{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Homework 7

# Homework 7 - (a Draw precedence graph for the schedule(b Is...

This preview shows pages 1–2. Sign up to view the full content.

CSC4402 Homework#7 Due Monday November 23, 2009 1. Consider the following precedence graph for a non-serial schedule S consisting of transactions T0, T1, T2, T3 and T4: T0 T1 T3 T2 T4 (a) Is the corresponding schedule S conflict serializable? Why? (b) If you answered "yes" ( S is conflict serializable) to part (a), then give serial schedule S (for the transactions T0, T1, T2, T3 and T4) such that the serial schedule S is compatible with the par- tial order specified by the above precedence graph. 2. Consider the following two transactions: T0: read (A); read (B); if A=0 then B := B + 1; write (B). T1: read (B); read (A); if B=0 then A := A + 1; write (A). Let the consistency requirement be (A=0 OR B=0), with A=B=0 as the initial values. (a) Show that every serial schedule consisting of T0 and T1 preserves the consistency of the database. (b) Show a concurrent (non-serial) schedule S for T0 and T1 which is NOT conflict serializ- able. Draw the precedence graph for your schedule S.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
-2- 3. Following is a schedule for three transactions T1, T2
This is the end of the preview. Sign up to access the rest of the document.

View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern