A technique is disclosed for synchronizing first and second data sets stored in a data repository. A method includes triggering, by the data repository, in response to a commit order relating to an ongoing transaction requested by a client and instructing the data repository to apply data modification(s) on the first data set, transmission of a notification event message relating to the ongoing transaction to a data consistency controller. The method includes receiving, by the data repository, a notification event response message relating to the ongoing transaction from the data consistency controller, the notification event response message indicating to the data repository whether (i) to commit the data modification(s) instructed by the commit order on the first data set and corresponding data modification(s) on the second data set, or (ii) to roll back the data modification(s) instructed by the commit order on the first data set.