Bram Verhoeven

Blameless review: the 'quick' migration that blocked every write to our orders table

Short incident review, because the lesson is more useful than the embarrassment. What happened A normal Tuesday deploy at 08:12 ran two migrations generated by our migration tool: ALTER TABLE orders ADD COLUMN priority int NOT NULL DEFAULT 0; CREATE INDEX orders_priority_idx ON orders (priority); Both look harmless. Since Postgres 11, adding a column with a constant default does not rewrite the table, so the ALTER…

Visited a client abroad. Their "cycle lane" was white paint on a 4-lane road that ended at a bus stop. Paint is not infrastructure. Paint is a suggestion. In 1975 Utrecht was also full of cars. It was a choice to change. Every city can make it. Most choose parking.

Kotlin coroutines in a Spring service: three leaks we shipped and what structured concurrency fixed

We run our routing service in Kotlin on Spring Boot. Coroutines were introduced two years ago by enthusiastic people, including me. Here are the three mistakes we made, all of them explained in the kotlinx.coroutines docs, which none of us had read properly. Hence the topic. 1. GlobalScope for fire-and-forget fun ship(order: Order) { GlobalScope.launch { auditClient.record(order.id, "shipped") }…

What is your main production database? No 'it depends', pick one.

The index that made our query slower, and other things EXPLAIN ANALYZE told me

Short version: someone added an index "because we order by that column", and the dispatcher dashboard went from 40 ms to 9 seconds for our smallest depots. The someone was me. I found out on the bike home, which is 14 km, which is enough time to stop being angry at yourself. The query SELECT id, reference, created_at FROM shipments WHERE depot_id = 42 AND status = 'pending' ORDER BY created_at DESC LIMIT 50;…

I go to the office for the bike, not for the office

Every few weeks there is a remote vs office fight in this topic. I want to give a different answer. I go to the office three days a week. Not because of the office. Because of the bike. Context. I live in Utrecht, the office is in an industrial area at the edge of the city, 14 km. I go with the bike. 35 to 40 minutes depending on wind, most of it on a separate fietspad next to a canal. It is boring. That is the…