Hash partitioning
Another way of partitioning the metrics
table is to hash partition on the host
and
metric
columns.
In the example above, the metrics
table is hash partitioned on the host
and metric
columns into four
buckets. Unlike the range partitioning example earlier, this partitioning strategy will spread
writes over all tablets in the table evenly, which helps overall write throughput. Scans over a
specific host and metric can take advantage of partition pruning by specifying equality
predicates, reducing the number of scanned tablets to one. One issue to be careful of with a pure
hash partitioning strategy, is that tablets could grow indefinitely as more and more data is
inserted into the table. Eventually tablets will become too big for an individual tablet server
to hold.