What approaches can you use to improve application efficiency when query speed to the database decreases under high traffic?

To reduce the load on the database and improve the efficiency of high-traffic applications, the following approaches can be used:

• Caching: storing frequently requested data in memory (e.g., using Redis, Memcached) to decrease database access.
• Pagination and limiting queries: requesting and processing only the necessary amount of data.
• Query optimization: using indexes, writing SQL queries correctly, avoiding N+1 problems.
• Asynchronous processing: performing heavy operations in the background to avoid blocking the main thread.
• Using CQRS: separating read and write operations for optimized reading.
• Sharding and database replication: distributing load across multiple servers.

Example of caching using Spring Cache:

@Service
public class ProductService {

    @Cacheable("products")
    public Product getProductById(Long id) {
        // Expensive database query
        return productRepository.findById(id).orElse(null);
    }
}