关键词: 数据库系统, 嵌套事务, 故障恢复, 日志模式

Abstract: Aiming at the characteristics of nested transactions, a novel failure recovery mode supporting the nested real-time transaction model was presented. Compared to the traditional recovery mode, log record type and structure were improved in the proposed recovery mode to better adapt to the characteristics of nested transactions and the timing constraint requirement of temporal data. On the allocation policy of log buffer, concurrent nested real-time transactions were allocated to independent active log areas, therefore the performance bottleneck caused by severe contention for the current log buffer page in the sequential log mode was solved. On the basis of guaranteeing the continuity of committed transactions, the recovery-processing algorithm after failures was optimized by selecting starting point and execution sequence of Redo to enhance the recovery performance to the largest extent. Performance test showed that the proposed recovery mode had better real-time performance than the traditional one.

Key words: database systems, nested transaction, failure recovery, log mode