1.148 INMEMORY_FORCE
INMEMORY_FORCE
allows you to specify whether tables and materialized views that are specified as INMEMORY
are populated into the In-Memory Column Store (IM column store) or not.
Property | Description |
---|---|
Parameter type |
String |
Syntax |
|
Default value |
|
Modifiable |
You can use
All other modifications of this parameter require you to update the initialization file and restart the instance. |
Modifiable in a PDB |
Yes |
Basic |
No |
Oracle RAC |
All instances should use the same value. |
The following values can be set:
-
DEFAULT
The IM column store is populated with objects that are specified as
INMEMORY
. -
OFF
Even if the IM column store is configured on this instance, no objects are populated in memory.
-
BASE_LEVEL
Enables Database In-Memory Base Level. The Base Level lets you to experiment with Oracle Database In-Memory features without purchasing the Oracle Database In-Memory option. This setting is available starting with Oracle Database release 19c, version 19.8.
When the Base Level is enabled, the value of the
INMEMORY_SIZE
initialization parameter is limited to 16 GB for a CDB. In an Oracle RAC environment, the value ofINMEMORY_SIZE
is limited to 16 GB for each instance. The compression level for all objects and columns is automatically and transparently set toQUERY
LOW
. Automatic In-Memory is disabled, and In-Memory Column Store feature tracking is tracked for "In-Memory Base Level" rather than "In-Memory Column Store." The CellMemory feature is disabled for Oracle Exadata. -
CELLMEMORY_LEVEL
This setting is valid only for on-premise Oracle Exadata systems. Such systems offer the CellMemory feature, which requires a license for the Oracle Database In-Memory option.
In previous releases of Oracle Database, in order to use the CellMemory feature, you were required to enable the IM column store, even if you had no intention of using it. This incurred the overhead of enabling the IM column store without any benefit. Starting with Oracle Database release 19c, version 19.8, you can use the CellMemory feature without enabling the IM column store by setting
INMEMORY_FORCE=CELLMEMORY_LEVEL
andINMEMORY_SIZE=0
. With these settings, the IM column store is not enabled and queries can use CellMemory to scan objects.Note that if the value of
INMEMORY_SIZE
is greater than0
, then settingINMEMORY_FORCE=CELLMEMORY_LEVEL
is equivalent to settingINMEMORY_FORCE=DEFAULT
. The IM column store is enabled, even if you use only CellMemory.
See Also:
-
Oracle Database In-Memory Guide for an introduction to the IM column store
-
Oracle Database In-Memory Guide for more information about the IM column store
-
Oracle Database Licensing Information User Manual to learn which database offerings support the Database In-Memory Base Level feature