| Based on the key R & D project of Ministry of science and technology,green livable village technology innovation project(2019yfd11104),this paper takes a supply and marketing agency in Shiyan City of Hubei Province as the pilot project.Aiming at the problems existing in traditional centralized purchasing and trading system,such as data easy to tamper,low reliability,difficult to handle large-scale user requests and poor concurrency,the paper uses distributed thought Queuing theory and block chain technology design and develop the transaction management subsystem of centralized procurement system,which can effectively help farmers to purchase production and living materials from the Internet and reduce production and living costs by relying on the platform of supply and marketing society.Firstly,aiming at the problem that a single server can’t handle large-scale requests,a distributed system architecture is built based on SSM framework.Dubbo is used as the communication architecture,Nginx is used as the reverse proxy server,and Redis,Solr,Fast DFS and other related technologies are integrated to distribute large-scale user requests to multiple servers for common processing,The response delay is effectively reduced.Aiming at the problem that the original load balancing algorithm of Nginx is difficult to adapt to the actual scene,a PL(performance and load)load balancing algorithm based on server performance and real-time load is designed on the basis of the traditional weighted polling algorithm.Secondly,in view of the response congestion problem caused by the different number of user requests in different periods,the M/M/N queuing model is established.The actual data collected is substituted into the model for example analysis and calculation of relevant parameters,so as to obtain the optimal number of servers under the user request congestion.Finally,in the process of using blockchain technology to ensure the authenticity and credibility of the integrated transaction data,we find that the response time is too slow.We adopt the idea of "capacity expansion under the chain",which processes the functions with high performance requirements but low importance under the chain,and puts the management of key information on the chain.Through the test of each functional module of the system,it meets the needs of users.The test results of PL load balancing algorithm show that the response time and throughput are improved by 14.2% and 14.5% respectively compared with the traditional weighted polling algorithm.In this paper,we use blockchain technology,PL load balancing algorithm and M /M / N queuing model to realize a data encryption,high concurrency agricultural procurement trading system,which provides convenience for farmers and supply and marketing cooperatives. |
