Fresh Boxes Empty Shelves

A read path serves 200,000 requests per second at a 98 percent cache hit ratio, so the database normally handles about 4,000 reads per second. A deploy restarts every cache node in the tier simultaneously and the caches come back empty. What does the database see in the seconds right after the restart?

Unchanged load, because the restarted nodes replay their persistence files before accepting reads

Close to the full 200,000 reads per second, roughly 50 times its normal load, until the cache refills

About 8,000 reads per second, since only the miss rate doubles while hits continue to be served

About 4,000 reads per second, because concurrent misses on the same key queue behind one in-flight query