1. Database Reference
  2. Dynamic Performance Views
  3. Dynamic Performance (V$) Views: V$IM_COLUMN_LEVEL to V$RULE_SET_AGGREGATE_STATS
  4. V$INMEMORY_AREA

9.6 V$INMEMORY_AREA

V$INMEMORY_AREA contains information on the space allocation inside the In-Memory Area.

The In-Memory Area is sub-divided into three pools:

  • 1MB POOL - stores the actual column formatted data populated into memory

  • 64K POOL - stores metadata about the objects that are populated into the In-Memory Column Store (IM column store)

  • IM POOL METADATA - contains information about In-Memory Compression Unit (IMCU) to data block mappings

The amount of available memory in each pool is visible in the V$INMEMORY_AREA view. The relative size of the three pools is determined by internal heuristics. The majority of the In-Memory Area memory is allocated to the 1MB POOL

Column Datatype Description

POOL

VARCHAR2(26)

Name of the pools in the In-Memory Area

ALLOC_BYTES

NUMBER

Total amount of memory allocated to this pool

USED_BYTES

NUMBER

Amount of memory currently used in this pool

POPULATE_STATUS

VARCHAR2(26)

Shows the status of the IM column store, for example, whether it is currently being populated or if it is done

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire multitenant container database (CDB). This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

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