[GitHub] leerho commented on issue #6853: horrible histogram post-aggregation

[GitBox <gi...@apache.org>]

leerho commented on issue #6853: horrible histogram post-aggregation 
URL: https://github.com/apache/incubator-druid/issues/6853#issuecomment-455671914
 
 
   @quenlang 
   
   There are very good reasons why it is not a good idea for a quantiles (or histogram) sketch to "interpolate" between actual values in the data.  Fundamentally, in order for the sketch to be independent of the input data distribution, it cannot make any assumptions about what that distribution might be.  And, in order to "interpolate", one must make assumptions about the input data distribution.  For example, interpolating using linear, power-law, Gaussian, or discontinuous step distributions would produce wildly different results. Therefore it is best to not to make any assumptions about the input data distribution and only return values actually sampled from the real data. 

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