Recent questions tagged transaction-and-concurrency

2 2 votes
1 1 answer
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221 views
If a transaction $t_{a}$ holds a lock on some data item $d$ in shared and intention-exclusive (SIX) mode, then which of the following is true for another transaction $t_{...
1 1 vote
1 1 answer
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159 views
In transactions, a write-item $(\mathrm{X})$ command includes the following steps. Arrange the following steps in correct sequence.Copy item $(\mathrm{X})$ from the progr...
9 9 votes
5 5 answers
1.7k
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Consider concurrent execution of two transactions $T 1$ and $T 2$ in a DBMS, both of which access a data object $A$. For these two transactions to not conflict on $A$, wh...
2 2 votes
2 2 answers
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764 views
We have a table Orders with a specific predicate range query Q: SELECT * FROM Orders WHERE Value 1000Transaction $T_1$ executes $Q$ and gets 5 rows.Transaction $T_2$ ins...
0 0 votes
0 0 answers
449
449 views
Consider a database system where transactions are executed concurrently. If transaction T1 holds an exclusive lock on resource R1 and requests a shared lock on resource R...
4 4 votes
1 1 answer
506
506 views
Considering the following statements:A non-serial schedule is said to be conflict serializable, if it is conflict-equivalent to some serial schedule.A non-serial schedule...
2 2 votes
1 1 answer
402
402 views
In concurrency control, phantom problem may occur, when-records are insertedrecords are deletedrecords are modifiedrecords are indexed
1 1 vote
1 1 answer
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Match the $\textbf{LIST-I}$ with $\textbf{LIST-II}$$\begin{array}{|l|l|c|l|} \hline & \textbf{ LIST-I } & & \textbf{ LIST-II } \\ \hline \text{A.} & \text{Project Join No...
1 1 vote
1 1 answer
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Consider the transactions $\mathrm{T}_{1}, \mathrm{~T}_{2}, \mathrm{~T}_{3}$ and the schedules $\mathrm{S}_{1}$ and $\mathrm{S}_{2}$ given below.$\begin{array}{ll} T_{1}:...
2 2 votes
1 1 answer
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Which one of the following statements are CORRECT?Granularity is the size of data item in a database.Two operations in a schedule are said to be conflict if they belong t...
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277 views
Consider the following schedule:T1: LOCK-X(A)T1: READ(A)T1: A = A + 3T1: WRITE(A)T2: LOCK-S(B)T2: READ(B)T2: LOCK-S(A)T1: LOCK-X(B)The above schedule is (select the most ...