When I run the following command in Cosmos DB 3.6,
db.collectionName.ensureIndex({"Contract.ContractNumber":1, "PBPNumber":1})
Contract.ContractNumber is the sub-document path.
I got his error
{
"ok" : 0,
"errmsg" : "Compound index does not currently support nested documents or arrays.",
"code" : 115,
"codeName" : "CommandNotSupported"
}
The same command succeeds in out of box Mongo.
Is there anyway to do it?
Thanks
Based on the CommandNotSupported error message,the feature is not supported exactly currently.
Per my knowledge, CosmosDB just supports a subset of the MongoDB API. CosmosDB has some different behaviours and results. But the onus is on CosmosDB to improve their emulation of MongoDB.
Surely, you could add feedback here to submit your requirements.Or you could consider using MongoDB Atlas on Azure if you'd like full MongoDB feature support.
Regarding @leopold.talirz answer:
It seems that it actually is possible to enable this feature all by yourself. Please see this document for overall reference, and then there's a link to another one which explains step-by-step how to do it.
EDIT: most recent news seem to be here:
https://github.com/MicrosoftDocs/azure-docs/issues/101394#issuecomment-1318041341
https://github.com/hashicorp/terraform-provider-azurerm/issues/19192#issuecomment-1341332461
It seems it WILL be available to users "shortly", but so far, it's only available to MSFT, and the docs were updated too soon.
what a mess
As of May 2022, indexing is available for nested compound indices, as long as none of the properties in the dot-notation path (excluding the last element) is an array.
However, as explained here.
Because of the difficulty of ensuring that all data within a collection cannot include an array on the property being set, we can only enable this via support ticket
P.S. We found that Azure support was able to enable the feature on an entire CosmosDB instance, not just on individual collections.
