ORACLE – Investigate the Memory Structures of the Instance

Below is a script to show the current, maximum and minimum sizes of the SGA components that can be dynamically resized.

SELECT 
   component, 
   current_size, 
   min_size, 
   max_size    
FROM 
   v$sga_dynamic_components;

Execute the script below to Determine how much memory has been, and is currently, allocated to program global areas

SELECT 
   name, 
   value 
FROM 
   v$pgastat 
WHERE 
   name IN ('maximum PGA allocated','total PGA allocated');