Hot partitions and uneven key distribution are common—and they quietly cap throughput. This session breaks down how purposeful partitioning (entity‑affinity keys, composite keys, and targeted salting) plus tuned producer configs (batch.size, linger.ms, acks, idempotent producers) reduced consumer lag by ~30% in a high‑throughput pipeline. We’ll align partition strategy with consumer concurrency, discuss sticky vs uniform distribution, and show practical skew detection (per‑partition lag, heatmaps) and mitigation (pre‑partitioning, re‑keying). You’ll leave with a field‑tested checklist to diagnose hotspots, tune batching, and roll out changes safely without thundering herd rebalances.