secondary clustering


Definition: The tendency for some collision resolution schemes to create long run of filled slots away from a key hash position, e.g., along the probe sequence.

See also primary clustering, clustering free, hash table, open addressing, clustering, linear probing, quadratic probing, double hashing, uniform hashing.

Note: Secondary clustering increases average search time. Even quadratic probing is susceptible to secondary clustering since keys that have the same hash value also have the same probe sequence. Clustering may be minimized with double hashing.

Author: PEB

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Entry modified 18 July 2005.
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Cite this as:
Paul E. Black, "secondary clustering", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 18 July 2005. (accessed TODAY) Available from: