queues – Page 4 – Türker Yıldırım

At-least-once, and the consumer that had to say so

NoteFebruary 14, 20232 min read

Every broker worth using delivers at least once, and every consumer that does not say how it handles that is claiming something it has not checked. Writing the…

A dead letter queue with an owner

NoteFebruary 2, 20232 min read

A dead letter queue that nobody owns is a queue where messages go to be forgotten, and ours had 8,000 of them. Owning a dead letter queue means…

The webhook we sent, and the retries we owed

Deep diveDecember 7, 202210 min read

Being the sender, for the first time, and the obligations that come with it. A customer endpoint that was down for six hours.

Natural idempotency, and when no claim table is needed

NoteNovember 16, 20221 min read

Some operations are safe to repeat by construction, and recognising them saves a table and a transaction. Setting a value is safe and adjusting one is not, which…

A queue worker that scales on the metric that matters

Deep diveNovember 9, 202210 min read

Six workers, always, whether there is work or not. A backlog at 09:00 and idle capacity at 03:00.

An idempotent consumer for a broker that redelivers

Deep diveNovember 8, 202210 min read

A message processed twice, and a customer charged twice. At-least-once delivery, treated as exactly-once by the handler.

A cache invalidation bug that only appeared under load

Deep diveOctober 17, 202210 min read

Correct in every test, wrong for about one request in four thousand. A read that races a write, and a cache that keeps the loser.

OpenTelemetry when the PHP SDK is still beta

Deep diveSeptember 20, 202210 min read

The traces specification is 1.0 and the PHP implementation is not. Three tracing formats and a vendor decision nobody wants to make.

Trace context across a queue is carried, never ambient

NoteSeptember 19, 20222 min read

A queue is a process boundary, so the trace context has to travel on the message or the trace ends at the dispatch. The W3C traceparent format is…

The scale-down that kills a job mid-flight

NoteSeptember 15, 20222 min read

An autoscaler removing a worker sends a termination signal, and a worker that does not handle it loses whatever it was doing. Scaling down is the case nobody…