Merge branch 'feat/distribution-chart' into feat/distribution-panel-kind

Histogram bins raw values; Distribution reads histogram buckets. Neither query converts.

docs/api/openapi.yml

@@ -4526,6 +4526,99 @@ components:
       required:
       - name
       type: object
+    DashboardtypesDistributionAxes:
+      properties:
+        x:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionXAxis'
+          description: The bucket axis.
+        "y":
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionYAxis'
+          description: The count axis.
+      type: object
+    DashboardtypesDistributionChartAppearance:
+      properties:
+        percentiles:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionPercentiles'
+          description: Percentile markers drawn across the bucket axis.
+        stack:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesStackMode'
+          description: 'How groups combine in a bucket: normal (default) stacks them,
+            none draws them side by side, percent stacks them as shares of the bucket.'
+      required:
+      - stack
+      type: object
+    DashboardtypesDistributionPanelSpec:
+      properties:
+        axes:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionAxes'
+          description: The X (bucket) axis range and Y (count) axis scale.
+        chartAppearance:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionChartAppearance'
+          description: Stacking and percentile markers.
+        formatting:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesPanelFormatting'
+          description: Unit and decimal precision of the bucket bounds; counts take
+            no unit.
+        legend:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesLegend'
+          description: Legend placement and series colors.
+        visualization:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesBasicVisualization'
+          description: The time range the bucket counts are summed over.
+      type: object
+    DashboardtypesDistributionPercentiles:
+      properties:
+        enabled:
+          description: Whether percentile markers are drawn. Defaults to true.
+          type: boolean
+        values:
+          description: The percentiles to mark, each in (0, 100), at most 5, no duplicates.
+            Defaults to [50, 90, 99].
+          items:
+            format: double
+            type: number
+          nullable: true
+          type: array
+      required:
+      - enabled
+      - values
+      type: object
+    DashboardtypesDistributionXAxis:
+      properties:
+        max:
+          description: Buckets wholly above this value are hidden. Null shows them
+            all.
+          nullable: true
+          type: number
+        min:
+          description: Buckets wholly below this value are hidden. Null shows them
+            all.
+          nullable: true
+          type: number
+      type: object
+    DashboardtypesDistributionYAxis:
+      properties:
+        scale:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionYScale'
+          description: 'How counts are spaced: linear (default) or log.'
+      required:
+      - scale
+      type: object
+    DashboardtypesDistributionYScale:
+      enum:
+      - linear
+      - log
+      type: string
     DashboardtypesDynamicVariableSignal:
       enum:
       - traces
@@ -5296,6 +5389,7 @@ components:
         mapping:
           signoz/AreaChartPanel: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesAreaChartPanelSpec'
           signoz/BarChartPanel: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesBarChartPanelSpec'
+          signoz/DistributionPanel: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpec'
           signoz/HeatmapPanel: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHeatmapPanelSpec'
           signoz/HistogramPanel: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHistogramPanelSpec'
           signoz/ListPanel: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesListPanelSpec'
@@ -5318,6 +5412,7 @@ components:
       - $ref: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesTextPanelSpec'
       - $ref: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHeatmapPanelSpec'
       - $ref: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesScatterPlotPanelSpec'
+      - $ref: '#/components/schemas/DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpec'
       type: object
     DashboardtypesPanelPluginKind:
       enum:
@@ -5332,6 +5427,7 @@ components:
       - signoz/TextPanel
       - signoz/HeatmapPanel
       - signoz/ScatterPlotPanel
+      - signoz/DistributionPanel
       type: string
     DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesAreaChartPanelSpec:
       properties:
@@ -5363,6 +5459,21 @@ components:
       - kind
       - spec
       type: object
+    DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpec:
+      properties:
+        kind:
+          description: The panel kind.
+          enum:
+          - signoz/DistributionPanel
+          type: string
+        spec:
+          allOf:
+          - $ref: '#/components/schemas/DashboardtypesDistributionPanelSpec'
+          description: The options for this panel kind. {} accepts every default.
+      required:
+      - kind
+      - spec
+      type: object
     DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHeatmapPanelSpec:
       properties:
         kind:
@@ -5516,9 +5627,9 @@ components:
           - $ref: '#/components/schemas/DashboardtypesPanelPlugin'
           description: 'The visualization: kind is one of signoz/TimeSeriesPanel,
             signoz/BarChartPanel, signoz/AreaChartPanel, signoz/NumberPanel, signoz/PieChartPanel,
-            signoz/TablePanel, signoz/HistogramPanel, signoz/ListPanel, signoz/TextPanel
-            or signoz/HeatmapPanel, and spec holds that kind''s options ({} accepts
-            every default).'
+            signoz/TablePanel, signoz/HistogramPanel, signoz/ListPanel, signoz/TextPanel,
+            signoz/HeatmapPanel or signoz/DistributionPanel, and spec holds that kind''s
+            options ({} accepts every default).'
         queries:
           description: The queries the panel runs. Use exactly one entry for a data
             panel and [] for signoz/TextPanel. To run several named queries or formulas,
@@ -5654,8 +5765,8 @@ components:
           - $ref: '#/components/schemas/Querybuildertypesv5RequestType'
           description: 'The result shape the panel requests: time_series for time
             series, bar, area and histogram panels, scalar for number, table and pie
-            panels, raw for list panels, heatmap for heatmap panels, trace for trace
-            panels.'
+            panels, raw for list panels, heatmap for heatmap panels, distribution
+            for distribution panels, trace for trace panels.'
         spec:
           allOf:
           - $ref: '#/components/schemas/DashboardtypesQuerySpec'
@@ -5812,9 +5923,9 @@ components:
             (builder query over AI observability traces), signoz/CompositeQuery (several
             named queries and formulas), signoz/Formula, signoz/PromQLQuery, signoz/ClickHouseSQL
             or signoz/TraceOperator, and spec holds that kind''s query. Pie and table
-            panels reject signoz/PromQLQuery; heatmap panels reject signoz/AIBuilderQuery
-            and signoz/TraceOperator; list panels accept only signoz/BuilderQuery
-            and signoz/AIBuilderQuery.'
+            panels reject signoz/PromQLQuery; heatmap and distribution panels reject
+            signoz/AIBuilderQuery and signoz/TraceOperator; list panels accept only
+            signoz/BuilderQuery and signoz/AIBuilderQuery.'
       required:
       - plugin
       type: object

frontend/jest.config.ts

@@ -11,7 +11,7 @@ const config: Config.InitialOptions = {
 	coverageReporters: ['text', 'cobertura', 'html', 'json-summary'],
 	collectCoverageFrom: ['src/**/*.{ts,tsx}'],
 	moduleFileExtensions: ['ts', 'tsx', 'js', 'json'],
-	modulePathIgnorePatterns: ['dist'],
+	modulePathIgnorePatterns: ['<rootDir>/dist/'],
 	moduleNameMapper: {
 		'\\.(png|jpg|jpeg|gif|svg|webp|avif|ico|bmp|tiff)$':
 			'<rootDir>/__mocks__/fileMock.ts',

frontend/src/api/generated/services/sigNoz.schemas.ts

@@ -6949,6 +6949,107 @@ export interface DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDa
 	spec: DashboardtypesScatterPlotPanelSpecDTO;
 }
 
