Platform Server transactions are fully integrated with external systems database transactions using one-phase commit distributed transactions. This means that, when committing/rolling back a Platform Server's transaction all external systems databases transactions are also committed/rolled back in a serialized way. The Platform Server's transaction is committed/rolled back only after all serialized commits/roll backs are finished.
To See Also
Handling Transactions | Managing Transactions in Exceptions | AbortTransaction Action | CommitTransaction Action