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Rick Greenwald, Robert Stackowiak, Jonathan Stern

"Oracle Essentials: Oracle Database 11g"

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Instance Memory and Processes | 49
Prior to Oracle9i, the size of the SGA was set when the Oracle instance was started.
The only way to change the size of the SGA or any of its components was to change
the initialization parameter and then stop and restart the instance. Since Oracle9i,
youcan also change the size of the SGA or its components while the Oracle instance
is running. Oracle9i also introduced the concept of the granule, which is the smallest
amount of memory that you can add to or subtract from the SGA.
Oracle Database 10g introduced Automatic Shared Memory Management, while
Oracle Database 11g added Automatic Memory Management for the SGA and PGA
instance components. Whenever the MEMORY_TARGET (new to Oracle Database
11g) or SGA_TARGET initialization parameter is set, the database automatically distributes
the memory among various SGA components providing optimal memory
management. The shared memory components automatically sized include the
shared pool (manually set using SHARED_POOL_SIZE), the large pool (LARGE_
POOL_SIZE), the Java pool (JAVA_POOL_SIZE), the buffer cache (DB_CACHE_
SIZE), and the streams pool (STREAMS_POOL_SIZE).


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