Database (3i Infotech Papers): Sample Questions 1 - 2 of 294
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Question number: 1
» Database » MySQL
Describe in Detail
What is System R? What are its two major subsystems?
Explanation
Figure of the System R
Figure of the system R
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System R was designed and developed over a period of 1974 - 79 at IBM San Jose Research Center.
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It is a prototype and its purpose was to demonstrate that it is possible to build a Relational System that can be used in a real life environment to solve real life problems, with performance at least comparable to that of existing system.
Its two subsystems are
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Research Storage
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System Relational Data System.
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Question number: 2
» Database » MySQL
Describe in Detail
What is a Phantom Deadlock?
Explanation
Explanation of Phantom Deadlocks.
Explanation of Phantom Deadlocks.
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In distributed deadlock detection, local information generates the deadlock detection algorithms to identify deadlocks that do not really exist.
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In systems that implement locking for concurrency control during transactions deadlocks can occur- so these systems need some kind of mechanism to detect solve the problem.
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Deadlock can also occur in distributed systems where transaction locks are held in different servers, this means that the loop in the entire wait-for graph will not be apparent to any one server.
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A solution is to introduce a coordinator to which each server forwards it’s wait-for graph- coordinator will be able to produce a wait-for graph for the entire system and can decide about process/transaction to be aborted to resolve the deadlock.
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The above introduces another problem known as Phantom Deadlock.