A PostgreSQL database migration is a challenging task, especially when dealing with mission-critical applications that handle large volumes of data, such as time-series data applications. The traditional "dump" and "restore" method can cause downtime, which may be unacceptable for businesses operating 24/7. An alternative approach called "ingest and backfill" aims to minimize migration downtime by sending duplicate data to a new instance for a while before backfilling the historical data needed for daily applications. This method allows for schema migration first, followed by converting PostgreSQL tables into hypertables, which are optimized for time-series data. The ingest process is then directed to the new Timescale Cloud instance, and once it's ready, the real-time production data can be sent to both databases, with the option to backfill historical data at a later stage. This approach provides extra peace of mind by allowing for parallel operation of two databases and enables verifying data consistency before flipping the switch.