+/**
+ * The panel kind.
+ */
+export enum DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTOKind {
+	'signoz/DistributionPanel' = 'signoz/DistributionPanel',
+}
+export interface DashboardtypesDistributionXAxisDTO {
+	/**
+	 * @type number,null
+	 * @description Buckets wholly above this value are hidden. Null shows them all.
+	 */
+	max?: number | null;
+	/**
+	 * @type number,null
+	 * @description Buckets wholly below this value are hidden. Null shows them all.
+	 */
+	min?: number | null;
+}
+
+export enum DashboardtypesDistributionYScaleDTO {
+	linear = 'linear',
+	log = 'log',
+}
+export interface DashboardtypesDistributionYAxisDTO {
+	/**
+	 * @description How counts are spaced: linear (default) or log.
+	 */
+	scale: DashboardtypesDistributionYScaleDTO;
+}
+
+export interface DashboardtypesDistributionAxesDTO {
+	/**
+	 * @description The bucket axis.
+	 */
+	x?: DashboardtypesDistributionXAxisDTO;
+	/**
+	 * @description The count axis.
+	 */
+	y?: DashboardtypesDistributionYAxisDTO;
+}
+
+export interface DashboardtypesDistributionPercentilesDTO {
+	/**
+	 * @type boolean
+	 * @description Whether percentile markers are drawn. Defaults to true.
+	 */
+	enabled: boolean;
+	/**
+	 * @type array,null
+	 * @description The percentiles to mark, each in (0, 100), at most 5, no duplicates. Defaults to [50, 90, 99].
+	 */
+	values: number[] | null;
+}
+
+export interface DashboardtypesDistributionChartAppearanceDTO {
+	/**
+	 * @description Percentile markers drawn across the bucket axis.
+	 */
+	percentiles?: DashboardtypesDistributionPercentilesDTO;
+	/**
+	 * @description How groups combine in a bucket: normal (default) stacks them, none draws them side by side, percent stacks them as shares of the bucket.
+	 */
+	stack: DashboardtypesStackModeDTO;
+}
+
+export interface DashboardtypesDistributionPanelSpecDTO {
+	/**
+	 * @description The X (bucket) axis range and Y (count) axis scale.
+	 */
+	axes?: DashboardtypesDistributionAxesDTO;
+	/**
+	 * @description Stacking and percentile markers.
+	 */
+	chartAppearance?: DashboardtypesDistributionChartAppearanceDTO;
+	/**
+	 * @description Unit and decimal precision of the bucket bounds; counts take no unit.
+	 */
+	formatting?: DashboardtypesPanelFormattingDTO;
+	/**
+	 * @description Legend placement and series colors.
+	 */
+	legend?: DashboardtypesLegendDTO;
+	/**
+	 * @description The time range the bucket counts are summed over.
+	 */
+	visualization?: DashboardtypesBasicVisualizationDTO;
+}
+
+export interface DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTO {
+	/**
+	 * @enum signoz/DistributionPanel
+	 * @type string
+	 * @description The panel kind.
+	 */
+	kind: DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTOKind;
+	/**
+	 * @description The options for this panel kind. {} accepts every default.
+	 */
+	spec: DashboardtypesDistributionPanelSpecDTO;
+}
+
 export type DashboardtypesPanelPluginDTO =
 	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesTimeSeriesPanelSpecDTO
 	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesBarChartPanelSpecDTO
@@ -6960,7 +7061,8 @@ export type DashboardtypesPanelPluginDTO =
 	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesListPanelSpecDTO
 	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesTextPanelSpecDTO
 	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHeatmapPanelSpecDTO
-	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesScatterPlotPanelSpecDTO;
+	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesScatterPlotPanelSpecDTO
+	| DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTO;
 
 export enum Querybuildertypesv5RequestTypeDTO {
 	scalar = 'scalar',
@@ -7449,14 +7551,14 @@ export interface DashboardtypesQuerySpecDTO {
 	 */
 	name?: string;
 	/**
-	 * @description The query: kind is one of signoz/BuilderQuery, signoz/AIBuilderQuery (builder query over AI observability traces), signoz/CompositeQuery (several named queries and formulas), signoz/Formula, signoz/PromQLQuery, signoz/ClickHouseSQL or signoz/TraceOperator, and spec holds that kind's query. Pie and table panels reject signoz/PromQLQuery; heatmap panels reject signoz/AIBuilderQuery and signoz/TraceOperator; list panels accept only signoz/BuilderQuery and signoz/AIBuilderQuery.
+	 * @description The query: kind is one of signoz/BuilderQuery, signoz/AIBuilderQuery (builder query over AI observability traces), signoz/CompositeQuery (several named queries and formulas), signoz/Formula, signoz/PromQLQuery, signoz/ClickHouseSQL or signoz/TraceOperator, and spec holds that kind's query. Pie and table panels reject signoz/PromQLQuery; heatmap and distribution panels reject signoz/AIBuilderQuery and signoz/TraceOperator; list panels accept only signoz/BuilderQuery and signoz/AIBuilderQuery.
 	 */
 	plugin: DashboardtypesQueryPluginDTO;
 }
 
