Spatial information cluster cache pre-fetching method for network spatial information service system

Abstract

The invention discloses a spatial information cluster cache pre-fetching method for a network spatial information service system. Combined with the long-term epidemic characteristics and short-term epidemic characteristics of tile access, the method comprises the following steps of: establishing a tile transition probability estimation method and establishing a basic Markov model according to theglobal property of tile access and based on the long-term epidemic characteristics of tile access conforming to the Zipf distribution rule; based on the space-time local change of the tile access mode, predicting the tile with large follow-up state access transition probability by use of the basic Markov model, wherein the tile is used as a cache object; and finally uniformly distributing the cache objects into the cluster cache server according to the access transition probability of the pre-fetched tile. In the method, the global property of the tile access mode as well as the space-time local change of the tile access mode are taken into consideration so that the cache pre-fetching object is relatively stable and can adapt to the access distribution change; and thus, the hit rate is relatively high, the cache replacement frequency can be reduced, and the stability and service efficiency of the cluster cache system are improved.

Description

technical field [0001] The invention belongs to the technical field of network space information services, and in particular relates to a space information cluster cache prefetch method for a network space information service system facing high-intensity roaming access by large-scale users. Background technique [0002] The increasing popularity of cyberspace information service system (web GIS) has experienced continuous rapid growth in its visits. For example, the number of data requests for NASA World Wind reached 6.5 million times per day, involving more than 155GB of spatial information; the visits of Google Earth and Google Maps exceeded 100 million in 2006; That is, it reached 5 million. In the face of large-scale and high-intensity user access requests, the spatial information cluster server-side cache prefetch technology has great advantages in saving network bandwidth, reducing the load pressure on the back-end server, shortening the response time of user requests...

AI Technical Summary

Problems solved by technology

[0007] In summary, we observe that some existing work on cache prefetching focuses on the spatial locality among tiles, ignoring the inherent high clustering of tile access; some work focuses on studying the popularity of access-intensive tiles. Singular properties, while ignoring tile access local mode changes

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