Buffer cache dynamically resized
Alter system set db_cache_size=50M;
V$SGA_DYNAMIC_COMPONENTS displays information about the dynamic SGA components. This view summarizes information based on all completed SGA resize operations since instance startup.
V$SGA_CURRENT_RESIZE_OPS displays information about SGA resize operations which are currently in progress. An operation can be a grow or a shrink of a dynamic SGA component.
V$SGA_DYNAMIC_FREE_MEMORY displays information about the amount of SGA memory available for future dynamic SGA resize operations.