 export interface DashboardtypesQueryDTO {
 	/**
-	 * @description The result shape the panel requests: time_series for time series, bar, area and histogram panels, scalar for number, table and pie panels, raw for list panels, heatmap for heatmap panels, trace for trace panels.
+	 * @description The result shape the panel requests: time_series for time series, bar, area and histogram panels, scalar for number, table and pie panels, raw for list panels, heatmap for heatmap panels, distribution for distribution panels, trace for trace panels.
 	 */
 	kind: Querybuildertypesv5RequestTypeDTO;
 	/**
@@ -7476,7 +7578,7 @@ export interface DashboardtypesPanelSpecDTO {
 	 */
 	links?: DashboardtypesLinkDTO[] | null;
 	/**
-	 * @description The visualization: kind is one of signoz/TimeSeriesPanel, signoz/BarChartPanel, signoz/AreaChartPanel, signoz/NumberPanel, signoz/PieChartPanel, signoz/TablePanel, signoz/HistogramPanel, signoz/ListPanel, signoz/TextPanel or signoz/HeatmapPanel, and spec holds that kind's options ({} accepts every default).
+	 * @description The visualization: kind is one of signoz/TimeSeriesPanel, signoz/BarChartPanel, signoz/AreaChartPanel, signoz/NumberPanel, signoz/PieChartPanel, signoz/TablePanel, signoz/HistogramPanel, signoz/ListPanel, signoz/TextPanel, signoz/HeatmapPanel or signoz/DistributionPanel, and spec holds that kind's options ({} accepts every default).
 	 */
 	plugin: DashboardtypesPanelPluginDTO;
 	/**
@@ -8247,6 +8349,7 @@ export enum DashboardtypesPanelPluginKindDTO {
 	'signoz/TextPanel' = 'signoz/TextPanel',
 	'signoz/HeatmapPanel' = 'signoz/HeatmapPanel',
 	'signoz/ScatterPlotPanel' = 'signoz/ScatterPlotPanel',
+	'signoz/DistributionPanel' = 'signoz/DistributionPanel',
 }
 /**
  * The RFC 6902 operations, applied in order against the dashboard's postable shape.

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

@@ -5,6 +5,7 @@ import { ToggleGroup } from '@signozhq/ui/toggle-group';
 import { Tooltip, TooltipProvider } from '@signozhq/ui/tooltip';
 import InputWithLabel from 'components/InputWithLabel/InputWithLabel';
 import { PANEL_TYPES } from 'constants/queryBuilder';
+import { isBucketCountingPanelType } from 'lib/query/bucketCountingPanelTypes';
 import { GroupByFilter } from 'container/QueryBuilder/filters/GroupByFilter/GroupByFilter';
 import { OrderByFilter } from 'container/QueryBuilder/filters/OrderByFilter/OrderByFilter';
 import { ReduceToFilter } from 'container/QueryBuilder/filters/ReduceToFilter/ReduceToFilter';
@@ -99,7 +100,7 @@ function QueryAddOns({
 		}
 
 		if (
-			panelType === PANEL_TYPES.HEATMAP &&
+			isBucketCountingPanelType(panelType) &&
 			query.dataSource === DataSource.METRICS &&
 			!HISTOGRAM_ATTRIBUTE_TYPES.has(query.aggregateAttribute?.type ?? '')
 		) {

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

@@ -107,8 +107,8 @@ export const BASE_ADD_ONS = (
 
 export const REDUCE_TO = toAddOn(QueryBuilderField.ReduceTo);
 
-// Offered only by a heatmap over metrics: the bucket axis is what a heatmap plots
-// against, and no other panel type sends one. A histogram brings its own buckets.
+// Offered only by a heatmap or distribution over metrics: the bucket axis is what they
+// plot against, and no other panel type sends one. A histogram brings its own buckets.
 export const HISTOGRAM_ATTRIBUTE_TYPES = new Set<string>([
 	ATTRIBUTE_TYPES.HISTOGRAM,
 	ATTRIBUTE_TYPES.EXPONENTIAL_HISTOGRAM,

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

@@ -438,6 +438,24 @@ describe('QueryAddOns', () => {
 			).toBeInTheDocument();
 		});
 
+		it('is offered on a metrics distribution too', () => {
+			render(
+				<QueryAddOns
+					query={baseQuery({ dataSource: DataSource.METRICS })}
+					version="v5"
+					isRawQuery={false}
+					showReduceTo={false}
+					panelType={PANEL_TYPES.DISTRIBUTION}
+					index={0}
+					isForTraceOperator={false}
+				/>,
+			);
+
+			expect(
+				screen.getByTestId('query-add-on-bucket_options'),
+			).toBeInTheDocument();
+		});
+
 		it('is not offered on other panel types', () => {
 			render(
 				<QueryAddOns

frontend/src/constants/panelTypes.ts

@@ -34,6 +34,7 @@ export const getComponentForPanelType = (
 		[PANEL_TYPES.HISTOGRAM]: Uplot,
 		// V2-only kind; it renders through the V2 panel registry.
 		[PANEL_TYPES.HEATMAP]: null,
+		[PANEL_TYPES.DISTRIBUTION]: null,
 		// Dashboards v2 renders this kind; nothing reaches the V1 chart map for it.
 		[PANEL_TYPES.TEXT]: null,
 		[PANEL_TYPES.SCATTER]: null,

frontend/src/constants/queryBuilder.ts

@@ -340,6 +340,7 @@ export enum PANEL_TYPES {
 	PIE = 'pie',
 	HISTOGRAM = 'histogram',
 	HEATMAP = 'heatmap',
+	DISTRIBUTION = 'distribution',
 	TEXT = 'text',
 	EMPTY_WIDGET = 'EMPTY_WIDGET',
 }

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

@@ -4,7 +4,7 @@ import InputWithLabel from 'components/InputWithLabel/InputWithLabel';
 import BucketOptions from 'components/QueryBuilderV2/QueryV2/QueryAddOns/BucketOptions/BucketOptions';
 import { parseLimit, sanitizeLimit } from 'components/QueryBuilderV2/utils';
 import { LEGEND } from 'constants/global';
-import { PANEL_TYPES } from 'constants/queryBuilder';
+import { isBucketCountingPanelType } from 'lib/query/bucketCountingPanelTypes';
 // ** Hooks
 import { useQueryBuilder } from 'hooks/queryBuilder/useQueryBuilder';
 import { useQueryOperations } from 'hooks/queryBuilder/useQueryBuilderOperations';
@@ -180,9 +180,9 @@ export function Formula({
 							</div>
 						</Col>
 					)}
-					{/* A heatmap draws its one enabled query, which is the formula when its
-					    inputs are disabled — so the formula states its own bucket axis. */}
-					{isQBV2 && panelType === PANEL_TYPES.HEATMAP && (
+					{/* A heatmap or distribution draws its one enabled query, which is the formula
+					    when its inputs are disabled — so the formula states its own bucket axis. */}
+					{isQBV2 && isBucketCountingPanelType(panelType) && (
 						<Col span={24}>
 							<BucketOptions
 								bucketOptions={formula.bucketOptions}

frontend/src/container/WidgetCard/Card/FullView/contants.ts

@@ -32,6 +32,7 @@ export const PANEL_TYPES_VS_FULL_VIEW_TABLE: PanelTypeAndGraphManagerVisibilityP
 		PIE: false,
 		HISTOGRAM: false,
 		HEATMAP: false,
+		DISTRIBUTION: false,
 		TEXT: false,
 		EMPTY_WIDGET: false,
 	};

