Design And Implementation Of Multi - Machine Hot Backup Memory Database

This paper is about the self-developed product of compact in-memory database. The purpose of this product is to meet enterprise customers’ requirement on database real-time response performance and cost concern.Traditional database management system puts all the data on the disk, so called disk database(DRDB: Disk Resident Database). The characteristic of databases is frequent disk access. The disk database is under challenge now regarding real-time performance. The main reason is the nature that disk reading and writing needs disk headers’ mechanical movement, meanwhile the real-time performance is also impacted by system IO lead-time. Although there are some commercial in-memory database products show good performance in many aspects, there is till restriction. For example high cost, opaque memory structures which prevents from the approach of "direct access to the contents". In ICT industry, a compact and high efficient database is also demanded with acceptable cost. This is the trigger point of this paper. In recent years, there are positive changes to support in-memory database such as increasing memory capacity, falling prices, larger memory address space supported by 64-bit operating system, meanwhile the requirement on database technology starts to show strong trend about real-time response performance. These factors support the implementation of this proposed software system. The advantage of in-memory database system is not only faster reading and writing than disk database but also creating an innovative way to manage data. The in-memory database system utilizes new database architect, faster algorithm, combining cache technology and new way of concurrent operation handling. As a result, the speed improves significantly comparing to traditional database. Generally more than 10 times, the ideal case even up to 1000 times. During working on the paper and software development, I studied various in-memory database technologies and finally an in-memory database is made based on C/S structure. Some advanced algorithms are used in this development, such as "consistency of the hash", "Quorum NRW", "Vector clock". JAVA language is utilized to develop the in-memory database system. The multi-threat feature of JAVA provides a good support during the implementation.