This Article 
 Bibliographic References 
 Add to: 
Estimating Block Accesses in Database Organizations
June 1994 (vol. 6 no. 3)
pp. 497-499

The exact expression for the expected number of disk accesses required to retrieve a given number of records, called the Yao function, requires iterative computations. Several authors have developed approximations to the Yao function, all of which have substantial errors in some situations. We derive and evaluate simple upper and lower bounds that never differ by more than a small fraction of a disk access.

[1] J. Bradley,File and Database Techniques. New York: Holt, Rinehart and Winston, 1981, pp. 108-110.
[2] A. Cardenas, "Analysis and performance of inverted data-base structures,"Commun. ACM, vol. 18, no. 5, pp. 253-263, 1975.
[3] T. Cheung, "Estimating block accesses and number of records in file management,"Commun. ACM, vol. 25, no. 7, pp. 484-487, July 1982.
[4] L. F. Mackert and G. M. Lohman, "Index scans using a finite LRU buffer: A validated I/O model,"ACM Trans. Database Syst., vol. 14, no. 3, pp. 401-424, Sept. 1989.
[5] D. Severance, "Differential files: their application to the maintenance of large databases,"ACM Trans. Data Base Syst., vol. 1, pp. 256-267, 1976.
[6] S. J. Waters, "Hit ratios,"Comput. J., vol. 19, pp. 21-24, 1976.
[7] K. Whang, G. Wiederhold, and D. Sagalowicz, "Estimating block accesses in database organizations: A closed noniterative formula,"Commun. ACM, vol. 26, no. 11, pp. 940-944, Nov. 1983.
[8] S. B. Yao, "Approximating block accesses in database organizations,"Commun. ACM, vol. 20, pp. 260-261, Apr. 1977.

Index Terms:
database management systems; file organisation; errors; performance evaluation; database theory; block access estimation; database organization; disk accesses; record retrieval; Yao function; iterative computations; approximation; errors; upper bound; lower bound; access path selection; physical database design; performance estimation
G. Diehr, A.N. Saharia, "Estimating Block Accesses in Database Organizations," IEEE Transactions on Knowledge and Data Engineering, vol. 6, no. 3, pp. 497-499, June 1994, doi:10.1109/69.334866
Usage of this product signifies your acceptance of the Terms of Use.