Have you ever face with delta data during migration process between upgraded systems? There are several standard approach to manage these delta. These approach can from simple to complex.
The Simple Way
The simple approach is usually relative to cost. This suits small and mid volume transactional data. You can choose to do a straight cutover from source system to target system. The focus will be on the delta data that reside between the two systems. There are two ways to handle this.
- Reconciliation of data between two system till the delta is cleared. These usually will take 2 to 4 weeks for the target system to reach a steady state.
- Stop processing of delta data in source system and to proceed in target system.
The Complex Way
If you have high transactions and a huge system. It is time to invest to manage the delta automatically. Complex way will usually involve tools or transient ETL (Extract Transform Load) integration between source and target system
- ETL tools are the most common approach to synchronise data at application level. It is automated and can be removed once steady state is reached.
- Another method is the building of a transient application to handle the delta data. This application is focus to manage the delta data and ensure a smooth transition between the two systems
Anyone and everyone will overthink Delta migration. It is always wise and wiser to consider the approach based on your transactions and budget. After all, you cannot request to fly to the moon with an aeroplane.
Danny Kwok 