📄️ COUNT DISTINCT 用ビットマップ
Use bitmaps in StarRocks for efficient COUNT(DISTINCT) calculations with the BITMAP type and bitmap functions, reducing storage space and improving speed.
📄️ おおよその重複排除にHLLを使用する
Use HyperLogLog (HLL) in StarRocks for approximate COUNT(DISTINCT) with ~1-10% error rate, significantly reducing memory usage for large-scale data.
