What is the role of query optimization in database performance?

Query optimization is the process of improving the efficiency of SQL queries to reduce

resource consumption and improve response time. The goal is to make sure that queries are

executed using the most efficient execution plan possible.

• Why it's important:
• Optimized queries help reduce CPU load, memory consumption, and I/O

operations, improving overall system performance.

• It prevents slow queries that might degrade the user experience or cause

resource contention in high-traffic applications.

• Common techniques:
• Indexing: Using appropriate indexes can drastically reduce query times.
• **Avoiding SELECT ***: Only select the necessary columns instead of

selecting all columns.

• Query refactoring: Break down complex queries into simpler ones, or

replace subqueries with joins when possible.

• Using appropriate joins: Ensure proper joins are used (e.g., INNER JOIN

vs. OUTER JOIN).

• Limit result set: Use LIMIT or TOP to reduce the number of rows returned.