To learn the Automatic Shared Memory Management, read the article titled “Oracle Memory Components(SGA and PGA)“.
For databases that do not use Automatic Shared Memory Management, ASMM(Automatic Shared Memory Management) configuration can be performed later. To perform this, it is necessary to change the required parameters and restart the database.
To use the huge page on the database side, ASMM or manual memory management is required. The Huge page will not be available when Automatic Memory Management is active.
Parameter Change
If Automatic Memory Management is used in the database, reset the memory_max_target and memory_target parameters as follows.
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SQL> alter system reset memory_max_target scope=spfile sid='*'; System altered. SQL> alter system reset memory_target scope=spfile sid='*'; System altered. |
Configure ASMM
You can set the necessary parameters for ASMM as follows.
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SQL> ALTER SYSTEM SET PGA_AGGREGATE_TARGET=5G SCOPE=SPFILE SID='*'; System altered. SQL> ALTER SYSTEM SET SGA_TARGET=20G SCOPE=SPFILE SID='*'; System altered. SQL> ALTER SYSTEM SET SGA_MAX_SIZE=20G SCOPE=SPFILE SID='*'; System altered. |
When changing parameters in RAC systems, sid = ‘*’ must be added to the end.
The database needs to be restarted after you change the parameter.
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srvctl stop database -d ORCL srvctl start database -d ORCL |
