Properties of VolumeBasedRangeShardingAlgorithm VOLUME_RANGE is not clear

[TeslaCN]

Question

My scenario is range sharding.

ID distributes in [1, 32]

Range sharding into 4 data sources: ds_0: [1, 8] ds_1: [9, 16] ds_2: [17, 24] ds_3: [25, 32]

I thought the configuration was:

    shardingAlgorithms:
      warehouse:
        type: VOLUME_RANGE
        props:
          range-lower: 1
          range-upper: 33
          sharding-volume: 8

But the proper configuration is the following:

    shardingAlgorithms:
      warehouse:
        type: VOLUME_RANGE
        props:
          range-lower: 9
          range-upper: 25
          sharding-volume: 8

The properties may confuse users.