Atomicity and consistency issues in service composition and transactional memory

事务的概念是为数据库应用程序提供容错、可靠性和健壮性的基础。多年来，研究人员一直试图为其他非数据库应用程序实现类似的事务保证。该建议涉及在服务计算领域中纳入服务的事务属性，以及在事务存储器领域中纳入存储器操作的事务属性。事务是程序的执行。它在执行完成并成功时提交。否则，它被中止，部分执行（如果有的话）被回滚。因此，事务是一个原子单元。每个事务在单独执行时都被认为是正确的。当多个事务的并发执行等价于相同事务的串行执行时，则认为该执行是正确的。在服务计算中，一般的愿景是服务可以（i）以独立于实现和“语义”的方式进行描述，（ii）在通常可访问的存储库中发布，（iii）由客户以标准方式找到，（iv）组成适合其需求的新服务，以及（v）通过引用其选择背后的服务提供者来执行。组合服务还可以被组合成更高级别的服务。“黑匣子”服务逐渐被其执行可以被消费者监视甚至控制（以有限的方式）的服务所取代。我的研究旨在为这些服务整合事务属性，以实现灵活和动态的组合。在transmitted Memory中，内存操作被分组为原子单元。划分为原子单元的目的是为了使程序员从使用锁、临界区等显式同步不同单元中解放出来。我建议工作的特点正确的并发执行的原子单位和组成性质。最终目标是使并发编程变得容易。这将有助于提高计算速度，特别是在多核机器中。

The concept of transactions has been fundamental for providing fault tolerance, reliability and robustness for database applications. Over the years, researchers have been trying to achieve similar transactional guarantees for other, non-database, applications. This proposal is concerned with incorporating transactional properties for services in the area of Services Computing and for memory operations in the area of Transactional Memory. A transaction is an execution of a program. It is committed when the execution is complete and successful. Otherwise, it is aborted and partial execution, if any, is rolled back. Thus, a transaction is an atomic unit. Each transaction, when executed alone, is assumed to be correct. A concurrent execution of several transactions is taken to be correct when the execution is equivalent to some serial execution of the same transactions. In Services Computing, the general vision is that services can be (i) described in an implementation-independent and ``semantic'' fashion, (ii) published in generally accessible repositories, (iii) found in standard ways, by clients, (iv) composed into new services fitting their needs, and (v) executed by referring back to the service providers behind their selection. Composite services may further be composed into higher level services. ``Black box'' services are gradually replaced by services whose executions can be monitored and even controlled (in a limited way) by consumers. My research aims at incorporating transactional properties for such services to enable flexible and dynamic compositions. In Transactional Memory, memory operations are grouped into atomic units. Demarcation into atomic units is intended to free the programmers from explicit synchronization of different units using locks, critical sections, etc. Nesting of the atomic units occurs naturally, with procedure calls. I propose to work on characterizing correct concurrent executions of atomic units and on compositional properties. The ultimate goal is to make concurrent programming easy. This will facilitate increasing the speed of computation, especially in multi-core machines.