Hedged reads

MongoDB 4.4 adds the ability to perform a hedged read (https://docs.mongodb.com/master/core/sharded-cluster-query-router/#hedged-reads) on a sharded cluster. By setting a hedged read preference option, applications are able to direct read requests to servers in replica sets other than the primary. The advantage of this approach is that the application simply takes the first result response, improving performance. The potential cost, of course, is that if a secondary responds, the data might be slightly out of date.