Refactor a legacy data processing pipeline that reads XML files, transforms them, and writes to a SQL database. The current implementation blocks I/O threads causing high latency. Rewrite the logic using a reactive programming paradigm (such as Project Reactor or RxJava) to achieve non-blocking backpressure. Specifically, handle the scenario where the database cannot keep up with the ingestion rate by implementing a buffering strategy that prioritizes recent data over old data, ensuring system stability under load.