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Recent questions tagged transactions

1 vote
4 answers
1
2 votes
1 answer
2
Consider the following schedule: The number of serial schedules which are view equal to schedule (S) ___________. Answer is 10 as per the given solution. Please explain how to solve these type of questions
asked Jan 12, 2018 in Databases ashish pal 331 views
1 vote
0 answers
3
As commit operations are ordered in each transcations, this schedule is recoverable right? Also please explain how to check for view serializabilty?
asked Jan 11, 2018 in Databases AnilGoudar 261 views
2 votes
1 answer
5
No. Of serial schedules view equal to S S: R1(A), R3(D), W1(B), R2(B), W3(B), R4(B), W2(C), R5(C), W4(E), R5(E), W5(B) . If possible please provide detailed solutions. Thank you in advance
asked Jan 7, 2018 in Databases thepeeyoosh 832 views
0 votes
1 answer
6
We have 2 Schedule S1 and S2 ... There are no Conflict Operation in S1 and S2. So can we say they are conflict equivalent ?
asked Dec 27, 2017 in Databases Anup patel 191 views
0 votes
0 answers
7
Hi Guys, Please tell following statement is T/F --> If there is a schedule which is conflict serializable. But there may not exist any 2 PL with lock upgrade scheme to execute it. PS: ping @Krish__, @rahul sharma 5, @Red_devil, @Shivam Chauhan, @Tuhin Dutta, @Anu007, @Ashwin Kulkarni @reena_kandari and @srestha ji.
asked Dec 26, 2017 in Databases Chhotu 508 views
0 votes
0 answers
8
asked Dec 23, 2017 in Databases soumayan bandhu 106 views
4 votes
2 answers
9
Assume basic timestamp ordering protocol and that time starts from $1$, each operation takes unit amount of time and start of transaction $T_i$ is denoted as $S_i$. The table of timestamp is given below: Find $rts(a), wts(a), rts(b)$ and $wts(b)$ at the end 1, 5, 2, 5 1, 7, 3, 3 3, 7, 3, 7 1, 7, 3, 7
asked Dec 16, 2017 in Databases ankitgupta.1729 1.4k views
0 votes
0 answers
10
S:- r1(a) , w2(a) c2 w1(a) c1 w3(a) c3 Is this strict recoverable and serializable ? c1 means commit of transaction T1
asked Dec 16, 2017 in Databases rahul sharma 5 288 views
0 votes
2 answers
11
A Phantom Read is when two SELECT queries within the same transaction return a different number of rows. But if the number of rows returned is the same and the data is different, is that also considered as Phantom?
asked Dec 15, 2017 in Databases Sumaiya23 867 views
1 vote
1 answer
12
does graph based and time stamp ordering protocol ensure freedom from cascadeless rollback?
asked Dec 11, 2017 in Databases iarnav 587 views
0 votes
1 answer
13
what is the difference btw ABORT AND FAIL IN TRANSACTION? PLEASE EXPLAIN WITH A SMALL EXAMPLE!
asked Dec 11, 2017 in Databases iarnav 150 views
–1 vote
1 answer
14
Please explain the concept of DIRTY READ In a simplified manner w/ a small example!
asked Dec 11, 2017 in Databases iarnav 370 views
3 votes
0 answers
15
Please explain the concept of Blind Write in a simplified manner w/ a small example!
asked Dec 10, 2017 in Databases iarnav 2.8k views
0 votes
0 answers
16
2 votes
1 answer
17
2 votes
0 answers
18
3 votes
0 answers
19
2 votes
1 answer
20
Consider the following schedule: S:R2(A) W1(B) W1(C) R3(B) R2(B) R1(A) C1 R2(C) C2 W3(A)C3 Please explain how it is allowed in 2 PL
asked Dec 6, 2017 in Databases shivangi5 295 views
0 votes
3 answers
21
Consider the 2 transactions T1: R(A) W(A) W(B) T2: 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 6, 2017 in Databases shivangi5 913 views
2 votes
1 answer
23
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) How many serial schedules conflict equal to schedules (S)?
asked Dec 5, 2017 in Databases shivangi5 447 views
1 vote
1 answer
24
How many concurrent schedules are conflict serializable of given transactions T1 and T2: T1 = r1(A) W1(A)R1(B)W1(B) T2 = R2(B)W2(B)R2(A)W2(A)
asked Dec 4, 2017 in Databases sunaina rawat 220 views
0 votes
0 answers
25
1 vote
0 answers
26
2 votes
2 answers
27
0 votes
1 answer
28
In 2PL protocol if all exclusive locks are acquired by transaction in increasing order of their accesses then is the 2PL starvation free ?
asked Nov 26, 2017 in Databases sumit chakraborty 275 views
–1 vote
0 answers
29
1 vote
1 answer
30
The number of concurrent schedules can be formed with 3 transactions having 3, 2 and 1 operations respectively _________ I am getting 54 but the given ans is 60. My doubt is are serial schedules counted or not in the concurrent schedules.
asked Nov 24, 2017 in Databases shivangi5 209 views
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