The instance uses internal views and statistics to oracle determine how to distribute memory optimally among the manual components.
When automatic SGA memory management is enabled, the sizes of the different SGA components are flexible and can manual adapt to the needs of a plsql workload without requiring any additional configuration.
If the system uses shared server architecture, then reference the request and response queues and some contents of the PGA are in the SGA.
As a result, the system does need to learn the characteristics reference of the workload again each time an instance is started.Oracle allocates memory from the shared pool when a new SQL statement is parsed, to store in the shared SQL area.The initialization parameter LOG_buffer determines the size (in bytes) of the redo log buffer.If the value for SGA_MAX_size in the initialization parameter file or server parameter file (spfile) is less than the sum the memory allocated for all components, either explicitly in the parameter file or by default, at the time the instance is initialized, then the database.Allocation and Reuse of Memory in the Shared Pool In general, any item (shared SQL area or dictionary row) in the shared pool remains until it plsql is flushed according to a modified LRU algorithm.Before reading a data block into the cache, the process must first find a free buffer. Thus, SGA_target gives you little precise control over the meaning size of the shared seamstress memory region allocated by the database.
This oracle transfer takes place only after the first use of Streams.In general, larger values reduce log file I/O, particularly if transactions are long or numerous.Such components are: Keep/Recycle buffer caches (controlled by DB_keep_cache_size and DB_recycle_cache_size).Oracle allocates a private SQL area on behalf of the session.By default the parameters for these components will appear to have values of zero.Oracle Database 10g includes the Automatic Shared Memory Management feature which simplifies the SGA memory management significantly.Accessing data balzac through a cache hit is faster than data access through a cache miss.You can view novel the circular buffer in the vsga_resize_OPS view.The SGA_target Initialization Parameter, the SGA_target initialization parameter reflects the total size of the SGA and includes memory for the following components: Fixed SGA and other internal allocations needed by the Oracle Database instance.The administrator needs to specify the sizes of these components explicitly, if needed by the application.Packed with examples and helpful recommendations, the book has helped everyone from little novices to experienced developers, and from Oracle Forms developers to database administrators make the most of PL/SQL.Oracle Built in Packages little by Steven Feuerstein et al, syntax Reference book for Oracle's built-in packages, with extensive examples.