Category
9 posts
5 posts
Should a survey be "completed" or "expired"? Store the flag and it lies between updates; compute it on read and it is always true. A design for lifecycle derivation, assignee coverage, and the short-circuits that keep it fast.
Third-party webhooks expire, get orphaned by restarts, and miss events. A reconcile-loop design that converges desired vs. live state, plus deduplication by join URL and latches that remember deliberate exits.
What if a language model compiles a procedure once and never runs again? A skill compiler with hard structural gates, a zero-model interpreter that walks the graph in plain code, and a trust ladder that must be earned run by run.
Background jobs that run for minutes, pause for human answers, and survive restarts need more than a status column. A design for pausable, resumable, auditable background work: explicit states, a question channel, generation gates, and append-only logs.
Dense embeddings find paraphrases; full-text finds exact terms. How to run both legs concurrently and fuse their rankings with RRF — a simple formula that consistently beats either leg alone.
4 posts
The small but sharp security machinery behind an API endpoint: in-memory token buckets, peppered SHA-256 with constant-time comparison, and deterministic session namespacing.
iCalendar RRULE looks like a solved problem until INTERVAL=0 hangs your sweep, BYHOUR means the wrong hour across timezones, and legacy rows encode their whole schedule in one string. A field guide to doing it safely.
How to run a distributed scheduler on a single table: advisory-lock leader election, SKIP LOCKED work claiming, semaphore-style concurrency caps, and heartbeat reaping.
Two small algorithms that make a notification service boring in the best way: cursor pagination that cannot skip rows, and exactly-once-flavored dispatch built on a single SQL statement.