Re: Relation between Redobuffer and SharedGlobalMemoryWhat is

[Aftab Khan]

RedoBuffer [default 32M) - sets the size of the buffer in which the REDO log is written. It is needed for both in-memory and disk based objects. Why set to 512M? If you are using long BLOBs, try to compress them. Typically you don't need to adjust this setting unless you are getting error code 1221 (REDO log buffers overloaded)

SharedGlobalMemory [default 128M)- it determines the amount of memory that is used for log buffers, disk operations (such as page requests and wait queues), and metadata for tablespaces, log file groups, UNDO files, and data files. The shared global memory pool also provides memory used for satisfying the memory requirements of the INITIAL_SIZE and UNDO_BUFFER_SIZE options used with CREATE LOGFILE GROUP and ALTER LOGFILE GROUP statements