Metric Check FAQ¶

Answers to common questions about what the Metric check measures, why it needs one row, and how its comparisons use history, grouped by topic.

Behavior¶

What does the check measure?¶

The value of one numeric field on one row, once per Scan. It records that value as a measurement and compares it with your limits, or with the previous measurement for a change comparison.

Why does it need exactly one row?¶

Because it follows a single value over time. With several rows there is no single number to record, so the Scan marks the check Not Asserted. Build the value in a computed table that returns one row, or narrow a summary table to one row with the filter clause.

Can I use it to check every row of a table?¶

No. To bound every row's value, use Between, Min Value, or Max Value. To compare an aggregate of the whole table, use Aggregation Comparison, or put a Metric check on a computed table that holds the aggregate.

When is the check evaluated?¶

On every Scan that includes the Data Integrity check category, for Active checks only. A Profile does not evaluate it or record a measurement.

History¶

What does a change comparison compare against?¶

The check's most recent measurement from an earlier Scan of the same read strategy. Incremental Scans compare with the last Incremental Scan, and Full Scans with the last Full Scan.

Why did the first Scan pass?¶

A change comparison has no previous measurement on its first Scan of each read strategy, so it only records the value. It starts comparing on the next Scan.

Does an anomalous value become the new baseline?¶

Yes. Every evaluation records a measurement, pass or fail, so the next Scan compares with the anomalous value. A one-day spike therefore usually produces a second anomaly the next day, when the value returns to normal.

Configuration¶

Can I change the field or comparison later?¶

Only until a Scan has included the check. After that, create a new check and archive the old one. The limits and the filter clause can still change.

Can I have several Metric checks on the same field?¶

Yes, as long as each Active check has its own combination of filter clause and comparison. A check per region on the same field, each with its own filter, is a common setup.

Does Qualytics create Metric checks automatically?¶

No. Metric checks are always authored. There is no AI Managed version of this rule.