39 long-form articles on production engineering — how real systems fail, why, and what actually fixed them.
12 articles matching “SQL”
Production Incidents18 min read
It's 3 AM. Inserts are failing with 'Duplicate entry 2147483647' — but you never inserted a duplicate. Welcome to one of MySQL's most quietly famous outages.
Query Optimization5 min read
What happens when your index outgrows your data — and how we fixed it without downtime in production.
Production Incidents45 min read
A payment commits, the API returns 200, the rack loses power, and after recovery the row does not exist. Before blaming the database, six questions have to be separated.
Query Optimization13 min read
“We sold 3 tickets but only had 1.” The code is inside a transaction, looks right, works a hundred times locally, and only breaks in production under load.
Query Optimization13 min read
Every list endpoint ends in LIMIT 20 OFFSET ?. It has an index, page one returns in 8ms, and it passes review — then one Tuesday page 4,000 takes four seconds and a nightly export job stops finishing.
Architecture Decisions18 min read
Everyone can define read-your-writes consistency; far fewer can implement it on a master/replica cluster without melting the master.
Architecture Decisions20 min read
Every process you run will be told to stop — the only question is whether it gets a request it can act on or a bullet it never sees coming.
Query Optimization18 min read
Every team ships with the same lie: throw everything on the database and it'll handle correctness. Works at 50 writes/sec.
Schema Design14 min read
A plain-English walkthrough: how B-tree inserts actually work, what a page split costs, why random UUID v4 keys bloat the index by 2× and blow the buffer pool.
Schema Design12 min read
Why DELETE is the most expensive DML operation in a relational database — and why a simple UPDATE SET deleted_at = NOW() is 4-8x faster under concurrent load.
Query Optimization18 min read
A deep-dive into non-SARGable SQL with B-tree diagrams, real EXPLAIN output, and the exact rewrites — told through a gaming dashboard that went from 4,200ms to 2ms without touching the schema.
Production Incidents28 min read
A timeout is not a failure. Ten real ways idempotency keys break in payment systems — lost gateway responses, two tabs, racing retries, Redis evictions, expired keys, duplicate webhooks — with the fix for each, ten…