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Consider the following database schedule with two transactions, T1 and T2.
S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2;
where ri(Z) denotes a read operation by transaction Ti on a variable Z, wi(Z) denotes a write operation by Ti on a variable Z and ai denotes an abort by transaction Ti . Which one of the following statements about the above schedule is TRUE?
  • a)
    S is non-recoverable
  • b)
    S is recoverable, but has a cascading abort
  • c)
    S does not have a cascading abort
  • d)
    S is strict
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
Consider the following database schedule with two transactions, T1 and...
As we can see in figure,
  • T2 overwrites a value that T1 writes
  • T1 aborts: its “remembered” values are restored.
  • Cascading Abort could have arised if - > Abort of T1 required abort of T2 but as T2 is already aborted , its not a cascade abort. Therefore, Option C
Option A - is not true because the given schedule is recoverable Option B - is not true as it is recoverable and avoid cascading aborts; Option D - is not true because T2 is also doing abort operation after T1 does, so NOT strict.
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Most Upvoted Answer
Consider the following database schedule with two transactions, T1 and...
Given Schedule:
S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2;

Explanation:
- The given schedule involves two transactions, T1 and T2, and a series of read and write operations on variables X and Y.
- Let's analyze the schedule step by step to determine if it has a cascading abort.

Step 1:
r2(X) - Transaction T2 reads the value of variable X.

Step 2:
r1(X) - Transaction T1 reads the value of variable X.

Step 3:
r2(Y) - Transaction T2 reads the value of variable Y.

Step 4:
w1(X) - Transaction T1 writes a new value to variable X.

Step 5:
r1(Y) - Transaction T1 reads the value of variable Y.

Step 6:
w2(X) - Transaction T2 writes a new value to variable X.

Step 7:
a1 - Transaction T1 aborts.

Step 8:
a2 - Transaction T2 aborts.

Analysis:
- In the given schedule, both transactions T1 and T2 abort at the end, which means neither of them commits successfully.
- However, there is no cascading abort in this schedule because the abort of one transaction does not cause the abort of another transaction.
- Cascade abort occurs when the abort of one transaction leads to the abort of another transaction, creating a chain reaction.
- In this case, even though T1 and T2 both abort, their aborts are not dependent on each other. Each transaction aborts independently due to its own specific reasons.
- Therefore, the given schedule does not have a cascading abort.

Conclusion:
The correct statement about the given schedule is that it does not have a cascading abort.
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Community Answer
Consider the following database schedule with two transactions, T1 and...
Correct answer is option C
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Consider the following database schedule with two transactions, T1 and T2.S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2;where ri(Z) denotes a read operation by transaction Ti on a variable Z, wi(Z) denotes a write operation by Ti on a variable Z and ai denotes an abort by transaction Ti . Which one of the following statements about the above schedule is TRUE?a)S is non-recoverableb)S is recoverable, but has a cascading abortc)S does not have a cascading abortd)S is strictCorrect answer is option 'C'. Can you explain this answer?
Question Description
Consider the following database schedule with two transactions, T1 and T2.S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2;where ri(Z) denotes a read operation by transaction Ti on a variable Z, wi(Z) denotes a write operation by Ti on a variable Z and ai denotes an abort by transaction Ti . Which one of the following statements about the above schedule is TRUE?a)S is non-recoverableb)S is recoverable, but has a cascading abortc)S does not have a cascading abortd)S is strictCorrect answer is option 'C'. Can you explain this answer? for Computer Science Engineering (CSE) 2024 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about Consider the following database schedule with two transactions, T1 and T2.S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2;where ri(Z) denotes a read operation by transaction Ti on a variable Z, wi(Z) denotes a write operation by Ti on a variable Z and ai denotes an abort by transaction Ti . Which one of the following statements about the above schedule is TRUE?a)S is non-recoverableb)S is recoverable, but has a cascading abortc)S does not have a cascading abortd)S is strictCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider the following database schedule with two transactions, T1 and T2.S = r2(X); r1(X); r2(Y); w1(X); r1(Y); w2(X); a1; a2;where ri(Z) denotes a read operation by transaction Ti on a variable Z, wi(Z) denotes a write operation by Ti on a variable Z and ai denotes an abort by transaction Ti . Which one of the following statements about the above schedule is TRUE?a)S is non-recoverableb)S is recoverable, but has a cascading abortc)S does not have a cascading abortd)S is strictCorrect answer is option 'C'. Can you explain this answer?.
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