Consider the following two transactions: TI-R(B), W(B), R(C), R(A) T2-R(B). W(B) Say that sharing lock, exclusive lock, and unlock actions are inserted by the scheduler, resulting in the following annotated transactions: T1= X(B), R(B), W(B), S(C), R(C), S(A), U(B), R(A), U(C), U(A) T2-X(B), R(B), W(B), U(B) Cascading rollback is not possible for the above schedule. O True O False

Consider the following two transactions: TI-R(B), W(B), R(C), R(A) T2-R(B). W(B) Say that sharing lock, exclusive lock, and unlock actions are inserted by the scheduler, resulting in the following annotated transactions: T1= X(B), R(B), W(B), S(C), R(C), S(A), U(B), R(A), U(C), U(A) T2-X(B), R(B), W(B), U(B) Cascading rollback is not possible for the above schedule. O True O False

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Similar questions

Consider the following two transactions: T1 = R(A). W(A), R(B), R(C) T2 - W(C). R(B), R(A). W(B) Say that sharing lock, exclusive lock, and unlock actions are inserted by the scheduler, resulting in the following annotated transactions: T1 - X(A), R(A), W(A), S(B), R(B), S(C), U(A), R(C), U(B), S(C) T2 - X(C), W(C), X(B), S(A), U(C), R(B), R(A), U(A), W(B), U(B) The above schedule follows 2 PL so conflict serializability is guaranteed. O True O False
We are given the following transaction schedule, where A,B,C are the addresses of the records in the database and T1 and T2 are the transactions. T1 R(A) W(A) R(B) W(B) R(C) W(C) COMMIT T2 R(C) R(B) W(B) a) Show that using strict two-phase locking leads to complications b) For example a, draw a »waits-for<< graph c) Resolve the problems in example a, using the "Wound-Wait" protocol R(A) W(A) W(C) COMMIT
We have the following transactions with associated schedulesT1: R(A) R(B) W(A)T2: R(A) R(B) W(A) W(B)a) Give the schedule of transactions T1 and T2 that leads to a WR conflict.b) Give the schedule of transactions T1 and T2 that lead to RW conflict.c) Give the schedule of transactions T1 and T2 that leads to a WW conflict.d) For each of the given schedules, show how a strict 2FZ would prevent this.
Consider a database with objects X and Y. There are two transactions, as follows: T1: read(X), write(Y), write(X), commit T2: read(Y), write(X), write(Y), commit Give an example schedule that results in a Read-Write (RW) conflict. Explain why Strict Two-Phase Locking (Strict 2PL) would not allow your schedule from part (a) above. Give an example schedule that results in a Write-Write (WW) conflict. Explain why Strict Two-Phase Locking (Strict 2PL) would not allow your schedule from part (c) above.
Consider the following 2 transactions: T1: R(A); R(B); B=A+B; W(B) T2: R(B); R(A); A=A+B; W(A) Change T1 and T2 by adding X lock and S lock to satisfy strict two-phase locking. (Please format your answer in the following way: for a simple read on A with S lock, you can write S(A); R(A); unlock(A)) Will the execution of your changed T1 and T2 cause deadlock? If so, please provide a schedule example. You can write the schedule in the table format with columns T1 and T2.
SIf a decomposition of a relation R into R¡ and R2 is lossless, then which of the followings are true? |(a) R can be reproduced by natural join of R1 and R2 (i.e, by R¡ ¤R2).. |(b) All the functional dependencies can be checked without computing Rị ¤ R2. (c) R1NR2 forms a super key for either R1 or R2. |(d) All of them.
Consider the following schedule that performs actions taken by transactions 71 and T2 on data items A and B T1: R(B), W(B), W(A), Commit T2: R(B). W(B). OAltisar sa OB. It is an unrecoverable schedule OC. It is a strict schedule. OD. It is a serial schedule. R(A), recoverable schedule. Abort
Consider the following lock requests as given below. S1(A), S2(B),X3(A),X2(C),S1(B),S1(C),X2(B) 12(B). X3(A) Note that • S(..) and X(..) stand for 'shared lock' and 'exclusive lock', respectively. • T1, T2, and T3 represent three transactions. • Transactions will never release a granted lock. a. Determine whether there exists a deadlock in the lock requests and explain why in detail supporting all the arguments
Q3: Define the Conflict Serializability, then consider three transactions T1, T2, and T3, and two schedules S1 and S2 given below such that: S1: R1(X), R3(K), R2(Y), R1(Y), R3(X), R3(Z), W1(X), W3(Z), R2(Z), W2(Y), W2(Z), W3(K). S2: R1(Y), R3(Z), R1(X), R2(K), W2(X), W1(X), W2(Y), W3(Y), W2(K), W1(Y), W3(Y), W3(Z). Test whether they are Conflict Serializability or not?
Consider a database with objects X and Y and assume that there are two transactions T1 and T2. Transaction T1 reads objects X and Y and then writes object X. Transaction T2 reads objects X and Y and then writes objects X and Y. 1. Give an example schedule with actions of transactions T1 and T2 on objects X and Y that results in a write-read conflict. 2. Give an example schedule with actions of transactions T1 and T2 on objects X and Y that results in a read-write conflict. 3. Give an example schedule with actions of transactions T1 and T2 on objects X and Y that results in a write-write conflict.
Let Tran1,Tran2 & Tran3 be three independent transactions. Where Tran1 transfers the one fourth of the A accounts fund to B account. Tran2 updates the balance of the B account by 32% & Tran3 transaction provides two third of the prior balance of the A account (before providing funds to B account) to the charity account. Now write down the concurrent transactions according to the serial given above.
Consider a database with objects A, B, X and Y. Assume that there are two transactions T1 and T2 performing R (read) and W (write) operations before they C (commit). Given are two example schedules. Identify them as serializable or not serializable. Also explain with reason(s). If any of the schedule(s) is identified as not serializable then show with proof that strict 2PL disallows this schedule. [6] a) RI[A] → W1[A] → R2[B] → W2[B] → R2[A] → W2[A] → RI[C] → W1[C] →C1 + C2 b) R1[X]→R1[Y] → R2[X] →W2[X] → R2[Y]→W1[X] → W1[Y] → W2[Y] →C1 C2