12c - Invisible Columns...
- by noreply(at)blogger.com (Thomas Kyte)
Remember when 11g first came out and we had "invisible indexes"? It seemed like a confusing feature - indexes that would be maintained by modifications (hence slowing them down), but would not be used by queries (hence never speeding them up). But - after you looked at them a while, you could see how they can be useful. For…