A one-time historical data generation process that runs when a persisted aggregation is first created. When you specify a backfill duration, LogScale generates aggregated results for past intervals as if the aggregation had been running historically. For example, specifying a 30-day backfill duration creates results for the previous 30 days of data. Unlike scheduled search backfill limits, persisted aggregation backfill is a one-time operation that executes sequentially from the earliest interval forward. Mutable references such as lookup files and saved queries are resolved using their current state at backfill execution time, not their historical state. Backfills follow the same considerations as backfilling any data in LogScale. If persisted aggregation execution lags too far beyond current time, the status may show as backfilling.