Please take a look at hbase-client/src/main/java/org/apache/hadoop/hbase/client/coprocessor/AggregationClient.java which shows several other aggregations.
BTW group by functionality would involve some more work since rows for the same group may span multiple regions. Cheers On Fri, Aug 7, 2015 at 9:42 AM, Nicolae Marasoiu <[email protected] > wrote: > Hi, > > I need to implement a limited sql like filter+group+order, and the group is > on a fixed-length prefix of the rowkey (fixed per query), and the results > are multiple metrics including some custom ones like statistical unique > counts. > > I noticed that available tooling with coprocessors, like > ColumnAggregationProtocol, involve just one metric e.g. one sum(column). We > collect many, and of course it is more efficient to scan the data once. > > Please advise, > Nicu >
