How many serial schedules exist for the three transactions in Figure 20.8(a)? What are they? What is the total number of possible schedules?

Figure 20.8(a)

Figure 20.8 Another example of serializability testing. (a) The read and write operations of three transactions T1, T2, and T3. (b) Schedule E. (c) Schedule F. (a) Transaction T, Transaction T, Transaction T3 read_item(X); read_item(Z); read_item(Y); write_item(X); read_item(Y); read_item(Z); read item(Y); write_item(Y); write_item(Y); write_item(Y); read_item(X); write_item(Z); write_item(X);