Exploiting inheritance and structure semantics for effective clustering and buffering in an object-oriented DBMS

Abstract

Object-oriented databases provide new kinds of data semantics in terms of inheritance and structural relationships. This paper examines how to use these additional semantics to obtain more effective object buffering and clustering. We use the information collected from real-world object-oriented applications, the Berkeley CAD Group's OCT design tools, as the basis for a simulation model with which to investigate alternative buffering and clustering strategies. Observing from our measurements that real CAD applications exhibit high data read to write ratios, we propose a run-time clustering algorithm whose initial evaluation indicates that system response time can be improved by a factor of 200% when the read/write ratio is high. We have also found it useful to limit the amount of I/O allowed to the clustering algorithm as it examines candidate pages for clustering at run-time. Basically, there is little performance distinction between limiting reclustering to a few I/Os or many, so a low limit on I/O appears to be acceptable. We also examine, under a variety of workload assumptions, context-sensitive buffer replacement policies with alternative prefetching policies.

References

1. ATWO85 Atwood, T., "An Object Oriented DBMS for Design Support Applications," Proc. IEEE COMPINT 85, Montreal, Canada, (Sept 1985).
2. BATO85b Batory, D., W. Kim, "Supporting Versions of VLSI CAD Objects," M.C.C. Technical Report, Austin, TX, (1985).
3. CHAN87a Chang, E. E., IL H. Katz, "Inheritance in Computer- Aided Design Databases: Semantics and Implementation Issues," UCB Technical Report 87/377,(1987), Submitted for publication in CAD ./oumM.
4. CHAN87b Chang, E. E., D. Gedye, R. H. Katz, "The Design and Implementation of a Version Server for Computer-Aided Design Databases," Software Pmc~ and Experience, in press.
5. CHAN89 Chang, EE., "Effective Buffering and Oustering in Object-oriented Database Management Systems", Ph.D. Dissertation, May 1989.
6. HARR86 Harrison, David, P. Moore, R. Spickelmier, A.R. Newton, "Database Management and Graphics Editing in the Berkeley Design Environment", Proc. IEEE ICCAD, November 1986.
7. KATZ87 Katz, R. H., E. Chang, "Managing Change in a Computer-Aided Design Database," 13th Very Large Database Conference, Brighton, England, (Sept. 1987).
8. KATZ86a Katz, R. H., E. Chang, R. Bhateja, "Version Modeling Concepts for Computer-Aided Design Database," ACM SIGMOD Conf., Washington, DC, (May 1986).
9. KATZ86b Katz, R. H., E. Chang, M. Anwarrudin, "A Version Server for Computer-Aided Design Databases," ACM/IEEE 24th Design Automation Conf., Las Vegas, NV, (June 1986).
10. KIM87 Kim, Won, Jay Banerjee, Hong-Tai Chou, Jorge F. Garza, Dan'el Woelk, "Oomposite Object Support in an Object- Oriented Database System," Proc. OOPSLA'87 Conf., Orlendo, FL, (Oct. 1987).
11. MAIE86 David Maier, Jacob Stein, Allen Otis, Alan Putty, "Development of an Object-oriented DBMS," Technical Report CS/F_AVPO05, (April, 1986).
12. PAWS83 Information Research Associates, Austin Texas, 1983, "Performance Analyst's Workbench System (PAWS)".
13. ZDON84 Zdonik, S. B., "Object Management System Concepts," Proc. 2nd SIGOA Conf. on Office Information Systems, Toronto, Canada, (June 1984).

Index Terms

• Applied computing

  • Arts and humanities

    • Architecture (buildings)

      • Computer-aided design

  • Physical sciences and engineering

    • Engineering

      • Computer-aided design

• Information systems

  • Data management systems

    • Database management system engines

• Software and its engineering

  • Software notations and tools

    • General programming languages

      • Language features

        • Abstract data types

• Theory of computation

  • Semantics and reasoning

    • Program semantics