#reliability

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Every LLM feature needs a kill switch

A model provider had a bad Tuesday, and our summarisation feature spent four hours returning empty strings to customers because nothing between the API and the user knew what to do with a 529. The feature now has a kill switch, a fallback, a budget and a canary. Without those four it was a demo.

llmreliabilityfeature-flags+1 more

Jun 16, 202610 min13 min

~/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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