Question

An Eventhouse ingests millions of IoT telemetry rows per hour into a KQL table. A dashboard runs a query that computes the count of events per device over the last 24 hours, and this same aggregation query is executed hundreds of times per minute by many concurrent users. Users report the dashboard is slow and consuming excessive query resources. You need to reduce query latency and resource consumption for this repeated aggregation with minimal ongoing maintenance. What should you do?

Accepted Answer

Create a materialized view that pre-aggregates the event count per device, and have the dashboard query the materialized view.

Answer

Increase the hot cache retention period on the source table so more raw data stays in memory.

Answer

Add an update policy that copies every ingested row into a second table for the dashboard to query.

Answer

Schedule a pipeline to export the aggregated results to a Lakehouse Delta table every hour.