No default compound index created on time series collection

I am using MongoDb version 7.0.2 and I am creating a new time series collections using Java MongoDb API with Spring.

This is the code that creates the collections:

TimeSeriesOptions tso = new TimeSeriesOptions("my_time_field")
                .granularity(TimeSeriesGranularity.HOURS)
                .metaField("my_meta_field");

CreateCollectionOptions cco = new CreateCollectionOptions().timeSeriesOptions(tso).expireAfter(30, DAYS);

mongoTemplate.getMongoDatabaseFactory().getMongoDatabase().createCollection("time_series_collection_name",  cco);

The collections are created successfully but here in the documentation it is stated that
MongoDB 6.3 and later automatically creates a compound index on the time and metadata fields for new time series collections.
It can be found on this page: https://www.mongodb.com/docs/v7.0/core/timeseries-collections/
The problem is that my time series collections don’t have any index associated with them when they are created.
Is this a bug or I am missing something?

Update: I am answering my own question.
I have executed the following create collection command using mongosh on two different MongoDB editions and the result is different:

db.createCollection("my_test_collection", {timeseries:{timeField:"timestamp",metaField:"metadata"}});

MongoDb Community edition v 7.0.2 - The time series collection is created but there is no default index created associated with this collection
MongoDb Atlas edition v 7.0.2 - The time series collection is created and a default index associated with this collection is created

[
  {
    v: 2,
    key: { metadata: 1, timestamp: 1 },
    name: 'metadata_1_timestamp_1'
  }
]

This is the default index that is created.

As a conclusion I can say that there is difference in the behaviour of different MongoDb editions but maybe it is good to state that in the documentation that I linked in my question.

Hey @Vladimir_Stoyanov,

Welcome to the MongoDB Community!

I tested it with MongoDB Community version 7.0.2, and it worked as expected for me. I’ve attached a screenshot for your reference, showing that it automatically created the compound index for the TS collection in the local deployment too.

Could you please share the workflow you are following to create a TS collection?

Best regards,
Kushagra

Hi @Kushagra_Kesav,
Thank you for your response.

Here are exactly the steps I follow.

I have installed my MongoDb using brew command on Mac OS

Thanks,
Vladimir