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Field Count Troubleshooting

Common problems when creating and running a Field Count check, their causes, and how to resolve them.

Validation Fails When Creating the Check

Clicking Validate returns an error instead of a success message.

Cause: The rule could not read the container's shape. The most common reasons are a connection problem with the source or a container that failed to load.

Resolution:

  1. Review the error message: it explains what needs attention.
  2. If the message says the container is marked as Unloadable, the container was skipped after repeated operation failures. Follow the steps in Unloadable Container Error.

The Check Fires After a Legitimate Schema Change

A column was added on purpose and the check now reports every scan.

Cause: The comparison is an equality against a fixed number, so any change in either direction fails.

Resolution: Update Number of Fields to the new count as part of shipping the schema change. When the table is expected to keep evolving, consider whether an equality on the count is the right rule at all.

A Renamed Column Is Not Detected

A field was renamed and the check stayed green.

Cause: A rename leaves the count unchanged, and Field Count only compares counts.

Resolution: Add an Expected Schema check, which asserts the names and the declared types.

There Is No Filter or Coverage Option

The form shows neither a Filter Clause nor a Coverage slider.

Cause: Both options are row-level concepts, and this rule evaluates the container's shape. They are absent from the form, and the API rejects them with 422 Unprocessable Entity.

Resolution: No action needed. To scope a structural rule to part of the data, model that part as its own container.

An Edited Check Keeps Behaving the Old Way

You changed the configuration but the anomaly list did not change.

Cause: Edits take effect on the next Scan. Saving the check does not re-evaluate the data, and anomalies raised under the previous configuration are not modified.

Resolution: Run a Scan on the container (or wait for the scheduled one). Old anomalies stay open until you triage them or a Full scan with Auto Resolve clears them. See What Happens to Existing Anomalies.

No Anomalies Although the Data Looks Wrong

A Scan ran, the data clearly breaks the rule, but nothing was reported.

Cause: The check is in Draft status: Draft checks are not evaluated by Scans.

Resolution: Set the check to Active and run a Scan on the container.