Accession Number:

ADA170092

Title:

Concurrency Control for Resilient Nested Transactions,

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s):

Report Date:

1986-01-01

Pagination or Media Count:

40.0

Abstract:

Concurrency control theory is extended to handle nested transactions with failures. The theory is used to present a rigorous correctness proof of a variant of Moss locking algorithm for implementing nested transactions. The proof has an interesting structure using many levels of abstraction. In the past few years, there has been considerable research on concurrency control, including both system design and theoretical study. The problem is roughly as follows. Data in a large centralized or distributed database is assumed to be assessible to users via transactions each of which is a sequential program which can carry out many steps accessing individual data objects. It is important that the transactions appear to execute atomically i.e., without intervening steps of other transactions. However, it is also desirable to permit as much concurrent operation of different transactions as possible, for efficiency. Thus it is not generally feasible to insist that transactions run completely serially. A notion of equivalence of executions is defined, where two executions are equivalent provided they look the same to all transactions and to all data objects. The serializable executions are just those which are equivalent to serial executions. One goal of concurrency control design is to ensure that all executions of transactions be serializable.

Subject Categories:

  • Theoretical Mathematics
  • Computer Programming and Software
  • Computer Hardware
  • Computer Systems
  • Cybernetics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE