I/O time dominates query execution causing slow performance

Scheduled time and physical input read time metrics dominate total query execution time, indicating I/O bottleneck rather than compute bottleneck. Often caused by small files in S3 or excessive partitions causing slow metadata listing.

Check scheduled time metric and physical input read time metric in query details to confirm I/O dominance. Investigate S3 bucket for small files and consider file compaction. Review partition count and partition pruning strategy. Use EXPLAIN ANALYZE to identify specific I/O bottlenecks.