An Optimistic Cache Consistency Protocol Using Preemptive Approach

SungHo CHO  Jeong-Hyon HWANG  Kyoung Yul BAE  Chong-Sun HWANG  

IEICE TRANSACTIONS on Information and Systems   Vol.E83-D   No.9   pp.1772-1780
Publication Date: 2000/09/25
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Databases
cache consistency protocol,  optimistic two-phase locking,  re-ordering scheme,  system performance modeling,  

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In Optimistic Two-Phase Locking (O2PL), when a transaction requests a commit, the transaction can not be committed until all requested locks are obtained. By this reason, O2PL leads to unnecessary waits and operations even though it adopts an optimistic approach. This paper suggests an efficient optimistic cache consistency protocol that provides serializability of committed transactions. Our cache consistency scheme, called PCP (Preemptive Cache Protocol), decides whether to commit or abort without waiting when transactions request commits. In PCP, some transactions that read stale data items can not be aborted, because it adopts a re-ordering scheme to enhance the performance. In addition, for re-ordering, PCP stores only one version of each data item. This paper presents a simulation-based analysis on the performance of PCP with other protocols such as O2PL, Optimistic Concurrency Control and Caching Two-Phase Locking. The simulation experiments show that PCP performs as well as or better than other schemes with low overhead.