The Importance of Benchmarks

7 hours ago

Aha! Develop team found a sprint report taking 15 minutes to load due to a 1,000-day sprint, triggering a performance investigation.
The performance bottleneck was identified in sprint progress parsing, affecting all sprint reports like retrospective and burndown.
The original algorithm cloned data for each sprint day, including empty days, causing memory and speed issues.
Hypothesis: memory usage scaled with days, making later days slower to clone as more records accumulated.
Solution #1 introduced a new data structure (ParsedSprintProgressData) that stores empty days as null, reducing memory usage by up to 90%.
Benchmarking revealed that memory improvements only led to a 20% runtime gain, disproving the initial hypothesis.
Profiling identified two hot paths: lodash.cloneDeep() and moment.format(), which were major performance overheads.
Solution #2 replaced cloneDeep() with explicit duplication and moment.format() with a custom date formatting function.
Combining both approaches resulted in faster parsing, less memory usage, and minimal impact from empty days.
The problematic report now parses in a fraction of a second, a three-order-of-magnitude improvement, though rendering still takes seconds.

Hasty Briefsbeta