R has a ordered clustering index file on its tuples: Read index file to get the location of the tuple with the next smallest value

Transcription

1 1 of 8 3/3/2018, 10:01 PM CS554, Homework 5 Question 1 (20 pts) Given: The content of a relation R is as follows: d d d d... d a a a a... a c c c c... c b b b b...b ^^^^^^^^^^^^^^ ^^^^^^^^^^^^^ ^^^^^^^^^^^^^^ ^^^^^^^^^^^^^ 100 tuples 100 tuples 100 tuples 100 tuples R has a ordered clustering index file on its tuples: (a b c d) The index file contains the record location of the first tuple with that given value We use the ordered index to accessall tuples of relation R in a sorted manner as follows: Read index file to get the location of the tuple with the next smallest value Access all (clustering) tuples with the next smallest value Questions: If each data block can store exactly 100 tuples, how many block accesses will this operation perform? (ignore the block accesses to the index file) If each data block can store exactly 50 tuples, how many block accesses will this operation perform? (ignore the block accesses to the index file)

2 2 of 8 3/3/2018, 10:01 PM If each data block can store exactly 51 tuples, how many block accesses will this operation perform? (ignore the block accesses to the index file) If each data block can store exactly 49 tuples, how many block accesses will this operation perform? (ignore the block accesses to the index file)

3 3 of 8 3/3/2018, 10:01 PM Question 2 (40 pts) Given: R = R(A, B, C) B(R) = 1000 block T(R) = tuples V(R, A) = 100 S = S(A, D, E) B(S) = 200 block T(S) = 4000 tuples V(S, A) = 100 // R has attributes A, B, C // We assume that # tuples with // attribute value A = a is equal to: // 10000/100 = 100 for any value a // S has attributes A, D, E // We assume that # tuples with // attribute value A = a is equal to: // 4000/100 = 40 for any value a What is the minimum memory requirement for the following algorithms: 1. One-pass join R S: 2. The IO-efficient version of the Two-pass TPMMS based join R S: 3. The IO-intensive version of the Two-pass TPMMS based join R S: 4. Two-pass Hashing based join R S:

4 4 of 8 3/3/2018, 10:01 PM 5. Three-pass Hashing based join R S: 6. Block-based nested loop join R S: 7. Suppose S has an ordered clustering index on it join attribute. (so you can use the Index join algorithm) What's the minimum # buffers needed for the Index join algorithm (you can ignore the buffers to read the index file): 8. Suppose S has an ordered non-clustering index on their join attribute. What's the minimum # buffers needed for the Index join algorithm (you can ignore the buffers to read the index file): 9. Suppose R and S both have a ordered clustering index on their join attribute. What's the minimum # buffers needed for the "zig-zag" join algorithm (you can ignore the buffers to read the index file):

5 5 of 8 3/3/2018, 10:01 PM 10. Suppose R and S both have a sorted non-clustering index on their join attribute. What's the minimum # buffers needed for the "zig-zag" join algorithm (you can ignore the buffers to read the index file):

6 6 of 8 3/3/2018, 10:01 PM Question 3 (40 pts) Given the same database: R = R(A, B, C) B(R) = 1000 block T(R) = tuples V(R, A) = 100 S = S(A, D, E) B(S) = 200 block T(S) = 4000 tuples V(S, A) = 100 // R has attributes A, B, C // We assume that # tuples with // attribute value A = a is equal to: // 10000/100 = 100 for any value a // S has attributes A, D, E // We assume that # tuples with // attribute value A = a is equal to: // 4000/100 = 40 for any value a What is the # disk I/O operations for the following algorithms: 1. One-pass join R S: 2. The IO-efficient version of the Two-pass TPMMS based join R S: 3. The IO-intensive version of the Two-pass TPMMS based join R S: 4. Two-pass Hashing based join R S:

7 7 of 8 3/3/2018, 10:01 PM 5. Three-pass Hashing based join R S: 6. Block-based nested loop join R S using M = 101 buffers : 7. Suppose S has an ordered clustering index on its join attribute. What's the I/O cost of the index join algorithm (you can ignore the I/O cost to read the index file): 8. Suppose S has an ordered non-clustering index on its join attribute. What's the I/O cost of the Index join algorithm (you can ignore the I/O cost to read the index file): 9. Suppose R and S are not sorted but have an ordered clustering index on their join attribute. What's the I/O cost of the "zig-zag" join algorithm: (you can ignore the I/O cost to read the index file)

8 8 of 8 3/3/2018, 10:01 PM 10. Suppose R and S are not sorted but have an ordered non-clustering index on their join attribute. What's the I/O cost of the "zig-zag" join algorithm: (you can ignore the I/O cost to read the index file)