Chapter 19, Problem 21E

Explanation of Solution

Crash during recovery:

• In the given figure, when the crash occurs at the given point, the recovery would occur as given below.
• Redo phase:
  • The contents of the undo list are T₀, T₁ .
  • Start the redo operation from checkpoint entry, C=600.
  • Remove T₁ from the undo-list as the commit record exists.
  • Add T₂ to the undo list because 2 start> record is seen.
  • Thus, A=400 and B=2000.
• Undo phase:
  • The contents of the undo list are T₀, T₂.
  • Scan the logs backward from the end, A=500...