1. A computer program product for controlling execution of a transaction in a computing environment, the computer program product comprising: a non-transitory computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: initiating, by a processor, execution of a transaction in a transaction mode via a transaction begin instruction, the transaction begin instruction to begin any one of a first type of transaction or a second type of transaction, the transaction comprising a plurality of instructions to be executed, and the transaction begin instruction explicitly indicating by a field of the transaction begin instruction the first type of transaction or the second type of transaction being initiated; based on being in transaction mode, effectively delaying committing transactional stores to main memory until completion of a selected transaction; based on the transaction aborting, determining the type of transaction initiated, the type of transaction being the first type of transaction or the second type of transaction, and the determining being based on the field of the transaction begin instruction; based on the transaction aborting and the transaction being the first type of transaction, resuming execution at the transaction begin instruction; and based on the transaction aborting and the transaction being the second type of transaction, resuming execution at a next sequential instruction directly following the transaction begin instruction in program order.