frontend/src/container/WidgetCard/Panels/constants.ts

@@ -24,4 +24,5 @@ export const PanelTypeVsPanelWrapper = {
 	[PANEL_TYPES.HISTOGRAM]: HistogramPanel,
 	// V2-only kind; it renders through the V2 panel registry.
 	[PANEL_TYPES.HEATMAP]: null,
+	[PANEL_TYPES.DISTRIBUTION]: null,
 };

frontend/src/hooks/queryBuilder/useQueryBuilderOperations.ts

@@ -54,6 +54,7 @@ import {
 } from 'types/common/queryBuilder';
 import { SelectOption } from 'types/common/select';
 import { getFormatedLegend } from 'utils/getFormatedLegend';
+import { isBucketCountingPanelType } from 'lib/query/bucketCountingPanelTypes';
 
 export const useQueryOperations: UseQueryOperations = ({
 	query,
@@ -177,10 +178,9 @@ export const useQueryOperations: UseQueryOperations = ({
 							(aggregateAttribute?.type as ATTRIBUTE_TYPES) || ATTRIBUTE_TYPES.GAUGE,
 					});
 
-			const histogramSpaceAggregationOptions =
-				panelType === PANEL_TYPES.HEATMAP
-					? metricsHeatmapHistogramSpaceAggregateOperatorOptions
-					: metricsHistogramSpaceAggregateOperatorOptions;
+			const histogramSpaceAggregationOptions = isBucketCountingPanelType(panelType)
+				? metricsHeatmapHistogramSpaceAggregateOperatorOptions
+				: metricsHistogramSpaceAggregateOperatorOptions;
 
 			switch (aggregateAttribute?.type) {
 				case ATTRIBUTE_TYPES.SUM:
@@ -304,13 +304,12 @@ export const useQueryOperations: UseQueryOperations = ({
 									timeAggregation: '',
 									metricName: newQuery.aggregateAttribute?.key || '',
 									temporality: '',
-									// A heatmap cell holds a count of observations per `le` band, which is
-									// the one option the kind offers — a percentile default would sit in the
+									// Heatmap and distribution count observations per `le` band, the one
+									// option those kinds offer — a percentile default would sit in the
 									// selector with nothing behind it.
-									spaceAggregation:
-										panelType === PANEL_TYPES.HEATMAP
-											? MetricAggregateOperator.COUNT
-											: MetricAggregateOperator.P90,
+									spaceAggregation: isBucketCountingPanelType(panelType)
+										? MetricAggregateOperator.COUNT
+										: MetricAggregateOperator.P90,
 									reduceTo: ReduceOperators.AVG,
 								},
 							];

frontend/src/lib/query/__tests__/bucketCountingPanelTypes.test.ts

@@ -0,0 +1,13 @@
+import { PANEL_TYPES } from 'constants/queryBuilder';
+
+import { isBucketCountingPanelType } from '../bucketCountingPanelTypes';
+
+describe('isBucketCountingPanelType', () => {
+	it('is true for heatmap and distribution only', () => {
+		expect(isBucketCountingPanelType(PANEL_TYPES.HEATMAP)).toBe(true);
+		expect(isBucketCountingPanelType(PANEL_TYPES.DISTRIBUTION)).toBe(true);
+		expect(isBucketCountingPanelType(PANEL_TYPES.HISTOGRAM)).toBe(false);
+		expect(isBucketCountingPanelType(PANEL_TYPES.TIME_SERIES)).toBe(false);
+		expect(isBucketCountingPanelType(null)).toBe(false);
+	});
+});

frontend/src/lib/query/__tests__/handleQueryChange.test.ts

@@ -49,8 +49,23 @@ describe('handleQueryChange bucket options', () => {
 		);
 	});
 
-	// The request rejects an axis on any type but heatmap, so a switch has to shed it
-	// from the query (via the field allowlist) and from the formula (by hand).
+	it('keeps both axes when a heatmap switches to a distribution', () => {
+		const result = handleQueryChange(
+			PANEL_TYPES.DISTRIBUTION,
+			queryWithFormulaAxis(),
+			PANEL_TYPES.HEATMAP,
+		);
+
+		expect(result.builder.queryData[0].bucketOptions).toStrictEqual(
+			bucketOptions,
+		);
+		expect(result.builder.queryFormulas[0].bucketOptions).toStrictEqual(
+			bucketOptions,
+		);
+	});
+
+	// The request rejects an axis on any type but heatmap and distribution, so a switch
+	// has to shed it from the query (via the field allowlist) and from the formula (by hand).
 	it('drops both axes when switching to another panel type', () => {
 		const result = handleQueryChange(
 			PANEL_TYPES.TIME_SERIES,

frontend/src/lib/query/bucketCountingPanelTypes.ts

@@ -0,0 +1,14 @@
+import { PANEL_TYPES } from 'constants/queryBuilder';
+
+/**
+ * Panel types whose request counts observations into buckets (`heatmap`,
+ * `distribution`): they share the bucket axis, its query-builder options and the
+ * count aggregation a histogram metric gets.
+ */
+export function isBucketCountingPanelType(
+	panelType: PANEL_TYPES | null | undefined,
+): boolean {
+	return (
+		panelType === PANEL_TYPES.HEATMAP || panelType === PANEL_TYPES.DISTRIBUTION
+	);
+}

frontend/src/lib/query/panelQuery.ts

@@ -8,6 +8,7 @@ import {
 	PANEL_TYPES,
 } from 'constants/queryBuilder';
 import { cloneDeep, isEqual, set, unset } from 'lodash-es';
+import { isBucketCountingPanelType } from 'lib/query/bucketCountingPanelTypes';
 import {
 	IBuilderFormula,
 	IBuilderQuery,
@@ -102,13 +103,13 @@ export const getIsQueryModified = (
 /**
  * Formulas are carried across a panel-type switch whole, not rebuilt from
  * `panelTypeDataSourceFormValuesMap` the way `queryData` is, so a bucket axis has to be
- * dropped by hand. The request rejects one on any type but heatmap.
+ * dropped by hand. The request rejects one on any type that does not count buckets.
  */
 const withHeatmapBucketOptions = (
 	formulas: IBuilderFormula[],
 	newPanelType: keyof PartialPanelTypes,
 ): IBuilderFormula[] => {
-	if (newPanelType === PANEL_TYPES.HEATMAP) {
+	if (isBucketCountingPanelType(newPanelType)) {
 		return formulas;
 	}
 

frontend/src/lib/query/panelTypeDataSourceFormValuesMap.ts

@@ -17,6 +17,7 @@ export type PartialPanelTypes = {
 	[PANEL_TYPES.SCATTER]: 'scatter';
 	[PANEL_TYPES.HISTOGRAM]: 'histogram';
 	[PANEL_TYPES.HEATMAP]: 'heatmap';
+	[PANEL_TYPES.DISTRIBUTION]: 'distribution';
 };
 
 export type BuilderField = keyof IBuilderQuery;
@@ -149,6 +150,7 @@ export const panelTypeDataSourceFormValuesMap: Record<
 	[PANEL_TYPES.BAR]: bySource(SERIES, SERIES_METRICS),
 	[PANEL_TYPES.HISTOGRAM]: bySource(SERIES, SERIES_METRICS),
 	[PANEL_TYPES.HEATMAP]: bySource(HEATMAP, HEATMAP_METRICS),
+	[PANEL_TYPES.DISTRIBUTION]: bySource(HEATMAP, HEATMAP_METRICS),
 	[PANEL_TYPES.TABLE]: bySource(SERIES, SCALAR_METRICS),
 	[PANEL_TYPES.PIE]: bySource(SERIES, SCALAR_METRICS),
 	[PANEL_TYPES.SCATTER]: bySource(SERIES, SCALAR_METRICS),

frontend/src/lib/uPlotV2/paths/__tests__/variableWidthBars.test.ts

@@ -0,0 +1,139 @@
+import type uPlot from 'uplot';
+
+import { createVariableWidthBarsPathBuilder } from '../variableWidthBars';
+
+class FakePath2D {
+	rects: number[][] = [];
+
+	rect(x: number, y: number, width: number, height: number): void {
+		this.rects.push([x, y, width, height]);
+	}
+}
+
+/** 10 px per unit on both axes; y grows downward from 100. */
+const fakePlot: Partial<uPlot> = {
+	valToPos: (value: number, scaleKey: string): number =>
+		scaleKey === 'x' ? value * 10 : 100 - value * 10,
+	ctx: {} as CanvasRenderingContext2D,
+};
+const plot = fakePlot as uPlot;
+
+type Fills = Map<CanvasRenderingContext2D['fillStyle'], Path2D>;
+
+function fillsOf(paths: ReturnType<uPlot.Series.PathBuilder>): Fills {
+	const fill = paths?.fill;
+	if (!(fill instanceof Map)) {
+		throw new Error('expected a fill per style');
+	}
+	return fill;
+}
+
+function rectsOf(path: Path2D | undefined): number[][] {
+	if (!(path instanceof FakePath2D)) {
+		throw new Error('expected a FakePath2D');
+	}
+	return path.rects;
+}
+
+describe('createVariableWidthBarsPathBuilder', () => {
+	const originalPath2D = globalThis.Path2D;
+
+	beforeAll(() => {
+		Object.defineProperty(globalThis, 'Path2D', {
+			value: FakePath2D,
+			configurable: true,
+		});
+	});
+
+	afterAll(() => {
+		Object.defineProperty(globalThis, 'Path2D', {
+			value: originalPath2D,
+			configurable: true,
+		});
+	});
+
+	function build(
+		pattern: CanvasPattern | null = null,
+	): ReturnType<uPlot.Series.PathBuilder> {
+		return createVariableWidthBarsPathBuilder({
+			getBars: () => [
+				{ x0: 0, x1: 1, y0: 0, y1: 2, hatched: false },
+				{ x0: 1, x1: 4, y0: 0, y1: 5, hatched: false },
+				{ x0: 4, x1: 6, y0: 1, y1: 3, hatched: true },
+			],
+			fill: '#ff0000',
+			hatchedFill: '#ff000066',
+			getHatchPattern: () => pattern,
+			gapPx: 2,
+		})(plot, 1, 0, 0);
+	}
+
+	it('draws each bar at its own width, inset by half the gap', () => {
+		const fills = fillsOf(build());
+
+		expect(rectsOf(fills.get('#ff0000'))).toStrictEqual([
+			[1, 80, 8, 20],
+			[11, 50, 28, 50],
+		]);
+	});
+
+	it('draws hatched bars in their own fill, with the pattern on top', () => {
+		const pattern = {} as CanvasPattern;
+		const fills = fillsOf(build(pattern));
+
+		expect([...fills.keys()]).toStrictEqual(['#ff0000', '#ff000066', pattern]);
+		expect(rectsOf(fills.get(pattern))).toStrictEqual([[41, 70, 18, 20]]);
+	});
+	it('reads a fill callback on every draw', () => {
+		let fill = '#ff0000';
+		const builder = createVariableWidthBarsPathBuilder({
+			getBars: () => [{ x0: 0, x1: 1, y0: 0, y1: 1, hatched: false }],
+			fill: () => fill,
+			hatchedFill: '#00ff00',
+			getHatchPattern: () => null,
+			gapPx: 0,
+		});
+
+		const first = fillsOf(builder(plot, 1, 0, 0));
+		fill = '#0000ff';
+		const second = fillsOf(builder(plot, 1, 0, 0));
+
+		expect([...first.keys()]).toStrictEqual(['#ff0000']);
+		expect([...second.keys()]).toStrictEqual(['#0000ff']);
+	});
+
+	it('keeps solid bars when the hatched fill is the same colour', () => {
+		const fills = fillsOf(
+			createVariableWidthBarsPathBuilder({
+				getBars: () => [
+					{ x0: 0, x1: 1, y0: 0, y1: 1, hatched: false },
+					{ x0: 1, x1: 2, y0: 0, y1: 1, hatched: true },
+				],
+				fill: 'red',
+				hatchedFill: 'red',
+				getHatchPattern: () => null,
+				gapPx: 0,
+			})(plot, 1, 0, 0),
+		);
+
+		expect(rectsOf(fills.get('red'))).toHaveLength(2);
+	});
+
+	it('hatches only overflow bars when both fills are the same colour', () => {
+		const pattern = {} as CanvasPattern;
+		const fills = fillsOf(
+			createVariableWidthBarsPathBuilder({
+				getBars: () => [
+					{ x0: 0, x1: 1, y0: 0, y1: 1, hatched: false },
+					{ x0: 1, x1: 2, y0: 0, y1: 1, hatched: true },
+				],
+				fill: 'red',
+				hatchedFill: 'red',
+				getHatchPattern: () => pattern,
+				gapPx: 0,
+			})(plot, 1, 0, 0),
+		);
+
+		expect(rectsOf(fills.get(pattern))).toStrictEqual([[10, 90, 10, 10]]);
+	});
+});

