Query optimization is the process of improving the performance of database queries by reducing execution time, minimizing resource usage, and ensuring scalability.

1. Why Does Query Optimization Matter?

1. Improves Application Speed – Faster queries mean better user experience.
2. Reduces Server Load – Optimized queries use fewer CPU and memory resources.
3. Supports Scalability – Efficient queries allow databases to handle more users without crashes.
4. Lowers Cloud Costs – Faster queries require fewer compute resources, reducing cloud bills.

2. How Query Execution Works

Before optimizing a query, we must understand how a database processes it.

1. Parsing – SQL is checked for syntax errors.
2. Planning – The database chooses the best way to execute the query.
3. Execution – The plan is executed, and results are fetched.

Databases don’t always pick the best plan automatically, so we use query optimization techniques to guide them.

3. Techniques for Query Optimization