My table is very huge , we have billions of rows and approximatively 10 000 partitions. my exact question is to force a single bucket in each partition with a partionning clause and a clustered by (col) bucketing 1 when creating the table. so we always have only one file in the score.   The other solution is to let the partitions fill up without a bucketing clause at creation but to compact the table to avoid full of files in the partition. I don't know which is the best solution. I think like you that we have a degradation of the performnaces during the loads because we no longer parrélize (only 1 bucket) ... View more