Web service built from other web services

Question

How can a web service built from other web services have transaction properties? Compare this mechanism with that provided by a TP monitor.

Answer 1

A web service built from other web services has transaction properties using nested transaction model. It allows transactions to consist of other transactions: a top-level transaction may contain sub-transactions. In a nested transaction model, the sub-transactions are within the scope of the top-level transaction (t). Transactions in a nested transaction model also adhere to the ACID properties of transactions—that is, t completes effectively only when ts1 and ts2 both complete successfully. When either sub-transaction fails, the top-level transaction would fail, thus guarantee atomicity.

The nested transaction model permits services to be built independently and later joined into applications. Each service can find out the scope of its transaction boundaries. The application or service which orchestrates the combination of services controls the scope of top-level transaction. The transaction processing (TP) monitors enhance the underlying operating system’s scalability and its capability to manage big transaction volumes, by taking on some of the roles of the underlying operating system. For illustration, a TP monitor, in addition to managing transactions, too performs connection pooling and task or thread scheduling and pooling.