[IMPALA-10021] Rewrite ds_kll_* functions to use Binary

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Backend, Frontend
• Epic Link: unlabelled-IMPALA-9594
• Epic Color: ghx-label-10
• Assignee: Unassigned
• Reporter: Gabor Kaszab
• Created: 29/Jul/20 09:56
• Updated: 02/Jan/24 12:26

Description

Once Impala supports BINARY type the ds_kll_* could use it instead of STRING to receive/return serialized KLL sketches.

To follow the BINARY support implementation - https://issues.apache.org/jira/browse/IMPALA-9579

Currently when sketches are written by Hive as BINARY to ORC table and this table is loaded to Impala where the sketch columns are STRINGs then we get an error

ERROR: Type mismatch: table column STRING is map to column binary in ORC file

Interestingly the works with Parquet format. Once we have binary support make sure to add coverage for ORC table where the table is created and populated by Hive and read for estimating by Impala.