In Memory Database Recovery Issues

这是连续三年获奖的第一个奖项。 的 半导体存储器的尺寸增大和成本降低， 促使人们研究驻留在内存中的数据库。 这些内存数据库（MMDB）系统的目标是高 吞吐量应用例如航空预订系统， 电话交换数据库和其他真实的时间系统， 存储器驻留数据的可用性是至关重要的。 实现 这种具有易失性RAM的高可用性需要备份 将数据库归档到磁盘上，以及使用高效算法 将数据库设置为存档的检查点，并从 在系统故障后存档到主存储器。 已经表明 内存数据库系统在延迟更新时通常性能更好 技术，其中要更新的数据首先被放置在一个特殊的 非易失性阴影区域，并且仅在事务提交时， 放在主内存中。 作者正在调查这两个 使用MMDB数据库的检查点设置和重新加载 更传统的即时更新（IU）技术以及 延迟更新（DU）策略。 最佳检查点 方法将被确定为部分重新加载 战略布局 部分重新加载允许将数据库 联机后系统故障更快，因为不是所有的内存数据库 在启动系统之前重新加载。 本研究 代表了第一次检查的技术， 重新加载MMDB系统。 由于RAM的易失性， 内存数据库应用程序的高吞吐量需求，以及 部分重新加载以显著增加数据库的可扩展性 系统，本研究的结果和影响都是 广泛而重要。

This is the first of a three year continuing award. The increasing size and decreasing cost of semiconductor memory has prompted research into databases which are memory resident. These Main Memory DataBase (MMDB) systems are aimed at high throughput applications such as airline reservation systems, phone switching databases, and other real time systems where the availability of the memory resident data is crucial. To achieve this high availability with volatile RAM requires a backup archive database on disk as well as efficient algorithms to checkpoint the database to the archive and to recover it from the archive to main memory after a system failure. It has been shown that MMDB systems often perform better with deferred update techniques where data to be updated is first placed in a special nonvolatile shadow area and only at transaction commit time is placed in main memory. The authors are investigating both checkpointing and reloading of MMDB databases with the use of more conventional immediate update (IU) techniques as well as deferred update (DU) strategies. The best checkpointing approaches are to be determined as are partial reloading strategies. A partial reload allows the database to be brought online after a system failure faster because not all of the MMDB is reloaded prior to bringing the system up. This research represents the first examination of techniques for partial reloading of MMDB systems. Due to the volatility of RAM, the high throughput needs of MMDB applications, and the potential for partial reloading to dramatically increase the uptime of database systems, the results and impact of this research are both widespread and significant.