oracle question related to db_block_buffers

[helloguru]

veediki db_block_buffers 1048576 era vachidho cheppagalara?

 

1. Set the parameter USE_INDIRECT_DATA_BUFFERS=TRUE: 

Without the setting of this parameter the Instance will not utilize the VLM so no AWE will be configured. 


2. Unset the DB_CACHE_SIZE parameter and disable the AMM (Automatic memory Management) and ASMM (Automatic Shared Memory Management) 

As the usage of the AWE is not implemented with Automatic Memory Management. make sure that parameters SGA_TARGET and MEMORY_TARGET are equal to 0 or removed from the pfile/spfile. 


3. Set the parameters DB_BLOCK_BUFFERS and DB_BLOCK_SIZE: 

The value for the DB_BLOCK_BUFFERS will be used for the buffer cache. The total size of the buffer cache can then be set to the amount of physical memory remaining above the 4GB barrier, plus AWE_WINDOW_MEMORY. 
On a machine with 12GB of RAM, using the default value of 1GB for AWE_WINDOW_MEMORY, your total buffer cache could theoretically be as high as 9GB: 
(Total RAM - 4GB + AWE_WINDOW_MEMORY) = 12GB - 4GB + 1GB = 9GB 


NOTE: 
You must set the DB_BLOCK_BUFFERS to value less than 9GB to allow for some overhead and additional processes running on the system. 
Attempting to startup the database with a buffer cache larger than the maximum value as calculated above may result in the following errors: 
SQL> startup 
ORA-27102 out of memory 
OSD-00034 Message 34 not found; Product=RDBMS;facility =SOSD 
O/S Error: (OS 8) Not enough storage is available to process this command 


To have a buffer cache of 8GB, the value of DB_BLOCK_BUFFERS should 1048576 with a DB_BLOCK_SIZE=8192. 
In the pfile/spfile, this would be defined as below : 
DB_BLOCK_BUFFERS = 1048576 
DB_BLOCK_SIZE = 8192 

 

Thanks!

[Discotek]

Buffersize 8GB undali annadu

buffer size = db_block_buffer * db _block_size

8GB =~ 1048576* 8192

buffer size GB lo ichi 

db_block_buffer bytes lo ichadu

that may have caused confusion

[helloguru]

46 minutes ago, Discotek said:

Buffersize 8GB undali annadu

buffer size = db_block_buffer * db _block_size

8GB =~ 1048576* 8192

buffer size GB lo ichi 

db_block_buffer bytes lo ichadu

that may have caused confusion

Thank so much Discotek.

So 4gb barrier should be constant kada even if I have 16 gb right?

Now, for 16 gb (16-4+1)=11GB...how many bytes for 11GB

Is there any formula for it?