backpressure

• 2026-06-15
  flatMap's Second Argument Saved 1.7 Million Requests

  Midway through a code review of the reactive pipeline, staring at this line in NeoService.java: .flatMap(neo -> saveAsteroidWithApproaches(sessionId, neo)) That's Flux.flatMap() with one argument. The function. No concurrency limit. Reactor's default: 256 …

  The Memory Benchmark · 10/41 6 min read
• 2026-06-12
  Seven Fixes, Zero Errors

  The fix for "JVM dies at 256 MB under load" was not a JVM flag. Part 4 ended with Serial GC — the only GC that fits in 256 MB — serving 4,550 requests before the OOM killer showed up. 81% error rate. Same flags, same container, same load profile. Seven code …

  The Memory Benchmark · 9/41 5 min read