Collection aliases

Rebuilding an index from scratch (a schema change, a bulk re-import) normally means either searching a half-populated collection or taking search offline while it fills. An alias breaks that trade-off: build the new collection under a fresh name, verify it, then repoint the alias — the swap is atomic and nothing in your app's code, which only ever knew the alias, has to change.

The same mechanism supports safe rollbacks: if the new collection turns out wrong, point the alias back at the previous one instead of re-running the import.