Cold-start dashboard responsiveness went from ~99s to ~6-11s. CPU profiling
identified two synchronous-spawn hotspots blocking the event loop:
- `GitHubTrackingReconciler` scanned up to 200 done tasks per startup,
each call into `getIssue` invoking `isGhAvailable()` + `isGhAuthenticated()`
via `execFileSync`. `gh auth status` makes a network roundtrip, so 400
sync spawns ≈ 71s of pure event-loop blocking (69% of cold-start CPU).
Memoized both checks with a 60s TTL; `resetGhAvailabilityCache()` is
exported for login/logout flows that need immediate invalidation.
- `PRAGMA integrity_check(100)` walks every page of the SQLite file (~7s
per database, multiple DBs × projects). The deferred check was scheduled
3s after init — right in the responsiveness-critical window. Pushed to
60s so the user is already interacting before it runs; check itself is
unchanged.
Also yields the event loop between major InProcessRuntime init phases and
between self-healing recovery steps (34 per project), defers orphan-task
AI agent resumption by 30s (env-overridable, auto-zero under Vitest), and
ships an opt-in `FUSION_TRACE_EL_LAG=/path/to/file` event-loop lag tracer
that diagnosed all of the above.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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