Consider a disk with block size B = 512 bytes. A block pointer is P = 6 bytes long, and a record pointer is PR = 7 bytes long. A file has r = 30,000 EMPLOYEE records of fixed length. Each record has the following fields: Name (30 bytes), Ssn (9 bytes), Department_code (9 bytes), Address (40 bytes), Phone (10 bytes), Birth_date (8 bytes), Sex (1 byte), Job_code (4 bytes), and Salary (4 bytes, real number). An additional byte is used as a deletion marker.
a. Calculate the record size R in bytes.
b. Calculate the blocking factor bfr and the number of file blocksb, assuming an unspanned organization.
c. Suppose that the file is ordered by the key field Ssn and we want to construct a primary index on Ssn. Calculate (i) the index
blocking factor bfri (which is also the index fan-out fo); (ii) the number of first-level index entries and the number of first-level index blocks; (iii) the number of levels needed if we make it into a multilevel index; (iv) the total number of blocks required by the multilevel index; and (v) the number of block accesses needed to search for and retrieve a record from the file-given its Ssn value-using the primary index.
d. Suppose that the file is not ordered by the key field Ssn and we want to construct a secondary index on Ssn. Repeat the previous exercise (part c) for the secondary index and compare with the primary index.
e. Suppose that the file is not ordered by the non key field Department_code and we want to construct a secondary index on Department_code, using option 3 of Section 18.1.3, with an extra level of indirection that stores record pointers. Assume there are 1,000 distinct values of Department_code and that the EMPLOYEE records are evenly distributed among these values. Calculate (i) the index blocking factor bfri (which is also the index fan-out fo); (ii) the number of blocks needed by the level of indirection that stores record pointers; (iii) the number of first-level index entries and the number of first-level index blocks; (iv) the number of levels needed if we make it into a multilevel index; (v) the total number of blocks required by the multilevel index and the blocks used in the extra level of indirection; and (vi) the approximate number of block accesses needed to search for and retrieve all records in the file that have a specific Department_code value, using the index.
f. Suppose that the file is ordered by the nonkey field Department_code and we want to construct a clustering index on Department_code that uses block anchors (every new value of Department_code starts at the beginning of a new block). Assume there are 1,000 distinct values of Department_code and that the EMPLOYEE records are evenly distributed among these values. Calculate (i) the index blocking factor bfri (which is also the index fan-out fo); (ii) the number of first-level index entries and the number of first-level index blocks; (iii) the number of levels needed if we make it into a multilevel index; (iv) the total number of blocks required by the multilevel index; and (v) the number of block accesses needed to search for and retrieve all records in the file that have a specific Department_code value, using the clustering index (assume that multiple blocks in a cluster are contiguous).
g. Suppose that the file is not ordered by the key field Ssn and we want to construct a B+-tree access structure (index) on Ssn. Calculate (i) the orders p and Pleaf of the B+-tree; (ii) the number of leaf-level blocks needed if blocks are approximately 69 percent full (rounded up for convenience); (iii) the number of levels needed if internal nodes are also 69 percent full (rounded up for convenience); (iv) the total number of blocks required by the B+-tree; and (v) the number of block accesses needed to search for and retrieve a record from the file-given its Ssn value-using the B+-tree.
h. Repeat part g, but for a B-tree rather than for a B+-tree. Compare your results for the B-tree and for the B+-tree.