Hi everyone, I’ve recently started using Apache Pinot 1.4 and set up a real-time table with upsert enabled, consuming data from Kafka. I ingested about 1.7 million rows across 12 segments, and during the initial load test, query performance was blazing fast. However, after restarting the server, I noticed: • The server’s memory usage dropped noticeably • A significant spike in query latency, especially in

schedulerWaitMs

Additional details: • Ingestion is stopped (so no extra Kafka load) • Increasing

pinot.query.scheduler.query_runner_threads

helped slightly, but performance is still slower than before the restart • Tried both MMAP and HEAP loading modes with similar results • I am running Pinot cluster on k8s nodes Has anyone run into similar behavior after a restart? Any idea why it happens? Any recommendations or configuration tips to improve performance would be much appreciated

A restart by itself cannot degrade performance. Did you change any configs (eg indexing) that may have been rebuilt due to restart?