branch-3.1: [Bug](aggregate) fix bitmap_union return error result in query sql #52033 (#53000)

zhangstar333 · web-flow · commit 7db692f37fbb · 2025-07-10T10:24:04.000+08:00
cherry-pick from master #52033
diff --git a/be/src/vec/aggregate_functions/aggregate_function_bitmap.h b/be/src/vec/aggregate_functions/aggregate_function_bitmap.h
@@ -54,6 +54,7 @@ struct AggregateFunctionBitmapUnionOp {
     template <typename T>
     static void add(BitmapValue& res, const T& data, bool& is_first) {
         res.add(data);
+        is_first = false;
     }
 
     static void add(BitmapValue& res, const BitmapValue& data, bool& is_first) {
@@ -67,6 +68,9 @@ struct AggregateFunctionBitmapUnionOp {
 
     static void add_batch(BitmapValue& res, std::vector<const BitmapValue*>& data, bool& is_first) {
         res.fastunion(data);
+        // after fastunion, res myabe have many datas, so is_first should be false
+        // then call add function will not reset res
+        is_first = false;
     }
 
     static void merge(BitmapValue& res, const BitmapValue& data, bool& is_first) {

Original file line number	Diff line number	Diff line change
`@@ -54,6 +54,7 @@ struct AggregateFunctionBitmapUnionOp {`
`54`	`54`	`template <typename T>`
`55`	`55`	`static void add(BitmapValue& res, const T& data, bool& is_first) {`
`56`	`56`	`res.add(data);`
	`57`	`+ is_first = false;`
`57`	`58`	`}`
`58`	`59`
`59`	`60`	`static void add(BitmapValue& res, const BitmapValue& data, bool& is_first) {`
`@@ -67,6 +68,9 @@ struct AggregateFunctionBitmapUnionOp {`
`67`	`68`
`68`	`69`	`static void add_batch(BitmapValue& res, std::vector<const BitmapValue*>& data, bool& is_first) {`
`69`	`70`	`res.fastunion(data);`
	`71`	`+ // after fastunion, res myabe have many datas, so is_first should be false`
	`72`	`+ // then call add function will not reset res`
	`73`	`+ is_first = false;`
`70`	`74`	`}`
`71`	`75`
`72`	`76`	`static void merge(BitmapValue& res, const BitmapValue& data, bool& is_first) {`