given how much RAM we have?
Since we are a data warehouse, we should probably give ourselves a lot of RAM for the PGA's (according to Oracle's documentation). So I would like to crank up the SGA_TARGET to (at least) 4 GB and set the underlying pool sizes to 0 to let Oracle manage it all. But it's the fight of my life in my office. I am convinced that giving the SGA more RAM will increase performance.
So, am I crazy or not?

Sam, if everyone else in the office thinks you are crazy then you probably are; however, that does not mean that you are not correct in your argument.
The total amount of memory on the machine is not really a good factor for setting your SGA size. It is a limitation. The SGA size should be set based on the application load. Nevertheless the odds are good that doubling the SGA would have a measurable benefit since your machine has so much spare resource available.
Here is an idea. Take a seriies of statspack snapshots or use the AWR reports to measure the system during normal load. Then bounce the database and double the SGA. Rerun the same load and take the measurement. Compare. You ought to be able to sell this idea. When you see the benefit you can then repeat the procedure a couple of times to get up to a 2G, 3G, or 4G SGA.
Remember that your applicaiton will also need PGA and it is easy for the PGA requirements to equal or exceed the SGA requirements. At some point it may also be necessary to add another database instance (and SGA) to the machine so just because you have the memory does not mean that all of it should be put to immediate use.
HTH -- Mark D Powell --

Database creation - SGA size

Hi all,
When I try to create a database using DBCA, My default SGA Size : 128. PGA:794. When I click Next button, I receive the following caution...
Following parameters do not meet the recommended minimum size requirements:
An SGA size of atleast 160MB is recommended
Do you want Database configuration Assistant to Change the Parameter? I gave ignore and I changed the SGA size to: 160, I received the bellow caution
SGA Size can not be greater than maxmimum shared memory segment size (1342177728). Refer to oracle installation guide to configrue your operation system kernel parameters.
Please suggest me on the same....
Thanks
Gir

user10737570 wrote:
My other database SGA_MAX_SIZE is 1G.
Now I'm trying to create database using DBCA. By default my sga size allocated is 128MB. It recommends SGA size should be 160MB. I'm not able to extend SGA size. Please refere my previous post...
Could you please tell me why my default screen is showing as 128MB.
ThanksThe oracle installer determines the available sga_size bij calculating free "shared memory"
This is the setting of the maximum shared memory as posted in the first message minus the memory used by your first database, minus some other shared memory stuff.
To overcome this, you have to increase the mamimum shared memory size in your kernel and if needed reboot the system.
If your system happens to be a Redhat Enterprise system, then lookup the variable called
kernel.shmmax = <a certain size>
in /etc/sysctl.conf
Increase that value, and save the file ( as root )
Next run /sbin/sysctl -p to activate the new config

Reduced SGA_TARGET, but SGA size not changing?

I reduced the sga_taget from 1536M to 512M:
alter system set sga_target = 500M scope = memory;
System altered.
select VERSION from v$instance;
VERSION
10.2.0.3.0
show parameter sga
NAME TYPE VALUE
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 1536M
sga_target big integer 512M
But the real memory still showing the original value
show sga
Total System Global Area 1610612736 bytes
Fixed Size 2030456 bytes
Variable Size 1509950600 bytes
Database Buffers 83886080 bytes
Redo Buffers 14745600 bytes
why is that while it's a dynamic parameter?
Thanks a lot for any help.
Edited by: user10484253 on May 13, 2011 8:36 AM
Edited by: user10484253 on May 13, 2011 8:39 AM
Edited by: user10484253 on May 13, 2011 8:41 AM

I would suggest you to check v$sgastat to find out the exact SGA memory you are using currently instead of using "SHOW SGA" when when you set SGA_MAX_SIZE & SGA_TARGET initialization parameters.
Below is a sample output from one of my test dbs. As you can see below my SGA size is only 1GB.
SHOW SGA shows 2GB thats because I have set SGA_MAX_SIZE to 2gb ( which only means that I can grow my sga up till 2 gig , it may not be my current sga size).
you can try increasing or decreasing SGA_TARGET and check memory usage on OS level to see the difference.
SQL>show parameter sga
NAME                                 TYPE        VALUE
lock_sga                             boolean     FALSE
pre_page_sga                         boolean     FALSE
sga_max_size                         big integer 2000M
sga_target                           big integer 1008M
SQL>show sga
Total System Global Area 2087780352 bytes
Fixed Size                  2155336 bytes
Variable Size            1744833720 bytes
Database Buffers          318767104 bytes
Redo Buffers               22024192 bytes
SQL>select name, round(sum(mb),1) mb
2        from (
3      select case when name = 'buffer_cache' then 'db_cache_size'
4                  when name = 'log_buffer'   then 'log_buffer'
5                  else pool
6              end name,
7              bytes/1024/1024 mb
8                   from v$sgastat
9           )group by name
10 /
NAME                  MB
db_cache_size        304
java pool            128
large pool            16
log_buffer            21
shared pool          528
                     2.1
6 rows selected.
SQL> -- V$SGA_DYNAMIC_FREE_MEMORY: Information about the amount of SGA memory available for future dynamic SGA resize operations.
SQL>select * from V$SGA_DYNAMIC_FREE_MEMORY;
CURRENT_SIZE
1040187392- Krishna

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

Increase SGA on 8i

Can someone please guide me on how to increase the SGA size on 8i?
It srunning on a Windows 2003 Server.
I know how to do it on 9i via Enterprise Manager but that feature is not available in 8i.
Anyone?

No. I can't see why ... with the numbers you provide I would guess that it's probably a good idea, but other than "it's available, therefore I wanna use it." I see no real justification. You have shown no stats or analysis indicating that you should increase it.
But that's beside the point. And my point was simply - go ahead and increase ... just be aware that there is a point where increasing buffer cache has a negative impact. For several reasons.
And yes, your steps are correct.
See also the ' Oracle8i Designing and Tuning for Performance' for 8.1.7 at http://download-west.oracle.com/docs/cd/doc/index.htm, and specifically Chapter 19 http://download-west.oracle.com/docs/cd/A87860_01/doc/server.817/a76992/ch19_mem.htm#832 for the other Buffer_Cache parameters
And see the Oracle (not SQL) Reference manuaaal for all the other parameters.

Increase SGA Size

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