A stale response can quietly break a recommendation tool
A recommendation page can perform the correct calculation and still show the wrong result. The failure happens when two valid requests finish in the wrong order. Consider a player who starts a Members search, then switches to F2P while the first request is still running. The F2P request finishes quickly and the page shows F2P methods. A moment later, the slower Members response arrives. If the…
The article discusses a common issue where a recommendation tool can display incorrect results due to race conditions when multiple requests are processed simultaneously. This occurs when two valid requests finish in the wrong order, causing the interface to show outdated information. The solution proposed is to give each request a unique identity by using a monotonic counter that increments with every request.
This counter is stored locally and compared against the current counter when a response is received. If the counters do not match, the stale result is discarded, ensuring that only the latest and most relevant data is displayed to the user. Additionally, the article suggests implementing similar protection mechanisms for other aspects of the interface, such as loading states, error messages, and UI actions, to prevent any stale or incorrect information from being shown to the user.
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