1. Database Reference
  2. Initialization Parameters
  3. Initialization Parameters
  4. INMEMORY_FORCE

2.164 INMEMORY_FORCE

INMEMORY_FORCE allows you to specify whether objects, such as tables, materialized views, and partitions, that are specified as INMEMORY are populated into the In-Memory Column Store (IM column store) or not.

Property Description

Parameter type

String

Syntax

INMEMORY_FORCE = { DEFAULT | OFF | BASE_LEVEL | CELLMEMORY_LEVEL }

Default value

DEFAULT

Modifiable

You can use ALTER SYSTEM to dynamically modify this parameter setting as follows:

  • From DEFAULT to OFF
  • From OFF to DEFAULT
  • From BASE_LEVEL to DEFAULT
  • From CELLMEMORY_LEVEL to DEFAULT
  • From CELLMEMORY_LEVEL to OFF

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.

    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 of INMEMORY_SIZE is limited to 16 GB for each instance. The compression level for all objects and columns is automatically and transparently set to QUERY 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

    CellMemory is an Exadata feature that allows you to use Exadata Smart Flash Cache to populate data in in-memory columnar format. In older releases of Oracle Database, in order to use the CellMemory feature, you were required to enable the IM column store (by setting INMEMORY_SIZE to a value greater than 0), even if you had no intention of using the IM column store. 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 and INMEMORY_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 than 0, then setting INMEMORY_FORCE=CELLMEMORY_LEVEL is equivalent to setting INMEMORY_FORCE=DEFAULT. The IM column store is enabled, even if you only use CellMemory.

See Also: