Sentry introduced Snuba, its primary storage and query service for event data, to mitigate risk while transitioning databases. The transition was complex due to the need to ensure data integrity and performance without downtime or compromising trust with users. To address this, Sentry used a Service Delegator, which executed queries against both existing backends and new Snuba backends, allowing for concurrent requests and logging results to Kafka for analysis. This enabled the identification of issues, such as race conditions, and informed improvements to Snuba's performance, including reducing latency and increasing similarity between results. After months of testing and iteration in production, Sentry successfully transitioned to Snuba without user impact, gaining operational experience and confidence in the new system before launch day.