Recent questions tagged transactions

+5 votes

3 answers

1

view serializable
$S: R_1(A),R_2(B),W_2(A),W_3(C),R_4(C),R_3(A),W_3(B),R_4(A),W_2(B),W_4(B),W_3(A)$ View serializable or not?

asked Jan 28, 2017 in Databases by Supremo (389 points) | 678 views

+1 vote

1 answer

2

Self Doubt
Do commit operations matter while checking serilizability?If yes why?

asked Jan 28, 2017 in Databases by Gate Madrista (363 points) | 148 views

0 votes

1 answer

3

MadeEasy Subject Test: Databases - Transactions

asked Jan 27, 2017 in Databases by vaishali jhalani Active (4.8k points) | 58 views

0 votes

1 answer

4

MadeEasy Subject Test: Databases - Transactions
Here T1 T2 T4 T5 will come in this order only and for T3 we have 5 positions So number of schedules will be 5 which are view eq to given schedule. But ans given is 10

asked Jan 26, 2017 in Databases by vaishali jhalani Active (4.8k points) | 64 views

+1 vote

1 answer

5

MadeEasy Subject Test: Databases - Transactions
Consider the following schedule S : r1(A) w2(A) r3(A) w4(A) r5(A) w6(A) The number of schedules equal to given schedule(s) which not conflict equal to schedule(s) are _______.

asked Jan 23, 2017 in Databases by Çșȇ ʛấẗẻ Active (1.9k points) | 86 views

0 votes

1 answer

6

MadeEasy Subject Test: Databases - Transactions
Statement # 5 is correct or not? how?

asked Jan 21, 2017 in Databases by Jason_Roy Junior (697 points) | 92 views

+1 vote

4 answers

7

Conflict Serializable and Timestamp based protocol
I know that every schedule produced by the Timestamp-based protocol is conflict serializable. But is vice versa is true? Means is all conflict serializable schedules produced by timestamp based protocol ?

asked Jan 21, 2017 in Databases by lifeisshubh (249 points) | 583 views

0 votes

1 answer

8

Ace Test Series: Databases - Transactions
Consider the following transaction T1 T2 T3 R(A) W(A) commit W(A) commit W(A) commit Which of the following is TRUE regarding above transaction? (1) Transaction is view serializable since it has a view-equivalent serial schedule < T1, ... schedule < T3, T2 T1 > (4) Transaction is not serializable Your Answer: 3 Correct Answer: 1 Status: incorrect

asked Jan 19, 2017 in Databases by vishwa ratna Active (2.4k points) | 108 views

+1 vote

2 answers

9

2PL protocol
how 2PL is allowed?

asked Jan 19, 2017 in Databases by Supremo (389 points) | 404 views

0 votes

0 answers

10

MadeEasy Subject Test: Databases - Transactions
Which of the following is true? In 2PL protocol if all exclusive lock are acquired by transactions in only increasing order of their addresses then 2PL protocol is deadlock free. In 2PL protocol if all exclusive lock are acquire by ... talking about the address it should be the address of resources right? in that case 4th should be the option

asked Jan 17, 2017 in Databases by Pankaj Joshi Active (2.7k points) | 115 views

+2 votes

2 answers

11

MadeEasy Test Series
Consider the following schedule S : r1(A) w2(A) r3(A) w4(A) r5(A) w6(A) The number of schedules equal to given schedule(s) which not conflict equal to schedule(s) are _______.

asked Jan 10, 2017 in Databases by vnc Active (2.9k points) | 380 views

0 votes

1 answer

12

MadeEasy Subject Test: Databases - Transactions
Consider the following schedule : S::r1(A),r3(D),w1(B),r2(B),r4(B),w2(C),r5(C),w4(E),r5(E),w5(B) The number of serial schedules which are view equal to schedule (S) ___________.

asked Jan 10, 2017 in Databases by vnc Active (2.9k points) | 93 views

0 votes

0 answers

13

MadeEasy Subject Test: Databases - Transactions
T2 is doing one blind write and it is recoverable,so why c is not correct? I agree though that b is also correct.Please help

asked Jan 10, 2017 in Databases by rahul sharma 5 Boss (25.6k points) | 64 views

0 votes

1 answer

14

MadeEasy Subject Test: Databases - Transactions
How to solve this??

asked Jan 9, 2017 in Databases by Lucky sunda Active (4.5k points) | 112 views

0 votes

3 answers

15

[DBMS Schedules] Lost update vs ww conflict
W1(A),R2(A),W2(A),W2(B),W1(B) This schedule has WW conflict but not Lost update problem,Please explain why? Is it possible to have WW conflict without lost update?

