Update pull_request_template.md

Add changelog for public field

.github/pull_request_template.md

@@ -11,6 +11,20 @@
 
 ---
 
+
+## 📝 Changelog 
+
+> Fill this only if the change affects users, APIs, UI, or documented behavior.
+Mention as N/A for internal refactors or non-user-visible changes.
+
+**Deployment Type:** Cloud / OSS / Enterprise
+
+**Type:** Feature / Bug Fix / Maintenance
+
+**Description:** Short, user-facing summary of the change
+
+---
+
 ## 🏷️ Required: Add Relevant Labels
 
 > ⚠️ **Manually add appropriate labels in the PR sidebar**  

frontend/src/components/QueryBuilderV2/QueryV2/QueryAddOns/QueryAddOns.tsx

@@ -32,6 +32,7 @@ const ADD_ONS_KEYS = {
 	ORDER_BY: 'order_by',
 	LIMIT: 'limit',
 	LEGEND_FORMAT: 'legend_format',
+	REDUCE_TO: 'reduce_to',
 };
 
 const ADD_ONS_KEYS_TO_QUERY_PATH = {
@@ -40,13 +41,14 @@ const ADD_ONS_KEYS_TO_QUERY_PATH = {
 	[ADD_ONS_KEYS.ORDER_BY]: 'orderBy',
 	[ADD_ONS_KEYS.LIMIT]: 'limit',
 	[ADD_ONS_KEYS.LEGEND_FORMAT]: 'legend',
+	[ADD_ONS_KEYS.REDUCE_TO]: 'reduceTo',
 };
 
 const ADD_ONS = [
 	{
 		icon: <BarChart2 size={14} />,
 		label: 'Group By',
-		key: 'group_by',
+		key: ADD_ONS_KEYS.GROUP_BY,
 		description:
 			'Break down data by attributes like service name, endpoint, status code, or region. Essential for spotting patterns and comparing performance across different segments.',
 		docLink: 'https://signoz.io/docs/userguide/query-builder-v5/#grouping',
@@ -54,7 +56,7 @@ const ADD_ONS = [
 	{
 		icon: <ScrollText size={14} />,
 		label: 'Having',
-		key: 'having',
+		key: ADD_ONS_KEYS.HAVING,
 		description:
 			'Filter grouped results based on aggregate conditions. Show only groups meeting specific criteria, like error rates > 5% or p99 latency > 500',
 		docLink:
@@ -63,7 +65,7 @@ const ADD_ONS = [
 	{
 		icon: <ScrollText size={14} />,
 		label: 'Order By',
-		key: 'order_by',
+		key: ADD_ONS_KEYS.ORDER_BY,
 		description:
 			'Sort results to surface what matters most. Quickly identify slowest operations, most frequent errors, or highest resource consumers.',
 		docLink:
@@ -72,7 +74,7 @@ const ADD_ONS = [
 	{
 		icon: <ScrollText size={14} />,
 		label: 'Limit',
-		key: 'limit',
+		key: ADD_ONS_KEYS.LIMIT,
 		description:
 			'Show only the top/bottom N results. Perfect for focusing on outliers, reducing noise, and improving dashboard performance.',
 		docLink:
@@ -81,7 +83,7 @@ const ADD_ONS = [
 	{
 		icon: <ScrollText size={14} />,
 		label: 'Legend format',
-		key: 'legend_format',
+		key: ADD_ONS_KEYS.LEGEND_FORMAT,
 		description:
 			'Customize series labels using variables like {{service.name}}-{{endpoint}}. Makes charts readable at a glance during incident investigation.',
 		docLink:
@@ -92,7 +94,7 @@ const ADD_ONS = [
 const REDUCE_TO = {
 	icon: <ScrollText size={14} />,
 	label: 'Reduce to',
-	key: 'reduce_to',
+	key: ADD_ONS_KEYS.REDUCE_TO,
 	description:
 		'Apply mathematical operations like sum, average, min, max, or percentiles to reduce multiple time series into a single value.',
 	docLink:
@@ -218,10 +220,9 @@ function QueryAddOns({
 		);
 
