What does query optimization involve?

What does query optimization involve?

• A. Storing results for caching
• B. Examining multiple ways of executing the same query and choosing the fastest option
• C. Enforcing access controls on queries
• D. Generating reports from query results

Answer: (B)

Query optimization focuses on how to run a query efficiently. A database system doesn’t just execute the statement as written; it explores several possible execution plans, such as which indexes to use, how to join tables, and the order of operations. The optimizer estimates the cost of each plan using statistics about the data (like row counts and data distribution) and then selects the plan with the lowest estimated cost. The chosen plan determines how resources—CPU, I/O, and memory—are used, which can dramatically affect response time. This is exactly what the correct option describes: examining multiple ways to execute the same query and picking the fastest option. Caching results can speed repeated work but isn’t the core optimization process; enforcing access controls handles security, and generating reports is about output, not query execution planning.

Query optimization focuses on how to run a query efficiently. A database system doesn’t just execute the statement as written; it explores several possible execution plans, such as which indexes to use, how to join tables, and the order of operations. The optimizer estimates the cost of each plan using statistics about the data (like row counts and data distribution) and then selects the plan with the lowest estimated cost. The chosen plan determines how resources—CPU, I/O, and memory—are used, which can dramatically affect response time. This is exactly what the correct option describes: examining multiple ways to execute the same query and picking the fastest option. Caching results can speed repeated work but isn’t the core optimization process; enforcing access controls handles security, and generating reports is about output, not query execution planning.