| Data cache technique is a classical technique that can promote the data access efficiency, and has been applied successfully in many areas of computation. There is a quantitative limit with in-memory pictures in applications based on spatial data base that must be worked out. Data cache technique is the very way to work out the problem mentioned above. In the meanwhile, data cache is also an effective method to promote query efficiency as well as to lighten the server load.This paper focused on client data cache technique and the main work done is as follows:1.The paper designed a client data cache architecture that consists of cache pool and cache files, and then narrated the structure of cache pool and the organization of cache files as well as the roles that they play in the data cache and recall. Client data cache is an effective way to improve the network performance.2.On the basis of the analysis of spatial data cache model the paper designed an element set based spatial data cache model, and by means of which the fast query and seamless span of vast spatial data, which meets the users'demand of fast querying vast spatial data.3.The paper designed a R-tree index nods structure, and detailed the solutions for special issues occurred in the creation and insertion process of R-tree index.4.The paper put forward a method for eliminating element sets which avoided the repeat of constructing and destroying objects, and thus reduced the memory pieces and in turn improved the memory use efficiency.5.The paper brought forward and designed a cache element mark based spatial data filtering method which worked out the technical problem of repeated transmission of spatial data and guaranteed the data transmission validity and thus improved the access performance of spatial data base.6.The paper implemented the two page layout replacement methods: LRU and FIFO, which balanced the relationship between limit memory and vast spatial data. |
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