I Made Our Attendance API 75% Faster By Fixing One Stupid Mistake

Short summary

An HRMS platform's attendance API was timing out at over 60 seconds for 6500 employees because the code made a database call inside a loop to fetch category names for each row—the classic N+1 problem hiding in a helper method. The fix: pre-fetch all categories in one query and use dictionary lookups instead. This minimal code change reduced response time by 75% without refactoring or dependencies.

• •N+1 query problem was hidden in a foreach loop calling the database per iteration
• •Solution: batch-fetch data once into a dictionary, replace DB calls with lookups
• •75% performance improvement from two small code changes, no refactoring needed

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