Use the following rules and guidelines while using concurrency:
Concurrency supports sorted input rows as multiple concurrent connections to a web service. Ordered output rows are not supported.
Use concurrency if the data set is more than 100 rows.
It is advisable not to increase the number of concurrent web service connections. The number of concurrent web service connections is linked to the number of sockets used by the operating system. Increasing the number of sockets is expensive.
Use systems that have multi-core processors with a minimum of 100 MB of RAM for optimal performance while using the concurrency feature.
Concurrency memory limit represents the memory consumed by concurrent work flows while invoking web services.
When you enable concurrency in the Web Service Consumer transformation, you can configure the memory consumption limit. Ensure that the memory consumption is not more than the physical RAM on the server.