Recent questions tagged conflict-serializable / GATE Overflow for GATE CSE

0 votes

1 answer

31

Self Doubt on serializable
If a schedule is not conflict-serializable. Is it serializable?

If a schedule is not conflict-serializable. Is it serializable?

abhinowKatore

262 views

abhinowKatore asked Sep 8, 2022

0 votes

0 answers

32

Serializability
What is Proof/Explanation for complexity to test if a schedule is conflict serializable is O(n^2) whereas for view serializable is O(2^n)-Exponential ?

What is Proof/Explanation for complexity to test if a schedule is conflict serializable is O(n^2) whereas for view serializable is O(2^n)-Exponential ?

SakarKoot

237 views

SakarKoot asked Sep 4, 2022

12 votes

2 answers

33

GATE CSE 2022 | Question: 29
Let $\textit{R}_{i}(z)$ and $\textit{W}_{i}(z)$ denote read and write operations on a data element $z$ by a transaction $\textit{T}_{i},$ respectively. Consider the schedule $\textit{S}$ ... $T_{4} \rightarrow T_{1} \rightarrow T_{3} \rightarrow T_{2}$ $T_{3} \rightarrow T_{1} \rightarrow T_{4} \rightarrow T_{2}$

Let $\textit{R}_{i}(z)$ and $\textit{W}_{i}(z)$ denote read and write operations on a data element $z$ by a transaction $\textit{T}_{i},$ respectively. Consider the sched...

Arjun

8.7k views

Arjun asked Feb 15, 2022

0 votes

1 answer

34

Self doubt - Serializability - DBMS
Can a schedule be serializable if it is not view serializable? Are conflict equivalence and view equivalence the only two ways to decide if a schedule is serializable?

Can a schedule be serializable if it is not view serializable? Are conflict equivalence and view equivalence the only two ways to decide if a schedule is serializable?

atulcse

462 views

atulcse asked Nov 2, 2021

0 votes

1 answer

35

conflict serializable
Find Total no of conflict serializable and view serializable T1: R1(A) W1(A) R1(B) W1(B) T2: R2(A) W2(A) R2(B) W2(B)

Find Total no of conflict serializable and view serializableT1: R1(A) W1(A) R1(B) W1(B)T2: R2(A) W2(A) R2(B) W2(B)

sambey4

316 views

sambey4 asked Oct 16, 2021

13 votes

2 answers

36

GATE CSE 2021 Set 2 | Question: 32
Let $S$ be the following schedule of operations of three transactions $T_1$, $T_2$ and $T_3$ in a relational database system: $R_2(Y), R_1(X), R_3(Z), R_1(Y)W_1(X), R_2(Z), W_2(Y), R_3(X), W_3(Z)$ Consider the statements $P$ and $Q$ below: $P$ ... Both $P$ and $Q$ are true $P$ is true and $Q$ is false $P$ is false and $Q$ is true Both $P$ and $Q$ are false

Let $S$ be the following schedule of operations of three transactions $T_1$, $T_2$ and $T_3$ in a relational database system:$$R_2(Y), R_1(X), R_3(Z), R_1(...

Arjun

7.2k views

Arjun asked Feb 18, 2021

9 votes

3 answers

37

GATE CSE 2021 Set 1 | Question: 32
Let $r_i(z)$ and $w_i(z)$ denote read and write operations respectively on a data item $z$ by a transaction $T_i$. Consider the following two schedules. $S_1: r_1(x)r_1(y)r_2(x)r_2(y)w_2(y)w_1(x)$ ... serializable, and $S_2$ is conflict serializable Both $S_1$ and $S_2$ are conflict serializable Niether $S_1$ nor $S_2$ is conflict serializable

Let $r_i(z)$ and $w_i(z)$ denote read and write operations respectively on a data item $z$ by a transaction $T_i$. Consider the following two schedules.$S_1: r_1(x)r_1(y)...

Arjun

5.6k views

Arjun asked Feb 18, 2021

2 votes

0 answers

38

NIELIT 2017 July Scientist B (CS) - Section B: 46
Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item $x$, denoted by $r(x)$ and $w(x)$respectively. Which one of them is conflict serializable? $r_1(x);r_2(x);w_1(x);r_3(x);w_2(x)$ ... $r_2(x);w_2(x);r_3(x);r_1(x);w_1(x)$ $1$ $2$ $3$ $4$

Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item $x$, denoted by $r(x)$ and $w(x)$respecti...

admin

831 views

admin asked Mar 30, 2020

2 votes

1 answer

39

Geeksforgeeks: GATE CS Mock 2018
Consider the given schedule and choose the suitable option S = T1:R(x), T1:R(y), T1:W(x), T2:R(y), T3:W(y), T1:W(x), T2:R(y) Schedule is view serializable Schedule is conflict serializable but not view serializable Schedule is view serializable but not conflict serializable Neither view serializable nor conflict serializable

Consider the given schedule and choose the suitable option S = T1:R(x), T1:R(y), T1:W(x), T2:R(y), T3:W(y), T1:W(x), T2:R(y)Schedule is view serializableSchedule is confl...

ushamya

8.1k views

ushamya asked May 22, 2019

1 votes

0 answers

40

Made Easy Databases
Consider the following schedules with data item x The number of serial schedules which are view equal to schedules but not conflict equal is ___________.

Consider the following schedules with data item xThe number of serial schedules which are view equal to schedules but not conflict equal is ___________.

Hirak

699 views

Hirak asked May 5, 2019

0 votes

0 answers

41

self doubt
In this answer, how is the number of conflict equivalent schedule equal to T1->T2 equal to 1(How is it being calculated). And how is the number of conflict equivalent schedule equal to T2->T1 being calculated??It is very confusing please Help!!!!!

In this answer, how is the number of conflict equivalent schedule equal to T1->T2 equal to 1(How is it being calculated). And how is the number of conflict equivalent sch...

_Bash_

484 views

_Bash_ asked Apr 2, 2019

0 votes

2 answers

42

Self doubt on 2PL protocol
How can 2PL protocol ( simple one ) ensure conflict serializability even though it cannot ensure freedom from deadlock ? I mean ,if a schedule is conflict serializable it has a conflict equivalent to a serial schedule and serial schedules won't have deadlocks .Right ?

How can 2PL protocol ( simple one ) ensure conflict serializability even though it cannot ensure freedom from deadlock ?I mean ,if a schedule is conflict serializable it...

ashunimbz

590 views

ashunimbz asked Mar 30, 2019

0 votes

2 answers

43

Gate Previous Year Question-2009
I am getting the answer as c but the given answer is b. How b can be ans, there is a cycle R1x->W1x (s1->s2) and W1y->w1y(s2->s1),so s1,s2 can not be conflict serializable… i m confused.. what is the right answer?

I am getting the answer as c but the given answer is b. How b can be ans, there is a cycle R1x->W1x (s1->s2) and W1y->w1y(s2->s1),so s1,s2 can not be conflict serializabl...

debasree88

910 views

debasree88 asked Feb 24, 2019

0 votes

0 answers

44

me adv test
Consider the following schedule: S:R2(A), W1(B), W1(C), R3(B), R2(B), R1 (A), commit_1, R2(C), commit_2, W3(A), commit_3 How many given statements true about schedule(S)____. (i) Schedule(S) is conflict serializable schedule. (ii) Schedule(S) is ... strict recoverable schedule. (iv) Schedule(S) is allowed by strict 2PL. only 1 is correct as per my answer but in answer they have given 3

Consider the following schedule:S:R2(A), W1(B), W1(C), R3(B), R2(B), R1 (A), commit_1, R2(C), commit_2, W3(A), commit_3How many given statements true about schedule(S)___...

newdreamz a1-z0

511 views

newdreamz a1-z0 asked Jan 24, 2019

0 votes

0 answers

45

Is there any example of schedule which is Strict but not serializable
I have gone through link https://stackoverflow.com/questions/40859477/is-a-strict-schedule-always-serializable But i don’t think example given there is correct.I don’t think it is strict schedule as T2 is reading x which is written by T1 , even before T1 commits. Hence is any other example which is strict but not serializable?

I have gone through link https://stackoverflow.com/questions/40859477/is-a-strict-schedule-always-serializableBut i don’t think example given there is correct.I don’t...

mehul vaidya

328 views

mehul vaidya asked Jan 22, 2019

0 votes

0 answers

46

UPPCL AE 2018:71
Consider the following transactions with data items $\text{P}$ and $\text{Q}$ initialized to zero: T1: read (P); read (Q); if P = 0 then Q : = Q + 1; write (Q); T2: read (P); read (P); if Q = ... concurrent execution leads to A serializable schedule A conflict serializable schedule A schedule for which a precedence graph cannot be drawn A schedule that is not conflict serializable

Consider the following transactions with data items $\text{P}$ and $\text{Q}$ initialized to zero:T1: read (P); read (Q); if P = 0 then Q : = Q + 1; write (Q); T2: read (...

admin

312 views

admin asked Jan 5, 2019

0 votes

0 answers

47

Conflict serializability
Is this statement"every conflict serializable schedule is also view serializable but vice-vice-versa is not true" is true?

Is this statement"every conflict serializable schedule is also view serializable but vice-vice-versa is not true" is true?

