Real-Time Systems

, Volume 19, Issue 3, pp 283–302

Improving Predictability of Transaction Execution Times in Real-time Databases

  • Rajeev Rastogi
  • S. Seshadri
  • Philip Bohannon
  • Dennis Leinbaugh
  • Avi Silberschatz
  • S. Sudarshan
Article

DOI: 10.1023/A:1008143228351

Cite this article as:
Rastogi, R., Seshadri, S., Bohannon, P. et al. Real-Time Systems (2000) 19: 283. doi:10.1023/A:1008143228351

Abstract

We present a design for multi-versionconcurrency control and recovery in a main memory database, anddescribe logical and physical versioning schemes that allowread-only transactions to execute without obtaining data itemlocks or system latches. Our schemes enable a system to providethe guarantee that updaters will never interfere with read-onlytransactions, and read-only transactions will not be delayeddue to data contention. Consequently, transaction executionsbecome more predictable—this partially alleviates a majorproblem in real-time database system (RTDBS) scheduling, namely,significant unpredictability in transaction execution times.As a result, in addition to a transaction's deadline, a moreaccurate estimate of its execution time can also be taken intoaccount, thus facilitating better scheduling decisions. Our contributionsinclude several space saving techniques for the main-memory implementation,including improved methods for logical aging of data items andthe introduction of physical aging for low-level structures.Some of these schemes have been implemented on a widely-usedsoftware platform within Lucent, and the full scheme is implementedin the Dalí main-memory storage manager.

transactionsversioningconcurrency-controlagingconsistencylockingtimestampsdeadlines

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • Rajeev Rastogi
    • 1
  • S. Seshadri
    • 1
  • Philip Bohannon
    • 1
  • Dennis Leinbaugh
    • 1
  • Avi Silberschatz
    • 1
  • S. Sudarshan
    • 2
  1. 1.Bell LaboratoriesMurray Hill
  2. 2.Computer Science and Engineering Dept.Indian Institute of TechnologyBombayIndia