Abstract: A system and method for an online transaction system to transition from operating under a first mode (FM) to operating under a second mode (SM), and vice versa. In the FM, transaction nodes identify transactions with sequential numbers obtained from a global transaction server (GTS). In the SM, transaction nodes identify consecutive transactions with timestamps based on global clock servers (GCSs). When transitioning from one mode to the other mode, a controller instructs the transactions nodes to provide GCS-based transaction timestamps and error bounds to the GTS, which modifies the timestamps and the error bounds based on previously received timestamps and error bounds, and on the latest transaction number issued by the GTS. Modified timestamps and error bounds are obtained at the transaction nodes. Each transaction is timestamped with its respective modified timestamp. But there is a delay equal to the modified error bound before requesting another modified timestamp.