Questions tagged [database-concurrency]
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8 questions
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violation of only the ACID Consistency property for these transactions
A question that appeared in the Competitive Exam (GATE CS 2025, Set 2) in India:
An audit of a banking transactions system has found that on an earlier occasion, two joint holders of account $A$ ...
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If two schedules have the same precedence graph, then they are conflict equivalent
Let $S_{1}$ and $S_{2}$ be two schedules over the same set of transactions. If both schedules have the same precedence graph, does it follow that $S_{1}$ and $S_{2}$ are conflict equivalent.
I think ...
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How are blind writes recoverable in a transaction schedule?
Consider the following schedule -
T1 T2
R(A)
W(A)
R(A)
W(A)
Commit
Commit
I understand that this schedule is non-recoverable, because if ...
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Checking if Schedule is recoverable
Consider the following schedule S.Is S conflict–serializable? Append the commit operations of these transactions at the end of the
schedule in an appropriate order such that S is recoverable. How many ...
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What will you do if multiple users access your application at the same time?
I'm an experienced Software Engineer but very weak in concurrency because of no prior experience in that. I've been interviewing with several companies in which I was asked similar kinds of questions ...
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2
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how two phase commit ensure serializability
Two phase commit is used in distributed transaction. For example, a client sends a transaction to two databases with a coordinator.
step1: client get a global transaction id from coordinator
step2: ...
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Does basic 2 PL always ensure conflict serializability?
While going through the DBMS book by Korth, it was mentioned :
" For a set of transactions, there may be conflict-serializable schedules that
cannot be obtained through the two-phase locking ...
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Why do OS and DBMS have their own synchronisation mechanisms, when OS can alone do it and it sits at the bottom of DB?
I know that synchronization is important in the OS, but why do we need a separate topic synchronization and concurrency in the DBMS? The OS concentrates on program synchronization while the DBMS ...
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