Hello Jason, IMPALA-5300 (https://issues.apache.org/jira/browse/IMPALA-5300) is in the works, and I think it fits your use case. Can you take a look?
Thanks! On 28 November 2017 at 15:11, Jason Heo <[email protected]> wrote: > Hi, > > I'm wondering impala team has any plans for approximate topN for single > dimension. > > My Web analytic system mostly serves top n urls. Such a "GROUP BY url ORDER > BY pageview LIMIT n" is slow especially for high-cardinality field. > Approximate topN can be used instead of GroupBy for single dimension with > extremely lower latency. > > Elastisearch, Druid, and Clickhouse already provide this feature. > > It would be great if I can use it on Druid. > > Thanks. > > Regards, > > Jason
