HI,
Batch Input Session method is asynchronous as told by others here. But the advantage of this is that you have all the error messages and the data for each transaction held persistantly. You don't have to code anything for processing them or writing the logs.
But at the same time, the same feature can be disadvantageous if you need to react to an error or if there are too many errors to manually correct in a session. Since the session are created in the program and its execution is done seperately, you loose the trackability of such transactions.
With a call transaction, what was a disadvantage above will become an advantage. Call transaction immediately gives you messages back and you can react to it in your program. But the disadvantage is that, if you have several hundreds of transactions to run, running them from within the program can be resource crunching affair. It will hamper the system performance and you cannot really distribute the load. Of course, you have some mechanisms with which you can overcome this, but you will have to code for it. Also, storing the messages and storing the errored transaction data etc will have to be handled by you in the program. Whereas, in batch input session, your program's job is to just create the session, after that everything is standard SAP system's responsibility.
Ideally, you should do a call transaction if the resources are not a problem and if it fails, put the errored transaction into a session.
You can decide based on the data volume that your BDC is processing. If data volume is high go for session else call transaction will do.The call transaction updates will be instantaneous where as session needs to be processed explictly after creation.
you can do it both manually and by using program RSBDCSUB
Regards
Bluesky
