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Graphics Interchange Format  |  1996-11-15  |  40KB  |  335x459  |  4-bit (15 colors)
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OCR: TASK A TASK B LOCK MANAGER Waiting for Waiting for release of release of RID 2001 by RID 4221 by TASK 8 TASK A 1. Task A issues Select*from Employee; (1000 shared locks set) 2. Task B issues Update employee set salary = salary" 1.1; (waits for Task a to release its shared locks) 3. Task A now issues Update employee set bonus_flag = 1; (Task A now waits for the exclusive locks set by TASK B to release, unaware that Task A is waiting on its own locks) FIGURE 3. Database deadlocks (the perpetual embrace).