Database Systems 6th Edition by Ramez Elmasri, Shamkant B. Navathe

Exercise 5

Suppose that a file initially contains r=120,000 records of R=200 bytes each in an unsorted (heap) file. The block size B=2400 bytes, the average seek time s=16 ms, the average rotational latency rd=8.3 ms and the block transfer time btt=0.8 ms. Assume thaT₁ record is deleted for every 2 records added until the total number of active records is 240,000.
(a) How many block transfers are needed to reorganize the file?
(b) How long does it take to find a record right before reorganization?
(c) How long does it take to find a record right after reorganization?