frontend/src/lib/uPlotV2/paths/variableWidthBars.ts

@@ -0,0 +1,88 @@
+import uPlot from 'uplot';
+
+/** A bar in scale space. Unlike uPlot's own bars, each one carries its own width. */
+export interface VariableWidthBar {
+	x0: number;
+	x1: number;
+	y0: number;
+	y1: number;
+	/** Drawn in `hatchedFill` with the hatch pattern on top. */
+	hatched: boolean;
+}
+
+/** A fill, or one read on every draw (e.g. to dim a series on hover). */
+type BarFill = string | (() => string);
+
+/** Bars narrower than this, in CSS pixels, keep no gap between them. */
+const MIN_WIDTH_FOR_GAP_PX = 3;
+
+/**
+ * Draws `[x0, x1] × [y0, y1]` rects on the `x` and `y` scales. uPlot's bar builder
+ * assumes one width for every bar, which a bucket axis with uneven bounds breaks.
+ *
+ * `getBars` runs on every redraw, so a caller can derive the bars from the plot's
+ * current state (e.g. which series are shown).
+ */
+export function createVariableWidthBarsPathBuilder({
+	getBars,
+	fill,
+	hatchedFill,
+	getHatchPattern,
+	gapPx,
+}: {
+	getBars: (u: uPlot, seriesIdx: number) => VariableWidthBar[];
+	fill: BarFill;
+	hatchedFill: BarFill;
+	getHatchPattern: (ctx: CanvasRenderingContext2D) => CanvasPattern | null;
+	/** Space between neighbouring bars, in CSS pixels. */
+	gapPx: number;
+}): uPlot.Series.PathBuilder {
+	return (u, seriesIdx): uPlot.Series.Paths => {
+		const solidFill = resolveFill(fill);
+		const overflowFill = resolveFill(hatchedFill);
+		const solidPath = new Path2D();
+		// The hatch overlays only overflow bars, so they keep a path of their own even
+		// when one colour fill covers both (a Map keyed by fill holds one path a fill).
+		const hatchedPath = new Path2D();
+		const isSharedFill = overflowFill === solidFill;
+		const inset = (gapPx * uPlot.pxRatio) / 2;
+		const minWidthForGap = MIN_WIDTH_FOR_GAP_PX * uPlot.pxRatio;
+		let hasHatched = false;
+
+		getBars(u, seriesIdx).forEach((bar) => {
+			const left = u.valToPos(bar.x0, 'x', true);
+			const right = u.valToPos(bar.x1, 'x', true);
+			const top = u.valToPos(bar.y1, 'y', true);
+			const bottom = u.valToPos(bar.y0, 'y', true);
+			const width = right - left;
+			const gap = width > minWidthForGap ? inset : 0;
+			const rect = [left + gap, top, width - 2 * gap, bottom - top] as const;
+			if (!bar.hatched || isSharedFill) {
+				solidPath.rect(...rect);
+			}
+			if (bar.hatched) {
+				hatchedPath.rect(...rect);
+				hasHatched = true;
+			}
+		});
+
+		const fills = new Map<CanvasRenderingContext2D['fillStyle'], Path2D>([
+			[solidFill, solidPath],
+		]);
+		if (hasHatched) {
+			if (!isSharedFill) {
+				fills.set(overflowFill, hatchedPath);
+			}
+			const pattern = getHatchPattern(u.ctx);
+			if (pattern) {
+				fills.set(pattern, hatchedPath);
+			}
+		}
+
+		return { stroke: null, fill: fills, clip: null, band: null, flags: 0 };
+	};
+}
+
+function resolveFill(fill: BarFill): string {
+	return typeof fill === 'function' ? fill() : fill;
+}

frontend/src/lib/visualization/charts/Distribution/Distribution.module.scss

@@ -0,0 +1,5 @@
+.notice {
+	padding: var(--spacing-2) var(--spacing-4);
+	font-size: var(--font-size-xs);
+	color: var(--muted-foreground);
+}

