Maintaining dictionaries: Space-saving modifications of B-trees
It is known that the data structure of B-trees leads to an exhaustive waste of memory, when lengths of keys differ very much from each other. This effect may be fixed with appropriate modifications of (he data structure. We introduce a variant of B-trees, called B-trees with unfixed key length, and compare it to another variant of B-trees, introduced by T.H. Martin, which we call B-trees with bounded key length. Space efficiency of those two variants is evaluated for the worst case. However, the efficiency for the more realistic average case remains unknown. We believe that in many applications B-trees with unfixed key length are more efficient.
KeywordsWeight Function Hash Function Linear Order Internal Vertex Direct Descendant
Unable to display preview. Download preview PDF.
- 1.[K71]D.E. Knuth, “The Art of Computer Programming, vol. 3 (Sorting and Searching),” Addison-Wesley, Reading, MA, 1973.Google Scholar
- 2.[TF82]T.J. Teorey, D.P. Fry, “Design of Database Structures, vol. 2,” Prentice-Hall, Englewood Cliffs, NJ, 1982.Google Scholar
- 3.[W86]N. Wirth, “Algorithms and Data Structure,” Prentice-Hall, Englewood Cliffs, NJ, 1986.Google Scholar
- 4.R. Bayer, Symmetric binary B-trees: Data Structure and Maintenance Algorithms, Acta Inf. 14 (1972), 290–306.Google Scholar
- 5.R. Bayer, E. McCreight, Organization and Maintenance of Large Ordered Indexes, Acta Inf. 13 (1972), 173–189.Google Scholar
- 6.D. Comer, The Ubiquitous B-Tree, Comp. Surv. 11 2 (1979), 121–137.Google Scholar
- 9.T. Johnson, D. Shasha, Utilization of B-Trees with Inserts, Deletes, and Modifies, In Proceedings of the ACM Principles of Database Systems Symposium (1989), 235–244.Google Scholar
- 10.G. Manacher, S.L. Graham, Pagination of B * -Trees with Variable-Length Records, Commun. ACM 20 9 (1977), 670–674.Google Scholar
- 11.A.L. Rosenberg, L. Snyder, Time-and Space-Optimality in B-Trees, ACM Trans. Database Syst. 6 1 (1981), 174–193.Google Scholar
- 12.W.E. Wright, Some Average Performance Measure for the B-tree, Acta Inf. 21 (1985), 541–557.Google Scholar