Consider the following ordering S of transactions T1 : R(X); T2 : R(X); T1 : w(x); T1 : r(y); T2 : w(x); T2 : Commit; T1: w(y) ; T1: Commit Which of the following is true?
A) It is a strict schedule
B) Cascade less schedule
Option (b) is correct
Cascade less schedule is the one in which, for each pair of transactions T1 & Ts such that Tj reads the data item previously written by Ti, the commit (or) abort operation of Ti must appear before read of Ij
Suppose three are 3 transactions T22, T23, T24 with time stamps 10, 20, 30 Now T23 occupy a data item which is required by T22 and T24. Among the four possibilities what will be the true in waid – die schema.
A) If T22 request the data item, T22 will wait
B) If T24 request the data item, T24 will wait
C) If T22 request the data item, T23 will wait
D) If T24 request the data item, T23 will wait
Option (a) is correct
Wait – die and wand – wait are dead lock prevention technique. Bases on a time stamp
Younger one rolled back