- /api/ai/ask: at most AI_MAX_CONCURRENT_PER_WORKER (12 of 32 threads) answers per worker;
beyond that 503 assistant_busy + Retry-After before any quota is reserved. Without it a
burst of questions (3-40 s each) took every thread and the map and quizzes queued behind.
The slot is held until the stream is actually finished or closed.
- Answer submission 21 -> 14 queries, 15.4 -> 11.0 ms: one query for all choices, locked
get_or_create for node progress and streak, and today's streak recorded once per day
via the cache instead of a transaction per answer.
- /api/home 12.4 -> 8.6 ms: the user's completions are read by user_id instead of an IN list
of ~600 lesson ids; the dict is returned directly (serializer stays the Swagger contract,
HomeMatchesItsSerializerTests keeps them equal).
- otp_login per-IP 30 -> 300/hour: a class of 30 on one school Wi-Fi filled it; guessing is
bounded per code and per phone.
- /api/health aiConcurrency.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
activeToday: activity recorded today (Tehran date). lost: length of a streak that broke (last active day
before yesterday), so the app can show it frozen. Same rule as effective_current_streak; the weekly report
keeps its own two-field streak serializer.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Found in a deeper pass over what the frontend's flow actually touches:
- Nothing in the app ever wrote StreakRecord: "days in a row" was 0 forever
for every real user. Answers and lesson/island completions now record the
day (Tehran time); a broken chain shows 0. A streak error never fails the
answer itself.
- /api/leaderboard only changed when someone ran rebuild_leaderboard by
hand. It is now computed live (60s cache); weekly counts island XP too.
- gunicorn ran 3 sync workers with a 30s timeout, so every "ask Pi" stream
pinned a whole worker (~10s, GapGPT buffers the answer) and three at once
queued the entire API. gunicorn.conf.py (read automatically from the
working directory) switches to gthread, 8 threads, 120s timeout.
- Every /api/ response now says Cache-Control: private, no-store, so turning
on caching in the ArvanCloud panel can never serve one student another's data.
- /api/user/summary named no active plan ever ("subscription app not
implemented yet" had long stopped being true).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