asked Jan 7, 2017 in Databases by rahul sharma 5 Boss (25.6k points) | 344 views

0 votes

1 answer

16

MadeEasy Subject Test: Databases - Transactions

asked Jan 5, 2017 in Databases by Akanksha Kesarwani Junior (989 points) | 64 views

0 votes

1 answer

17

Ace Test Series: Databases - Time Stamp Ordering

asked Dec 30, 2016 in Databases by chaser (321 points) | 201 views

+2 votes

0 answers

18

Determining Strict 2PL
Which of the following schedules are allowed by strict 2pl with shared and xclusive locks - r1(A); r2(B); r3(C); w1(B); c1; w2(C); c2; w3(D); c3 r1(A); r2(B); r3(C); r1(B); r2(C); r3(D); c3; ... and strict recoverability and both must be satisfied. In the above 1) and 2) satisfy conflict serializablility and strict recoverability. Then which is the correct solution?

asked Dec 26, 2016 in Databases by yg92 Active (3.2k points) | 305 views

+1 vote

0 answers

19

view serializable
S1: R(A) W(A) W(B) S2: R(A) W(A) R(B) W(B) How many view serializable schedules are possible which are not conflict serializable? (A) 0 (B) 1 (C) 2 (D) 3

asked Dec 25, 2016 in Databases by indrajeet Active (1.7k points) | 243 views

+5 votes

1 answer

20

Schedule's
$1)$ Consider schedule below. Determine whether schedule is cascadeless or not ? r1(x); r2(z); r1(z); r3(x); r3(y); w1(x); c1; w3(y); c3; r2(y); w2(z); w2(y);c2

asked Dec 24, 2016 in Databases by Prabhanjan_1 Boss (12.5k points) | 280 views

+5 votes

3 answers

21

Schedules
$1)$ Find the number of all possible conflict-equivalent and view-equivalent schedules to the following serial schedules. (a) r1(A), w1(B), r2(A), w2(B), r3(A), w3(B).

asked Dec 24, 2016 in Databases by Prabhanjan_1 Boss (12.5k points) | 1.2k views

+2 votes

1 answer

22

ACE TEST SERIES:-Transaction 2pl and Time stamp based protocol

asked Dec 22, 2016 in Databases by KISHALAY DAS Active (4.9k points) | 336 views

+1 vote

2 answers

23

ME-FST6:Transaction,Recoverability and 2PL

asked Dec 21, 2016 in Databases by KISHALAY DAS Active (4.9k points) | 694 views

0 votes

2 answers

24

Transactions

asked Dec 8, 2016 in Databases by Neal Caffery Junior (959 points) | 76 views

0 votes

1 answer

25

MadeEasy Test Series: Databases - Transactions
#plz check i am right ??

asked Dec 6, 2016 in Databases by Hradesh patel Loyal (6.5k points) | 97 views

0 votes

1 answer

26

2Phase locking question.
Which of the following 2PL schemes guarantee conflict serializability? Basic 2PL Conservative 2PL Strict 2PL Rigorous 2PL

asked Dec 3, 2016 in Databases by Aghori Loyal (6.3k points) | 222 views

+4 votes

2 answers

27

Virtual Gate Test Series: Databases - Recover Schedule
Assume there are n transactions$:T_{1},T_{2},.,T_{n}.$ Every transaction writes value of $X$ that is read by its successive transaction like $T_{1}$ writes value of $X$ that is read by $T_{2}, T_{2}$ writes a value of ... $X$ that is read by Tn. Now,if $T_{1}$ fails,then total how many transaction rollbacks are required to recover the schedule?

asked Nov 30, 2016 in Databases by smartmeet Active (4.9k points) | 291 views

+6 votes

2 answers

28

What is "Strict recoverable" schedule?
Consider the following schedule: $S: r_1(A), w_2(A), Commit_2, w_1(A),w_3(A), Commit_3, Commit_1$ Which of the following is true? a. Schedule is view serializable schedule and strict recoverable schedule b. Schedule is ... know what is "strict schedule" and "recoverable schedule", But then what it means by "strict recoverable"?

asked Nov 6, 2016 by GateAspirant999 Active (2.5k points) | 1.8k views

+3 votes

3 answers

29

What equates to definition of irrecoverable schedule?
Which of the following is correct? a. A schedule will be irrecoverable if a transaction reads a data item and commit after it is written by an uncommitted transaction. b. A schedule will be irrecoverable if a transaction writes a data ... given options are not making me any sense in order to relate them to above definition. Whats going on here?

asked Nov 6, 2016 in Databases by GateAspirant999 Active (2.5k points) | 457 views

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