V$IM_COLUMN_LEVEL presents the selective column compression levels that are defined using the inmemory_memcompress clause of the inmemory_column_clause of the CREATE TABLE statement.
This view returns no rows for a table which has no associated selective column compression levels.
Username of the table owner
Table object number
Segment column number
Column compression level. Possible values:
DEFAULT: This value appears for physical columns of a table that do not have a selective column clause. It also appears when a virtual column has been explicitly enabled for in-memory storage using ALTER TABLEtable-nameINMEMORY(VC).
UNSPECIFIED: This value appears for virtual columns of a table that do not have a selective column clause.
If the INMEMORY_VIRTUAL_COLUMNS initialization parameter is set to MANUAL, a virtual column with a DEFAULT INMEMORY_COMPRESSION clause will be materialized while a virtual column with an UNSPECIFIED value will not be.
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
The SYS_IME hidden virtual columns automatically added by the In-Memory Expression (IME) infrastructure will not be shown in this view.