A Real-Time Locking Protocol

Lui Sha, Ragunathan Rajkumar, Sang Hyuk Son, Chun Hyon Chang

Research output: Contribution to journalArticlepeer-review


When a database system is used in a real-time application, the concurrency control protocol must not only satisfy the consistency of shared data but also observe the priorities of the transactions. This is because priority scheduling is a commonly used method. In this paper, we examine a prioritydriven two-phase lock protocol called the read/write priority ceiling protocol. We show that this protocol leads to freedom from mutual deadlock. In addition, a high-priority transaction can be blocked by lower priority transactions for at most the duration of a single embedded transaction. These properties can be used by schedulability analysis to guarantee that a set of periodic transactions using this protocol can always meet their deadlines. Finally, we examine the performance of this protocol for randomly arriving transactions using simulation studies.

Original languageEnglish (US)
Pages (from-to)793-800
Number of pages8
JournalIEEE Transactions on Computers
Issue number7
StatePublished - Jul 1991
Externally publishedYes

ASJC Scopus subject areas

  • Software
  • Theoretical Computer Science
  • Hardware and Architecture
  • Computational Theory and Mathematics


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