Automatic PGA Memory Management in 9i and 10g

Hi,
I read the Doc# 223730.1 for Auto PGA advisory.
At one point in the document, there is given a query to calculate percentage of times work areas were executed in optimal, one-pass, or multi-pass mode since start-up.
My question is why there is a clause low_optimal_size > 64*1024); ---- for 64 K optimal size
Why it is safe to ignore all the workareas below 64 K.
How to decide which entries should be ignored?
Thanks,
Neeraj

I think 64K value used in that document is just an example.
You can use the prior query (one above which you have cited here) for finding non-empty buckets and then view histograms for range of your concern (the range which is getting used more frequently in your environment).

Similar Messages

Oracle 9i Automatic PGA Memory Management

Hello,
my team and me, we are facing difficulties to change the size of the PGA used by our server processes for HASH JOIN, SORT... operators,
here you can see the results of "select * from v$pgastat":
[pgastat dynamic view results|http://pastebin.com/m210314dc]
We have been increasing consecutively our pga_aggregate_target parameter from 1.7 Gb initially to 4Gb then at the end 6Gb, the value of "Global memory bound" and " aggregate pga auto target" on the link above are still equal to 0.
I have been reading threads on the forum and documentation see below, I understand how the global memory manager (CKPT) computest the sql memory target and then the global memory bound, as far as I understand I can only "play" on the pga_aggregate_target value in order to increase the size of our PGAs (I exclude to play with hidden parameters).
- Joze Senegacnik: Advanced Management of working areas in Oracle 9i/10g : http://tonguc.yilmaz.googlepages.com/JozeSenegacnik-PGAMemoryManagementvO.zip
- Dageville Benoit and Zait Mohamed: SQL memory management in oracle 9i
Here different information that could be usefull:
OS: solaris 10 (db running in a non global zone)
Arch: 64-bit sparcv9 kernel modules
Physical memory: 32 Gb (being shared between all non global zones)
Oracle version: 9.2.0.5 32bits
Values of init parameters and hidden parameters that could be relevant:
[init parameters|http://pastebin.com/m40340cf4]
[hidden parameters|http://pastebin.com/m50d74c53]
Maybe useful queries:
over work areas views, I use the following script:
[wa_analysis.sql|http://pastebin.com/d606ebd9b]
and the result of it:
[result of script wa_analysis.sql|http://pastebin.com/m5f49a2e5]

