代写代考 COMP9315 Final Exam

COMP9315 Final Exam

COMP9315 Final Exam

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The University of Wales

COMP9315 DBMS Implementation
Final Exam

DBMS Implementation

[Instructions] [Notes] [PostgreSQL] [C]

[Q1] [Q2] [Q3] [Q4] [Q5] [Q6] [Q7] [Q8]

Question 5 (5 marks)

Consider two tables R(x,y,z) and S(a,x,b)
with bR = 100
and bS = 20,
and a natural join on these two tables (via attribute x).
If we have a buffer pool with B = 20
buffers, then calculate how many pages would be read/written
when performing the join operation using the methods below.
Do not include the cost of writing the final result.

Block nested loop join, with R as outer table and S as inner.

Sort merge join, using intermediate files for sorting.

Do not assume any sort order on the original files.

Grace hash join, with R as outer table and S as inner.

Use buffers as appropriate for input, output and in-memory hash tables.

You can assume that all hash functions distribute tuples uniformly

and that all partitions of R will fit in the in-memory hash table.

Show all working.

Instructions:

Type your answer to this question into the file called q5.txt

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End of Question

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