Research And Implementation For Technology Of Data Consistency Maintenance In Multidatabase System

With the rapid development of information technology, in information integrated field, multi-database system is one of the effective methods that deal with information-exchange and integration among multiple heterogeneous date source.The main purpose of the system to offer authentic and good quality data to the the Decision System by supporting the general data integration and data access platform. Data-Consistency in multi-database system is one of the key factor about quality of data integration , Especially on many application background,in order to improve usability and disaster-tolerance ability of multiple database system, introduced by all kinds of technology and corresponding solution scheme, which make data consistency in the system become more complex.So this paper has deeply analyzed and discussed on this issue,proposes a Data-Consistency Maintenance management sub-system in MDBS. The following contents are the main research of the paper.1. this paper put forward the structure of Data-Consistency Maintenance management subsystem. This subsystems apply hierarchical management structure to resolve data-consistency of different lay. Among those,the ectype-consistency managment is consist of node agency way,through task execute issue control,task finished subsequence control and task execute exception handling, which has effective resolved ectype consistency of data physical storage; through synchronizing update control structure that based on C/S, use updating information list and temporary integration resource list, the structure depart whole synchronizing process into two subsequent execute , this way is effect resolve global data synchronizing updating problem, viz. the consistency between local source-data and global-data.2. in the matter of local data ectype consistency maintenance, the paper design and realize management strategy which based on consistency maintenance task. Using consistency maintenance task, the strategy adopt the way that updating requirement issue multidrop to accelerate ectype consistency rate, reduce time consume of consistency maintenance. The structure utilizes"fastest updating—accessing"to improve requirement processing rate, through preference scheduling control after phycial consistency maintenance task, the structure can shorten waitting time of block task; also, the structure combines task abnormity control to guarantee data consistency under updating abnormity state. The design effective resolves ectype consistency among data-source node, at the same time, improve the system whole throughput rate and resource utilization ratio of node.3. The author put forward two-segment global data synchronized updating control technology,and use it to maintain the data-consistency between the local source-data and global-data.According to low efficiency and complex about the existed strategies,the author put forward the technology that divide the whole synchronized updating process into two parts: local source-data updating information extraction and global data integrated updating. This technology makes concurrent executing these two progresses. It can improve updating rate and resist hazard performance of maintenance management. During the first process, it makes use of resolution-assemble control to reduce data quantity of network transmission and shorten data different time. During the second process, it mainly solves that how can fast make sure failure global data subject, reduces objection application in order to avoid starting unnecessary global data updating process.On the base of above research, the author concrete realizes data consistency maintenance management, and made relative experimental. Through analyzing result, the author verifies its feasibility and effectivenes.