Joze Senegacnik wrote:
- either your sessions are using a lot of memory for storing variables like pl/sql arrays which is subtracted from automatic management: PGA_AGGREGATE_TARGET - (aggregated persistent area + a part of the run time area of all server processes)
- you are hitting a bug
- or maybe something elseI am really happy you come to this conclusion too, they are the same we made with my team and we have submitting to Oracle support via metalink SR 3-1216060641, we were asking if we hit the following bug (in note 1) or we leak about pl/sql or java... or else indeed,
note 1: PGA_AGGREGATE_TARGET Assigned Memory Is Left Unconsumed When Set High [ID 844542.1]
Joze Senegacnik wrote:
I would like to know:
1.) what were the values for global memory bound and autotarget immediately (or in short time) after the database restart or when you have increased them Just after the restart of the database and just after the change of P_A_T, we query v$pgastat immediately after and the value of global memory bound and auto target were equal to 0 byte,
2.) If you are able to change value of PGA_AGGREGATE_TARGET (P_A_T) to 10GB what happens with global memory bound and auto traget. They should be positive at least for a short time. As this is a dynamic parameter you can change it for a short time, run queries and set it back.We plan to do this tonight, we have an "heavy" ITIL change management procedures that allow us to make changes approved by change manager and only during night maintenance window on production system, I come back to you tomorrow. But we have been increasing from 1,7Gb to 4Gb to 6Gb, each time I have been querying v$sgastat in the next 2 mins and global memory bound and auto target were equal to 0 byte.
3.) Have you checked on the OS level how much memory are using server processes - do these numbers come along with what Oracle says. Not during problematic activities, meaning active work areas performing HASH-JOIN, SORT... operators,
unfortunately it is a production system, even if he performs poorly, we are not allowed to try or retry the poor queries, but if it comes again I'll do it,
during low activities, here the results paste with the scripts I used:
[pga processes info in oracle|http://pastebin.com/f2e540062]
I spooled the result rows of this previous script in /var/tmp/pga_processes.log then I loop over all processes pid and display pmap output anon info like this:
h5. cat /var/tmp/pga_processes.log | awk -F' ' '{print $5}' | xargs -n 1 -i pmap -x {}| grep -v 'Addres' |egrep 'Kb' 2>&1 > /var/tmp/pga_processes_os.log
then I merge line by line the two files with unix paste command, here the results:
[os and oracle pga informations|http://pastebin.com/f4135c8a6]
4.) How many server processes are running on you system in average/max and are you using just dedicated processes or also shared?in average 250, we are only using dedicated processes,
5.) At time of low activity is the global memory bound still 0 or becomes > 0. I have been querying every 15 min during more than 24 hours low activities, it still stay to 0,
5.) Are you experiencing paging/swapping on OS level?No, here orca figures for details:
[free memory|http://img509.imageshack.us/img509/5897/ohuron1asd2gauge1024xfr.png]
swap
[pagein pageout|http://img121.imageshack.us/img121/6946/ohuron1asd2gaugepginper.png]
[memory usage|http://img19.imageshack.us/img19/2213/ohuron1asd2gaugeppkerne.png]
6.) Please post the result of: select * from X$QESMMSGA ;during low activities, [results X$QESMMSGA|http://pastebin.com/f61df7093]
While you will be answering to my questions I'll try to figure out what we can do to properly diagnose the problem. As you are on 9i it is a little bit harder.I am really kind of your help, as we say in my country, "if you need tow arms one day to carry something, call me."
--Jeremy Baumont

Questions about db_keep_cache_size and Automatic Shared Memory Management

Hello all,
I'm coming upon a server that I'm needing to pin a table and some objects in, per the recommendations of an application support call.
Looking at the database, which is a 5 node RAC cluster (11gr2), I'm looking to see how things are laid out:
SQL> select name, value, value/1024/1024 value_MB from v$parameter
2 where name in ('db_cache_size','db_keep_cache_size','db_recycle_cache_size','shared_pool_size','sga_max_size');
NAME VALUE VALUE_MB
sga_max_size 1694498816 1616
shared_pool_size 0 0
db_cache_size 0 0
db_keep_cache_size 0 0
db_recycle_cache_siz 0 0
e
Looking at granularity level:
SQL> select granule_size/value from v$sga_dynamic_components, v$parameter where name = 'db_block_size' and component like 'KEEP%';
GRANULE_SIZE/VALUE
2048
Then....I looked, and I thought this instance was set up with Auto Shared Mem Mgmt....but I see that sga_target size is not set:
SQL> show parameter sga
NAME TYPE VALUE
lock_sga boolean FALSE
pre_page_sga boolean FALSE
sga_max_size big integer 1616M
sga_target big integer 0
So, I'm wondering first of all...would it be a good idea to switch to Automatic Shared Memory Management? If so, is this as simple as altering system set sga_target =...? Again, this is on a RAC system, is there a different way to do this than on a single instance?
If that isn't the way to go...let me continue with the table size, etc....
The table I need to pin is:
SQL> select sum (blocks) from all_tables where table_name = 'MYTABLE' and owner = 'MYOWNER';
SUM(BLOCKS)
4858
And block size is:
SQL> show parameter block_size
NAME TYPE VALUE
db_block_size integer 8192
So, the space I'll need in memory for pinning this is:
4858 * 8192 /1024/1024 = 37.95.......which is well below my granularity mark of 2048
So, would this be as easy as setting db_keep_cache_size = 2048 with an alter system call? Do I need to set db_cache_size first? What do I set that to?
Thanks in advance for any suggestions and links to info on this.
cayenne
Edited by: cayenne on Mar 27, 2013 10:14 AM
Edited by: cayenne on Mar 27, 2013 10:15 AM

