Field-safe SERVER net. A device opening duplicate/rapid sockets (the APK duplicate-socket bug,
separate track) currently churns through evictions during the reconnect-throttle's 30s
post-restart WARM-UP (only the hard ceiling 20 applies then, so an 8-in-9s burst passes
undamped and each new socket evicts the prior). This makes the server absorb it: a thrashing
PAIRED device converges to ONE stable connection and stays online.
- lib/session-settle.js (decision only; bounded, swept): shouldHold(deviceId, incumbentAlive)
— true only when a socket was accepted for this device within SESSION_SETTLE_WINDOW_MS
(config, default 2500ms) AND the incumbent is alive. Warm-up-independent.
- deviceSocket register gate (just before evictPriorSocket): if a LIVE incumbent exists and
we're inside the window, SOFT-REFUSE the new socket (device:throttled reason=session_settle
+ disconnect) and keep the incumbent; else accept + evict + (re)arm the window.
- LIVENESS SAFEGUARD (load-bearing): only hold when the incumbent socket is actually in the
/device namespace — a dead/half-open incumbent is replaced, NEVER stranding the device (max
hold is the 2.5s window from the incumbent's accept, then any new socket is accepted).
- Soft refusal, NEVER a quarantine (reuses patch1's paired-safe philosophy); single-session
enforcement intact for a legitimate move; unpaired/abusive flapping still caught by the
existing limiters. O(1), no loop impact.
Tests (liveness first-class): live incumbent holds + DEAD incumbent replaced (not stranded);
storm of 6 sockets converges to ONE, stays online, not quarantined (during warm-up); single-
session move past the window replaces cleanly; unit decision + bounded sweep. The
evicted-socket-rearm test shrinks its settle window so it still exercises the eviction path.
Suite 336/336.
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>
