Managing Kudu tables with range-specific hash schemas
he custom hash partition feature enables you to vary the number of hash buckets per range partition, both at table creation and alteration time.
It is possible to specify a different number of hash buckets per range partition when creating or altering a table. This allows for accommodating new ranges of already existing Kudu tables to changes in workload patterns. For example, for a table range-partitioned by date or timestamp it makes sense to increase the number of hash buckets with an increase in ingestion rate to maximize write throughput.
When no hash schema per range is specified for a table’s range either during creation or alteration time, it defaults to the table-wide hash schema. If no table-wide hash schema is specified when the table is created, no hash bucketing for the data is done at all.
Any hash schema specified for a range partition overrides the table-wide hash schema. However, the number of hash dimensions in any range-specific hash schema must be the same as in the table-wide hash schema.
The newly introduced range-specific hash schemas in Kudu are supported by impala-shell.