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

8.3 V$IM_USER_SEGMENTS

V$IM_USER_SEGMENTS presents information about the in-memory segments for the current user in the database.

Only segments that have an in-memory representation are displayed. If a segment is marked for the In-Memory Column Store (IM column store) but is not populated, no corresponding row for that segment is displayed in this view.

Column Datatype Description

SEGMENT_NAME

VARCHAR2(128)

Name of the segment, if any

PARTITION_NAME

VARCHAR2(128)

Object partition name (set to NULL for non-partitioned objects)

SEGMENT_TYPE

VARCHAR2(18)

Type of segment:

  • TABLE

  • TABLE PARTITION

  • TABLE SUBPARTION

TABLESPACE_NAME

VARCHAR2(30)

Name of the tablespace containing the segment

INMEMORY_SIZE

NUMBER

Size of the in-memory version of the segment, in bytes

BYTES

NUMBER

Total size of the on-disk segment, in bytes

BYTES_NOT_POPULATED

NUMBER

Size of the portion of the on-disk segment that is not populated in memory, in bytes

POPULATE_STATUS

VARCHAR2(9)

Status of segment population:

  • STARTED

  • COMPLETED

  • FAILED

INMEMORY_PRIORITY

VARCHAR2(8)

Indicates the priority for IM column store population:

  • LOW

  • MEDIUM

  • HIGH

  • CRITICAL

  • NONE

INMEMORY_DISTRIBUTE

VARCHAR2(15)

Indicates how the IM column store is distributed in an Oracle Real Application Clusters (Oracle RAC) environment:

  • AUTO

  • BY ROWID RANGE

  • BY PARTITION

  • BY SUBPARTITION

INMEMORY_DUPLICATE

VARCHAR2(13)

Indicates the duplicate setting for the IM column store in an Oracle RAC environment:

  • NO DUPLICATE

  • DUPLICATE

  • DUPLICATE ALL

INMEMORY_COMPRESSION

VARCHAR2(17)

Compression level for the IM column store:

  • NO MEMCOMPRESS

  • FOR DML

  • FOR QUERY [ LOW | HIGH ]

  • FOR CAPACITY [ LOW | HIGH ]

INMEMORY_SERVICE

VARCHAR2(12)

Specifies how the IM-enabled table is populated on various instances:

  • DEFAULT: Pre-Oracle Database 12c Release 2 (12.2.0.1) behavior

  • NONE: Do not populate on any instance

  • ALL: Populate on all instances

  • USER_DEFINED: Populate only on the instances on which the user-specified service is active. The service name corresponding to this is stored in the INMEMORY_SERVICE_NAME column.

INMEMORY_SERVICE_NAME

VARCHAR2(129)

Specifies the service name on which the IM-enabled table should be populated. This column has a value only when the corresponding INMEMORY_SERVICE column has a value of USER_DEFINED.

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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