#debugging

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Tracing an agent like a distributed system

An agent that runs for forty turns, calls twelve tools and talks to three models is a distributed system with one process. We spent two years learning to debug those with traces. OpenTelemetry's GenAI semantic conventions let you do the same here, and the first trace I looked at explained a bug that logs had hidden for a month.

observabilityai-agentsopentelemetry+1 more

May 19, 20268 min9 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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