JohnWatson wrote:
This is what you need,alter system set db_keep_cache_size=40M;I do not understand the arithmetic you do here,select granule_size/value from v$sga_dynamic_components, v$parameter where name = 'db_block_size' and component like 'KEEP%';it shows you the number of buffers per granule, which I would not think has any meaning.I'd been looking at some different sites studying this, and what I got from that, was that this granularity gave you the minimum you could set the db_keep_cache_size, that if you tried setting it below this value, it would be bumped up to it, and also, that each bump you gave the keep_cache, would be in increments of the granularity number....?
Thanks,
cayenne

Large SGA On Linux and Automatic Shared Memory Management problem

Hello
I use Oracle10gR2 in linux 32bit and I use http://www.oracle-base.com/articles/linux/LargeSGAOnLinux.php manual
for larger SGA it works fine but when I set sga_target parameter for using Automatic Shared Memory Management
I recieve this error
ERROR at line 1:
ORA-02097: parameter cannot be modified because specified value is invalid
ORA-00824: cannot set sga_target due to existing internal settings, see alert
log for more information
and in alert log it has been wrote
Cannot set sga_target with db_block_buffers set
my question is when using db_block_buffers can't use Automatic Shared Memory Management ?
Is any solution for using both Large SGA and Automatic Shared Memory Management ?
thanks
Edited by: TakhteJamshid on Feb 14, 2009 3:39 AM

TakhteJamshid wrote:
Do it means that when we use large SGA using Automatic Shared Memory Management is impossible ?Yes its true. An attempt to do so will result inthis,
>
ORA-00825: cannot set DB_BLOCK_BUFFERS if SGA_TARGET or MEMORY_TARGET is set
Cause: SGA_TARGET or MEMORY_TARGET set with DB_BLOCK_BUFFERS set.
Action: Do not set SGA_TARGET, MEMORY_TARGET or use new cache parameters, and do not use DB_BLOCK_BUFFERS which is an old cache parameter.>
HTH
Aman....

Confusion about Automatic Shared Memory Management

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

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

In 11g, How to Enable Automatic Shared Memory Management (ASMM)

hi experts,
I have a new 11.2 g database and I want to configure it to use ASMM.
To enable ASMM, should I assign a non-zero size to the Memory_Target parameter or the SGA_Target ? I have read conflicting statements.
Thanks, John

If you mean Automatic Memory Management, pl see
http://download.oracle.com/docs/cd/E11882_01/server.112/e10595/memory003.htm#ADMIN11011
http://download.oracle.com/docs/cd/E11882_01/server.112/e10897/instance.htm#ADMQS12039
HTH
Srini

Memory Management with NSString and synthesized properties

I thought I understood memory management but now I'm getting some odd behavior and that's the only thing I can see that I might be doing incorrectly:
I have a synthesized NSString propery called displayText. At one point I attempt to set a label with the displayText property (label.text = [[note displayText]]). The first one works, but the second one does not:
[note setDisplayText:[[note fileName]]]; // - works
[note setDisplayText:[[self getCharacterInFileName:[[note fileName]]]]; // - does not work
And here is getCharacterInFileName:
// Given the fileName for the image, get the specific part of that fileName for the note letter
- (NSString *)getCharacterInFileName:(NSString *)fileName
NSRange range = {1,1};
NSString *characterInString = [[[NSString alloc]] initWithString:[[fileName substringWithRange:range]]];
return characterInString;
Is there some pointer mismanagement going on here that I'm missing?
Message was edited by: darkpegasus

Nevermind, I'm an idiot. I forgot to close an if/else block with a brace and it screwed everything up.

