Database-MySQL (3i Infotech Papers): Sample Questions 1 - 2 of 162

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Question number: 1

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Essay Question▾

Describe in Detail

What is System R? What are its two major subsystems?

Explanation

Figure of the system R

Figure of the System R

Figure of the system R

  • System R was designed and developed over a period of 1974 - 79 at IBM San Jose Research Center.

  • 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

    • Research Storage

    • System Relational Data System.

Question number: 2

» Database » MySQL

Essay Question▾

Describe in Detail

What is a Phantom Deadlock?

Explanation

Explanation of Phantom Deadlocks.

Explanation of Phantom Deadlocks.

Explanation of Phantom Deadlocks.

  • In distributed deadlock detection, local information generates the deadlock detection algorithms to identify deadlocks that do not really exist.

  • 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.

  • 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.

  • 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.

  • The above introduces another problem known as Phantom Deadlock.