 		const availableAddOnKeys = new Set(filteredAddOns.map((addOn) => addOn.key));
-
 		// Filter and set selected views: add-ons that are both active and available
 		setSelectedViews(
-			ADD_ONS.filter(
+			filteredAddOns.filter(
 				(addOn) =>
 					activeAddOnKeys.has(addOn.key) && availableAddOnKeys.has(addOn.key),
 			),

frontend/src/components/QueryBuilderV2/__tests__/QueryAddOns.test.tsx

@@ -1,6 +1,12 @@
 /* eslint-disable */
-import { fireEvent, render, screen } from '@testing-library/react';
-import React from 'react';
+import {
+	fireEvent,
+	render,
+	screen,
+	userEvent,
+	waitFor,
+	within,
+} from 'tests/test-utils';
 
 import QueryAddOns from '../QueryV2/QueryAddOns/QueryAddOns';
 import { PANEL_TYPES } from 'constants/queryBuilder';
@@ -55,16 +61,7 @@ jest.mock('../QueryV2/QueryAddOns/HavingFilter/HavingFilter', () => ({
 	),
 }));
 
-jest.mock(
-	'container/QueryBuilder/filters/ReduceToFilter/ReduceToFilter',
-	() => ({
-		ReduceToFilter: ({ onChange }: any) => (
-			<button data-testid="reduce-to" onClick={() => onChange('sum')}>
-				ReduceToFilter
-			</button>
-		),
-	}),
-);
+// ReduceToFilter is not mocked - we test the actual Ant Design Select component
 
 function baseQuery(overrides: Partial<any> = {}): any {
 	return {
@@ -140,7 +137,7 @@ describe('QueryAddOns', () => {
 		expect(screen.getByTestId('order-by-content')).toBeInTheDocument();
 	});
 
-	it('limit input auto-opens when limit is set and changing it calls handler', () => {
+	it('limit input auto-opens when limit is set and changing it calls handler', async () => {
 		render(
 			<QueryAddOns
 				query={baseQuery({ limit: 5 })}
@@ -183,4 +180,88 @@ describe('QueryAddOns', () => {
 		expect(screen.getByTestId('limit-content')).toBeInTheDocument();
 		expect(limitInput.value).toBe('7');
 	});
+
+	it('shows reduce-to add-on when showReduceTo is true', () => {
+		render(
+			<QueryAddOns
+				query={baseQuery()}
+				version="v5"
+				isListViewPanel={false}
+				showReduceTo
+				panelType={PANEL_TYPES.TIME_SERIES}
+				index={0}
+				isForTraceOperator={false}
+			/>,
+		);
+
+		expect(screen.getByTestId('query-add-on-reduce_to')).toBeInTheDocument();
+	});
+
+	it('auto-opens reduce-to content when reduceTo is set', () => {
+		render(
+			<QueryAddOns
+				query={baseQuery({ reduceTo: 'sum' })}
+				version="v5"
+				isListViewPanel={false}
+				showReduceTo
+				panelType={PANEL_TYPES.TIME_SERIES}
+				index={0}
+				isForTraceOperator={false}
+			/>,
+		);
+
+		expect(screen.getByTestId('reduce-to-content')).toBeInTheDocument();
+	});
+
+	it('calls handleSetQueryData when reduce-to value changes', async () => {
+		const user = userEvent.setup({ pointerEventsCheck: 0 });
+		const query = baseQuery({
+			reduceTo: 'avg',
+			aggregations: [{ id: 'a', operator: 'count', reduceTo: 'avg' }],
+		});
+		render(
+			<QueryAddOns
+				query={query}
+				version="v5"
+				isListViewPanel={false}
+				showReduceTo
+				panelType={PANEL_TYPES.TIME_SERIES}
+				index={0}
+				isForTraceOperator={false}
+			/>,
+		);
+
+		// Wait for the reduce-to content section to be visible (it auto-opens when reduceTo is set)
+		await waitFor(() => {
+			expect(screen.getByTestId('reduce-to-content')).toBeInTheDocument();
+		});
+
+		// Get the Select component by its role (combobox)
+		// The Select is within the reduce-to-content section
+		const reduceToContent = screen.getByTestId('reduce-to-content');
+		const selectCombobox = within(reduceToContent).getByRole('combobox');
+
+		// Open the dropdown by clicking on the combobox
+		await user.click(selectCombobox);
+
+		// Wait for the dropdown listbox to appear
+		await screen.findByRole('listbox');
+
+		// Find and click the "Sum" option
+		const sumOption = await screen.findByText('Sum of values in timeframe');
+		await user.click(sumOption);
+
+		// Verify the handler was called with the correct value
+		await waitFor(() => {
+			expect(mockHandleSetQueryData).toHaveBeenCalledWith(0, {
+				...query,
+				aggregations: [
+					{
+						...(query.aggregations?.[0] as any),
+						reduceTo: 'sum',
+					},
+				],
+			});
+		});
+	});
 });

frontend/src/container/QueryBuilder/components/SpaceAggregationOptions/SpaceAggregationOptions.tsx

@@ -1,7 +1,5 @@
 import { Select } from 'antd';
 import { ATTRIBUTE_TYPES, PANEL_TYPES } from 'constants/queryBuilder';
-import { useEffect, useState } from 'react';
-import { MetricAggregateOperator } from 'types/common/queryBuilder';
 
 interface SpaceAggregationOptionsProps {
 	panelType: PANEL_TYPES | null;
@@ -22,39 +20,13 @@ export default function SpaceAggregationOptions({
 	operators,
 	qbVersion,
 }: SpaceAggregationOptionsProps): JSX.Element {
-	const placeHolderText =
-		panelType === PANEL_TYPES.VALUE || qbVersion === 'v3' ? 'Sum' : 'Sum By';
-	const [defaultValue, setDefaultValue] = useState(
-		selectedValue || placeHolderText,
-	);
-
-	useEffect(() => {
-		if (!selectedValue) {
-			if (
-				aggregatorAttributeType === ATTRIBUTE_TYPES.HISTOGRAM ||
-				aggregatorAttributeType === ATTRIBUTE_TYPES.EXPONENTIAL_HISTOGRAM
-			) {
-				setDefaultValue(MetricAggregateOperator.P90);
-				onSelect(MetricAggregateOperator.P90);
-			} else if (aggregatorAttributeType === ATTRIBUTE_TYPES.SUM) {
-				setDefaultValue(MetricAggregateOperator.SUM);
-				onSelect(MetricAggregateOperator.SUM);
-			} else if (aggregatorAttributeType === ATTRIBUTE_TYPES.GAUGE) {
-				setDefaultValue(MetricAggregateOperator.AVG);
-				onSelect(MetricAggregateOperator.AVG);
-			}
-		}
-
-		// eslint-disable-next-line react-hooks/exhaustive-deps
-	}, [aggregatorAttributeType]);
-
 	return (
 		<div
 			className="spaceAggregationOptionsContainer"
 			key={aggregatorAttributeType}
 		>
 			<Select
-				defaultValue={defaultValue}
+				defaultValue={selectedValue}
 				style={{ minWidth: '5.625rem' }}
 				disabled={disabled}
 				onChange={onSelect}

frontend/src/container/QueryBuilder/filters/ReduceToFilter/ReduceToFilter.test.tsx

@@ -0,0 +1,88 @@
+import { render, screen } from '@testing-library/react';
+import { MetricType } from 'api/metricsExplorer/getMetricsList';
+import { IBuilderQuery } from 'types/api/queryBuilder/queryBuilderData';
+
+import { ReduceToFilter } from './ReduceToFilter';
+
+const mockOnChange = jest.fn();
+
+function baseQuery(overrides: Partial<IBuilderQuery> = {}): IBuilderQuery {
+	return {
+		dataSource: 'traces',
+		aggregations: [],
+		groupBy: [],
+		orderBy: [],
+		legend: '',
+		limit: null,
+		having: { expression: '' },
+		...overrides,
+	} as IBuilderQuery;
+}
+
+describe('ReduceToFilter', () => {
+	beforeEach(() => {
+		jest.clearAllMocks();
+	});
+
+	it('initializes with default avg when no reduceTo is set', () => {
+		render(<ReduceToFilter query={baseQuery()} onChange={mockOnChange} />);
+
+		expect(screen.getByTestId('reduce-to')).toBeInTheDocument();
+		expect(
+			screen.getByText('Average of values in timeframe'),
+		).toBeInTheDocument();
+	});
+
+	it('initializes from query.aggregations[0].reduceTo', () => {
+		render(
+			<ReduceToFilter
+				query={baseQuery({
+					aggregations: [{ reduceTo: 'sum' } as any],
+					aggregateAttribute: { key: 'test', type: MetricType.SUM },
+				})}
+				onChange={mockOnChange}
+			/>,
+		);
+
+		expect(screen.getByText('Sum of values in timeframe')).toBeInTheDocument();
+	});
+
+	it('initializes from query.reduceTo when aggregations[0].reduceTo is not set', () => {
+		render(
+			<ReduceToFilter
+				query={baseQuery({
+					reduceTo: 'max',
+					aggregateAttribute: { key: 'test', type: MetricType.GAUGE },
+				})}
+				onChange={mockOnChange}
+			/>,
+		);
+
+		expect(screen.getByText('Max of values in timeframe')).toBeInTheDocument();
+	});
+
+	it('updates to sum when aggregateAttribute.type is SUM', async () => {
+		const { rerender } = render(
+			<ReduceToFilter
+				query={baseQuery({
+					aggregateAttribute: { key: 'test', type: MetricType.GAUGE },
+				})}
+				onChange={mockOnChange}
+			/>,
+		);
+
+		rerender(
+			<ReduceToFilter
+				query={baseQuery({
+					aggregateAttribute: { key: 'test2', type: MetricType.SUM },
+				})}
+				onChange={mockOnChange}
+			/>,
+		);
+
+		const reduceToFilterText = (await screen.findByText(
+			'Sum of values in timeframe',
+		)) as HTMLElement;
+		expect(reduceToFilterText).toBeInTheDocument();
+	});
+});

frontend/src/container/QueryBuilder/filters/ReduceToFilter/ReduceToFilter.tsx

@@ -1,6 +1,7 @@
 import { Select } from 'antd';
+import { MetricType } from 'api/metricsExplorer/getMetricsList';
 import { REDUCE_TO_VALUES } from 'constants/queryBuilder';
-import { memo } from 'react';
+import { memo, useEffect, useRef, useState } from 'react';
 import { MetricAggregation } from 'types/api/v5/queryRange';
 // ** Types
 import { ReduceOperators } from 'types/common/queryBuilder';
@@ -12,19 +13,46 @@ export const ReduceToFilter = memo(function ReduceToFilter({
 	query,
 	onChange,
 }: ReduceToFilterProps): JSX.Element {
-	const reduceToValue =
-		(query.aggregations?.[0] as MetricAggregation)?.reduceTo || query.reduceTo;
-
-	const currentValue =
-		REDUCE_TO_VALUES.find((option) => option.value === reduceToValue) ||
-		REDUCE_TO_VALUES[0];
+	const isMounted = useRef<boolean>(false);
+	const [currentValue, setCurrentValue] = useState<
+		SelectOption<ReduceOperators, string>
+	>(REDUCE_TO_VALUES[2]); // default to avg
 
 	const handleChange = (
 		newValue: SelectOption<ReduceOperators, string>,
 	): void => {
+		setCurrentValue(newValue);
 		onChange(newValue.value);
 	};
 
+	useEffect(
+		() => {
+			if (!isMounted.current) {
+				const reduceToValue =
+					(query.aggregations?.[0] as MetricAggregation)?.reduceTo || query.reduceTo;
+
+				setCurrentValue(
+					REDUCE_TO_VALUES.find((option) => option.value === reduceToValue) ||
+						REDUCE_TO_VALUES[2],
+				);
+				isMounted.current = true;
+				return;
+			}
+
+			const aggregationAttributeType = query.aggregateAttribute?.type as
+				| MetricType
+				| undefined;
+
+			if (aggregationAttributeType === MetricType.SUM) {
+				handleChange(REDUCE_TO_VALUES[1]);
+			} else {
+				handleChange(REDUCE_TO_VALUES[2]);
+			}
+		},
+		// eslint-disable-next-line react-hooks/exhaustive-deps
+		[query.aggregateAttribute?.key],
+	);
+
 	return (
 		<Select
 			placeholder="Reduce to"

frontend/src/hooks/queryBuilder/__tests__/useQueryBuilderOperations.test.ts

@@ -188,7 +188,7 @@ describe('useQueryBuilderOperations - Empty Aggregate Attribute Type', () => {
 							timeAggregation: MetricAggregateOperator.RATE,
 							metricName: 'new_sum_metric',
 							temporality: '',
-							spaceAggregation: '',
+							spaceAggregation: MetricAggregateOperator.SUM,
 						},
 					],
 				}),
@@ -239,7 +239,7 @@ describe('useQueryBuilderOperations - Empty Aggregate Attribute Type', () => {
 							timeAggregation: MetricAggregateOperator.RATE,
 							metricName: 'new_sum_metric',
 							temporality: '',
-							spaceAggregation: '',
+							spaceAggregation: MetricAggregateOperator.SUM,
 						},
 					],
 				}),
@@ -315,7 +315,7 @@ describe('useQueryBuilderOperations - Empty Aggregate Attribute Type', () => {
 							timeAggregation: MetricAggregateOperator.AVG,
 							metricName: 'new_gauge',
 							temporality: '',
-							spaceAggregation: '',
+							spaceAggregation: MetricAggregateOperator.AVG,
 						},
 					],
 				}),

frontend/src/hooks/queryBuilder/useQueryBuilderOperations.ts

@@ -317,7 +317,7 @@ export const useQueryOperations: UseQueryOperations = ({
 									timeAggregation: MetricAggregateOperator.RATE,
 									metricName: newQuery.aggregateAttribute?.key || '',
 									temporality: '',
-									spaceAggregation: '',
+									spaceAggregation: MetricAggregateOperator.SUM,
 								},
 							];
 						} else if (newQuery.aggregateAttribute?.type === ATTRIBUTE_TYPES.GAUGE) {
@@ -326,7 +326,20 @@ export const useQueryOperations: UseQueryOperations = ({
 									timeAggregation: MetricAggregateOperator.AVG,
 									metricName: newQuery.aggregateAttribute?.key || '',
 									temporality: '',
-									spaceAggregation: '',
+									spaceAggregation: MetricAggregateOperator.AVG,
+								},
+							];
+						} else if (
+							newQuery.aggregateAttribute?.type === ATTRIBUTE_TYPES.HISTOGRAM ||
+							newQuery.aggregateAttribute?.type ===
+								ATTRIBUTE_TYPES.EXPONENTIAL_HISTOGRAM
+						) {
+							newQuery.aggregations = [
+								{
+									timeAggregation: '',
+									metricName: newQuery.aggregateAttribute?.key || '',
+									temporality: '',
+									spaceAggregation: MetricAggregateOperator.P90,
 								},
 							];
 						} else {