Memory manager in ML and Lion flawed

I've been finding many 'flaws' eh? Well every OS has it's fair share of fails, and Apple isn't exempt from it. But anyway:
1. I was running SL on my old-ish, early 2011 Macbook (7,1). So I decided to upgrade to Lion when it came out. The problem started to appear.
What's the problem then? Too. Much. Inactive. Memory.
2. So I thought I didn't have enough RAM (I maxed out to 4GB at the reseller, but they didn't have an 8GB option) so I got 8GB. I installed (had to go through a long process to underclock one of the chips) the RAM... but still there.
3. Truth is: After installing Lion, I went back after a few days. First 10.7, then 10.7.1, then 10.7.2. I stayed on 10.7.3. Reason: Lag. But the problem persisted.
4. When ML came out with it's "Over 200 new features", I thought maybe they fixed it. But NO. Neither did 10.8.1. (although that seemed to help me battery, now at 4220mAh, 73% health)
The problem in detail: As I speak, Safari and the system in general is having bouts of lag. As I said before, I have 8GB of RAM. 873MB is wired. 895MB is active. **6.24GB** is inactive. free memory? 32MB. Of. Free. Memory.
As I understand, Inactive memory is used for applications that have recently closed, so that they can start faster. No problem with that. According to Apple, it's supposed to be freed when an application asks for more memory. Doesn't seem the case.
I'm not some overly-paranoid user that wants all his memory to be free, I just want my apps to stop lagging because they can't use memory that is reserved for that VMWare Fusion I opened 3 hours ago. (Yes, true story)
I have to use the purge command to free that.
Is this ever going to be fixed? Is it the OS, or just me?
EDIT: So it turns out 10.8.1 broke the 'purge' command. Geniuses. (Well it worked to a certain extend, now I have 5GB+ of free memory, but 1GB+ of inactive memory. But I don't mind.)

aperturedev wrote:
And no, I also don't think VMWare is not optimised for ML or Lion. I'm using version 6, which is optimised for the Retina MPB so it's definitely optimised for the 64-bit kernels.
That's impressive considering version 5 was just released the other day.
And when the above scenario was given, VMWare was *not* running. And only 4GB of memory was given to the Guest OS, albeit both my CPU cores. But that is completely unrelated. (right? right)
Then which application had all of your RAM?
Perhaps RAM isn't even the issue. People like to dwell on it but a misbehaving application taking your CPU is far more likely to be the culprit for system lag.

Sort Area Size in Automatic memory management

Hello All
I am aware that the AREASIZE is ignored of the PGA_AGGREGATE_TARGET is set.
So how is it possible that if we incrase the SORT_AREA_SIZE, the performance improves?
does this necessarily mean that the PGA_AGGREGATE_TARGET was not set to a proper value that it instead used the SORT_AREA_SIZE instead?
thanks

Hi,
If you have set workarea_size_policy=auto then under the automatic PGA memory management mode, sizing of work
areas for all sessions becomes automatic and the AREASIZE parameters are
ignored by all sessions running in that mode.
In auto mode if you change any AREASIZE parameters will be ignored.
If you want to manually handle ARASIZE then turnoff the Automatic pga memory by setting workarea_size_policy=MANUAL and then your changes to parameter will take effect but it's advisable to set pga to automatic.
To check whether your pga is set proper or not check v$pga_target_advice view
SELECT round(PGA_TARGET_FOR_ESTIMATE/1024/1024) target_mb,
ESTD_PGA_CACHE_HIT_PERCENTAGE cache_hit_perc,
ESTD_OVERALLOC_COUNT
FROM V$PGA_TARGET_ADVICE;
This will give you how your pga is set.
chirag

SQL memory manager latch at top of the list

select * from V$LATCH order by wait_time desc shows wait time = 451524661079 on SQL memory manager latch. What is making this so high?

user498912 wrote:
Thank you .. the pointer to the bug is helpful. We are having performance issues and complaints of slowness only during about a 2 or 3 hour window each weekday from about 7AM to 10AM EDT. This is definitely peak load. AWR is showing mostly disk i/o issues. Plan is to add about 20 GB more memory on the server. SGA currently at around 61GB with Automatic Shared Memory Management enabled. PGA advice showing nothing with a Cache Hit Percentage (%) 95.93
I would look at v$sga_resize_ops (or v$memory_resize_ops) to see if there is pressure to move memory around in that time period. Your symptoms could simply be showing load on the buffer cache causing the library cache to shrink leading to agressive demands for library cache locks etc. If so, then fixing a minum shared_pool_size (or generally going to manual memory management) may be the best bet. Also worth checking if there is some inefficient SQL running at that time that results in lots of random I/O - eliminating the cause of disk reads may be the best solution to reducing demand for memory.
Regards
Jonathan Lewis

