“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.
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.
We're trained to demand our data structures be correct — so here's one that's wrong on purpose, and runs inside Cassandra, RocksDB, Bigtable, most CDNs, and your browser's malware check.
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.