frontend/src/lib/visualization/charts/Distribution/Distribution.tsx

@@ -0,0 +1,279 @@
+import { useCallback, useMemo } from 'react';
+import Legend from 'lib/uPlotV2/components/Legend/Legend';
+import {
+	LegendPosition,
+	type TooltipRenderArgs,
+} from 'lib/uPlotV2/components/types';
+import type { LegendItem } from 'lib/uPlotV2/config/types';
+import { StackMode } from 'lib/uPlotV2/config/types';
+import ChartWrapper from 'lib/visualization/charts/ChartWrapper/ChartWrapper';
+import { resolveBoundaryPrecision } from 'lib/visualization/charts/Heatmap/utils';
+import { DistributionChartProps } from 'lib/visualization/charts/types';
+import { useLegendVisibility } from 'lib/visualization/hooks/useLegendVisibility';
+import type { LegendLayout } from 'lib/visualization/layout/ChartLayout/ChartLayout';
+
+import { resolveOtherColor, resolveSeriesColor } from './colors';
+import DistributionTooltip from './components/DistributionTooltip/DistributionTooltip';
+import { buildDistributionConfig } from './config';
+import {
+	clampDistributionXAxis,
+	cropDistributionXAxis,
+	resolveDistributionBars,
+	resolveDistributionXAxis,
+	sumVisibleCounts,
+} from './layout';
+import { computeDistributionPercentiles } from './percentiles';
+import { groupIntoOther, resolveMaxDrawnGroups } from './topGroups';
+import { DistributionYScale } from './types';
+import { useDistributionBarClick } from './useDistributionBarClick';
+
+import styles from './Distribution.module.scss';
+import { createBoundFormatter, prepareDistributionChartData } from './utils';
+
+/** Rough share of the panel width the plot gets, for fitting side-by-side bars. */
+const PLOT_SHARE = 0.9;
+const PLOT_SHARE_WITH_RIGHT_LEGEND = 0.65;
+/** Vertical space the Other notice takes out of the container. */
+const NOTICE_HEIGHT = 20;
+const NO_PERCENTILES: readonly number[] = Object.freeze([]);
+
+export default function Distribution({
+	id,
+	buckets,
+	series,
+	width,
+	height,
+	isDarkMode,
+	xMin,
+	xMax,
+	yScale = DistributionYScale.Linear,
+	stack = StackMode.Normal,
+	xAxisUnit,
+	decimalPrecision,
+	customColors,
+	percentiles = NO_PERCENTILES,
+	onBarClick,
+	showLegend = true,
+	legendPosition = LegendPosition.BOTTOM,
+	showTooltip = true,
+	canPinTooltip = false,
+	renderTooltipFooter,
+	tooltipPortalRoot,
+	layoutChildren,
+	'data-testid': testId,
+}: DistributionChartProps): JSX.Element {
+	const labels = useMemo(() => series.map((entry) => entry.label), [series]);
+	const counts = useMemo(() => series.map((entry) => entry.counts), [series]);
+
+	const { visibleKeys, focusedSeriesIndex, onLegendAction } =
+		useLegendVisibility({ keys: labels, indexOffset: 1, id });
+
+	const visible = useMemo(
+		() => labels.map((label) => visibleKeys.includes(label)),
+		[labels, visibleKeys],
+	);
+
+	const colors = useMemo(
+		() =>
+			labels.map((label) => resolveSeriesColor(label, isDarkMode, customColors)),
+		[labels, isDarkMode, customColors],
+	);
+
+	const { xAxis, totals } = useMemo(() => {
+		const full = resolveDistributionXAxis(buckets);
+		const visibleTotals = sumVisibleCounts(counts, visible, full.rows.length);
+		// An explicit max may reach past the last occupied bucket; only auto-crop without one.
+		const fitted =
+			xMax === undefined ? cropDistributionXAxis(full, visibleTotals) : full;
+		return {
+			xAxis: clampDistributionXAxis(fitted, xMin, xMax),
+			totals: visibleTotals,
+		};
+	}, [buckets, xMin, xMax, counts, visible]);
+
+	// Over the visible groups combined, so a legend toggle moves them without a refetch.
+	const markers = useMemo(
+		() => computeDistributionPercentiles({ xAxis, totals, percentiles }),
+		[xAxis, totals, percentiles],
+	);
+
+	const isLogY =
+		yScale === DistributionYScale.Log && stack !== StackMode.Percent;
+
+	// The legend lists every group; the plot draws the largest and sums the rest into
+	// Other, so a toggle re-ranks without a refetch.
+	const drawn = useMemo(
+		() =>
+			groupIntoOther({
+				labels,
+				counts,
+				colors,
+				visible,
+				maxGroups: resolveMaxDrawnGroups({
+					stack,
+					xAxis,
+					plotWidth:
+						width *
+						(legendPosition === LegendPosition.RIGHT
+							? PLOT_SHARE_WITH_RIGHT_LEGEND
+							: PLOT_SHARE),
+				}),
+				otherColor: resolveOtherColor(isDarkMode),
+			}),
+		[
+			labels,
+			counts,
+			colors,
+			visible,
+			stack,
+			xAxis,
+			width,
+			legendPosition,
+			isDarkMode,
+		],
+	);
+
+	const layout = useMemo(
+		() =>
+			resolveDistributionBars({
+				xAxis,
+				counts: drawn.counts,
+				stack,
+				isLogY,
+			}),
+		[xAxis, drawn, stack, isLogY],
+	);
+
+	const boundaryPrecision = useMemo(
+		() =>
+			resolveBoundaryPrecision({
+				yAxis: xAxis,
+				yAxisUnit: xAxisUnit,
+				decimalPrecision,
+			}),
+		[xAxis, xAxisUnit, decimalPrecision],
+	);
+
+	const formatBound = useMemo(
+		() => createBoundFormatter(xAxisUnit, boundaryPrecision),
+		[xAxisUnit, boundaryPrecision],
+	);
+
+	const config = useMemo(
+		() =>
+			buildDistributionConfig({
+				id,
+				xAxis,
+				layout,
+				labels: drawn.labels,
+				colors: drawn.colors,
+				stack,
+				isLogY,
+				isDarkMode,
+				markers,
+				xAxisUnit,
+				decimalPrecision: boundaryPrecision,
+			}),
+		[
+			id,
+			xAxis,
+			layout,
+			drawn,
+			stack,
+			isLogY,
+			isDarkMode,
+			markers,
+			xAxisUnit,
+			boundaryPrecision,
+		],
+	);
+
+	const renderTooltip = useCallback(
+		(args: TooltipRenderArgs): React.ReactNode => (
+			<DistributionTooltip
+				uPlotInstance={args.uPlotInstance}
+				isPinned={args.isPinned}
+				dismiss={args.dismiss}
+				xAxis={xAxis}
+				layout={layout}
+				labels={drawn.labels}
+				colors={drawn.colors}
+				counts={drawn.counts}
+				formatBound={formatBound}
+				renderTooltipFooter={renderTooltipFooter}
+			/>
+		),
+		[xAxis, layout, drawn, formatBound, renderTooltipFooter],
+	);
+
+	const handleClick = useDistributionBarClick({
+		xAxis,
+		layout,
+		drawn,
+		series,
+		onBarClick,
+	});
+
+	const data = useMemo(
+		() => prepareDistributionChartData(xAxis, drawn.counts),
+		[xAxis, drawn],
+	);
+
+	const legendItems = useMemo<LegendItem[]>(
+		() =>
+			labels.map((label, index) => ({
+				seriesIndex: index + 1,
+				label,
+				color: colors[index],
+				show: visible[index],
+			})),
+		[labels, colors, visible],
+	);
+
+	const groupLegend = useCallback(
+		({ averageLegendWidth, showSearch }: LegendLayout): React.ReactNode => (
+			<Legend
+				items={legendItems}
+				position={legendPosition}
+				averageLegendWidth={averageLegendWidth}
+				showSearch={showSearch}
+				itemLabel="groups"
+				focusedSeriesIndex={focusedSeriesIndex}
+				onAction={onLegendAction}
+			/>
+		),
+		[legendItems, legendPosition, focusedSeriesIndex, onLegendAction],
+	);
+
+	return (
+		<ChartWrapper
+			config={config}
+			data={data}
+			width={width}
+			height={
+				drawn.otherGroupCount > 0 ? Math.max(0, height - NOTICE_HEIGHT) : height
+			}
+			legendConfig={{ position: legendPosition }}
+			showLegend={showLegend}
+			customLegend={groupLegend}
+			legendLabels={labels}
+			showTooltip={showTooltip}
+			canPinTooltip={canPinTooltip}
+			decimalPrecision={decimalPrecision}
+			customTooltip={renderTooltip}
+			onClick={handleClick}
+			contentFooter={
+				drawn.otherGroupCount > 0 && (
+					<div className={styles.notice} data-testid="distribution-other-notice">
+						Showing top {drawn.labels.length - 1} of {drawn.visibleGroupCount} groups;
+						the rest are summed into Other.
+					</div>
+				)
+			}
+			renderTooltipFooter={renderTooltipFooter}
+			tooltipPortalRoot={tooltipPortalRoot}
+			layoutChildren={layoutChildren}
+			data-testid={testId}
+		/>
+	);
+}

frontend/src/lib/visualization/charts/Distribution/__tests__/Distribution.test.tsx

