Exercise Database Management Systems (CO3021) - Chapter 7: Database Recovery Techniques

Question 7.1. Describe some non-catastrophic failures and catastrophic failures. Introduce some
approaches to deal with these failures.
Question 7.2. State the purposes of database recovery from transaction failures.
Question 7.3. What are transaction commit points? Why are they important?
Question 7.4. What are checkpoints? Why are they important? What is fuzzy checkpointing?
Question 7.5. Distinguish deferred update with immediate update.
Question 7.6. What are the before image (BFIM) and after image (AFIM) of a data item? What is the
difference between in-place updating and shadowing, with respect to their handling of BFIM and AFIM?
Question 7.7. Describe UNDO and REDO operations. Distinguish them from transaction rollback and rollforward. 
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Nội dung text: Exercise Database Management Systems (CO3021) - Chapter 7: Database Recovery Techniques

  1. Question 7.17. Given the log corresponding to a particular schedule at the point of a system crash for four transactions T1, T2, T3, and T4. Describe the recovery process from the system crash. Specify which transactions are rolled back, which operations in the log are redone and which (if any) are undone, and whether any cascading rollback takes place. (1). use the deferred update protocol with checkpointing (2). use the immediate update protocol with checkpointing 2
  2. The Transaction Table and Dirty Page Table: Question 7.20. Given the log when the system crashes as follows. Describe the recovery process using: (1). deferred update, (2). immediate update, and (3). ARIES methods. 4