What is a primary drawback of referencing in MongoDB?

In MongoDB, referencing refers to the practice of storing a reference to a document in another document rather than embedding the entire document structure. This approach has several implications for how data is managed and accessed.

When using references, one of the primary drawbacks is that querying requires accessing multiple documents. This is because the data you want may be split across various collections. Each reference must be resolved with a separate query to fetch the related documents, which can introduce additional read latency and complexity. Consequently, this impacts read performance, especially in scenarios with many associations or where the data model is heavily reliant on references.

Read operations may necessitate more extensive use of aggregation or multiple queries to gather the needed information, which can compound the effect on performance. Therefore, while referencing can help maintain normalized data structures and reduce duplication, it comes at the cost of increased complexity in query execution and potential performance issues when reading data that involves multiple collections.