Mathematical studies on a transaction's waits and deadlocks in a 2pl environment

Abstract

The “straw man” analysis is based on the assumption that the accessible unit and locking unit are both a record occurrence (or a tuple); consequently the results cannot be applied when a locking unit is a large granule such as an area, a file, an index (or a data) block. In this study, the probabilities of a transaction's waits and deadlocks are derived when the accessible unit is a data object and the locking unit is a granule. The results can be used to explain a transaction's wait and deadlock situations for (1) various sizes of a granule and (2) different distributions of data objects accessed by a transaction. To determine the degree of consistency between a theoretical result and an experimental test, a simulation model is set, and the experimental results are nearly consistent with the probabilistic model.

Keywords:

• Concurrency control
• locking
• deadlocks
• probabilistic analysis

C.R. Categories:

• H.2.4

^∗To whom correspondence shall be addressed.

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Notes

^∗To whom correspondence shall be addressed.