What is Partitioning in Cosmos DB?
Partitioning in Cosmos DB refers to the mechanism of distributing and organizing data across multiple physical partitions within a container. It is a fundamental feature of Cosmos DB’s distributed database architecture that enables scalability, performance, and efficient data storage and retrieval.
Here are key aspects of partitioning in Cosmos DB:
- Logical Partition: A container in Cosmos DB is divided into logical partitions. Each logical partition contains a subset of data stored within the container. Logical partitions are defined based on a chosen partition key, which is a property within each item.
- Physical Partition: Logical partitions are mapped to physical partitions. Physical partitions are the underlying storage units that hold the actual data. The number of physical partitions is automatically managed by Cosmos DB based on the throughput requirements and storage size of the container.
- Data Distribution: When data is inserted or updated in the container, Cosmos DB uses a hashing algorithm on the partition key to determine the target physical partition for storing the data. Items with the same partition key value are grouped together within the same physical partition.
- Scalability: Partitioning enables horizontal scalability in Cosmos DB. By distributing data across multiple physical partitions, Cosmos DB can handle a high volume of read and write operations in parallel. As the workload increases, Cosmos DB can dynamically split or merge physical partitions to accommodate the changing demands.
- Load Balancing: Cosmos DB automatically balances the data and workload across physical partitions to avoid hotspots and ensure even distribution. It helps distribute the traffic evenly and prevents any single partition from becoming a performance bottleneck.
- Performance and Parallelism: Partitioning allows Cosmos DB to achieve high throughput and low latency by enabling parallel processing. Multiple read and write operations can be executed concurrently on different partitions, providing efficient data access and processing.
It’s important to choose an appropriate partition key that evenly distributes the data across partitions and aligns with the access patterns of your application. A well-designed partitioning strategy ensures optimal performance, scalability, and efficient utilization of resources in Cosmos DB.