A system performs masking of data stored in a database. The system receives change logs from a source database and masks the change logs to generate masked change logs. The system stores the masked change logs in a pre-buffer. If the system determines that the set of masked change logs stored in the pre-buffer corresponds to a complete transaction, the system determines whether any conflicts exist between masked change logs stored in the pre-buffer and masked change logs stored in a main buffer. If the system identifies conflicts, the system applies the masked change logs stored in the main buffer to a masked replica database. This causes the system to move masked change logs corresponding to a complete transaction from the pre-buffer to the main buffer.