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Pessimistic Concurrency Control

悲观并发控制(Pessimistic Concurrency Control, PCC) 指让可能对系统一致性造成影响的 事务 排他地独占资源,其他冲突 事务 只能等待或回滚,是 并发控制 的一种方式。

悲观并发控制 包含:


Pessimistic - Block an operation of a transaction, if it may cause violation of the rules, until the possibility of violation disappears. Blocking operations is typically involved with performance reduction.[1]

Database System Concepts

In contrast, locking and timestamp ordering are pessimistic in that they force a wait or a rollback whenever a conflict is detected, even though there is a chance that the schedule may be conflict serializable.[2]

  1. ↩︎

  2. Silberschatz, Abraham, Henry F. Korth, and S. Sudarshan. Database System Concepts. Seventh edition. New York, NY: McGraw-Hill, 2020. ↩︎