CS186-L13: Transactions & Concurrency I

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Intro

transaction’s principle ACID

Isolation (Concurrency)

however, do not consider serial execution 😅

Atomicity and Durability

Consistency

Concurrency Control

基本符号表达

序列等价性：

• $Def1:$ Serial Schedule
  • each transaction executes in a serial order, one after the other, without any intervening
• $Def2:$ schedules Equivalent
  • involve same transaction
  • each transaction’s actions are the same order
  • both transactions have the same effect on the database’s final state
• $Def3:$ Serializable
  • if a schedule is serializable, then it is equivalent to some serial schedule

Conflict Serializability

conflict operations?

Intuitive Understanding of Conflict Serializable

Conflict Dependency Graph

View Serializability

Conclusion

Neither definition allows all schedules that are actually serializable.

because they can not check the meaning of the operation 😈