The official documentation here says “delete all partitions less than the given expression.” I guess this means “merge all partitions less than the given expression into the new first partition”?
Deleting partitions gives the impression that the data in the partitions is also deleted~
It makes more sense that the data in the partitions less than the given expression still exists.
This means that data will be deleted because you have set a new minimum partition. Therefore, the data in the partitions smaller than the new one will be deleted and cleaned up, which is in line with the original design.
The original intention of the official partition table design was to facilitate the deletion of large amounts of data. If you want to merge a large amount of data into a new partition, it would be inconsistent with the original design and usage on one hand; on the other hand, merging partition data means reorganizing the data, which consumes a lot of resources. Although after merging, you only need to query one partition, you can achieve the same purpose by expanding the query range without merging. In short, the benefits of merging are minimal and completely unnecessary.