What is the difference between SGA and PGA in oracle database?
Both SGA and PGA are oracle instance’s memory structures.
The SGA (System Global Area) is used to store database information that is shared by database processes. It contains data and control information for the Oracle server and is allocated in the virtual memory of the computer where Oracle resides.
The Program Global Area (PGA) is a memory region that contains data and control information for a single server process or a single background process.
SGA is shared by several processes where as PGA( memory reserved for each user process that connects to an Oracle database) is used by only one process.
SGA is allocated at instance startup where as PGA is Allocated when the
server process is started.