At 50,000 inserts per second, a skewed partition key can route 40,000 of them into a single partition. That one partition throttles your entire write path while the other 199 sit idle. This happens constantly in field telemetry. Teams partition by the column they already filter on, which in oilfield platforms usually means well_id, pad_id, or asset_id. The schema looks correct. Storage looks balanced. Then p95 write latency drifts from 8ms to 25ms over six weeks and every other metric reads healthy. This session shows you how to find it and fix it. We run the diagnostic against a partitioned tag table, identify the hot partition by dead tuple ratio and index bloat, and then walk through two schema-level fixes. You leave with queries you can run against your own largest table today.