[IMPALA-10105] Implement KLL functions that return array of doubles

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Backend
• Epic Link: unlabelled-IMPALA-9594
• Epic Color: ghx-label-9
• Assignee: Unassigned
• Reporter: Gabor Kaszab
• Created: 25/Aug/20 08:42
• Updated: 25/Aug/20 08:42

Description

There are functions that originally meant to return Array<Double> but since Impala doesn't have support for returning complex types these functions were implemented to return a comma separated string.

To avoid breaking compatibility these functions got "_as_string" postfix:

• ds_kll_quantiles_as_string()
• ds_kll_pmf_as_string()
• ds_kll_cdf_as_string()

This ticket is to implement the version of these functions that actually return an array of doubles.

• ds_kll_quantiles()
• ds_kll_pmf()
• ds_kll_cdf()

This is the Jira that track complex types support as return type:
https://issues.apache.org/jira/browse/IMPALA-9520

Issue Links

• is blocked by: IMPALA-9520 Allow returning complex types from UDFs