How to optimize the performance of database queries without increasing the data volume?

To optimize the performance of queries to an existing DBMS without increasing data volume, the following approaches can be used:

• Indexing: Creating and optimizing indexes on columns frequently used in WHERE, JOIN, and ORDER BY clauses.
• Query optimization: Rewrite queries to reduce the number of operations, use more efficient constructs (for example, replace subqueries with JOINs).
• Caching: Implement caching of results for frequently repeated queries at the application or DBMS level.
• Profiling and execution plan analysis: Use EXPLAIN or similar tools to identify bottlenecks.
• Parallelism and batch processing: Break large queries into smaller ones or use parallel queries if supported.
• DBMS configuration optimization: Adjust memory, caching, and parallelism settings.

Example of using EXPLAIN for query analysis:

EXPLAIN SELECT * FROM orders WHERE customer_id = 123;

This helps understand which indexes are used and where improvements can be made.