/tags/distributed-systems/Recent content in Distributed Systems on Yiwei ShiHugoen-usMon, 11 May 2026 22:52:17 -0400/posts/20260511-readtime-olap/Mon, 11 May 2026 22:52:17 -0400/posts/20260511-readtime-olap/<p>A comparison of ClickHouse, StarRocks, Apache Druid, and Apache Pinot — the four engines defining real-time analytics in 2026.</p> <h2 id="why-real-time-olap-matters-now">Why Real-Time OLAP Matters Now</h2> <p>The old split was clean: OLTP for operations, batch warehouses for BI. Data freshness measured in hours was fine, because the workloads were retrospective.</p> <p>That model has broken. User-facing analytics, fraud detection, ad bidding, and RAG-style AI applications all need sub-second queries over billions of rows, with data that&rsquo;s seconds old. Real-time OLAP databases close the gap between streaming ingestion (Kafka, Flink) and interactive analytical queries.</p>