Advanced Transactions

Abstract

The reliable and correct execution of programs is a key concern in the engi- neering of distributed systems. Transactions represent one of the mechanisms commonly used to address reliability and correctness. A transaction groups a set of actions (such as object requests)as one single unit-of-work for which re- liability and correctness properties hold. The properties of atomicity (A) and durability (D)define the notion of reliability in the context of transactions: a set of actions is either executed as one atomic unit-of-work, or none of the ac- tions are executed, and the committed state changes caused by the set of actions are guaranteed to be persistent. The properties of consistency (C)a nd isolation (I)define the notion of correctness in the context of transactions: a transac- tion transforms the system from one consistent state into another consistent state only, and any intermediate system states of an ongoing transaction are not visible to any other concurrent transaction. The two papers in this session describe research on transaction processing that each advance a certain kind of transaction model and transactional middleware technology. This session sum- mary provides a short background on transactions first, and then discusses the presented research papers.