CCPP: 一个并发C++语言的设计与实现

USING SEMANTICS PASSING TECHNIQUES TO PROCESS MULTILEVEL TRANSACTIONS

并发面向对象语言ＣＯＯＬ（ｃｏｎｃｕｒｅｎｔｏｂｊｅｃｔ－ｏｒｉｅｎｔｅｄｌａｎｇｕａｇｅ）是一种有效的并发程序设计语言．本文提出了一种并发对象模型（ＣｏｎｃｕｒｅｎｔＣ＋＋，ＣＣＰＰ）及其语言．在ＣＣＰＰ并发对象模型中，所有对象都是并发对象，对象间的通讯都采用异步消息发送方式．对象间的同步采用“需要时等待”策略，同一对象内并发线程间的同步用路径表达式描述．ＣＣＰＰ语言是对Ｃ＋＋语言的扩充，采用预编译方法实现．

Traditional read/write transaction model is machine-oriented, i.e., every operation of a transaction is described as a low level access to database, and the transaction has two layer: logical and physical layer. The logical layer is used to express operations to logical database, i.e., update or query to records; the physical layer is used to describe operations to pages of disks. Therefore, it can not capture semantics of applications effectively. The authors present a three layer transaction model, which is constructed by adding a Semantic layer on traditional transaction model. The layer can express various semantic information about application for transaction processing. They also design a concurrency control mechanism ML protocol based on the transaction model. The mechanism can exploit the semantics from semantic layer for scheduling subtransaction at lower level, that is, the semantics can be passed from high level to low level to reduce the ratio of conflicts. ML protocol can pass three kinds of semantics: parallelity, commutativity, and conflict. The schedules produced by ML protocol are serializable.