Components of oracle Memory Structure

The oracle memory structure is composed of two parts: sga (system global area) and pga (program global area ). SGA: allocated when an instance is started. It is an integral part of the instance. PGA: a service process is allocated with one PGA when it is started ). SGA can occupy 80% of the memory linux commands: ipcssga composition: share pool, database buffer cache, redolog buffer, large pool, java pool view sga: show sga; dynamically adjust the basic unit granules of the memory allocated by SGA_MAX_SIZE.SGA. for sga less than 128 M, granules is equal to 4 M, for sga greater than 128 M, granules is equal to 16 M sga is a continuous memory zone. Select component, granule_size from v $ hour; DB_CACHE_SIZE, LOG_BUFFER_SIZE, SHARED_POOL_SIZE, LARGE_POOL_SIZE, JAVA_POOL_SIZE. After the maximum sga size is specified, the size of each part is automatically allocated and automatically. Shared pool: stores parsed SQL statements. Including libarary cache, data dictionary cache. libarary cache: stores parsed compiled SQL area and pl/SQL area. data dictionary cache: stores database control information. Database buffer cache: contains the data from the data file and the data to be written into the data file. DB_CACHE_SIZE, DB_KEEP_CACHE_SIZE, fetch system set DB_CACHE_SIZE = 96 M; Use DB_CACHE_ADVICE to SET whether to monitor or not, and check monitoring information V $ modify redo log buffer: A redo entries is generated when a database changes. Large pool: parallel processing, IO operations, and arm backup. Jave pool: used to deal with java.