Hae Kyung Rhee, Ung Mo Kim

The Transactions of the Korea Information Processing Society (1994 ~ 2000), Vol. 6, No. 12, pp. 3447-3455, Dec. 1999
10.3745/KIPSTE.1999.6.12.3447,   PDF Download:

Abstract

Database correctness is guaranteed by standard transaction scheduling schemes like two-phase locking for the context of concurrent execution environment in which short-lived ones are normally mixed with long-lived ones. Traditional syntax-oriented serializability notions are considered to be not enough to handle in particular various types of transaction in terms of duration of execution. To deal with this situation, altruistic locking has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of altruism has also been deployed in extended altruistic locking in a way that scope of data to be early released is enlarged to include even data initially not intended to be donated. In this paper, we first of all investigated limitations inherent in both altruistic scheme from the perspective of alleviating starvation occasions for transactions in particular of short-lived nature. The idea of two-way donation lockig(2DL) has then been experimented to see the effect of more than single donation in distributed database systems. Simulation experiments shows that 2DL outperforms the conventional two-phase locking in terms of the degree of concurrency and average transaction waiting time under the circumstances that the size of long-transaction is in between 5 and 9.

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