[KUDU-1291] Efficiently support predicates on non-prefix key components

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: perf, tablet
• Labels: performance roadmap-candidate
• Target Version/s: Backlog
• Assignee: Unassigned
• Reporter: Todd Lipcon
• Created: 08/Jan/16 20:47
• Updated: 30/Jun/22 12:17

Description

In a lot of workloads, users have a compound primary key where the first component (or few components) is low cardinality. For example, a time series workload may have (year, month, day, entity_id, timestamp) as a primary key. A metrics or log storage workload might have (hostname, timestamp).

It's common to want to do cross-user or cross-date analytics like 'WHERE timestamp BETWEEN <a> and <b>' without specifying any predicate for the first column(s) of the PK. Currently, we do not execute this efficiently, but rather scan the whole table evaluating the predicate.