Optimizes polling for large Immich albums (tested path targets ~200k
assets). Combined impact on idle albums drops per-tick cost from ~150 MB
fetch to ~few hundred bytes; active albums fetch O(changes) instead of
O(library).
Core changes
- ImmichAlbumMeta + get_album_meta() using ?withoutAssets=true as a
cheap change-detection probe.
- poll() fast-path: skip full fetch when meta fingerprint matches and
no pending assets are outstanding.
- poll() delta-path: search/metadata with updatedAfter when fingerprint
changed, falling back to full fetch on count decrease or mixed
add+remove that delta can't reconcile.
- asyncio.gather over meta probes so a 20-album tracker pays one
round-trip of latency instead of 20.
- Event payload cap (50 added / 200 removed) so a bulk import can't
explode a Jinja template or exceed Telegram's message limits.
- Module-level users cache (1h TTL, sha256-keyed) shared across
providers on the same Immich server.
- Tick-scoped shared-links cache via new
get_all_shared_links_by_album() — one /api/shared-links request per
tick instead of one per changed album.
Server changes
- meta_fingerprint JSON column on NotificationTrackerState + migration.
- watcher skips the asset_ids DB rewrite when the fingerprint didn't
change, avoiding ~8 MB JSON writes on idle ticks for huge albums.
- Adaptive polling: after 10 empty ticks skip 1-in-2, after 30 skip
1-in-4, reset on first detected change; resets on schedule changes.
- APScheduler jitter (interval/4, capped at 30s) to smooth thundering-
herd bursts when many trackers share the same scan_interval.
alexei.dolgolyov
fe38d20b96