.tip

Jun 14, 2026 · one of the small things

An on-call agent gets one action, then a human

Autonomous systems usually fail through a chain of reasonable actions that add up. The restart didn't help, so scale up, then roll back, and now three things have changed. Let the agent take one action per incident, announced and picked from a fixed list. If that didn't clear the alert, a person decides what happens next.

ai-agentssre

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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