Q2. Give the optimal estimate for the disk-IO cost of r JOIN s using (2.a) Sort-merge join, assuming that the two relations are sorted on the join attributes and r’s join attribute is a key for r. (2.b) Block nested loop join Assume r has 2,000 tuples with 20 tuples per block; s has 4,000 tuples with 4 tuples per block; and the main memory buffer for this operation is 22 blocks

Question 1 Demonstrate the operation of quicksort using median of 3 and cutoffs of length 3 on the data below. Clearly show the result of each median of 3 process and each partitioning process. You do not need to show me the insertion sort process. 12 2 9 16 20 41 13 8 9 1 51 18 19 5 10 14  Full explain this question and text typing work only thanks

Transaction management deals with the problems of always keeping the database in a consistent state even when concurrent accesses and failures occur. Isolation requires that each transaction sees a consistent database at all times and that an executing transaction cannot reveal its results to other concurrent transactions before its commitment. ANSWER If two concurrent transactions access a data item that is being updated by one of them, it is not possible to guarantee that the second will read the correct value. Dirty reads and nonrepeatable reads may occur when one transaction can see intermediate results of another transaction before it has been committed.. Given below are two concurrent transactions T1 and T2 whose balances of amount x (balx) were recorded at times t, between t₁ and tg. As shown in the table below: If these two transactions interfere with each other, fill in the table below by selecting from the drop down list the values of balance X (bal,) at specified times…

The Oracle database system uses undo log records to provide a snapshot view of the database under snapshot isolation. The snapshot view seen by transaction Ti reflects updates of all transactions that had committed when Ti started and the updates of Ti; updates of all other transactions are not visible to Ti. Describe a scheme for buffer handling whereby transactions are given a snapshot view of pages in the buffer. Include details of how to use the log to generate the snapshot view. You can assume that operations as well as their undo actions affect only one page.