How a Single Loop Triggered 400 Database Queries and Slowed Pages to 9 Seconds

A common but hard-to-spot backend bug known as the N+1 query problem can cause a single loop to generate hundreds of individual database round trips. In the case described, iterating over 400 orders — each triggering its own hidden query — stretched a list page load time to nine seconds. The problem is difficult to catch because the offending code looks like a simple field access during review, testing, and standard metrics monitoring. The fix involves pulling all required data before the loop runs, rather than fetching it one record at a time. Developers are advised to count queries — not just measure milliseconds — and test against real data volumes to surface this class of bug early.