Adjusting Oracle memory

To do a fine tuning on memory area, you should first look the shared pool, then go to PGA and at the end adjust the db_cache

SELECT SHARED_POOL_SIZE_FOR_ESTIMATE MB_ESTIMATE,SHARED_POOL_SIZE_FACTOR
FACTOR_PERCENT,
ESTD_LC_TIME_SAVED_FACTOR TIME_PERCENT FROM V$SHARED_POOL_ADVICE;

SELECT PGA_TARGET_FOR_ESTIMATE MB_ESTIMADO,PGA_TARGET_FACTOR
FATOR_PERCENT,
ESTD_PGA_CACHE_HIT_PERCENTAGE ACERTO_PERCENT FROM V$PGA_TARGET_ADVICE;

SELECT SIZE_FOR_ESTIMATE MB_ESTIMADO, SIZE_FACTOR
FATOR_PERCENT,
ESTD_PHYSICAL_READ_FACTOR TEMPO_PERCENT,name FROM V$DB_CACHE_ADVICE order by name,1;

Below are good notes from metalink
Metalink Note: 223730.1 Automatic PGA Memory Management in 9i and 10g

Metalink Note: 62172.1 Understanding and Tuning Buffer Cache and DBWR

Metalink Note: 255409.1 Size Shared Pool using V$shared_pool_advice.