1.135 INMEMORY_AUTOMATIC_LEVEL

INMEMORY_AUTOMATIC_LEVEL is used to enable the Automatic In-Memory feature, which automates the management of the In-Memory Column Store (IM column store) to help ensure that the working data set is in the IM column store at all times.

Property Description

Parameter type

String

Syntax

INMEMORY_AUTOMATIC_LEVEL = { LOW | MEDIUM | OFF }

Default value

OFF

Modifiable

ALTER SYSTEM

Modifiable in a PDB

Yes

Basic

No

Oracle RAC

All instances should use the same value.

Typically, among all the IM enabled segments, only a subset is actively queried at any time. This subset is known as the working data set. The working data set is expected to change over time for many applications.

INMEMORY_AUTOMATIC_LEVEL attempts to keep the working data set in the IM column store at all times by moving segments in and out of the IM column store based on access patterns.

Oracle recommends that you provision enough memory for the working data set to fit in the IM column store.

The following values can be set:

  • LOW: When this value is set, the database evicts cold segments from the IM column store when it is under memory pressure.

  • MEDIUM: This level includes an additional optimization that ensures that any hot segment that was not populated because of memory pressure is populated first.

  • OFF: When this value is set, Automatic In-Memory is disabled. This value returns the IM column store to the behavior that existed prior to Oracle Database 18c is used. If you do not expect a stable working data set, set the parameter to OFF. This is the default value.

Note:

This parameter is available starting with Oracle Database release 18c, version 18.1.

See Also:

Oracle Database In-Memory Guide for more information about configuring the Automatic In-Memory feature