Data Monitoring / Power BI Refresh & Data Reliability
Power BI: Query folding regression
A small transformation change causes refresh to read far more source rows. Inspect folding indicators or a query plan where supported and compare source-side row filtering before and after the change.
Environment and inputs: Power BI Desktop and Power BI service; gateway, connector, capacity and license capabilities depend on the deployed configuration.
Failure scenario
A small transformation change causes refresh to read far more source rows. Confirm the cause before choosing a fix.
Evidence to collect
Inspect folding indicators or a query plan where supported and compare source-side row filtering before and after the change. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Move compatible filters earlier and verify that source work falls without changing returned records. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for query folding regression using the same scope and a representative interval. Check that the symptom is resolved, expected records are present and downstream results are correct. If coverage, correctness or latency worsens, restore the recorded configuration through the agreed rollback process.
Scope and precautions
Prefer read-only access and limit queries to the relevant period or dataset. This example has not been tested on your systems. Test changes in an approved environment. Keep credentials and sensitive data out of shared evidence.