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Chapter 17
  • Introduction to Transaction Processing Concepts and Theory
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FIGURE 17.1
Interleaved processing versus parallel processing of concurrent transactions.
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FIGURE 17.2
Two sample transactions. (a) Transaction T1. (b) Transaction T2.
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FIGURE 17.3
Some problems  that occur when concurrent execution is uncontrolled. (a) The lost update problem.
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FIGURE 17.3 (continued)
Some problems  that occur when concurrent execution is uncontrolled. (b) The temporary update problem.
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FIGURE 17.3 (continued)
 Some problems  that occur when concurrent execution is uncontrolled. (c) The incorrect summary problem.
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FIGURE 17.4
State transition diagram illustrating the states for transaction execution.
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FIGURE 17.5
Examples of serial and nonserial schedules involving transactions T1 and T2. (a) Serial schedule A: T1 followed by T2. (b) Serial schedules B: T2 followed by T1.
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FIGURE 17.5 (continued)
Examples of serial and nonserial schedules involving transactions T1 and T2. (c) Two nonserial schedules C and D with interleaving of operations.
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FIGURE 17.6
Two schedules that are result equivalent for the initial value of X = 100 but are not result equivalent in general.
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FIGURE 17.7
Constructing the precedence graphs for schedules A and D from Figure 17.5 to test for conflict serializability. (a) Precedence graph for serial schedule A. (b) Precedence graph for serial schedule B. (c) Precedence graph for schedule C (not serializable). (d) Precedence graph for schedule D (serializable, equivalent to schedule A).
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FIGURE 17.8
Another example of serializability testing. (a) The READ and WRITE operations of three transactions T1, T2, and T3.
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FIGURE 17.8 (continued)
Another example of serializability testing. (b) Schedule E.
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FIGURE 17.8 (continued)
Another example of serializability testing. (c) Schedule F.
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FIGURE 17.8 (continued)
Another example of serializability testing.
(d) Precedence graph for schedule E.
(e) Precedence graph for schedule F.
(f) Precedence graph with two equivalent serial schedules.