The materialized art update rewrote every artist row on every library-changing sync. That fired the FTS5 content-sync triggers for each artist, which was the real cost: the same SQL is ~10ms with the triggers removed and ~4.7s for 100 changed artists with them in place. Only update rows whose cover lists actually changed, and replace the generated artist search triggers with UPDATE OF name, sortName so art-only writes never touch the FTS index. Existing databases get this through migration 36->37; fresh databases get it from the onCreate callback.
Room's statement cache resets a statement when returning it to the cache, so starting the timer at reset counted idle time in the cache and reported normal queries as tens of seconds. Start timing on the first step instead, and finish on the completing step. Also downgrade Room @Upsert uniqueness-conflict errors (its insert-then-catch-then-update control flow) from ERROR to DEBUG, and log successful HTTP requests at VERBOSE so debug logs aren't flooded by cover-art requests.
Never let a log-write or export failure reach the uncaught handler: wrap the async writer and crash path, synchronize export with rotation, and tolerate vanished files. Redact the Logcat stack-trace copy, stop leaking rows=0 on writes, shut down the previous writer on re-init, and drop unused API. Strengthen tests for the batched write path, rotation count and throwable redaction.
Capture logs to rotating app-private files with Subsonic credential and URL basic-auth redaction, mirror to Logcat, and capture uncaught crashes. Log slow SQL (>100ms), SQL errors, migrations and DB lifecycle via a decorating SQLiteDriver. Add a Send logs row in Settings that zips the logs and opens the share sheet through a FileProvider.
austinried