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Recent questions tagged transactions

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1
how to find total number of concurrent schedule possible when any schedule is given ? for example consider this schedule T1 : R1(A) , W1(A) , R1(B) , W1(B) ; T2 : R2(A) , W2(A) , R2(B) , W2(B) ;
asked Dec 28, 2018 in Databases Rahul_Rathod_ 301 views
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IN CASE OF PRIORITY QUEUE OR WE CAN SAY MAX HEAP OR MIN HEAP. .WHEN DUPLICATE ENTRIES EXIST THEN WHICH ELEMENT OUT OF TWO SAME ONE WILL GET FIRST CHANCE… . SOME TIME IT NOT METTER MUCH BUT LET SAY YOU’R PERFORMING DIJKSTRA ALGORITHM THEN BECOME CONFUSING SOME TIME???/ ANYONE HAVE AN IDEA???
asked Dec 24, 2018 in Algorithms CHïntän ÞäTël 66 views
3 votes
2 answers
3
Why is Blind write necessary for a view serializable schedule that is not conflict serializable?
asked Dec 24, 2018 in Databases Saurabh1997 167 views
1 vote
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4
ANY EXAMPLE OF AN SCHEDULE WHICH IS RECOVERABLE BUT NOT CASCADLESS.?
asked Dec 21, 2018 in Databases junaid ahmad 60 views
1 vote
1 answer
5
Number of serial schedules but not conflict to schedule (S) S: r1(A),r2(A),r3(A),r4(A),w1(B),w2(B),w3(B),w4(B)
asked Dec 17, 2018 in Databases manisha11 263 views
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https://gateoverflow.in/39703/gate2016-1-51 In this question What if the transactions T1 and T2 are scheduled in this manner X1(A)X1(B)X2(C)X2(D)S1(C)S2(A)…. will this schedule cause deadlock according to the implementation of the above question ? here X1(P) is exclusive lock on data variable P by transaction T1 and S1(P) is shared lock on P by transaction T1.
asked Dec 16, 2018 in Databases Shivam Kasat 89 views
1 vote
2 answers
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8
pls explain why C is correct not A? isn’t every schedule that is supported by 2PL conflict serializable?
asked Dec 8, 2018 in Databases aditi19 97 views
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9
1 vote
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10
there is a schedule which is allowed in Thomas write rule so it is view serializable. Suppose at a point write operation of an older transaction is ignored. then the same operation will be ignored in its serial order?
asked Dec 1, 2018 in Databases aditi19 331 views
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11
'A' is set of all possible schedules 'C' is set of all possible schedules that are guaranteed to produce a correct final result 'S' is the set of all serializable schedules 'P' is the set of all schedules possible under 2-phase locking protocol Which is FALSE? (A) P⊆C (B) S⊂P (C) S⊆P (D) P⊂C Please provide reason for the answer. (Given answer is A)
asked Nov 27, 2018 in Databases !KARAN 132 views
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1 answer
12
S=r1(A),w2(A),r3(A),w1(A),w3(A) Is this Schedule Non Recoverable? As there is a dirty read happening at w2(A)->r3(A)
asked Nov 25, 2018 in Databases sripo 181 views
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1 answer
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Consider the following schedule : S:r1(A);w1(B);r2(A);w2(B);r3(A);w3(B); Here ri(X) denotes read on data item X and wi(X) denoted write on data item X .The total number of schedules that are view equivalent to S are _______
asked Nov 25, 2018 in Databases Bharat patra 652 views
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14
If I have dirty read which is write-read conflict does it imply that the schedule is non recoverable? Do all anomalies result of conflict result in non recoverable thereby non serializable schedules?
asked Nov 25, 2018 in Databases sripo 185 views
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1 answer
15
T1: W(X), T2: R(Y), T1: R(Y), T2: R(X) does 2PL protocol allows it? T1 T2 L-X(X) W(X) L-S(Y) R(Y) U(X) L-S(Y) R(Y) L-S(X) R(X) here T2 is granted lock on X as T1 enters shrinking phase as no exclusive locks are held on X is my solution correct?
asked Nov 25, 2018 in Databases aditi19 111 views
0 votes
2 answers
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S1 : r1(A) ; w1(A) ; w2(B) ; w3(C) ; r1(D) ; w2(D) S2 : r3(A) ; w4(B) ; r1(C) ; r3(D) ; w3(B) ; w2(D) ; r3(A) ; w1(D) ; r3(B) ; r2(C) ; r1(A) One more doubt which of the ... ==> Conflict Serializable Schedule If Conflict Serializable Schedule ==> Must have 2PL If Conflict Serializable Schedule ==> Allowed under 2PL If Conflict Serializable Schedule ==> Allowed under Timestamp Ordering Protocol
asked Nov 25, 2018 in Databases jatin khachane 1 170 views
0 votes
1 answer
17
T1 T2 T3 R(X) W(X) commit W(X) commit R(X) commit is this transaction conflict serializable and view serializable?
asked Nov 18, 2018 in Databases aditi19 878 views
0 votes
1 answer
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T1 T2 T3 W(Y) commit R(X) R(Y) W(Z) commit W(X) commit is this schedule a strict schedule?
asked Nov 18, 2018 in Databases aditi19 153 views
0 votes
0 answers
19
Tl:W(X), T2:R(X), Tl:W(X), T2:Commit, Tl:Abort is this schedule conflict serializable?
asked Nov 17, 2018 in Databases aditi19 287 views
1 vote
1 answer
20
Tl:R(X), T1:R(Y), T1:W(X), T2:R(Y), T3:W(Y), Tl:W(X), T2:R(Y) is this schedule view serializable?
asked Nov 16, 2018 in Databases aditi19 150 views
0 votes
1 answer
21
Is it recoverable and why?
asked Nov 13, 2018 in Databases Shamim Ahmed 126 views
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22
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23
https://gateoverflow.in/1484/gate1999-2-6 in this questions after T2 is not granted exclusive lock on A does the transaction T2 gets blocked entirely or it can continue to acquire exclusive lock on B? and if T2 continues to acquire lock on B followed by T1 requesting for read and write lock on B successively, is it deadlock situation here? And is that why it is not 2PL?
asked Nov 11, 2018 in Databases aditi19 120 views
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24
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25
In Log-Based Recovery why do we redo committed transactions?
asked Nov 2, 2018 in Databases jatin khachane 1 42 views
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26
Is this schedule is recoverable. Doubt : Here W(A) is BLIND WRITE in T1 ..does this make any difference T1 T2 W(A) R(A) COMMIT COMMIT
asked Nov 1, 2018 in Databases jatin khachane 1 54 views
2 votes
1 answer
27
Which of the following are RECOVERABLE schedules
asked Oct 31, 2018 in Databases jatin khachane 1 295 views
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1 answer
28
Let a schedule be strict recoverable schedule then it will suffer from which problem? 1.ww 2.rw 3.wr 4.lost update
asked Oct 31, 2018 in Databases Shukrayani 104 views
2 votes
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29
i am finding difficulty in view serializable schedule please tell me how to check view serializablity with polygraph
asked Oct 27, 2018 in Databases Shivani gaikawad 231 views
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30
T1 T2 R(X) W(X) W(X) aborts commit find conflict serializability,view serializability, recoverable,cascadeless and strict schedule
asked Oct 26, 2018 in Databases amit166 86 views
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