Operations must reprocess historical partitions for one corrected transformation. Normal daily ingestion will continue. Which practices support a safe and repeatable backfill? Select 2 answers.

1. Delete all historical partitions even though only a bounded interval requires correction.
2. Use an appropriate idempotent replacement or merge strategy and validate counts and quality before exposing corrected results.
3. Record every partition as complete before its corrected output is written.
4. Define an explicit source interval and transformation version, and identify the affected target partitions or logical records.
5. Append corrected rows without any source identity while leaving all erroneous copies indistinguishable.