.tip

Jul 24, 2026 · one of the small things

A flaky test goes to quarantine the day it flakes

A test that fails one run in twenty teaches everyone to click retry, and then a real failure gets retried too. Move it out of the blocking suite the same day, with a ticket and an owner.

it.skip("…", …); // QUARANTINE: flaky since 2026-05-02, ENG-1840

Run the quarantine suite nightly so you can confirm the fix. If a test has been in quarantine for over a month, delete it.

testingengineering-practice

~/tips/today — 2026-10-19

~cat tips/today

Never build an index on a live table without CONCURRENTLY

postgresqlmigrations

A plain CREATE INDEX takes a lock that blocks every write to the table for the whole build. On a big table that means minutes of outage that look like a hung app.

CREATE INDEX CONCURRENTLY orders_customer_idx ON orders (customer_id);

It's slower and can't run inside a transaction, so you'll have to tell your migration tool. If it fails halfway, it leaves an invalid index behind, so check pg_index.indisvalid and drop it before you retry.

↵ open y yesterday l ls /tips

esc close