1 Description
12.2 from the beginning to support dynamic modification of the size of the IM database in an open state, without the need to restart the database. And before that, all you need to restart the database.
Use this feature must meet the following criteria:
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The column store must be enabled.
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The compatibility level must be 12.2.0 or higher.
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The database instances must be started with an SPFILE.
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The new size of the IM column store must be at least 128 megabytes greater than the current INMEMORY_SIZE setting.
Experiment 2
Note: The current SGA have enough available memory. But can only increase, not decrease.
View the current size of 2.1 IM
SQL> set linesize 200
SQL> SHOW PARAMETER INMEMORY_SIZE
NAME TYPE VALUE
---------- -------------- -------------------
inmemory_size big integer 100M
2.2 increase the size of IM
SQL> ALTER SYSTEM SET INMEMORY_SIZE = 500M SCOPE=BOTH;
System altered.
Note: it must be a SCOPE = BOTH, or SCOPE = MEMORY;
2.3 magnitude IM View
In the case without rebooting, it has become the 500M.
SQL> show parameter inmemory_size
NAME TYPE VALUE
--------------- ------------- ------------------------
inmemory_size big integer 500M