[CASSANDRA-14956] Paged Range Slice queries with DISTINCT can drop rows from results

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.1.21, 2.2.14
• Component/s: CQL/Interpreter
• Severity: Normal
• Assignee: Sam Tunnicliffe
• Reporter: Sam Tunnicliffe

Authors

Sam Tunnicliffe

Reviewers

Marcus Eriksson

• Created: 07/Jan/19 11:45
• Updated: 16/Apr/19 09:29
• Resolved: 17/Jan/19 13:12

Description

If we have a partition where the first CQL row is fully deleted (possibly via TTLs), and that partition happens to fall on the page boundary of a paged range query which is using SELECT DISTINCT, the next live partition after it is omitted from the result set. This is due to over fetching of the pages and a bug in trimming those pages where overlap occurs.

This does not affect 3.0+.