Abstract
Sequentiality of access is an inherent characteristic of many database systems. We use this observation to develop an algorithm which selectively prefetches data blocks ahead of the point of reference. The number of blocks prefetched is chosen by using the empirical run length distribution and conditioning on the observed number of sequential block references immediately preceding reference to the current block. The optimal number of blocks to prefetch is estimated as a function of a number of “costs,” including the cost of accessing a block not resident in the buffer (a miss), the cost of fetching additional data blocks at fault times, and the cost of fetching blocks that are never referenced. We estimate this latter cost, described as memory pollution, in two ways. We consider the treatment (in the replacement algorithm) of prefetched blocks, whether they are treated as referenced or not, and find that it makes very little difference. Trace data taken from an operational IMS database system is analyzed and the results are presented. We show how to determine optimal block sizes. We find that anticipatory fetching of data can lead to significant improvements in system operation.
- 1 AHo, A.V,, DENNING, P.J., AND ULLMAN, J.D. Principles of optimal page replacement. J. ACM 18, 1 (Jan. 1971), 80-93. Google ScholarDigital Library
- 2 BAER, J.L., AND SAGER, G.R. Dynamic improvement of locality in virtual memory systems. IEEE Trans. Software Eng. SE-2, 1 (March 1976), 54-62.Google ScholarDigital Library
- 3 BARD, Y. Characterization of program paging in a time-sharing environment. IBM J. Res. Develop. 17, 3 (Sept. 1973), 387-393.Google ScholarDigital Library
- 4 COrtBATO, F.J. A paging experiment with the Multics system. In In Honor of P.M. Morse, M.I,T. Press, Cambridge, Mass., 1969, pp. 217-228.Google Scholar
- 5 DATE, C.J. An Introduction to Data Base Systems. Addison-Wesley, Reading, Mass,, 1975. Google ScholarDigital Library
- 6 DENNING, P.J. The working set model for program behavior. Comm. ACM I1, 5 (May 1968), 323-333. Google ScholarDigital Library
- 7 GAV~,R, D.P., LAVENBERG, S.S., AND PRICE, T.G. JR. Exploration analysis of access path length data for a data base management system. IBM J. Res. Develop. 20, 5 (Sept. 1976), 449-464.Google Scholar
- 8 GOLD, D.E., AND KUCK, D.J. A model for masking rotational latency by dynamic disk allocation. Comm. ACM 17, 5 (May 1974), 278-288. Google ScholarDigital Library
- 9 HELD, G.D., STONEBRAKER, M.R., AND WON(}, E. INGRES--a relational data base system. Proc. AFIPS 1975 NCC, AFIPS Press, Montvale, N.J., pp. 409-416.Google Scholar
- 10 IBM CORP. Information Management System/360, Version 2, General information Manual. Form GH20-0765-3, IBM Corp. Tech. Pub. Dept., Palo Alto, Calif., 1973.Google Scholar
- 11 IBM CORP. Information Management System/360, Version 2, Application Programming Reference Manual. Form SH20-0912, IBM Corp., Palo Alto, Calif., Nov. i973.Google Scholar
- 12 IBM CORP. Information Management System/360, Version 2, System Programming Reference Manual. Form SH20-0911, IBM Corp., Palo Alto, Calif., Sept. 1974.Google Scholar
- 13 JOSEPH, M. An analysis of paging and program behavior. Comptr. J. 13, 1 (Feb. 1970), 48-54.Google ScholarCross Ref
- 14 LAVENBERG, S.S., AND SCHEDLER, G,S. A queueing model of the DL/I component of IMS. Res. Rep. RJ 1561, IBM Res. Lab., San Jose, Calif., April 1975. Republished as {15}.Google Scholar
- 15 LAVENBERC, S.S., AND SHEDLER, G.S. Stochastic modelling of processor scheduling with application to data base management systems. IBM J. Res. Develop. 20, 5 (Sept. 1976), 437-448.Google Scholar
