What methods exist for extending a database to improve performance and reliability?

The following methods are used to improve the performance and reliability of a database:

• Indexing — creating indexes on frequently queried fields to speed up searches.
• Sharding — horizontally partitioning data across multiple servers or databases to distribute load.
• Replication — copying data to multiple servers to enhance fault tolerance and read scalability.
• Caching — using external caches (e.g., Redis) to reduce database load.
• Query optimization — rewriting queries and using profilers to reduce execution time.
• Parallelism and asynchronous operations — executing database operations in parallel threads or asynchronously.

The application of these methods depends on specific requirements and the architecture of the application.