What is the role of a query optimizer in database management?

The role of a query optimizer in database management is crucial as it focuses on determining the most efficient way to execute a given SQL query. When a query is submitted to the database, the query optimizer assesses various possible execution plans based on factors such as available indexes, statistics about data distribution, and system resources. By evaluating these plans, the optimizer can select the one that minimizes resource usage, such as CPU and memory, and reduces the time taken to retrieve the requested data. This optimization process is essential for maintaining performance, especially in complex queries that access large datasets or involve multiple joins.

Other tasks such as sorting data alphabetically, creating database backups, or visualizing data relationships are important but do not fall under the scope of the query optimizer's function. These tasks serve different purposes in database management, while the query optimizer specifically enhances the efficiency of query execution.