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About Dynamic SGA Sizing (Doc ID 266702.1)

Last updated on JULY 24, 2019

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 9.0.1 to 9.2]
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Information in this document applies to any platform.


Introduce basic concepts associated with dynamic SGA tuning (in Oracle 9i).

The information in this note is originally meant for Oracle 9i where the dynamic SGA resizing is limited.
The dynamic resizing of shared_pool_size was introduced in 9iR1, for large_pool_size in 9iR2 and for java_pool_size in 10gR1.
However, the basic information is essentially also applicable to Oracle 10g and 11g when no Automatic Shared Memory Management (10g: ASMM) or Automatic Memory Management (11g: AMM) is used.
In case ASMM or AMM is used, the pool sizes need to be established differently, e.g. using parameters sga_target or memory_target and active values for pool sizes using underscore parameters like "__shared_pool_size". Normal user defined pool sizes, e.g. shared_pool_size can still be set and function as a minimum value.


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