Research And Optimization Of The Mosquitto Transmission And Changing Storage Mode

The MQTT(Message Queue Telemetry Transport)protocol is designed for the communication among a large number of remote sensors and control devices which have limited computing capacity.It's particularly suitable for the low bandwidth and unreliable network condition.Mosquitto is an open source software which provides the message pushing service by using the publish/subscribe model.Mosquitto implements the MQTT protocol versions 3.1,which is applied to the lightweight message pushing service.With the increase of the data-handling capacity of the Intelligent terminal,however,the amount of the data transferred via Mosquitto will become larger.The transferred data,for example,is a high-definition picture or a small video.The server memory usage will rise sharply with the increase of the number of the subscribers in the current transmission mode of Mosquitto.Furthermore,Mosquitto is used in many researches at home and abroad presently,while few studies are done to improve it.Therefore,the research and optimization on the Mosquitto transmission mode are of great significance in the large file transfer.Moreover,it's of positive exploration significance to study the Mosquitto changing storage mode for a further improvement of the Mosquitto real-time performance.Aiming at the disadvantages of the Mosquitto transmission and changing storage mode,the corresponding improvement schemes are provided after the Mosquitto transmission and changing storage mode are studied and analyzed.Then the optimization of the Mosquitto transmission and changing storage mode are realized by the in-depth analysis of the problems.The effects of improvement schemes on the system performance are also analyzed.The main works are as follows:1)The Mosquitto transmission and changing storage mode are deeply analyzed,the cause that the server memory usage rises sharply with the increase of the message subscribers while the message is being transferred is analyzed from the perspective of the source code,and the lack of memory management mechanism is discovered.Based on these facts,the corresponding improvement schemes are provided.2)For the large file transfer,a more suitable scheme that can avoid the memory overflow and the failure of the server to push the message leaded by the large memory usage is designed and implemented.3)An improvement scheme that introduces a memory management mechanism is designed and implemented,which improves the real-time performance of Mosquitto to some degree.4)the two schemes above are applied to the practical application,which proves the practicality and effect of the two schemes by a series of tests.This thesis mainly studies the Mosquitto transmission and changing storage mode and provides two improvement schemes,which has certain practical value and reference significance in improving the overall performance of Mosquitto when messages being pushed.