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Recent questions tagged transaction-and-concurrency

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1 answer
91
ISRO2020-22
Raymonds tree based algorithm ensures no starvation, but deadlock may occur in rare cases no deadlock, but starvation may occur neither deadlock nor starvation can occur deadlock may occur in cases where the process is already starved
Raymonds tree based algorithm ensuresno starvation, but deadlock may occur in rare casesno deadlock, but starvation may occurneither deadlock nor starvation can occurdead...
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0 answers
94
DBMS Korth Edition 4 Exercise 16 Question 31 (Page No. 636)
Give example schedules to show that if any of lookup, insert or delete do not lock the next key value, the phantom phenomenon could go undetected.
Give example schedules to show that if any of lookup, insert or delete do not lock the next key value, the phantom phenomenon could go undetected.
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2 answers
97
DBMS Korth Edition 4 Exercise 16 Question 27 (Page No. 635)
Explain the phantom phenomenon. Why may this phenomenon lead to an incorrect concurrent execution despite the use of the two-phase locking protocol ?
Explain the phantom phenomenon. Why may this phenomenon lead to an incorrect concurrent execution despite the use of the two-phase locking protocol ?
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100
DBMS Korth Edition 4 Exercise 16 Question 24 (Page No. 635)
Under what conditions is it less expensive to avoid deadlock than to allow deadlocks to occur and then to detect them ?
Under what conditions is it less expensive to avoid deadlock than to allow deadlocks to occur and then to detect them ?
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104
DBMS Korth Edition 4 Exercise 16 Question 20 (Page No. 635)
Show that there are schedules that are possible under the two-phase locking protocol, but are not possible under the timestamp protocol, and vice versa.
Show that there are schedules that are possible under the two-phase locking protocol, but are not possible under the timestamp protocol, and vice versa.
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106
DBMS Korth Edition 4 Exercise 16 Question 17 (Page No. 634)
Although SIX mode is useful in multiple-granularity locking, an exclusive and intend-shared (XIS) mode is of no use. Why is it useless ?
Although SIX mode is useful in multiple-granularity locking, an exclusive and intend-shared (XIS) mode is of no use. Why is it useless ?
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108
DBMS Korth Edition 4 Exercise 16 Question 15 (Page No. 634)
When a transaction is rolled back under timestamp ordering, it is assigned a new timestamp. Why can it not simply keep its old timestamp ?
When a transaction is rolled back under timestamp ordering, it is assigned a new timestamp. Why can it not simply keep its old timestamp ?
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116
DBMS Korth Edition 4 Exercise 16 Question 7 (Page No. 633)
Show by example that there are schedules possible under the tree protocol that are not possible under the two-phase locking protocol, and vice versa.
Show by example that there are schedules possible under the tree protocol that are not possible under the two-phase locking protocol, and vice versa.
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118
DBMS Korth Edition 4 Exercise 16 Question 5 (Page No. 632)
Most implementations of database systems use strict two-phase locking. Suggest three reasons for the popularity of this protocol.
Most implementations of database systems use strict two-phase locking. Suggest three reasons for the popularity of this protocol.
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119
DBMS Korth Edition 4 Exercise 16 Question 4 (Page No. 632)
What benefit does rigorous two-phase locking provide ? How does it compare with other forms of two-phase locking ?
What benefit does rigorous two-phase locking provide ? How does it compare with other forms of two-phase locking ?
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