The article presents a benchmarking exercise comparing MySQL, PostgreSQL, and SingleStore database engines on their performance with heavy joins, rolling-window sums, and hot analytic queries. The benchmark used identical Docker containers, realistic workloads, and measured the execution times of each platform for three scenarios: total transaction volume (last 30 days), top transfer recipients, and join users, accounts, and transactions. The results show that SingleStore consistently outperformed MySQL and PostgreSQL across all scenarios, with significant performance advantages in queries involving multiple joins and aggregations. This highlights the strengths and weaknesses of each database engine for handling large-scale, real-time data in fintech and analytics applications.