Had a similar scenario, where we had to deploy a new search feature in our product. This required a large and complex DB migration and backfill. We resorted to

Had a similar scenario, where we had to deploy a new search feature in our product. This required a large and complex DB migration and backfill. We resorted to cloning our prod DB to our staging env, and thus where able to test our migration scripts, review the search feature's performance on the real data, verify the release plan and the downtime needed, and even run a few load tests. I cannot see how we could have done this without a staging env.