Question 1

Consider a B+-tree index to be built on the attribute StudentID of a table Students, with the following properties: - The length of the attribute StudentID is 10 bytes. - The size of each child pointer is 14 bytes. - The size of each disk block size is 470 bytes. With the given information, what is the best choice for the order of the non-leaf nodes of the B+-tree? Consider a log of a transaction as shown below, where the immediate database modification scheme is used. | step | log details | |---|---| | 1 | $< T_1, start >$ | | 2 | $< T_1, A, 1000, 700 >$ | | 3 | $< T_1, B, 600, 450 >$ | | 4 | $< T_1, C, 800, 1300 >$ | | 5 | $< T_1, Commit >$ | Table 1: log table Suppose the transaction failed before step 5, then which of the following is true? Consider the following monthly backup schedule used by a company: | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday | |---|---|---|---|---|---|---| | 1/ Full | 2/ Incremental | 3/ Incremental | 4/ Incremental | 5/ Incremental | 6/ Incremental | 7/ Differential | | 8/ Incremental | 9/ Incremental | 10/ Incremental | 11/ Incremental | 12/ Differential | 13/ Incremental | 14/ Incremental | | 15/ Incremental | 16/ Incremental | 17/ Differential | 18/ Incremental | 19/ Incremental | 20/ Incremental | 21/ Incremental | | 22/ Differential | 23/ Incremental | 24/ Incremental | 25/ Incremental | 26/ Incremental | 27/ Incremental | 28/ Incremental | | 29/ Incremental | 30/ Incremental | | | | | | If a failure occurs on the 12th day of the month before the backup for the day has been completed, how many backup sets have to be loaded for a full recovery?