An Adaptable Multithreaded Prefetching Technique for Client-Server Object Bases

this paper, we examine the way in which prefetching can exploit parallelism. Prefetching has been studied before in many areas of computing such as operating systems, microprocessor design, compiler construction, the world wide web and databases. Although prefetching has been studied for a long time, the problem prefetching is facing has changed over the years as a result of technology advances. Fig. 1 shows the performance/price development of semiconductor memories and magnetic disks. There is a two-order of magnitude gap in access time between memory and disks. Memory access is faster and the rate of improvement is also higher. The prices of memory are falling which makes database N. Knafla / An Adaptable Multithreaded Prefetching Technique 3 caches cheaper and buffer replacement less of a problem. Prices of disks are also falling dramatically which is good for cheap secondary storage, allowing increased use of RAIDs. CPU performance improves at an even higher rate than memory (fig. 2). CPU is doubling its performance every 18 months whereas disk retrieval time only improves about 5% per year. Memory access time improves at about 10 to 12% per year. Client workstations will become powerful multi-processors machines with high speed CPUs, most of which will tend to be idle most of the time. 1 10 100 1000 1980 1985 1990 199