Aggregation operations under-partition causing multi-fold performance degradation

Aggregation operations default to Final (single partition) mode when FinalPartitioned would provide better performance. TPC-DS query 4 shows 1.95x speedup and TPC-H query 3 shows 1.10x speedup when forced to partitioned mode. Issue becomes significant when accumulating more than 200k groups.

Monitor datafusion.aggregate.groups metric. When group count exceeds 200k, consider forcing partitioned aggregation by reviewing optimizer settings. Examine query plans for Final mode aggregations on high-cardinality group-by operations. Dynamic switching proposed but not yet implemented.