v.21.1Improvements
Fix SimpleAggregateFunction in SummingMergeTree for Correct Aggregate Behavior
Fix SimpleAggregateFunction in SummingMergeTree. Now it works like AggregateFunction. In previous versions values were summed together regardless to the aggregate function. This fixes #18564 . #8052. #18637 (Amos Bird). Another fix of usingSimpleAggregateFunctioninSummingMergeTree. This fixes #18676 . #18677 (Amos Bird).
Why it matters
Previously, values inSimpleAggregateFunction columns within SummingMergeTree were summed directly without respecting the aggregate function logic, leading to incorrect results. This fix resolves that issue by making the aggregation respect the function semantics, improving data correctness and reliability.How to use it
Users benefit from this fix automatically when upgrading to this version. To useSimpleAggregateFunction correctly with SummingMergeTree, define the table with SimpleAggregateFunction as the column type and use the SummingMergeTree engine as usual; the aggregation behavior will now be correct without additional configuration.