30-01-2006 evening oracle

Optimizer is a program which makes plan for execution

Each and every task is divided into fragments. This is called planning and it is done by optimizer.

Difference between rule based and cost based optimizer:

Rule based optimizer takes into consideration number of blocks it has to scan.

Oracle automatically adjusts the sizes of different pools of shared pool area i.e. data dictionary cache and cursor area.

Large Pool Area:

It is an optional area unlike other areas which are mandatory.

It is used for bulk handling of the data.

When large pool area is not there, Oracle uses data buffer pool. It will some how affect the normal working of Oracle. Hence large pool is often configured so that users are not affected.