Nishtha_Agarwal

1.3k views

Nishtha_Agarwal asked Dec 26, 2018

1 votes

1 answer

48

SCHEDULING
Consider the transactions T1, T2, T3 with the following schedule S: S : T1: Read (x); T2: Read (z); T1:Read(z); T3:Read(x);T3:Read(y); T1:Write(x); T3:Write (y);T2:Read(y); T2:Write(z); T2:Write(y) If the schedule S is serializable, the equivalent serial schedule is ____. i am getting T3T1T2 but answer given is T3T2T1

Consider the transactions T1, T2, T3 with the following schedule S:S : T1: Read (x); T2: Read (z); T1:Read(z); T3:Read(x);T3:Read(y); T1:Write(x); T3:Write (y);T2:R...

Satbir

4.4k views

Satbir asked Dec 11, 2018

1 votes

2 answers

49

Transaction dbms self doubt
T1 T2 R(A) W(A) W(A) IS THIS IS VIEW SERIALIZABLE?PLZ EXPLAIN

T1T2R(A) W(A)W(A) IS THIS IS VIEW SERIALIZABLE?PLZ EXPLAIN

gatecrack

735 views

gatecrack asked Dec 10, 2018

1 votes

0 answers

50

2 Phase Locking
is it supported by 2PL?

is it supported by 2PL?

aditi19

599 views

aditi19 asked Dec 8, 2018

2 votes

1 answer

51

Raghuramkrishnan
T1 T2 T3 R(X) W(X) commit W(X) commit R(X) commit is this transaction conflict serializable and view serializable?

T1T2T3R(X)W(X)commitW(X)commitR(X)commit is this transaction conflict serializable and view serializable?

aditi19

2.3k views

aditi19 asked Nov 18, 2018

0 votes

1 answer

52

Raghuramkrishnan
T1 T2 T3 W(Y) commit R(X) R(Y) W(Z) commit W(X) commit is this schedule a strict schedule?

T1 T2 T3W(Y)commitR(X)R(Y)W(Z)commitW(X)commitis this schedule a strict schedule?

aditi19

634 views

aditi19 asked Nov 18, 2018

1 votes

1 answer

53

RaghuramKrishnan
Tl:W(X), T2:R(X), Tl:W(X), T2:Commit, Tl:Abort is this schedule conflict serializable?

Tl:W(X), T2:R(X), Tl:W(X), T2:Commit, Tl:Abortis this schedule conflict serializable?

aditi19

1.2k views

aditi19 asked Nov 17, 2018

0 votes

0 answers

54

Serializable

smsubham

556 views

smsubham asked Nov 12, 2018

0 votes

0 answers

55

Serializable Schedule
It's a question I already asked and correct answer is 2 but what's wrong with this approach help me :(

It's a question I already asked and correct answer is 2 but what's wrong with this approach help me :(

Na462

467 views

Na462 asked Oct 18, 2018

0 votes

0 answers

56

Number of Conflict Equal and View Equal Schedules
How many Conflict Serializable and View serializable schedules for the Schedule given below $S:r_1(A),w_1(B),w_1(C),r_2(A),w_2(B),w_2(C)$ To both my answer comes to be 7. Is it correct?

How many Conflict Serializable and View serializable schedules for the Schedule given below$S:r_1(A),w_1(B),w_1(C),r_2(A),w_2(B),w_2(C)$To both my answer comes to be 7.Is...

Ayush Upadhyaya

870 views

Ayush Upadhyaya asked Oct 11, 2018

5 votes

1 answer

57

Conflict Serializabilty
How many conflict equivalent schedules are possible for the given schedule ? $R_1(A), R_2(A), R_3(A), R_4(A), W_1(B), W_2(B), W_3(B), W_4(B)$

How many conflict equivalent schedules are possible for the given schedule ?$R_1(A), R_2(A), R_3(A), R_4(A), W_1(B), W_2(B), W_3(B), W_4(B)$

Hardik Maheshwari

1.0k views

Hardik Maheshwari asked Oct 10, 2018

0 votes

0 answers

58

2pl protocol
Can someone explain how transactions can be serialized in order of their lock points (the point where the transactions acquire their final lock)?

Can someone explain how transactions can be serialized in order of their lock points (the point where the transactions acquire their final lock)?

Parimal Paritosh

422 views

Parimal Paritosh asked Sep 2, 2018

2 votes

2 answers

59

Databases
State true or false: a schedule has only constrained write operations and the schedule is view serializable then it's also conflict serializable

State true or false: a schedule has only constrained write operations and the schedule is view serializable then it's also conflict serializable

Ajaaz

491 views

Ajaaz asked Aug 6, 2018

1 votes

1 answer

60

Serializability

Na462

1.1k views

Na462 asked Jul 14, 2018

tags	tag:apple
author	user:martin
title	title:apple
content	content:apple
exclude	-tag:apple
force match	+apple
views	views:100
score	score:10
answers	answers:2
is accepted	isaccepted:true
is closed	isclosed:true