hash 分区的用途是什么?

Hash partitioning enables easy partitioning of data that does not lend itself to range
or list partitioning. It does this with a simple syntax and is easy to implement. It is a
better choice than range partitioning when:
You do not know beforehand how much data maps into a given range
The sizes of range partitions would differ quite substantially or would be
difficult to balance manually
Range partitioning would cause the data to be undesirably clustered
Performance features such as parallel DML, partition pruning, and
partition-wise joins are important
The concepts of splitting, dropping or merging partitions do not apply to hash
partitions. Instead, hash partitions can be added and coalesced.