The documenation states that the Cosmos DB engine "natively supports multiple data models: key-value, documents, graphs, and columnar ".
However, I can't seem to find any other information relating specifically to the columnar model.
There is also information available on the following APIs:
- DocumentDB APIs
- Table APIs
- Graph APIs
But nothing on Columnar or Column-family, as described in various summaries.
Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/introduction