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Size of SGA Areas


Notes:

Dynamic performance view V$SGA contains the current size of the major areas within the SGA. (This can also be displayed with the SQL*Plus command SHOW SGA.)
The FIXED SIZE is used to hold Oracle internal information. It is typically small; we have no control over its size.
We will discuss these areas in more detail in this lesson:
The VARIABLE SIZE is used by many areas including the shared pool, large pool and the java pool.
DATABASE BUFFERS is memory used by the database buffer cache.
REDO BUFFERS is memory used for caching redo records.
Supplemental Notes
Oracle9i allocates memory in “granules. If the size of your SGA is less than 128MB, then granules are 4MB in size, otherwise they are 16MB. With this in mind, Oracle will – when the size of the memory areas are adjusted – round your requested values based on the granule size being used.
Mini-Workshop
Determine the size of the SGA memory structures on your instance by executing the query shown above.