Consider merge join for "select * fromr,swherer.B= s.A", assuming both joining attributes inrandsare sorted. The pseudo- code is shown in Figure 12.7 in the textbook and can also be found in the merge-join.pptx.
(1) Discuss the assumptions behind the given pseudo-code for the number of reading disk blocks for the merge join to bebr+bswhen the number of blocks assigned to the merge join isM= 3 (one for each relation, and one for writing the join results).
(2) Discuss whether the given pseudo-code can always get correct answers in general. Justify your answers using examples.
(3) Give your modified merge join to give the correct answers for all cases with explanation in details.