https://nalar.dev/tags/backpressure/ Recent content in Backpressure on Nalar Hugo en-us Sun, 13 Sep 2026 00:00:00 +0700 https://nalar.dev/request-coalescing-turns-cache-miss-bursts-into-shared-work/ Sun, 13 Sep 2026 00:00:00 +0700 https://nalar.dev/request-coalescing-turns-cache-miss-bursts-into-shared-work/ <p>A cache entry expires at a single instant, but requests for that entry do not necessarily arrive one at a time. If twenty callers observe the same miss before any caller has repopulated the cache, a conventional cache-aside path can send twenty equivalent reads to the origin. The cache is functioning according to its contract; the concurrency around the miss is creating duplicated work.</p> <p>Request coalescing changes that boundary. Instead of treating each miss as permission to start an origin operation, callers for the same key can share one in-flight operation. One caller becomes the producer of the pending result. Other callers wait for that result rather than starting equivalent work.</p>