[IMPALA-11582] Implement table sampling for Iceberg tables

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 4.2.0
• Component/s: Frontend
• Labels: impala-iceberg
• Epic Color: ghx-label-3
• Assignee: Zoltán Borók-Nagy
• Reporter: Zoltán Borók-Nagy
• Created: 13/Sep/22 13:40
• Updated: 27/Sep/22 07:16
• Resolved: 27/Sep/22 07:16

Description

Currently Iceberg tables cannot be sampled.

We should allow table sampling for Iceberg tables in SELECT and COMPUTE STATS statements.

Predicates in the WHERE clause should affect the results of table sampling similarly to how legacy tables work (sampling is applied after static partition pruning).

Make the operation repeatable via the REPEATABLE clause.

See details at https://impala.apache.org/docs/build/html/topics/impala_tablesample.html