V$ZONEMAP_USAGE_STATS

V$ZONEMAP_USAGE_STATS displays zone map usage statistics.

Column	Datatype	Description
ZONEMAP	VARCHAR2(257)	Name of the zone map in the form of owner.name
PRUNING_TYPE	VARCHAR2(11)	Type of data pruning performed using the zone map
EXECUTIONS	NUMBER	Number of executions, including parallel worker executions
BASE_COUNT	NUMBER	Base count accumulated over number of executions
PRUNED_COUNT	NUMBER	Pruned count accumulated over number of executions
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 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 ratio (PRUNED_COUNT / BASE_COUNT) shows the fraction of data pruned by the zone map.