###############################################
# - Modification de la mémoire
# - Info sur la SGA
#
# Date: 23.04.2003
# S.Koller
###############################################

>show sga
 Total System Global Area   101781824 bytes
 Fixed Size                    450880 bytes
 Variable Size               83886080 bytes
 Database Buffers            16777216 bytes
 Redo Buffers                  667648 bytes


>select name, value from v$parameter
 where name in ('sga_max_size', 'shared_pool_size', 
	        'db_cache_size', 'large_pool_size',
		'java_pool_size');

shared_pool_size = 33554432
sga_max_size = 101781824
large_pool_size = 0
db_cache_size = 16777216
java_pool_size = 33554432

#on peut diminuer java_pool_size si on ne l'utilise pas.
#Attention laisser au minimum 1M, car sinon erreur.

>alter system set java_pool_size=1M scope=spfile;
>alter system set sga_max_size=70M scope=spfile;
>shutdown immediate;
>startup;

>show sga
 Total System Global Area    76615880 bytes
 Fixed Size                    450880 bytes
 Variable Size               58720256 bytes
 Database Buffers            16777216 bytes
 Redo Buffers                  667648 bytes



Pour information sur les sous-divisions de la SGA
==================================================

Exemple d'un SHOW SGA:

 Total System Global Area    76615880 bytes
 Fixed Size                    450880 bytes
 Variable Size               58720256 bytes
 Database Buffers            16777216 bytes
 Redo Buffers                  667648 bytes

Total System Global Area
- Total in bytes of all the sub-divisions that makes up the SGA. 

Fixed Size 
- Contains general information about the state of the database and the 
instance, which the background processes need to access. 
- No user data is stored here. 
- This area is usually less than 100k in size.

Variable Size 
- This section is influenced by the following init.ora parameters 
shared_pool_size 
large_pool_size 
java_pool_size 
- See 'Approximating Size of the SGA' section of this article for version 
specific information.
 
Database Buffers 
- Holds copies of data blocks read from datafiles. 
size = db_block_buffers * block size 

Redo Buffers 
- A circular buffer in the SGA that holds information about changes made to 
the database. 
- Enforced mininum is set to 4 times the maximum database block size for the 
host operating system.