An automatic transaction allows the transaction to span more than one remote procedure call. That is, once an automatic transaction is started through some remote procedure call, you can explicitly terminate it in the same procedure call or in a subsequent procedure call running in the same AppServer session. To control this type of transaction, the AppServer provides attributes and methods that you can use to specify how and when you want the transaction to end.

With automatic transactions, transactions tend to grow large, with greater potential for lock conflicts and other concurrency problems. (For more information on small and large transactions, see OpenEdge Getting Started: ABL Essentials.) Even so, automatic transactions can be extremely useful where the application requires the transaction to span multiple AppServer requests. This is especially true where client response is entirely programmatic and does not depend on user interaction for a transaction to complete.

An example of a useful application might be where a transaction commit depends on a real-time status from a process control or financial trading system. Depending on this status, the AppServer might require additional information from the client to resolve the transaction. As long as the client does not have to wait to make this information available to the AppServer, the impact of the automatic transaction on system performance can be minimal. For more information on managing automatic transactions, see Implementing automatic transactions.