quantile(0) = min value quantile(1) = max value you can use sketch-to-quantiles post agg to get min, max or any number of other quantiles
Regarding your observation that sketch-to-histogram(num bins) does not give information about the computed split points. That is valuable feedback. Perhaps, we could consider returning the split points somehow, but I am not quite sure what the return type should be. We need to return two arrays: probability mass in each bin as we do currently - that is one array of doubles, and split points computed from min, max, and given number of bins. And this post agg can accept split points - should we return them in that case as well for consistency? On Fri, Nov 6, 2020 at 3:30 AM Jérémie Girault <jere...@hubvisor.io> wrote: > Hello everyone, > > I previously asked a question on the ASF slack and someone replied to me > by asking me to send the question on the dev list. I just subscribed to the > list to forward the message I sent : > > I was playing with the DataSketches Quantiles Sketch module in druid > trying to retrieve some histograms using quantilesDoublesSketchToHistogram. > However I couldn't label the values I retrieved for each bin when using > numBins when trying to plot them. > I can’t seem to find any postAggregator that allows me to get min/max > values in order to recompute bins on the client side. > Should I use min/max aggregators when ingesting, and query them alongside > my histogram as a workaround ? It seem a lot of space/time that would seem > to be « free » to retrieve using Quantile Sketches. > Wouldn’t it be useful to have min/max postAggregators for > quantilesDoubleSketches aggregator and/or histogram bins labels ? > I located this chunk of code: > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_apache_druid_blob_master_extensions-2Dcore_datasketches_src_main_java_org_apache_druid_query_aggregation_datasketches_quantiles_DoublesSketchToHistogramPostAggregator.java&d=DwIFaQ&c=sWW_bEwW_mLyN3Kx2v57Q8e-CRbmiT9yOhqES_g_wVY&r=0TpvE_u2hS1ubQhK3gLhy94YgZm2k_r8JHJnqgjOXx4&m=PUk1rdn3YFgKzf5pRy7hKdCZt_J-_DZgbh_wjexBneI&s=fb3Uh150BuY9jtM8DqGofrqtwQrM9jDfupPq6MwF5hk&e= > That does not seem overly complicated in a way I could not contribute, but > I’m not used to java dev these days and it would take me a while to get it > right. > Would such features be considered if requested/submitted ? > > Thank you, > > -- > > Jérémie Girault >
