.tip

Aug 28, 2026 · one of the small things

A test that fails for more than a day gets fixed or deleted

Nobody trusts a suite that's 91 percent green, and a suite nobody trusts has stopped doing its job. Either the test is wrong and it goes, or the code is wrong and gets fixed. "We'll look at it later" is how you end up with the other 9 percent.

testingengineering-practice

Longer version: the post this came from.

~/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

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