Is Replica Of Check FAQ

Answers to common questions about the deprecation, the migration to Data Diff, and how anomalies are reported, grouped by topic.

Deprecation

Is Is Replica Of still supported?

Existing checks keep running, but the rule is no longer maintained and should not be used for new checks. Data Diff is its replacement.

What does Data Diff add?

Diff Change Types, which restricts anomalies to a chosen subset of added, removed, and changed. Everything else, including Row Identifiers, Passthrough Fields, and the Comparators, works the same way.

How do I migrate?

Create a Data Diff check with the same fields, Row Identifiers, Passthrough Fields, reference container, and Comparators, confirm it reports what you expect, then archive the Is Replica Of check.

Will my existing checks stop working?

No. They continue to evaluate. They simply will not receive new capabilities, and the guidance is to replace them.

Behavior

Why is there no Coverage setting?

The rule reports any difference the Comparators do not tolerate, so there is no per-row violation rate to threshold. The coverage field on the API payload accepts only null or 1; any other value is rejected with 422.

What happens without Row Identifiers?

The two sides are compared as sets, so the check can only report that they differ. With identifiers, each target row is paired with its reference row and the per-row detail becomes readable.

How are NULLs compared?

A value that is NULL on both sides matches. A value present on one side and NULL on the other counts as a difference.

Anomaly Reporting

What does the anomaly report?

A single Shape Anomaly reading For <fields>, the referred fields do not replicate the targeted fields, where <fields> is the comma-separated list of compared fields. When a filter is set, the message ends with [filter: <expression>].

Does Is Replica Of produce Record Anomalies?

No. The rule is Shape-only; the divergence belongs to the dataset.

Where do I see the differing rows?

In the anomaly's Comparison Source Records view, provided Row Identifiers are configured.

What permission do I need to create or edit an Is Replica Of check?

The Drafter team permission on the datastore covers Draft work (creating a check as Draft or editing it while it stays Draft). Anything that puts the check into evaluation, such as creating or editing an Active check, archiving, or deleting, requires the Author team permission (or above). Viewing only requires Reporter. See Permissions for the full matrix.