Release : CAPM 3.7
When an interface goes to filtered due to adminstatus down, it is removed from CAPC and Odata (OpenAPI). So the only way to see data is to use vsql (in Vertica on the DR). We don't have a way to see historical data on filtered interfaces. However, the data is still there in the DB until it ages out and is rolled up based on retention period in REST. By default: 45 days for as polled, 90 for hourly, etc.
If the interface is deleted, the data is still in the DB until it ages out. We don't go and delete data for an item_id when we delete the item from the item table. Rollups stop for any deleted item, and any filtered item also.