v.24.4Improvement
Allow cancellation of parallel merge in aggregate state aggregation
Allow to cancel parallel merge of aggregate states during aggregation. Example: uniqExact. #61992 (Maksim Kita).Why it matters
This feature addresses the issue of long-running parallel merges of aggregate states by enabling their cancellation. This improves query performance and resource utilization when using aggregate functions that rely on state merging.How to use it
The cancellation of parallel merges is enabled automatically during aggregation processes involving functions such asuniqExact. Users do not need to apply any special settings to benefit from this feature.