Is having the same Partition Key in multiple containers a good idea?
Having the same partition key in multiple containers is generally not recommended in Cosmos DB. Each container in Cosmos DB represents a logical boundary for data storage and management, and the choice of partition key plays a crucial role in achieving optimal performance and scalability. Here’s why having the same partition key in multiple containers is not typically considered a good idea:
- Data Distribution and Scalability: The partition key determines how data is distributed and spread across physical partitions in Cosmos DB. By having the same partition key in multiple containers, you limit the ability to distribute and scale the data effectively. It can lead to a concentration of data within a few physical partitions, potentially resulting in hot partitions and performance bottlenecks.
- Limited Partition Key Value Range: Partition keys should have a wide range of values to ensure even data distribution across partitions. If the same partition key is used across multiple containers, the range of values for that partition key is limited to the documents within each container. This can result in suboptimal distribution and partitioning of data.
- Query Performance: The partition key is fundamental for efficient query execution in Cosmos DB. By having the same partition key in multiple containers, you limit the ability to perform queries efficiently across the containers. Cross-container queries may become necessary to retrieve related data, which can be less performant and more complex to implement.
- Container-Specific Indexing and Throughput: Each container in Cosmos DB allows you to define its own indexing policies, throughput settings, and other configuration options. By having the same partition key in multiple containers, you lose the ability to fine-tune these settings on a per-container basis, potentially affecting query performance and cost optimization.
While there might be some rare use cases where having the same partition key in multiple containers could be applicable, it’s generally advisable to design the partitioning strategy and partition keys to align with the unique characteristics of each container and its data. This ensures optimal distribution, scalability, query performance, and flexibility for managing the data within each container.