Can you describe your approach and experience in performance tuning of SQL queries?

How To Approach: Associate

  1. Highlight role in performance tuning of SQL queries.
  2. Describe techniques used for performance tuning.
  3. Share a specific real-world project involving SQL query optimization.
  4. Illustrate the improvements achieved.

Sample Response: Associate

As an Associate SQL Developer at DataAware Ltd., part of my responsibilities involves ensuring the optimal performance of our database queries. To do this, I frequently employ techniques such as proper indexing, query partitioning, normalization, and leveraging stored procedures.

One memorable project was when our team noticed a significant slowdown in reports generation for a critical client-facing application. Analysing the issue, we found that certain complicated SQL queries were running inefficiently. I redesigned these queries using a combination of proper indexing and query partitioning to avoid expensive table scans and reduce IO costs. Post-optimization, we saw a 70% reduction in report generation time and a significant reduction in application latency which resulted in an overall improved user experience.