Routing and Results
- During query routing, a mongos instance evaluates all shards in the cluster to identify the shard responsible for processing the query.
- Once the shard is identified, the mongos instance retrieves data from that shard.
- Mongos instances aggregate the results from all shards before returning them to the client.
- To distribute queries evenly across shards, mongos instances use strategies such as “round–robin.”
- Mongos instances also manage query modifiers like sorting and result size limits.
- The use of mongos instances helps in abstracting the sharded cluster’s complexity from client applications, providing a single interface for querying the entire cluster.
Sharded Cluster Components in MongoDB
MongoDB’s sharding capability enables horizontal scaling by distributing data across multiple servers or “shards.” Understanding the components of a sharded cluster is crucial for managing and scaling database infrastructure efficiently.
In this article, We will explores the key components of a sharded cluster in MongoDB, including shards, primary shards, config servers, and mongos instances.