11i and 10g

Hi,
Can I use 10g DB on EBS 11i on rapid install? Or can I migrate 9i to 10g the DB
of EBS 11i?
Thanks

There are many reasons. Automatic Memory Management, Automatic Undo, Flashback, PL/SQL optimizations are the first ones that come to mind. You can spend less time tuning the database to free up time hunting down suboptimally performing customized processes that tend to bring production to it's knees.
Oracle Database 10g Automated SGA Memory Tuning
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=257643.1
PERFORMANCE TUNING USING 10g ADVISORS AND MANAGEABILITY FEATURES
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=276103.1
How To Use Automatic Shared Memory Management (ASMM) In Oracle10g
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=295626.1
FAQ – Automatic Undo Management (AUM) / System Managed Undo (SMU)
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=461480.1
New Features For Oracle10g PL/SQL 10.x
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=311971.1
What Do All 10g Flashback Features Rely on and what are their Limitations ?
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=435998.1

Memory Management of SAP HANA

Hi All,
I went through one of the documentation in SAP HANA Memory management .
http://www.saphana.com/servlet/JiveServlet/download/2299-2-12806/HANA_Memory_Usage_v2.pdf
This gave me a really good understanding about the Memory management of HANA . Queries for Used and Resident memory and comparison with Overview tab numbers
I had few questions , Which was almost answered in other discussed in one :
But i still have few questions about Resident and used memory
Used Memory : Code + Tables + DB Managment
Resident : what is the formula or content ?
What does this picture refers to ?
Infact the below statements are bit confusing
When memory is required for table growth or for temporary computations, the SAP HANA code obtains it from the existing memory pool. When the pool cannot satisfy the request, the HANA memory manager will request and reserve more memory from the operating system. At this point, the virtual memory size of the HANA processes grows.
Once a temporary computation completes or a table is dropped, the freed memory is returned to the memory manager, who recycles it to its pool, usually without informing Linux6. Thus, from SAP HANA’s perspective, the amount of Used Memory shrinks, but the process’ virtual and resident sizes are not affected. This creates a situation where the Used Memory may even shrink to below the size of SAP HANA’s resident memory, which is perfectly normal.
My doubt here is how in any given point of time used memory can go below the used memory , because resident memory is always loaded with what is there in used memory , When used memory itslef is less , what does resident contains extra .
Also how to make a relation with HANA used memory , Database Resident memory , Virtual memory .
In case of a memory issue , what should we check , Used memory of HANA   OR resident memory of HANA ?
Thanks,
Razal

Hi all,
I am trying understand memory part bit in details , as i am building a complete monitoring infrastructure for HANA , and memory is core of HANA all part of HANA
Can you also help me to understand how to make some difference for used memory in HANA and Resident memory
When we say that the Resident memory is something from OS point of view , this is the memory of the OS which is really being used .
So if the used memory from HANA Perspective is full , OS still have some free memory which can be used , How that part is managed .
When i say we are out of memory , Both used memory from HANA
Resident memory from OS is full ?
OR does the used memory is simply a calculation of Code + table + etc from HANA point of view .
When execute query :
SELECT SERVICE_NAME,ROUND(SUM(TOTAL_MEMORY_USED_SIZE/1024/1024/1024), 2) AS
"Used Memory GB", ROUND(SUM(PHYSICAL_MEMORY_SIZE/1024/1024/1024), 2) AS
"DB RESIDENT Memory GB" FROM SYS.M_SERVICE_MEMORY GROUP BY SERVICE_NAME
SERVICE_NAME     Used Memory GB DB RESIDENT Memory GB
1 nameserver         6.73           1.7
2 preprocessor       5.38           0.24
3 indexserver        9.19           4.35
4 scriptserver       7.52           1.83
5 statisticsserver 8.52           3.87
6 xsengine          7.92           1.82
7 compileserver    5.31           0.23
On top of all this , In admin view i get used memory as 17.87 as used memory and 18.89 as peak .
How this used memory is summed up in admin view .
I am using version 70 .
Thanks,
Razal