- 16 LEwis, P.A.W., ANt) Sn~.DLErt, G.S. Statistical analysis of transaction processing in a data base system. Res. Rep. RJ 1629, IBM Res. Lab., San jose, Calif., Sept. 1975. Republished as: Statistical analysis of non-stationary series of events in a data base system. IBM J. Res. Develop. 20, 5 (Sept. 1976), 465-482.Google Scholar
- 17 MATTSON, R., GECSEI, J., SLUTZ, D.R., AND TRAIGER, I.L. Evaluation techniques for storage hierarchies. IBM Syst. J. 2 (I970), 78-117. Google ScholarDigital Library
- 18 RAGAZ, N., AND RODRIGUEZ-ROSELL, J. Empirical studies of storage management in a data base system. Res. Rep. RJ 1834, IBM Res. Lab., San Jose, Calif., Oct. 1976.Google Scholar
- 19 RITCHIE, D.M., AND THOMPSON, K. The UNIX time-sharing system. Comm. ACM 17, 7 (July 1974), 365-375. Google ScholarDigital Library
- 20 RODRIGUEZ-ROSELL, J. Empirical data reference behavior in data base systems. Computer 9, 11 (Nov. 1976), 9-13.Google ScholarDigital Library
- 21 RODR{GUEZ-ROSELL, J., AND HILDEBRAND, D. A framework for evaluation of data base systems. Res. Rep. RJ 1587, IBM Res. Lab., San Jose, Calif., May 1975. Also in Proc. Int. Comput. Syrup., Antibes, France, June 1975.Google Scholar
- 22 SMITH, A.J. A locality model for disk reference patterns. Proc. IEEE Comptr. Soc. Conf., San Francisco, Feb. 1975, 109-112.Google Scholar
- 23 SMITH, A.J. Analysis of a locality model for disk reference patterns. Proc. Second Conf. Inform. Sci. and Syst., Johns Hopkins U., Baltimore, Md., April 1976, 593-601.Google Scholar
- 24 SMITH, A.J. Sequential program prefetching in memory hierarchies. April 1977; submitted for publication. To appear, Computer.Google Scholar
- 25 TRIVEDI, K.S. Prepaging and applications to array algorithms. IEEE Trans. Comptrs. C-25, 9 (Sept. 1976), 915-921.Google ScholarDigital Library
- 26 TRIV}~DI, K.S. Prepaging and applications to the STAR-100 computer. Proc. Symp. High Performance Comptr. and Algorithm Organization, Champaign, Ill., April 1977.Google Scholar
- 27 TRIVF.DI, K.S. An analysis of prepaging. Comptr. Sci. Rep. CS-1977-7, Duke U., Durham, N.C., Aug. 1977.Google Scholar
- 28 TRIVED1, K.S. On the paging performance of array algorithms. IEEE Trans. Comptrs. C-26, i0 (Oct. 1977), 938-947.Google ScholarDigital Library
- 29 TUgL, W.G. JR. An analysis of buffer paging in virtual storage systems. Res. Rep. RJ 1421, IBM Res. Lab., San Jose, Calif., 1974.Google Scholar
- 30 TU~L, W.G. Jm, AN~ RODamUEZ-ROSELL, J. A methodology for the evaluation of data base systems. Res. Rep. RJ 1668, IBM Res. Lab., San Jose, Calif., Oct. 1975.Google Scholar
Index Terms
- Sequentiality and prefetching in database systems
Recommendations
Stealth prefetching
Proceedings of the 2006 ASPLOS ConferencePrefetching in shared-memory multiprocessor systems is an increasingly difficult problem. As system designs grow to incorporate larger numbers of faster processors, memory latency and interconnect traffic increase. While aggressive prefetching ...
Stealth prefetching
ASPLOS XII: Proceedings of the 12th international conference on Architectural support for programming languages and operating systemsPrefetching in shared-memory multiprocessor systems is an increasingly difficult problem. As system designs grow to incorporate larger numbers of faster processors, memory latency and interconnect traffic increase. While aggressive prefetching ...
Stealth prefetching
Proceedings of the 2006 ASPLOS ConferencePrefetching in shared-memory multiprocessor systems is an increasingly difficult problem. As system designs grow to incorporate larger numbers of faster processors, memory latency and interconnect traffic increase. While aggressive prefetching ...
Comments