What is primary and secondary clustering in hash?

Question

I am confused for the last few days in finding the difference between primary and secondary clustering in hash collision management topic in the textbook I am reading.

Answer 1

Primary clustering means that if there is a cluster and the initial position of a new record would fall anywhere in the cluster the cluster size increases. Linear probing leads to this type of clustering.

Secondary clustering is less severe, two records do only have the same collision chain if their initial position is the same. For example quadratic probing leads to this type of clustering.