Difficulty: 7/10shard key selection, data distribution, migration strategyEvery shared collection has a shard key.1connect to a mongos instance and run the db.printShardingStatus() method2connect to a mongos instance and run the sh.status()Scenario Questions0-2 years experience1We have a collection of user activity logs that we need to shard. How would you choose a shard key for this collection?2If you pick `userId` as the shard key and notice most queries filter only by `timestamp`, what impact does that have on performance?3Given a small dataset, how would you verify that your chosen shard key is providing balanced chunks?Follow-up QuestionsWhat metrics would you set up to know the shard key is working well?How would you handle a situation where the chosen key becomes a hotspot after traffic changes?Can you describe a rollback plan if the new shard key causes performance regression?Suggest Improvement
