pysqlite's legacy mode emitted BEGIN only at the first DML, so every read
before it ran outside any transaction and a lock wait surfaced as "database is
locked" at an arbitrary later statement; place_bet also mistook that error for
a write-snapshot conflict, which SQLite cannot produce.
- _register_sqlite_pragmas: synchronous=FULL, isolation_level=None and a
`begin` event that emits BEGIN / BEGIN IMMEDIATE.
- begin_immediate(session): takes the write lock before the first read; called
first thing in place_bet, request_withdrawal, the scheduler transitions,
_trigger_payout, the confirmation poller, the reconciler, bump_fee's persist
phase, deposit crediting / external-spend marking / reinstating, and the
derivation-index allocation at registration.
- A lock not granted before a broadcast answers service_busy (503, all seven
languages), nothing built or sent; after a broadcast nothing is undone, the
rows stay `building` for the reconciler.
- Spec, storico, BUGS.md and CLAUDE.md updated; 37 new tests on a real file DB.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
create_async_engine had no connect_args and there was no PRAGMA
anywhere in the repo. SQLite's default rollback-journal mode lets a
writer block every reader for the duration of its transaction, and a
second writer arriving while one is already active fails immediately
with "database is locked" rather than waiting at all - realistic given
five concurrent background tasks (scheduler, confirmation poller, RBF
bumper, two reconcilers) plus every HTTP handler share one file, and
nothing previously handled that error.
app/db/base.py now registers a "connect" event on the engine that sets
journal_mode=WAL, synchronous=NORMAL and a 5-second busy_timeout on
every new DBAPI connection - applied only when the dialect is sqlite,
so a future PostgreSQL DATABASE_URL is unaffected. WAL lets readers and
writers proceed without blocking each other, and busy_timeout gives a
second writer a real window to wait instead of failing instantly.
Left out: an explicit application-level retry wrapper for "database is
locked" in the background loops, the other half of the proposed fix -
busy_timeout already gives SQLite itself several seconds to resolve
writer-vs-writer contention before ever raising, and every background
loop already catches and logs an unhandled exception before its next
scheduled tick, which is itself a retry, just not an immediate one.
Suite grows from 211 to 214 tests. BUGS.md moves B-39 to Previously
fixed.
davideandClaude Sonnet 5.5