Design And Analysis Of Real-time History Database

Real-time historical database is a key technology in the industrial enterpriseautomation system, which has extensive application in the process industry such aspower enterprises. On the basis of GDREAL real-time historical database systemco-developed with a company affiliated with the China Electric Power ResearchInstitute, this thesis is completed after the theoretical and practical innovations.GDREAL is a large real-time historical database system. The disk historical databaseand real-time memory database are major components of GDREAL.This thesis analyzes in-depth the problems in the design of disk historicaldatabase, and the disk I/O, file's index and organizational structure of data which are thebottleneck to the development of historical database. It proposes a new disk storingstructure-Z tree, which reduces the number of disk I/O operation and greatly improvesthe performance of disk storage and querying. By the adopting of file sets, an efficientfile management system is designed. The size of pages and querying performance arealso analyzed.This thesis analyzes the storage procedure of the real-time data and the designand implementation of the real-time memory database and historical data buffers on thebackground of development of real-time memory database. A memory pool is designedto avoid the memory chips. To make the change from the dynamic memory allocation tothe pre-allocation, it decreases the overhead of dynamic memory allocation and release.The management of history data buffers uses the LRU algorithm based on the bi-queueto process the page elimination. For the destination of returning a large volume of datain batches, a new technology named broken point retransmission is proposed.This thesis displays the transactions and concurrency control of real-timedatabase. On the basis of the traditional transaction concurrency control protocols anddistinguishing the difference of real-time transactions and non-real-time transactions, itbrings forward the two phrases protocol with ordered sharing lock based on the prioritysuccession.