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Recent questions tagged transaction-and-concurrency

2 votes

4 answers

211

Conflict serializability

Balaji Jegan asked in Databases Jan 17, 2018

by Balaji Jegan

1.5k views

2 votes

1 answer

212

MadeEasy Test Series 2018: Databases - Transactions
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

ashish pal asked in Databases Jan 12, 2018

650 views

1 vote

0 answers

213

Is this recoverable schedule?
As commit operations are ordered in each transcations, this schedule is recoverable right? Also please explain how to check for view serializabilty?

AnilGoudar asked in Databases Jan 11, 2018

727 views

2 votes

2 answers

214

Database question : Transactions

thepeeyoosh asked in Databases Jan 9, 2018

1.1k views

3 votes

1 answer

215

No. Of serial schedules view equal to S
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

thepeeyoosh asked in Databases Jan 7, 2018

2.2k views

0 votes

1 answer

216

We have 2 Schedule S1 and S2 ... There are no Conflict Operation in S1 and S2.
We have 2 Schedule S1 and S2 ... There are no Conflict Operation in S1 and S2. So can we say they are conflict equivalent ?

Anup patel asked in Databases Dec 27, 2017

339 views

1 vote

0 answers

217

2 PL with lock upgrade and Conflict serializability
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.

Chhotu asked in Databases Dec 26, 2017

by Chhotu

782 views

0 votes

0 answers

218

doubt in strict schedule
To determine it is strict we have to go from left to right or from right to left ??

sumit goyal 1 asked in Databases Dec 25, 2017

by sumit goyal 1

339 views

0 votes

0 answers

219

soumayan bandhu asked in Databases Dec 23, 2017

by soumayan bandhu

228 views

5 votes

2 answers

220

Timestamp Ordering Protocol
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

ankitgupta.1729 asked in Databases Dec 16, 2017

by ankitgupta.1729

5.5k views

1 vote

0 answers

221

DBMS schedules
S:- r1(a) , w2(a) c2 w1(a) c1 w3(a) c3 Is this strict recoverable and serializable ? c1 means commit of transaction T1

rahul sharma 5 asked in Databases Dec 16, 2017

by rahul sharma 5

701 views

0 votes

1 answer

222

Transactions & Concurrency Control
The above question has a blind write so it should be View Serializable. But can it be Conflict Serializable?

Kaustubh _15 asked in Databases Dec 16, 2017

by Kaustubh _15

347 views

0 votes

2 answers

223

DBMS Phantom Read
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?

Sumaiya23 asked in Databases Dec 15, 2017

1.2k views

1 vote

1 answer

224

#dbms locking protocol
does graph based and time stamp ordering protocol ensure freedom from cascadeless rollback?

iarnav asked in Databases Dec 11, 2017

by iarnav

1.3k views

1 vote

1 answer

225

#DBMS FAIL V/S ABORT
what is the difference btw ABORT AND FAIL IN TRANSACTION? PLEASE EXPLAIN WITH A SMALL EXAMPLE!

iarnav asked in Databases Dec 11, 2017

by iarnav

730 views

–1 vote

1 answer

226

# dbms DIRTY READ
Please explain the concept of DIRTY READ In a simplified manner w/ a small example!

iarnav asked in Databases Dec 11, 2017

by iarnav

608 views

5 votes

1 answer

227

#DBMS Blind Write
Please explain the concept of Blind Write in a simplified manner w/ a small example!

iarnav asked in Databases Dec 10, 2017

by iarnav

9.3k views

1 vote

0 answers

228

Abhijeet_Kumar asked in Databases Dec 8, 2017

by Abhijeet_Kumar

239 views

2 votes

1 answer

229

Abhijeet_Kumar asked in Databases Dec 8, 2017

by Abhijeet_Kumar

273 views

3 votes

1 answer

230

Abhijeet_Kumar asked in Databases Dec 8, 2017

by Abhijeet_Kumar

400 views

4 votes

0 answers

231

Abhijeet_Kumar asked in Databases Dec 8, 2017

by Abhijeet_Kumar

288 views

3 votes

1 answer

232

2 Phase Locking
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

shivangi5 asked in Databases Dec 6, 2017

792 views

2 votes

3 answers

233

VIEW SERIALIZABILITY
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

shivangi5 asked in Databases Dec 6, 2017

2.0k views

2 votes

1 answer

234

Conflict and View serializable

Parshu gate asked in Databases Dec 5, 2017

680 views

2 votes

1 answer

235

MadeEasy Test Series: 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) How many serial schedules conflict equal to schedules (S)?

shivangi5 asked in Databases Dec 5, 2017

1.4k views

2 votes

1 answer

236

Transaction
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)

sunaina rawat asked in Databases Dec 4, 2017

by sunaina rawat

568 views

1 vote

0 answers

237

MadeEasy Test Series: Databases - Transactions
Deadlock prevention(wait-kill && wound-wait) is free from both starvation as well as deadlock? True or false?

learner_geek asked in Databases Dec 1, 2017

by learner_geek

226 views

1 vote

0 answers

238

MadeEasy Subject Test: Databases - Transactions
In below schedule (S) it has cascading abort or not?

learner_geek asked in Databases Dec 1, 2017

by learner_geek

274 views

2 votes

2 answers

239

recoverable and cascadeless

Parshu gate asked in Databases Nov 28, 2017

708 views

0 votes

1 answer

240

Database 2PL protocol
In 2PL protocol if all exclusive locks are acquired by transaction in increasing order of their accesses then is the 2PL starvation free ?

sumit chakraborty asked in Databases Nov 26, 2017

by sumit chakraborty

923 views

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Recent questions tagged transaction-and-concurrency