Estimate the time in milliseconds to update the search-key value of a row in the table of Exercise 9.17 when each of the following is used:

Question

a. No index (?le sorted on the search key)
b. A static hash index (where the updated row goes in a di?erent bucket than the original row’s page, but no over?ow pages are required)
c. A clustered, unintegrated B+ tree index (where the updated row goes on a di?erent page than the original row’s pages, but no node splitting is required)

Answer 1

a. As in Exercise 9.18 it takes 280ms to locate the row to be updated and another 20ms to delete the row from the page. Another 280+20ms is required to locate and update the new page in which the row is to reside. Hence a total of 600ms is required.
b. 40ms to update the old bucket and 40ms to update the newbucket.
c. Using the answer to Exercise 9.18 it takes 120ms to delete the row and update the index and another 120ms to insert the updated row and update the index. Hence, 240ms are required.