嵌入式内存数据库崩溃恢复研究(IJWMT-V2-N5-6)

Crash Recovery for Embedded Main Memory Database

I.J. Wireless and Microwave Technologies, 2012, 5, 41-45

Published Online October 2012 in MECS ()

DOI: 10.5815/ijwmt.2012.05.06

Available online at /ijwmt

Yi-bing Lia,*1, Shuang Wanga,*2, Fang Yea

a Crash Recovery for Embedded Main Memory Database College of Information & Communication Engineering, Harbin Engineering University, Harbin, China Abstract

In the last years, the deployment of embedded real-time communication systems has increased dramatically. At the same time, the amount of data that needs to be managed by embedded real-time main memory databases is increasing, thus requiring an efficient data management. However, system crash will cause data loss in main memory, which will seriously affect the normal operation of the entire communication system. This paper introduces an algorithm of system crash recovery applied in main memory database of embedded real-time communication system. This paper expatiates the software architecture of SDR base station, the cause of crash occurring, and proposes the flash recovery algorithm using for system recovery. A main memory database using this algorithm has been applied in a real communication system——multimode SDR base station communication system.

Index Terms: Crash Recovery; Embedded Main Memory Database; System Crash; Multimode SDR Base Station

© 2012 Published by MECS Publisher. Selection and/or peer review under responsibility of the Research Association of Modern Education and Computer Science

1. Introduction

Memory database history can be traced back to 1969 when IMS was developed by IBM. And main memory database has aroused stronger and stronger concern by database researchers since the early 1980’s. The most prominent feature of main memory database is that the working copy of the database is resident in memory but the data is very weak, so recovery in main memory database is extremely important. Furthermore, recovery is the only part related to I/O process so that the performance of the recovery is the key to the performance of the entire system [1].

Main memory database is very different from the traditional database system because of the data structure, transaction processing methods and optimization, concurrent control and recovery, etc [2]. It is necessary to design new algorithms and data structures for main memory database [3-5] which are different from disk database system. A new crash recovery algorithm for main memory database is proposed in this paper, and it is particularly effective for system crash recovery. The algorithm combines the features of flash saving and This work is supported by shipbuilding Defense Advance Research Program (10J3.1.6) and Research on technological innovation Harbin Special Fund (2008RFQXG0205).

* Corresponding author:

E-mail address: *1*2

Crash Recovery for Embedded Main Memory Database

42 Crash Recovery for Embedded Main Memory Database

introduces flash writing logo to ensure data consistency real-timely. In addition, the algorithm is suitable for multimode SDR base station communication system.

2. Crash Recovery for Embedded Main Memory Database

2.1. SDR base Station Communication System

SDR base station can be upgraded and evolved just by adding or replacing the base band processor board, the rest of the base station can be realized through software configuration to another format of a standard smooth evolution of the technology. The software architecture of SDR base station system is as shown in Figure 1.

Fig. 1. Software Architecture of SDR Base Station System

SPS is to complete the business functions of the system, such as GSM service, LTE service and CDMA service. The responsibility of SCS is power control of the system. OAM manages the entire system initialization at power, and resource allocation and maintenance at run-time. PS includes network protocol layers. MMDBS is the core of the system, and it is responsible for data management and maintenance of the entire system, and provides data interfaces to other subsystems, and receives configuration data from the background by OAM. All the above subsystems are required to obtain the supports from OSS and OS.

2.2. Crash in Main Memory Database

The crash of main memory database can be divided into three categories [2], the crash in transaction, media crash and system crash. When the crash in transaction happens, the database may be in incorrect state, and the internal affairs don’t achieve the desired end. While media crash means external memory crash, such as disk crash, disk head impact and transient electromagnetic interference. This kind of crash will affect the whole database or part of it, but the possibility of such crash is small. System crash contains all kinds of events which can cause the system to stop running, and the system must restart. This kind of crash includes some certain

Crash Recovery for Embedded Main Memory Database

Crash Recovery for Embedded Main Memory Database 43 types of hardware errors, OS crash, DBMS code error, and sudden power down. Such crash will influence all the running affairs, data in main memory will loss, and all the running business will unusually terminate. When system crash happens, it is difficult to ensure data consistency. Some child tables may have been sent to the physical database, but the corresponding father tables have not. It is necessary to clear all changes made by this transaction to ensure data consistency.

As the different design between main memory database and traditional database, there are great differences in crash causes and recovery methods, which is mainly in the following two aspects:

1) The focus in main memory database is to recover the memory database rather than the disk database. I …… 此处隐藏：6043字，全部文档内容请下载后查看。喜欢就下载吧 ……