Free Transactions and concurrency lessonsTransactions and concurrency · Stage 1 · Many users at once · Step 1
Schedules and serializability
Interleave two transactions, find which operations conflict, and test whether the result equals some serial order. About 15 minutes.
The precedence graph of a schedule has the edges T1 → T2, T2 → T3 and T3 → T1. What is true?
- AIt is not conflict-serializable: the edges form a cycle
- BIt is conflict-serializable as T1, T2, T3
- CIt depends on the data values
Show the answer
It is not conflict-serializable: the edges form a cycle. No serial order can place each of them before the next all the way round.
4 questions on this idea
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