CMPT 454 Assignment 3 Solutions - All Answers are Correct - Simon Fraser University
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Course
CMPT 454
Institution
CMPT 454
CMPT 454 Assignment 3 Solution
Question 1
For each of the operations described below you are to calculate the number of disk reads (and
writes) to perform the operation in the most efficient way. Do not include the cost to write out
the result of the operation. Briefly explain the process of ea...
CMPT 454 Assignment 3: Query Evaluation This assignment is worth approximately 7 % of your final grade. Question 1 For each of the operations described below you are to calculate the numb er of disk reads (and writes) to perform the operation in the most efficient way . Do not include the cost to write out the result of the operation. Briefly explain the process of ea ch operation a nd its components . For e xample, use the index on a, read x nodes of the index and y records of the file . Assume the root node of tree indexes and directory of extensible hash index es are not held in main memory at the start of the operation . [2 marks each , unless noted otherwise ] Product = {pid, pname , ptype , pnumber , description , manu facturer , mcountry , mcity , price } Table Statistics (note for all V the table is the Product table ) B(Product) T(Product) V(pid) V(pname ) V(ptype ) V(pnumb er) 25,000 250,000 250,000 50,000 500 1,000 V(mcountry ) V(mcity ) V(manu facturer ) V(price) V(description ) 40 1,000 10,000 50,000 125,000 V({ptype , pnumber }) V({mcountry , mcity }) 250,000 2,500 Indexes ▪ Primary dense B+ tr ee index on {ptype , pnumber } wh ere ptype is the pre fix of the search key. The index is height 4 (includes lea f and root level ) and interior and leaf nodes contain 50 search ke ys on average. ▪ B+ tr ee index on {mcountry , mcity } wh ere mcountry is the pre fix of the search key. The index is height 5 (includes lea f and root level ) and interior and leaf nodes contain 30 search ke ys on average. ▪ B+ tr ee index on pname . The index is height 4 (includes lea f and root level ) and interior and leaf nodes contain 60 search ke ys on average. ▪ Extensible hash index on pid. The director y resides on two disk blocks and each bucket contain s 100 search ke ys on average. ▪ Linear hash index on manufacturer . Each bucket contain s 40 search ke ys on average – there are no overflow blo cks. a) (ptype = 'AB C' pnumber = 13) (Product ) b) (ptype = 'AB C') (Product) c) (pid = 123456 pid = 678324 ) (Product) This study source was downloaded by 100000850872992 from CourseHero.com on 07-03-2023 11:35:59 GMT -05:00
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