算法 Proc 2-way-exsort(file Read each page into memory, sort it, write it out While the number of runs at end of previous pass> 1 while there are runs to be merge from previous pass is choose next two runs(from previous pass) read each run into an input buffer; Merge the runs and write to the output buffer force output buffer to disk one page at a time wndproc算法 Proc 2-way-exsort(file) Read each page into memory, sort it, write it out While the number of runs at end of previous pass>1 while there are runs to be merge from previous pass is choose next two runs(from previous pass) read each run into an input buffer; Merge the runs and write to the output buffer force output buffer to disk one page at a time endproc