How Session Or call Transaction works in case of failuers

Hi All,

Please let me know what happens when a failure occurs while processing in a session or call transaction.

For example, if there are 1000 records in flat file- whemn processed in the session (SM30), if any faliure or system breaksdown, what happens-

Will the records be processed

Or Will it start again from the first

Or Do we need to remove the processed ones from flat file or

And run the session again for the error ones.

What if same is applied to CALL TRANSACTION.

Reward if helpful.

Chandralekha