PGA Memory increase indefinitely

Hello.
I'm using Oracle XE and doing some load tests on a java application using JDBC as connector.
During the load, 6 data tables increase but every 3 minutes, a scheduled job purge everything.
My problem is that my PGA memory size increase indefinitely and, after 12 hours, I exceed the 1GB memory in total and oracle doesn't respond.
I have about 40 query each seconds.
Thank you very much !
Bruno

Sounds like some pretty serious testing. Might want to try backing off some of the workload, get a successful test baseline established. Memory might be the fastest storage method, but its not infinite. Even more so when using XE with the 1G/1CPU limits.
What are you trying to accomplish, what do you want the database to do, and what are you asking the database to do? Those aren't always quite the same things ... ;)

Question about 11gR2 Grid, RAC, /dev/shm and Automatic Memory Management

Hello,
i've recently installed grid and rdbms software 11.2.0.2 on a two node Oracle Linux cluster with 128gb ram each node.
I'm using ASM to store data and ocr and I'm testing Automatic Memory Management.
When I finished Grid+RDBMS installation I've seen that /dev/shm size is 64gb (half of my total RAM).
I've created a database with dbca and when I was asked to choose if I wanted to use AMM I've noticed that I could
allocate only about 60gb for Oracle. If I chose more than 90gb I got an error saying:
Using Automatic Memory Management requires 60gb available in my two nodes.
The current available space in the two nodes is only 30gb and 30gb.
If you want to use AMM you should either free up some space in /dev/shm
or reduce the memory allocated to Oracle
I was wondering when (during the installation or the settings of kernel parameters) did I define the space of /dev/shm ?
Since I have 128gb of RAM wouldn't it be better to use more than 64gb of ram for my /dev/shm tmpfs partition ?
Is there a limit or a ratio for best practice for my RAM and the /dev/shm ?
thanks in advance.

user9051299 wrote:
Is the "half of the RAM size" a kernel's default value or Oracle's ? Neither. There are a number of unique factors that determine the best memory size and fit for Oracle - including just how much memory is effectively available (i.e. how much is needed for other services and processes).
And from what I understand i don't "break" any Oracle's best practice by increasing the /dev/shm right ?Correct. (at least none that I'm aware of, and none that I have read in Oracle's RAC Starter Kit documentation).

