In-Memory Views

15 In-Memory Views

This topic describes data dictionary and dynamic performance views related to the In-Memory Column Store (IM column store).

Table 15-1 In-Memory Views

Initialization Parameter	Description
`DBA_EXPRESSION_STATISTICS`	Provides expression usage tracking statistics for all the tables in the database.
`DBA_EXTERNAL_TABLES`	Describes all external tables in the database. The `INMEMORY` column indicates whether the table is enabled for `INMEMORY`, and `INMEMORY_COMPRESSION` indicates the compression level. Related views include `ALL_XTERNAL_PART_TABLES`, `ALL_XTERNAL_TAB_PARTITIONS`, and `ALL_XTERNAL_TAB_SUBPARTITIONS`.
`DBA_FEATURE_USAGE_STATISTICS`	Displays information about database feature usage statistics. When the IM column store is accessed, the `NAME` column shows `In-Memory Column Store`.
`DBA_HEAT_MAP_SEGMENT`	Displays the latest segment access time for all segments. The timestamps in the view are coarse with a granularity of a day reflecting the flush times of the heat map.
`DBA_INMEMORY_AIMTASKS`	Describes the status of tasks created by Automatic In-Memory.
`DBA_INMEMORY_AIMTASKDETAILS`	Describes the object and action taken by Automatic In-Memory.
`DBA_ILMDATAMOVEMENTPOLICIES`	Contains information specific to data movement-related attributes of an Automatic Data Optimization policy in a database.
`DBA_IM_EXPRESSIONS`	Describes the IM expressions, which have the column prefix `SYS_IME`, that have the `INMEMORY` attribute.
`DBA_JOINGROUPS`	Describes join groups in the database. A join group is a user-created object that lists two columns that can be meaningfully joined.
`DBA_SEGMENTS`	Describes the storage allocated for all segments in the database. Several columns, including `INMEMORY` and `INMEMORY_PRIORITY`, describe In-Memory attributes of the segment.
`DBA_TABLES`	Indicates which tables have the `INMEMORY` attribute set (the `INMEMORY` column is `ENABLED`) or not set (`DISABLED`).
`V$ACTIVE_SESSION_HISTORY`	Displays sampled session activity. Several columns, including `INMEMORY_QUERY` and `INMEMORY_POPULATE`, describe session activity relating to the In-Memory Column Store at the time of sampling.
`V$HEAT_MAP_SEGMENT`	Displays real-time segment access information.
`V$IM_COLUMN_LEVEL`	Presents the selective column compression levels that are defined using the `INMEMORY` clause of the `CREATE TABLE` statement. `SYS_IME` hidden virtual columns are not shown in this view.
`V$IM_SEGMENTS`	Presents information about all In-Memory segments in the database. Only segments that have an In-Memory representation are displayed. If a segment is marked for the IM column store but is not populated, the view does not contain a corresponding row for this segment.
`V$INMEMORY_AREA`	Displays information about the space allocation inside the In-Memory Area.
`V$INMEMORY_FASTSTART_AREA`	Provides information about the In-Memory FastStart (IM FastStart) area.
`V$SGA`	Displays the size of the In-Memory Area.