[jira] [Created] (IMPALA-9632) Implement ds_hll_sketch() and ds_hll_estimate() functions

["Gabor Kaszab (Jira)" <ji...@apache.org>]

Gabor Kaszab created IMPALA-9632:
------------------------------------

             Summary: Implement ds_hll_sketch() and ds_hll_estimate() functions
                 Key: IMPALA-9632
                 URL: https://issues.apache.org/jira/browse/IMPALA-9632
             Project: IMPALA
          Issue Type: New Feature
          Components: Backend, Frontend
            Reporter: Gabor Kaszab


These should be built-in functions that use DataSketches functionality that was integrated by [IMPALA-9631|https://issues.apache.org/jira/browse/IMPALA-9631].

ds_hll_sketch() should receive a primitive expression and return a sketch.
ds_hll_estimate() should receive a sketch and return a primitive that is the cardinality estimate for that set of data provided to the sketch.

Usage:
select ds_hll_estimate(ds_hll_sketch(col_name)) from table_name;
Returns a cardinality estimate (similarly to ndv() ) for that particular column.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org