A study of the behavior of the read: Write ratio under two-phase locking schemes

摘要

A number of synchronization techniques have been proposed for managing the concurrent execution of transactions. The performance study of these mechanisms has been done mainly with update transactions but the behavior of read-only transactions and the effect of read: write ratio have not been looked at in depth. Since the effect of read-only transactions and read: write ratios seems significant we have employed detailed and realistic simulation models of two two-phase locking schemes to study the behavior of read-only transactions and the effect of read: write ratios on several aspects of database systems. We report that the effect of read: write ratio is not as global as usually expected. We show that it is not the write-only transactions but the read-only transactions that require special treatment for achieving improved throughput.