Develop a comprehensive solution for a product search system that Amazon could use to handle millions of concurrent user queries efficiently. This system should allow users to search for products using keywords.

Your design must include a scalable architecture that supports real-time search, handles massive datasets, and maintains high performance under heavy user traffic. Consider implementing efficient data storage, retrieval mechanisms, and a caching strategy to reduce latency.

Additionally, your system should incorporate a relevance algorithm to ensure that the search results are pertinent to the user's query.

Discuss the potential challenges you might face regarding data consistency and system scalability, and how you plan to address them to ensure the system remains robust and reliable.

Develop a comprehensive solution for a product search system that Amazon could use to handle millions of concurrent user queries efficiently.

This system should allow users to search for products using keywords.

Your design must include a scalable architecture that supports real-time search, handles massive datasets, and maintains high performance under heavy user traffic.

Consider implementing:

• Efficient data storage
• Retrieval mechanisms
• A caching strategy to reduce latency

Additionally, your system should incorporate a relevance algorithm to ensure that the search results are pertinent to the user's query.

Discuss the potential challenges you might face regarding data consistency and system scalability, and how you plan to address them to ensure the system remains robust and reliable.