Common use of Parallelization Clause in Contracts

Parallelization. ▇▇▇▇▇▇▇ offers to possibility to make multiple calls to the same service in one workflow. This parallelization makes workflows with multiple iterations to finish earlier. The first simple test, carried out in UPF about parallelization demonstrated that simply doubling (x2) one web service in a workflow with only that service reduced the execution time in half. Parallelization seems to be a great advantage but it has its drawbacks. Web services are run on machines with limited resources (processors, memory, etc.) which cannot handle infinite parallel calls to their web services. One problem is that most of those limits can only be measured empirically. Some web service providers offer information about the limits of their web services on the Registry. A bad use of parallelization may cause the server to fail or to be very slow which is the opposite of the desired behavior. To avoid this situation WSP and users can both take precautions: WSP can implement a system to limit the amount of parallel requests. On the other hand, users should follow the recommendations found on the documentation of the web service (Usage conditions). Figure 5 shows how to use the parallelization parameter for a web service in Taverna. The documentation about Parallelization can be found on the Taverna tutorial.