Weblogic managed server crash and automatic restart on Solaris SPARC platform

hi Everyone,
We are facing a problem a problem with Weblogic managed server where the managed server crashes and automatically restarts (via nodemanager) on Solaris SPARC platform.
The system info is as below:
OS:                            Oracle Solaris 11.1 SPARC
Copyright (c) 1983, 2012, Oracle and/or its affiliates. All rights reserved.
                           Assembled 19 September 2012
uname:SunOS 5.11 11.1 sun4v
(T2 libthread)
rlimit: STACK 8192k, CORE infinity, NOFILE 65536, AS infinity
load average:1.04 0.52 0.32
CPU:total 4 v9, popc, vis1, vis2, vis3, blk_init, cbcond, sun4v, niagara_plus
Memory: 8k page, physical 16777216k(5930008k free)
vm_info: Java HotSpot(TM) 64-Bit Server VM (23.25-b01) for solaris-sparc JRE (1.7.0_25-b11), built on May 15 2013 04:30:17 by "" with Sun Studio 12u1
The pstack output of analyzing the core file is as below (for the particular thread, I can attach the entire output of pstack if required):
--- called from signal handler with signal 11 (SIGSEGV) ---
ffffffff7ec1a7c4 memcpy%sun4v-hwcap3 (103d34720, 10a7e7710, 108ae1060, 6300, 0, ffffffff5f66394b) + 990
ffffffff36102fa4 ZIP_GetEntry (103d34720, ffffffff636f66a4, bd, 103d347f0, a26f1c, 2f) + e4
ffffffff36103440 Java_java_util_zip_ZipFile_getEntry (2b, ffffffff636f66a4, 103d34720, ffffffff636f6b70, 2b, 1) + a8
ffffffff7586ac1c * *java/util/zip/ZipFile.getEntry(J[BZ)J [compiled]
ffffffff75b61b58 * *java/util/zip/ZipFile.getEntry(Ljava/lang/String;)Ljava/util/zip/ZipEntry; [compiled] +39 (line 606)
ffffffff75b61b58 * *java/util/jar/JarFile.getEntry(Ljava/lang/String;)Ljava/util/zip/ZipEntry;+3 (line 452)
ffffffff75b61b58 * *weblogic/utils/classloaders/ZipClassFinder.getSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source;+36 (line 75)
ffffffff75b6eb84 * *weblogic/utils/classloaders/JarClassFinder.getSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +6 (line 100)
ffffffff75a40938 * *weblogic/utils/classloaders/AbstractClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +74 (line 58)
ffffffff75976c88 * *weblogic/utils/classloaders/MultiClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +30 (line 114)
ffffffff75976c88 * *weblogic/utils/classloaders/MultiClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +30 (line 114)
ffffffff75976c88 * *weblogic/utils/classloaders/MultiClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +30 (line 114)
ffffffff75806d10 * weblogic/application/utils/CompositeWebAppFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source;+5 (line 176)
ffffffff75976c88 * *weblogic/utils/classloaders/MultiClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +30 (line 114)
ffffffff75976c88 * *weblogic/utils/classloaders/MultiClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source; [compiled] +30 (line 114)
ffffffff75806d10 * weblogic/utils/classloaders/CodeGenClassFinder.getClassSource(Ljava/lang/String;)Lweblogic/utils/classloaders/Source;+43 (line 48)
ffffffff75806d10 * weblogic/utils/classloaders/GenericClassLoader.findLocalClass(Ljava/lang/String;)Ljava/lang/Class;+87 (line 571)
ffffffff75806d10 * weblogic/utils/classloaders/GenericClassLoader.findClass(Ljava/lang/String;)Ljava/lang/Class;+117 (line 515)
ffffffff75806d10 * weblogic/utils/classloaders/ChangeAwareClassLoader.findClass(Ljava/lang/String;)Ljava/lang/Class;+60 (line 121)
ffffffff75a465c8 * *java/lang/ClassLoader.loadClass(Ljava/lang/String;Z)Ljava/lang/Class; [compiled] +71 (line 836)
ffffffff75db42c0 * *java/lang/ClassLoader.loadClass(Ljava/lang/String;)Ljava/lang/Class; [compiled] +4 (line 714)
ffffffff75806d10 * weblogic/utils/classloaders/GenericClassLoader.loadClass(Ljava/lang/String;)Ljava/lang/Class;+2 (line 358)
ffffffff75806d10 * weblogic/utils/classloaders/ChangeAwareClassLoader.loadClass(Ljava/lang/String;)Ljava/lang/Class;+27 (line 83)
