Understand backfilling and recalculation of analyses

Asset Analytics provides four options for backfilling and recalculating historical data:

• Backfilling: Manually calculates missing data for a selected time range and fills in the gaps for analysis outputs.

• Recalculation: Manually deletes data in a selected time range and recalculates analysis outputs.

• Automatic Backfilling: Automatically fills in gaps caused by PI Analysis Service downtime (up to 72 hours by default).

• Automatic Recalculation: Runs analyses when new time-stamped input is received before the latest evaluated trigger occurs.This setting is useful for late-arriving inputs.

Backfilling compared to recalculation

When you backfill an analysis, it calculates missing data for the selected time range and fills in any gaps. In contrast, recalculation deletes all data in the time range and regenerates analysis results. For more information, see the AVEVA Knowledge Base article: Asset analytics backfilling and recalculation milestones and requirements.

Expression, rollup, and statistical quality control (SQC) analyses can be backfilled or recalculated for an earlier time period if their outputs are mapped to PI point attributes. Backfilling retains existing data, while recalculation deletes and regenerates all data in the selected time range. Recalculating event frame generation analyses deletes all event frames and their annotations in a selected time range before creating new ones.

Backfilling or recalculation may write out‑of‑order events when outputs map to PI point attributes. These events are stored in Data Archive without compression.

Note: You must have execute permission to perform backfilling or recalculation. To obtain this permission, map the user account to the Asset Analytics Recalculation identity. For more information on identity mappings, see Learn about PI AF identities and mappings.

Automatic backfilling compared to automatic recalculation

Automatic backfilling fills gaps caused by short periods of PI Analysis Service downtime (up to 72 hours by default).

Automatic recalculation is enabled by default using the AutoRecalculationEnabled setting. To use it for late‑arriving or out‑of‑order data, enable recalculation at the analysis template level.

For more information about automatic backfilling and recalculation, see the following topics:

• Understand PI Analysis Service settings

• Configure automatic recalculation of analyses and analyses templates

• Enable or disable automatic recalculation for multiple analyses

• Open the recalculation log folder

  Note: Event frame generation and SQC analyses that generate event frames are excluded from automatic recalculation.