commit | 28d94851b1418ddd57e4c046646f7a2df0e702d7 | [log] [tgz] |
---|---|---|
author | Gabor Kaszab <gaborkaszab@cloudera.com> | Tue Aug 25 10:20:13 2020 +0200 |
committer | Impala Public Jenkins <impala-public-jenkins@cloudera.com> | Wed Aug 26 10:59:49 2020 +0000 |
tree | 5dc71251cbd81169599c8d905e443a1baa434cbe | |
parent | a8a35edbc407e02187279ac8d090a345d026c57a [diff] |
IMPALA-10020: Implement ds_kll_cdf_as_string() function This is the support for Cumulative Distribution Function (CDF) 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), (-inf, 5), (-inf, 10), (-inf, +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_cdf() 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_cdf_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_cdf_as_string(ds_kll_sketch(float_col), 2, 4, 10) from alltypes; +----------------------------------------------------------+ | ds_kll_cdf_as_string(ds_kll_sketch(float_col), 2, 4, 10) | +----------------------------------------------------------+ | 0.2,0.401644,1,1 | +----------------------------------------------------------+ Change-Id: I77e6afc4556ad05a295b89f6d06c2e4a6bb2cf82 Reviewed-on: http://gerrit.cloudera.org:8080/16359 Reviewed-by: Gabor Kaszab <gaborkaszab@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Lightning-fast, distributed SQL queries for petabytes of data stored in Apache Hadoop clusters.
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