Database Systems: The Complete Book
▼ ❑ Chapter 17
▼ ❑ Section 1
▼ ❑ 1
• ❑ a Yes
• ❑ b No
• ❑ c Yes
▼ ❑ 2
• ❑ a Read(A, t)
Read(b, u)
• ❑ b Read(A, t)
Read(B, u)
• ❑ c Read(A, t)
Read(B, u)
t = u + 1
▼ ❑ Section 2
▼ ❑ 1
• ❑ a
• ❑ b
• ❑ c
▼ ❑ 2
• ❑ a
• ❑ b
• ❑ 3 n!
▼ ❑ 4
• ❑ a T is undone.
▼ ❑ 5
▼ ❑ a
▼ ❑ T
• ❑ must: { }
• ❑ might: {A}
▼ ❑ U
• ❑ must: {B, D}
• ❑ might: { }
▼ ❑ c
▼ ❑ T
• ❑ must: { }
• ❑ might: {A, C, E}
• ❑ 6 If a crash occurs before <U, D, 40>, A is recoverable for transaction T. If a
cash occurs after, A is recoverable for transaction U. Logging does not
preserve atomicity.
▼ ❑ 7
• ❑ a
• ❑ c
▼ ❑ Section 3
▼ ❑ 1
• ❑ a
• ❑ b
• ❑ c
▼ ❑ 2
• ❑ a
• ❑ b Same as 17.3.2a
▼ ❑ 3
▼ ❑ 4
▼ ❑ a
▼ ❑ T
• ❑ must: { }
▼ ❑ b
▼ ❑ T
• ❑ must: { }
• ❑ might: { }
• ❑ must: { }
• ❑ might: {B, D}
▼ ❑ d
▼ ❑ 5
• ❑ a
• ❑ c
• ❑ d
• ❑ e
▼ ❑ Section 4
▼ ❑ 1
• ❑ a
• ❑ b
• ❑ c
• ❑ 2 Same as 17.2.2
▼ ❑ 3
▼ ❑ a
• ❑ T undone
▼ ❑ b
▼ ❑ U redone
• ❑ 4 Same as 17.2.5
▼ ❑ 5
• ❑ c
• ❑ d