Question: How can you increase MongoDB requests per second?

Answer

MongoDB, a leading NoSQL database, is widely adopted for its scalability, flexibility, and performance. When optimizing the number of requests per second (RPS) a MongoDB server can handle, several strategies can be employed to ensure efficiency and high throughput. Here are some techniques:

1. Indexing

Ensure that your queries are backed by appropriate indexes. Indexes can drastically reduce the amount of work MongoDB has to do to fulfill a query.

db.collection.createIndex({ field1: 1, field2: -1 });

2. Use Projection

Limit the fields returned by your queries to only those that are necessary. This reduces the amount of data transferred over the network and processed by your application.

db.collection.find({}, { field1: 1, field2: 1 });

3. Sharding

Distribute your data across multiple machines using sharding. This allows your database to grow beyond the limits of a single server and increases read/write throughput proportionally to the number of shards.

sh.shardCollection(\"mydatabase.mycollection\", { \"shardKey\" : 1 } )

4. Connection Pooling

Use connection pooling to reuse connections rather than establishing a new connection for every request. This reduces the overhead of connecting to the database.

5. Hardware Improvements

• RAM: More RAM means more data can be cached in memory, reducing disk I/O.
• SSD: SSDs can provide lower latency and higher throughput compared to traditional hard drives.
• Network: Ensure your network bandwidth and latency are not bottlenecks.

6. Write Concerns

Adjust write concerns according to your requirements for data durability versus performance.

db.collection.insert(
   { item: \"card\", qty: 15 },
   { writeConcern: { w: 1, j: true, wtimeout: 5000 } }
)

7. Read Preferences

For replicated environments, use read preferences to distribute read operations across instances, balancing the load.

8. Monitoring and Profiling

Regularly monitor your MongoDB's performance using tools like MongoDB Atlas or Ops Manager and enable profiling to identify slow queries.

By carefully considering these aspects, you can significantly improve the number of requests per second your MongoDB instance can handle, thus boosting overall performance.