screentinker/server/db
ScreenTinker 81e7d58099 fix(#146): reconnect/heartbeat storm containment (beta5)
Second head of the OTA-loop root cause (#144), on the connection/heartbeat
layer: unbounded device-driven work with no circuit-breaker. Symptoms in Bold
prod — devices shown OFFLINE in CMS while online+playing, loop-lag simmer
(p99 300-1145ms), device_status_log grown to 1.1M rows.

False-offline (two causes, both fixed):
- evicted-socket re-arm race: evictPriorSocket runs before registerConnection,
  so the evicted old socket's disconnect armed a fresh offline timer for a
  just-reconnected device. Tag evicted socket ids and bail in the disconnect
  handler (ws/deviceSocket.js).
- heartbeat checker false-positive: a device with a live socket in /device is
  UP even if its in-memory lastHeartbeat is stale under lag; skip it instead of
  marking offline (services/heartbeat.js).

Storm containment:
- batched/coalescing device_status_log writer (lib/status-log-writer.js): net
  state per device per flush, breaking the storm->bloat->slow-write->lag loop.
- newest-N-per-device row-count cap in the global sweep (db/database.js): hard
  bound regardless of churn; trims the existing 1.1M backlog on the first sweep.
  Per-device prune unified to statusLogRetentionDays (was hardcoded 7d).
- reconnect-throttle idle-bucket sweep (lib/reconnect-throttle.js): the #142
  throttle already existed; added the memory-bound sweep it lacked (wired in
  server.js). No second breaker.
- cosmetic: cap the OTA breaker level counter (lib/ota-breaker.js).
- best-effort status-log flush on the crash path (server.js).

Tests: load harness (test/reconnect-storm-load.test.js) proves breaker engage,
clean offline-clear, no-throttle-on-normal-reconnect, batched writes, bounded
loop-lag; cause-1 re-arm race proven with teeth (test/evicted-socket-rearm.test.js).
Both mutation-checked (fail without their fix). Full suite 240/240.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-29 22:12:13 -05:00
..
database.js fix(#146): reconnect/heartbeat storm containment (beta5) 2026-06-29 22:12:13 -05:00
schema.sql fix(#143): enforceable device block + fix the null-token auth short-circuit 2026-06-27 22:40:30 -05:00