SGA_MAX_SIZE and swap

Hello,
When I read Doc 778777.1, I found it said: "On most OSs(except solaris) if you specify SGA_MAX_SIZE, then the complete size of SGA_MAX_SIZE is reserved from Swap at instance startup, not from physical RAM." I want to konw why SGA_MAX_SIZE is reserved from Swap? I always thought it was reserved from physical RAM.
Thanks.

Even I am not much clear so could be wrong ;) [See note 761960.1 also]
What i can make out from above 2 notes is that Oracle doesn't want to waste physical memory for additional memory requirement above SGA_TARGET (ie SGA_MAX_SIZE - SGA_TARGET).

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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

Satellite S50T-B - Adding RAM and swapping HDD for SSD

HI there,
I have recently purchased the Satelitte S50t-B laptop and have a few question about upgrading:
1. What is the recommended RAM to add (8GB)
2. What is the recommended SSD to add?
3. Are there any instructions to add RAM and an SSD to my laptop?
4. Will I void my warranty by installing more RAM and swapping the current hard drive for an SSD?
Thank you for your help

This notebook is listed on Toshiba page:
http://www.mytoshiba.com.au/products/computers/satellite/s50/pspq8a-008008/specifications
- What is the recommended RAM to add (8GB)
The unit supports 16GB RAM, so you can add an second PC3-12800 8GB DDR3L (1600Mhz) SO-DIMM module (i.e PA5104U-1M8G)
- 2. What is the recommended SSD to add?
Its up to you there are different SSD drive on the market and most of the 2.5 SATA SSD drives should be compatible.
- 3. Are there any instructions to add RAM and an SSD to my laptop?
It looks like both parts (RAM as well as SSD/HDD) are not user upgradable since there is no separate access to the memory or HDD bay. This means that whole plastic cover at the bottom of the unit needs to be remove in order to get access to these part.
But as far as I know this would cancel the device warranty!!!
- 4. Will I void my warranty by installing more RAM and swapping the current hard drive for an SSD?
If you want to keep the warranty valid, such upgrade should be performed by authorized engineer.

My MacBook (late 2009 Mac OS X Lion 10.7.5 (11G63) often runs VERY slow...beach ball of death frequently. My page ins (5.29GB), page outs (5.64BG), and swap files (10GB) seem extremely high in comparison to most other discussions in here. HELP!!??

My MacBook (late 2009 Mac OS X Lion 10.7.5 (11G63) often runs VERY slow...beach ball of death frequently. My page ins (3.29GB), page outs (5.64BG), and swap files (10GB) seem extremely high in comparison to most other discussions in here. I don't know how to copy the pie chart so it shows on here but here's what it says right now:
Free - 176 MB
Wired - 592MB
Active - 843MB
Inactive - 432MB
Used - 1.82 GB
VM size - 198GB
The page ins and page outs have 0 bytes/sec in the parenthesis even though the numbers are so high.
Any help anyone could provide would be greatly appreciated!!!

You difinately need more ram. 2gb is the bare minimum to run just the Lion OS, anything extra will slow your Mac to a crawl. Upgrade to 8gb from either Crucial http://www.crucial.com/ or OWC http://eshop.macsales.com/
And you will be a happy camper!

Difference between SGA_MAX_SIZE and SGA_TARGET

Difference between SGA_MAX_SIZE and SGA_TARGET

user8645026 wrote:
Difference between SGA_MAX_SIZE and SGA_TARGETIs discussed in the database forum, not the forum for which the title is " Community Feedback and Suggestions (Do Not Post Product-Related Questions Here)".
Is also discussed in the documentation at http://tahiti.oracle.com

Issue creating a database: SGA_MAX_SIZE and SGA_TARGET

Hello:
While creating a custom database, I am running into issues with the values I specify for SGA_MAX_SIZE and SGA_TARGET.
The install manual for the product I am creating the database for says that SGA_MAX_SIZE should be >= SGA_TARGET_SIZE. It also wants a minimum of 1Gig for SGA_Target
The Database Configuration Assistant defaulted to 0.64GB for SGA_TARGET and 0.168 for SGA_MAX_SIZE (This is clearly against the instruction in the installation manual).
Who is right? Me or the vendor?
I read some threads that indicate that the vendor may be wrong.
venki

Follow the vendor's instructions.
DBCA has never in its existence made a correct decision yet. It puts all control files and redo logs into one directory.
It doesn't create multiple members for the log file groups.
And its memory management is based on a simple algorithm that has nothing to do with any specific reality.
DBCA is intended for creating a generic database for generic purposes ... and that it does very very well.

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 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

SGA_MAX_SIZE and SGA_TARGET

DBAs,
can any one tell me in brief how SGA_MAX_SIZE and SGA_TARGET helps to tune the instance?
i have gone through with vairous link but still confuse.
Regards,
BK

hi BK,
SGA_MAX_SIZE is the maximum sizeof the shared global area (system global area), and SGA_TARGET is set when you want to use ASSM (automatic shared memory management) which is a 10g feature.
You are alos adviced to post oracle version and os.. SGA_TARGET when set, then oracle automatically manages the memory and if not set then you have to set SGA_MAX _SIZE and manually set others memory components accordingly and tune them.
I hope this helps you in a small manner
Thanks and Regards
VD

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I can go into a apple store and swap sides of my iPhone 5?

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MultiThreaded compare and swap question.

