Recitation #3

*** Still not finished (but you can at least start...) ***

Paper Problems

1. r_1(x), r_2(x), w_1(x),w_2(x)

Write the DSG for the above schedule.
Is this schedule conflict serializable?
Is this schedule view serializable?

2. w_2(z),r_1(x),r_1(y),r_2(y),w_1(x),r_2(x),w_2(y),w_1(z),w_2(z)

Is this schedule conflict serializable?
Is this schedule view serializable?

3. Assume that the following schedule with locks is executed over a SVCC mechanism.

rlk_1(x), r_1(x), rlk_2(x), wlk_1(x),w_1(x),ulk_1(x),cmt_1, wlk_2(x),w_2(x),ulk_2(x), cmt_2

Describe what happens.
Does this schedule respect 2PL, SS2PL (AKA ‘Rigorous’), Conservative 2PL?  

4. Which SQL isolation levels are met with schedules that observe:
  a. locking protocols
  b. 2PL
  c. SS2PL (AKA 'Rigorous')
  d. Conservative and Rigorous

System Exercises 

Consider we have 2 runways and three time slots that planes may land. We represent this scenario in the following table: