24.8.14 Backport of #95301: Fix sparse column aggregation with sum() and timeseries

src/AggregateFunctions/AggregateFunctionSum.h

@@ -566,7 +566,8 @@ class AggregateFunctionSum final : public IAggregateFunctionDataHelper<Data, Agg
         size_t to = std::lower_bound(offsets.begin(), offsets.end(), row_end) - offsets.begin();
 
         for (size_t i = from; i < to; ++i)
-            add(places[offsets[i]] + place_offset, &values, i + 1, arena);
+            if (places[offsets[i]])
+                add(places[offsets[i]] + place_offset, &values, i + 1, arena);
     }
 
     void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs, Arena *) const override

tests/queries/0_stateless/03811_sparse_column_aggregation_with_sum.sql

@@ -0,0 +1,21 @@
+CREATE TABLE 03811_sparse_column_aggregation_with_sum(key UInt128, val UInt16) ENGINE = MergeTree ORDER BY tuple();
+
+INSERT INTO 03811_sparse_column_aggregation_with_sum
+    SELECT number, number % 10000 = 0 FROM numbers(100000)
+    SETTINGS min_insert_block_size_rows = 1000,
+             max_block_size =1000,
+             max_threads = 2;
+
+SELECT key, sum(val) AS c
+FROM 03811_sparse_column_aggregation_with_sum
+GROUP BY key
+ORDER BY c DESC
+LIMIT 100
+FORMAT Null
+SETTINGS group_by_overflow_mode = 'any',
+         max_rows_to_group_by = 100,
+         group_by_two_level_threshold_bytes = 1,
+         group_by_two_level_threshold = 1,
+         max_threads = 2;
+
+DROP TABLE 03811_sparse_column_aggregation_with_sum;