Homework Answers
a)
We effectively have to perform two nested-loop joins of 500 and 250blocks, respectively, using 101 blocks of memory. Such a join takes 250 + 500*250/100 = 1500 disk I/O's, so two of them takes 3000. Tothis number, we must add the cost of sorting the two relations, which takes four disk I/O's per block of the relations, or another 6000. The total disk I/O cost is thus 9000.
b)
1000+1000*500/100=6000*4=24000 i/o
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