commit | a8a35edbc407e02187279ac8d090a345d026c57a | [log] [tgz] |
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author | Gabor Kaszab <gaborkaszab@cloudera.com> | Tue Aug 11 15:59:55 2020 +0200 |
committer | Impala Public Jenkins <impala-public-jenkins@cloudera.com> | Wed Aug 26 01:50:16 2020 +0000 |
tree | 6b16502ca1402f2231728bfe531cdab8304a8140 | |
parent | e133d1838ab05e75007fef24e2ce1b6f18113c8d [diff] |
IMPALA-10019: Implement ds_kll_pmf_as_string() function This is the support for Probabilistic Mass Function (PMF) from Apache DataSketches KLL algorithm collection. It receives a serialized KLL sketch and one or more float values to represent ranges in the sketched values. E.g. [1, 5, 10] will mean the following ranges: (-inf, 1), [1, 5), [5, 10), [10, +inf) Returns a comma separated string where each value in the string is a number in the range of [0,1] and shows that what percentage of the data is in the particular ranges. Note, ds_kll_pmf() should return an Array of doubles as the result but with that we have to wait for the complex type support. Until, we provide ds_kll_pmf_as_string() that can be deprecated once we have array support. Tracking Jira for returning complex types from functions is IMPALA-9520. Example: select ds_kll_pmf_as_string(ds_kll_sketch(float_col), 2, 4, 10) from alltypes; +----------------------------------------------------------+ | ds_kll_pmf_as_string(ds_kll_sketch(float_col), 2, 4, 10) | +----------------------------------------------------------+ | 0.202192,0.199452,0.598356,0 | +----------------------------------------------------------+ Change-Id: I222402f2dce2f49ab2b3f6e81a709da5539293ba Reviewed-on: http://gerrit.cloudera.org:8080/16336 Reviewed-by: Gabor Kaszab <gaborkaszab@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
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