Real-Time BI: Enabling Sub-Second Queries on Apache Iceberg Data Lakehouses

This article discusses how to enable real-time, sub-second interactive BI queries on Apache Iceberg data lakehouses, despite the inherent latency of cloud object storage like S3. It identifies three key sources of latency: file scan latency, metadata scan overhead, and data transfer latency. Solutions include file layout optimization (e.g., targeting 128-512 MB files, partition pruning, compaction) and Dremio's Columnar Cloud Cache (C3) for caching frequently accessed data on local SSDs. The article provides a technical architecture for achieving low-latency analytics, making it relevant for data engineers and BI professionals working with modern data lakehouses.