Cluster keys go hand in hand with micro-partitions. It may not be evident that all object micro-partitions have a cluster key, but they do. Identifying the constituent attributes of an undeclared cluster key will prove difficult if not impossible to determine, but rest assured every micro-partition has a cluster key.
If you read the previous chapter, you have encountered some of the tooling used to identify micro-partitions counts and, as a side effect, will already have begun to gather some information about cluster ...
