87.3 % served from cache. Does that mean it returned a result existing in the cache because the very same query was executed before? Probably still a relevant result, if you have to process millions of queries every second, it seems not unlikely that you will see a lot of repeated queries. But at that point you are measuring cache performance more than query performance. But unless you run some standardized query benchmark, a single queries per second number is not that informative anyway because query complexity and therefore execution time can span many others of magnitude. Looking up a name by ID and aggregating across a billion rows from seventeen tables joined together are both a single query.