{
  "id": 10442211,
  "title": "Our 72-hour soak lost 81% of its throughput. We had to prove it wasn't the runtime.",
  "url": "https://urgent.news/2026/09/28/our-72-hour-soak-lost-81-of-its-throughput-we-had-to-prove-it-wasnt",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-28T12:42:07.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/hasanh47/our-72-hour-soak-lost-81-of-its-throughput-we-had-to-prove-it-wasnt-the-runtime-3jml"
  },
  "original_language": "en",
  "account": "The 72-hour soak test, conducted on September 19-24, 2026, on a single VM with production-like setup, revealed that the Usai runtime lost 81% of its throughput despite maintaining flat CPU, memory, and open descriptor counters. A 24-hour control run with the application's data pruned showed no slowdown, implicating the ever-growing table as the cause. The workload generated approximately 7.4 million invoices into one table, which resulted in bigger indexes, larger write-ahead logs, and more checkpoint and autovacuum work. This led to longer wait times for PostgreSQL for each closed-loop client, causing a decline in successful requests per second. The CPU per request remained flat, and memory stayed within a narrow range, but the slow tail of latency increased tenfold, reducing throughput to a fifth of its initial value. The control run confirmed the application's table as the source of the decay, disproving the idea that the runtime was responsible.",
  "summary": "Evidence box : every Usai post states the limits of its claims. Status: Usai v0.0.15, alpha. The soaks ran on 2026-09-19/22 and 2026-09-23/24, on the builds of those days. Setup: one VM (16 vCPU Xeon) running a production-shaped deployment: Caddy in front of the published Usai runtime image, PostgreSQL 18, and the examples/invoicing app. Eight closed-loop clients; a status sample once a minute.…",
  "key_points": [
    "72-hour soak test on September 19-24, 2026",
    "Usai runtime lost 81% of throughput",
    "Table growth caused slowdown"
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}