Freshness Check FAQ¶

Answers to common questions about when the Freshness check runs, where its time comes from, and how AI Managed Freshness checks behave, grouped by topic.

Behavior¶

Does the check read my data?¶

It does not load your records into Qualytics. It needs only the container's last modification time, which is why the rule has neither a filter nor a coverage setting. Snowflake, BigQuery, and Databricks tables provide that time from their metadata. Elsewhere the source computes the newest value of the incremental field, which reads that column across the container.

When is the check evaluated?¶

Only when a Scan that includes the Metadata category runs on the container. The daily Observability measurement updates the chart but never evaluates the check.

How is the age calculated?¶

As the time between the Scan's reading and the container's last modification time. The check fails when that age exceeds the Maximum Age by more than a small margin of up to one minute.

What is the difference between Freshness and Volumetric?¶

Freshness answers when data last arrived by reading the container's last modification time. Volumetric answers how much data arrived by reading the row count. See Freshness or Volumetric?.

Last Modification Time¶

Where does the last modification time come from?¶

For tables on Snowflake, BigQuery, and Databricks, from the platform's own record of the last change. For other tables, views, and computed containers, from the newest value of the incremental field. For files, from the most recent file modification time, or the latest commit or snapshot for Delta and Iceberg tables. See Where the Last Modification Time Comes From.

Why is my check always Not Asserted?¶

The container has no source for its last modification time, usually a view or a table outside Snowflake, BigQuery, and Databricks without a Last Modified incremental field. Set one in the container's settings. See Troubleshooting.

Does a Scan record a measurement?¶

Yes. A Scan that evaluates a Freshness check records the time it read as a measurement, next to the daily Observability measurement. A Profile does not.

Configuration¶

Which units can I use for the Maximum Age?¶

Millis, Seconds, Minutes, Hours, Days, and Weeks, with decimals. The check stores the value as a duration, so the unit only changes how it is entered and displayed. Through the API, the value is in milliseconds.

Can a container have more than one Freshness check?¶

Not at the same time. A container holds one Active Freshness check, AI Managed ones included, so change the Maximum Age of the existing check instead.

AI Managed Checks¶

When does Qualytics create a Freshness check automatically?¶

With Create AI Freshness checks on, once the container has a recorded modification time on at least 8 days within the last 90, and at least three distinct modification times. The Maximum Age follows the usual gap between updates.

What happens if I edit an AI Managed check?¶

Changing its Maximum Age converts it to Authored, and Qualytics stops updating it. Changing only its description, tags, or metadata keeps it AI Managed.