• How does querying work in MongoDB?

  • What query operators are available in MongoDB?

  • What is projection in MongoDB?

  • What is aggregation in MongoDB?

  • What is the aggregation framework?

  • What is an aggregation pipeline?

  • Explain $match, $group, $sort, $project

  • What is $lookup and how does it work?

  • What is a compound index?

  • What are TTL indexes?

  • What are capped collections?

  • What are geospatial indexes?

  • How does MongoDB ensure high availability?

  • What is replication in MongoDB?

  • What is a replica set?

  • What is automatic failover?

  • What is sharding?

  • How does sharding work internally?

  • What is a shard key?

  • What are hashed shard keys?

  • Difference between horizontal and vertical scaling?

  • What is write concern?

  • What is read concern?

  • How does MongoDB handle data consistency?

  • What is journaling?

  • What is the oplog?

  • What is GridFS and when is it used?

  • How does MongoDB handle schema design?

  • Embedding vs Referencing – when to use which?

  • How do you optimize MongoDB queries?

  • What is explain()?

  • What is a covered query?

  • How do you import and export data in MongoDB?

  • How do you backup and restore MongoDB?

  • What is MongoDB Atlas?

  • Atlas vs Self-Hosted MongoDB

  • What is change stream?

  • How do you paginate results?

  • How do you monitor MongoDB performance?

  • What are common MongoDB performance issues?