In this detailed analysis, Andrew Morgan discusses a performance issue encountered in a customer's application using MongoDB, which was traced back to inefficient indexing of embedded objects. The application suffered from slow read performance due to 15 indexes consuming more space than available RAM, leading to slow disk fetches. The text emphasizes the importance of using compound and partial indexes effectively, avoiding indexing entire objects, and ensuring queries match the indexed fields to optimize performance. The document also highlights the utility of MongoDB design reviews, which can help applications meet performance requirements by advising on appropriate schema and indexing strategies. Additionally, the article underscores the significance of a well-informed indexing approach to maintain database efficiency even as data volumes grow.