Notes
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Outline
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Chapter 18
  • Concurrency Control Techniques
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FIGURE 18.1
Lock and unlock operations for binary locks.
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FIGURE 18.2
Locking and unlocking operations for two-mode (read-write or shared-exclusive) locks.
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FIGURE 18.3
Transactions that do not obey two-phase locking. (a) Two transactions T1 and T2. (b) Results of possible serial schedules of T1 and T2.
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FIGURE 18.3
Transactions that do not obey two-phase locking. (c) A nonserializable schedule S that uses locks.
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FIGURE 18.4
Transactions T1¢ and T2 ¢, which are the save as T1 and T2 of Figure 18.3 but which allow the two-phase locking protocol. Not that they can produce a deadlock.
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FIGURE 18.5
Illustrating the deadlock problem. (a) A partial schedule of T1¢ and T2 ¢ that is in a state of deadlock. (b) A wait-for graph for the partial schedule in (a).
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FIGURE 18.6
Lock compatibility tables. (a) A compatibility table for read/write locking scheme. (b) A compatibility table for read/write/certify locking scheme.
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FIGURE 18.7
A granularity hierarchy for illustrating multiple granularity level locking.
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FIGURE 18.8
Lock compatibility matrix for multiple granularity locking.
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FIGURE 18.9
Lock operations to illustrate a serializable schedule.