.tip

Aug 25, 2026 · one of the small things

Temperature 0 for anything with a right answer

For classification, extraction, routing or a yes or no, sampling only adds variance, and your eval numbers wobble for no reason. At zero, the same input gives the same output, which is what a test needs.

Save temperature for generation, where variety is the point. Even there, going lower than the default is usually better for anything a customer reads.

ai-engineeringllm

~/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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