A transaction processing system provides the capability to use one two-phase commit engine over multiple protocols and products, while being able to vary the log presumptions according to the requirements of each protocol and product. The transaction processing system comprises a coordinator operable to receive a commit or abort request from a transaction and to perform a two-phase commit protocol on behalf of the transaction and a recovery presumption mechanism operable to perform a recovery process on the transaction upon recovery of the transaction processing system from a failure.