Applying similarity in concurrency control for real-time database application
Most of the proposed concurrency control protocols for real-time database systems (RTDBS) are based on serializability theorem. Owing to the unique characteristics of real-time database applications and the importance of satisfying the timing constraints of the transactions, serializable concurrency control protocols are not suitable for RTDBS for most cases. In this paper, similarity, which is a less restrictive correctness criterion, is used for concurrency control in RTDBS, for instance, a stock trading database system. By studying the correctness requirements of the system, similarity is defined and incorporated into a real-time two phase locking protocol, High Priority Two Phase Locking (H2PL). With the use of similarity, although serializability is not ensured, the amount of inconsistency in the database is tolerable and is within the system requirements. On the other hand, the performance of the system can be much improved.
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