ffffffff7580024c * StubRoutines (1)
ffffffff3691f44c __1cJJavaCallsLcall_helper6FpnJJavaValue_pnMmethodHandle_pnRJavaCallArguments_pnGThread__v_ (ffffffff636f7f98, 10234f000, 2, c, 2, 10) + 2f4
ffffffff36e546c0 __1cJJavaCallsMcall_virtual6FpnJJavaValue_nGHandle_nLKlassHandle_pnGSymbol_63pnGThread__v_ (ffffffff636f7f98, 1013e7748, 10234f000, 10011bf30, 100119ec0, 772d4ec08) + 1b8
ffffffff3725bf0c __1cQSystemDictionaryTload_instance_class6FpnGSymbol_nGHandle_pnGThread__nTinstanceKlassHandle__ (105cb6100, 1013e7978, 10234f000, 102b6e500, 0, 1013e7748) + 494
ffffffff3725a028 __1cQSystemDictionarybEresolve_instance_class_or_null6FpnGSymbol_nGHandle_3pnGThread__pnMklassOopDesc__ (105cb6100, 19dc00, 70, 10234f000, 70, 1013e7700) + ae0
ffffffff37257800 __1cQSystemDictionaryPresolve_or_fail6FpnGSymbol_nGHandle_3bpnGThread__pnMklassOopDesc__ (105cb6100, 1013e76f0, 1013e76f8, 1, 10234f000, 1) + 290
ffffffff368ba9dc __1cTconstantPoolOopDescNklass_at_impl6FnSconstantPoolHandle_ipnGThread__pnMklassOopDesc__ (10201b6e0, 1013e7978, 10234f000, 10201b6e0, 783cfb098, ffffffff37588000) + 264
ffffffff36937380 __1cSInterpreterRuntimeE_new6FpnKJavaThread_pnTconstantPoolOopDesc_i_v_ (10234f000, 77548b730, 49, 10201b6e0, 1013e76e8, 10234f000) + b8
ffffffff7581ab58 * com/jdedwards/base/logging/log4j/JdeLogger.warn(ILjava/lang/String;Ljava/lang/String;Ljava/lang/Object;Ljava/lang/Throwable;)V+14
ffffffff75807bcc * com/jdedwards/system/security/proxy/SecurityServerProxyImpl.install(Ljava/util/Hashtable;)Lcom/jdedwards/system/security/proxy/SecurityServerProxyImpl;+30
ffffffff75806d10 * com/jdedwards/system/security/proxy/SecurityServerProxyFactory.create(Ljava/util/Hashtable;)Lcom/jdedwards/system/security/SecurityServer;+1
ffffffff75807898 * com/jdedwards/system/security/SecurityServerInstance.getInstance()Lcom/jdedwards/system/security/SecurityServer;+27
ffffffff75806d10 * com/jdedwards/mgmt/security/UserManager.checkPassword(Ljava/lang/String;Ljava/lang/String;)Z+59
ffffffff75806b24 * com/jdedwards/mgmt/security/UserManagerImpl.checkPassword(Ljava/lang/String;Ljava/lang/String;)Z+5
ffffffff75806b24 * com/jdedwards/mgmt/security/SCFLoginModule.login()Z+481
The output of the hs_err_pid1127.log file is as below:
# A fatal error has been detected by the Java Runtime Environment:
# SIGSEGV (0xb) at pc=0xffffffff7ec1a544, pid=1127, tid=20
# JRE version: 7.0_25-b11
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.25-b01 mixed mode solaris-sparc compressed oops)
# Problematic frame:
# C [libc.so.1+0x11a544] memcpy%sun4v-hwcap3+0x710
# Core dump written. Default location: /slot/ems9437/appmgr/Oracle/Middleware/user_projects/domains/smc_domain/core or core.1127
# If you would like to submit a bug report, please visit:
#   http://bugreport.sun.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
--------------- T H R E A D ---------------
Current thread (0x000000010294d000): JavaThread "[ACTIVE] ExecuteThread: '1' for queue: 'weblogic.kernel.Default (self-tuning)'" daemon [_thread_in_native, id=20, stack(0xffffffff62f00000,0xffffffff63000000)]
siginfo:si_signo=SIGSEGV: si_errno=0, si_code=1 (SEGV_MAPERR), si_addr=0xffffffff5f6ce000
I ran the suspect code which i believed was causing the issue as a standalone Java program using the same Java executable and it worked fine without any crash.
Appreciate any inputs / discussion / feedback / thoughts on this topic.
Good day.

I just wanted to throw in one more thought. I have also seen that there is a restart=true parameter. Maybe if we set this to true, and just issue the command to shut down the server in the script, the managed server will restart on its own.
Would greatly appreciate any advice!

Automatic PGA Memory Management in 9i and 10g

Similar Messages

Maybe you are looking for