Question

A telemetry pipeline lands IoT device readings into a KQL database table in an Eventhouse. Devices frequently resend the same reading (identified by DeviceId and ReadingTimestamp) due to network retries, producing duplicate rows. Analysts must always query only the most recent version of each reading with minimal query latency, and the deduplication logic should be precomputed and kept current automatically as new data arrives. What should you implement?

Accepted Answer

A materialized view using arg_max() over the ingestion time, grouped by DeviceId and ReadingTimestamp

Answer

An update policy that writes deduplicated rows into a second table on each ingestion batch

Answer

A stored function that applies summarize arg_max() at query time whenever analysts run reports

Answer

A retention policy that automatically deletes older duplicate rows after a short soft-delete window