Term Kind Topic What it is
Key Skew concept Partition Keys & Ordering An uneven distribution of records across partitions, which caps throughput at the busiest partition regardless of how many exist.
Partition Count Immutability Fixed Partition Count, Key-to-Partition Remap Hazard concept Partition Keys & Ordering The partition count of a keyed log is effectively permanent, because raising it changes which partition a key hashes to and therefore breaks per-key ordering and every table rebuilt by replaying that log.
Partition Key Skew Hot Partition, Key Skew concept Partition Keys & Ordering One partition receiving disproportionate traffic because a small number of key values dominate, capping throughput at what a single consumer can handle.