Hierarchical partition keys: feature completion and production use readiness

Chango V [MSFT] 5 Reputation points Microsoft Employee
2023-01-27T17:37:14.5633333+00:00

Very promising feature, but a few important questions are not addressed in the documentation.

  • What is the change feed support? Specifically, can you define a change feed with only a subset (prefix) of the PKs?
  • How can one tell that a query makes proper use of the PKs? It seems unless you have more than 20 GB of data in a logical partition (or 50 GB in a physical partition?), there is no query fanout, and the RUs charge is the same regardless of whether you provide any PK at all.
  • When is completion of the SDK and the portal UI expected?
  • Is the CDB server-side support production-ready already? (It seems to have been in Preview since 2021).

Thanks.

Azure Cosmos DB
Azure Cosmos DB
An Azure NoSQL database service for app development.
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  1. Mark Brown - MSFT 2,766 Reputation points Microsoft Employee
    2023-02-07T22:25:28.24+00:00

    Will try to answer your different questions.

    Change Feed support. I don't understand your comment. Change Feed is defined for a container, not for a subset of partition keys. Change feed works the same regardless of partition keys. A logical partition is defined as a combination of one or more partition key values within the array of partition key paths. Logical partition keys remain 20 GB in size as does physical partitions. Change feed operates at the physical partition level so can be parallelized by physical partition.

    There are multiple ways users can determine proper use of partition keys within queries. Reviewing Client Diagnostics to look for requests that are fanning out across a large number of partitions, looking at Query Metrics and run queries in the Portal as well as using Dianostic logs. At smaller scale (< 10K RU or 50GB of storage), queries that do not use the partition key will run on the same physical partition. But such queries will not perform at scale which is why it is recommended users understand their partitioning strategy as well as conduct tests at scale.

    For the last two questions, I cannot share forward looking dates on when features or various aspects of them will be released or otherwise share nonpublic information.

    Thank you for your inquiry.


  2. Chango V [MSFT] 5 Reputation points Microsoft Employee
    2023-02-08T04:14:12.48+00:00

    Is this site broken? I'm typing my lengthy replies and lost them twice already! :-(


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