I'v got this assignment and I'm not sure which approach to take. I think I've got it right with my second try, but I was wondering if I could get some sort of verification or something.
"Use Java monitors to implement the atomic Compare-And-Swap instruction, which has the following effect: CSW(a,b,c): < if (a==c) { c = b; return(0);} else {a = c; return 1;} > (In most concurrency books and papers instructions within angle brackets < > means that everything within the brackets is done in one uninterruptible, atomic action.) "
Is this right?
public synchronized int compareAndSwap(Object a, Object b, Object c)
 if ( a.equals( c ) )
 c = b;
 return 0;
 a = c;
 return 1;
 }Or is this?
public int compareAndSwap(Object a, Object b, Object c)
 synchronized ( a )
 synchronized ( b )
 synchronized ( c )
 if ( a.equals( c ) )
 c = b;
 return 0;
 a = c;
 return 1;
 }Or am I totally off base? I think the latter is right as it prevents the objects themselves from being messed with.

As far as making it an atomic action, you do that
with synchronized, BUT more detail might be needed
about the context in which it's supposed to be atomic
to know what to sync on.OK, thanks. I was thinking I was crazy or something, but his question is just unclear. I have no idea what he wants and I'm not sure he does either.
Thanks.

Database block size and swap

Hi,
I changed the db_block_size from 4k(oracle 9.2.0.1) to 8k on my solaris machine. The swap use has increased dramatically I am wondering is there any relation between db_block_size and swap.

Dup Database Block Size, please check our replies in other post.

Zfs cache vs. Physical and swap memory

On Solaris 10: We are calculating the available physical and swap memories by using these
@ system calls 'sysconf' and 'swapctl' with appropriate parameters.
I don'tthink these system calls explicitly take the 'zfs cache' into account.
Can you please confirm, Or do we have any other command set to include 'zfs cache pool' also.
regards,
-ashokM
Edited by: aMohanty on Sep 8, 2009 3:24 AM

Not exactly sure what you are asking - Total VM = Real RAM + swap. The ZFS arc (as well as the UFS cache) competes to get RAM, as does running processes and kernel memory allocation. The arc will not add anything to the Total VM amount.

Multiple homes and swap allocation

I have 10gb of hp-Unix and i have 2 oracle homes what swap parameter should be.
2 oracle software installations 10gR2

user586263 wrote:
I have 10gb of hp-Unix and i have 2 oracle homes what swap parameter should be.Couldn't you clarify ? Is it 10Gb RAM ? What's the link between the number of Oracle home and swap size ?
What Oracle version ? There are some advices in Oracle documentation, have you read the hardware requirement for you version ?
Nicolas.

Problems analizing compares and swaps in my algorithims

What I need to do is analize my sorting algorthims, in terms of the number of compares and swaps. I have about 6 different sorts in one class, a couple of them came from help by, other posters, on this board. And I have a simple file reader in another class that reads a txt file, sorts, then prints, but also prints the numbers of compares, swaps, using varibles from my sorting class.
The txt file has 64 strings(names of people). Some of the sort I get what seems to me correct, or least close to correct results, but for a couple I"m getting downright strange results. I'm trying to figure out where to put the counting variables so I can get decent results.
In my quicksort, the results I'm getting is 1 compares 1 swaps, now obviously that's wrong but I'm trying to figure out where to put, the variables to get the correct results.
 public static void quicksort(List data, int first, int last){
 int lower = first + 1, upper = last;
 swap(data,first,(first+last)/2);
 Comparable Bound = (Comparable)data.get(first);
 while (lower <= upper){
 while ((((Comparable)data.get(lower)).compareTo(Bound)) < 0)
 lower++;
 while (Bound.compareTo(data.get(upper)) < 0)
 upper--;
 if (lower < upper)
 swap(data,lower++,upper--);
 else lower++;
 swap(data,upper,first);
 if (first < upper-1)
 quicksort(data,first,upper-1);
 if (upper+1 < last)
 quicksort(data,upper+1,last);
 public static void quicksort(List data){
 if (data.size() < 2)
 return;
 int max = 0;
 //find largest data and put at end of data
 for (int i = 1; i < data.size(); i ++)
 if (((((Comparable)
 data.get(max)).compareTo(data.get(i))) < 0))
 max = i;
 compares++; // <----------------------- COMPARE
 swap(data,data.size()-1,max);
 swaps++; // <-------------------------- SWAP
 quicksort(data,0,data.size()-2);
} The selection sort results give me exactly the same for both compares, and swaps 2016.
public static void selectionSort (List data)
 int i,j, least;
 final int size = data.size();
 for (i = 0; i < size - 1; i++)
 for (j = i+1, least = i; j < size; j++)
 compares++; // <-------------------- COMPARE
 if (((((Comparable) (data.get(j))).compareTo(data.get(least)))) < 0)
 least = j;
 swap(data,least,i);
 swaps++; // <------------------------ SWAP
 Thanks for your help.

jkc532 wrote:
.. Is the fact that the CachedJarFile class doesn't attempt to reload the resource when it can't retrieve it from MemoryCache a bug? From your comprehensive investigation and report, it seems so to me.
..I've dug as deep as I can on this and I'm at wits end, does anybody have any ideas?Just after read the summary I was tired, so I have some understanding of the effort you have already invested in this (the 'wits' you have already spent). I think you should raise a bug report and seek Oracle's response.

SGA_MAX_SIZE and swap

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