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Deadlock

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• Deadlock
  • Deadlock:

    Deadlock = a state of execution where 2 or more transactions are unable to proceed because the transactions involved are waiting of each other's locks

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  • Example:

    Consider the following 2 transactions: A possible interleaved execution (that obeys the locking rules) is:

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• 2PL and deadlocks
  • Fact:

    2PL can not prevent deadlocks

    Evidence:

    In the example above, both transactions are 2PL However, their execution resulted in deadlock

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• Resolving deadlocks
  • Deadlock detection and deadlock resolution are topics in the next chapter.....

    In this chapter, we focus on ensuring serializability