SGA shared Pool consisting of 1) Session Memory 2) Library Cache 3) Dictionary Cache
This is the memory allocated by db_block_buffer to hold the incoming Oracle data blocks.
This is the area of memory reserved for the redo logs before they move into the online redo log files.
This area of memory resides within the shared pool and holds session information such as cursors and host variables.
This area of memory resides within the shared pool and holds shared SQL, PL/SQL procedures, locks and latches.
This memory area resides within the shared pool and holds data dictionary objects.
SGA_TARGET
Specifies the total size of all SGA components. If SGA_TARGET is specified, then the buffer cache (DB_CACHE_SIZE),
Java pool (JAVA_POOL_SIZE), large pool (LARGE_POOL_SIZE), and shared pool (SHARED_POOL_SIZE) memory pools are automatically sized.