@@ -0,0 +1,115 @@
+import type React from 'react';
+import type { LegendItem } from 'lib/uPlotV2/config/types';
+import { render, screen, userEvent } from 'tests/test-utils';
+
+import Distribution from '../Distribution';
+import type { DistributionSeries } from '../types';
+
+// The shared Legend virtualises its items; render them all so they are queryable.
+jest.mock('react-virtuoso', () => ({
+	VirtuosoGrid: ({
+		data,
+		itemContent,
+	}: {
+		data: LegendItem[];
+		itemContent: (index: number, item: LegendItem) => React.ReactNode;
+	}): JSX.Element => (
+		<div>
+			{data.map((item, index) => (
+				<div key={item.seriesIndex}>{itemContent(index, item)}</div>
+			))}
+		</div>
+	),
+}));
+
+const BUCKETS = [5, 10, 100, 1000];
+
+const SERIES: DistributionSeries[] = [
+	{ label: 'service.name=cart', counts: [3, 40, 12, 1, 0] },
+	{ label: 'service.name=checkout', counts: [1, 10, 30, 6, 2] },
+];
+
+function renderDistribution(
+	props: Partial<React.ComponentProps<typeof Distribution>> = {},
+): ReturnType<typeof render> {
+	return render(
+		<Distribution
+			id="panel-1"
+			buckets={BUCKETS}
+			series={SERIES}
+			width={800}
+			height={400}
+			isDarkMode
+			data-testid="distribution"
+			{...props}
+		/>,
+	);
+}
+
+describe('Distribution', () => {
+	// Legend items count from 1, as uPlot's data series do.
+	const CART = 1;
+	const CHECKOUT = 2;
+
+	// The selection persists under the panel id, which every case here shares.
+	beforeEach(() => localStorage.clear());
+
+	function legendItem(seriesIndex: number): HTMLElement {
+		return screen.getByTestId(`legend-item-${seriesIndex}`);
+	}
+
+	it('renders the plot container', () => {
+		renderDistribution();
+
+		expect(screen.getByTestId('distribution')).toBeInTheDocument();
+	});
+
+	it('lists every group in the legend, all shown', () => {
+		renderDistribution();
+
+		expect(legendItem(CART)).toHaveAttribute('aria-checked', 'true');
+		expect(legendItem(CHECKOUT)).toHaveAttribute('aria-checked', 'true');
+	});
+
+	it('isolates a group when its row is clicked', async () => {
+		const user = userEvent.setup({ pointerEventsCheck: 0 });
+		renderDistribution();
+
+		await user.click(legendItem(CART));
+
+		expect(legendItem(CART)).toHaveAttribute('aria-checked', 'true');
+		expect(legendItem(CHECKOUT)).toHaveAttribute('aria-checked', 'false');
+	});
+
+	it('hides only that group when its marker is clicked', async () => {
+		const user = userEvent.setup({ pointerEventsCheck: 0 });
+		renderDistribution();
+
+		await user.click(screen.getByTestId(`legend-marker-${CHECKOUT}`));
+
+		expect(legendItem(CHECKOUT)).toHaveAttribute('aria-checked', 'false');
+		expect(legendItem(CART)).toHaveAttribute('aria-checked', 'true');
+	});
+	it('sums groups past the stacked cap into Other, with a notice', () => {
+		renderDistribution({
+			series: Array.from({ length: 12 }, (_, index) => ({
+				label: `group-${index}`,
+				counts: [index, 1, 1, 0, 0],
+			})),
+		});
+
+		expect(screen.getByTestId('distribution-other-notice')).toHaveTextContent(
+			'Showing top 9 of 12 groups; the rest are summed into Other.',
+		);
+		// The legend still lists every group, so any can be isolated.
+		expect(legendItem(1)).toHaveAttribute('aria-label', 'group-0');
+	});
+
+	it('shows no notice when every group fits', () => {
+		renderDistribution();
+
+		expect(
+			screen.queryByTestId('distribution-other-notice'),
+		).not.toBeInTheDocument();
+	});
+});

frontend/src/lib/visualization/charts/Distribution/__tests__/config.test.ts

@@ -0,0 +1,126 @@
+import { StackMode } from 'lib/uPlotV2/config/types';
+import type uPlot from 'uplot';
+
+import { resolveDistributionBars, resolveDistributionXAxis } from '../layout';
+import { buildDistributionConfig } from '../config';
+
+// Buckets ≤ 10, (10, 20], (20, 40], > 40 in slots [0, 1] … [3, 4]. Only (10, 20] is occupied.
+const xAxis = resolveDistributionXAxis([10, 20, 40]);
+const counts = [
+	[0, 4, 0, 0],
+	[0, 6, 0, 0],
+];
+
+function setCursorHook(drawnCounts = counts): (u: uPlot) => void {
+	const config = buildDistributionConfig({
+		id: 'panel-1',
+		xAxis,
+		layout: resolveDistributionBars({
+			xAxis,
+			counts: drawnCounts,
+			stack: StackMode.Normal,
+			isLogY: false,
+		}),
+		labels: drawnCounts.map((_, index) => `group-${index}`),
+		colors: drawnCounts.map(() => '#ff0000'),
+		stack: StackMode.Normal,
+		isLogY: false,
+		isDarkMode: true,
+		markers: [],
+	}).getConfig();
+	const [hook] = config.hooks?.setCursor ?? [];
+	return hook as (u: uPlot) => void;
+}
+
+/** Pixels are values, so the cursor sits at `(left, top)` in scale space. */
+function plotAt(
+	left: number,
+	top: number,
+): { u: uPlot; setSeries: jest.Mock; redraw: jest.Mock } {
+	const setSeries = jest.fn();
+	const redraw = jest.fn();
+	const plot: Partial<uPlot> = {
+		cursor: { left, top },
+		posToVal: (position: number) => position,
+		setSeries,
+		redraw,
+	};
+	return { u: plot as uPlot, setSeries, redraw };
+}
+
+describe('buildDistributionConfig cursor', () => {
+	it('turns off drag-to-zoom', () => {
+		const config = buildDistributionConfig({
+			id: 'panel-1',
+			xAxis,
+			layout: resolveDistributionBars({
+				xAxis,
+				counts,
+				stack: StackMode.Normal,
+				isLogY: false,
+			}),
+			labels: ['group-0', 'group-1'],
+			colors: ['#ff0000', '#ff0000'],
+			stack: StackMode.Normal,
+			isLogY: false,
+			isDarkMode: true,
+			markers: [],
+		}).getConfig();
+
+		expect(config.cursor?.drag).toMatchObject({ x: false, y: false });
+	});
+});
+
+describe('buildDistributionConfig setCursor', () => {
+	// TooltipPlugin only shows a tooltip for a focused series.
+	it('focuses the group under the cursor, 1-based as uPlot counts series', () => {
+		const { u, setSeries, redraw } = plotAt(1.5, 8);
+
+		setCursorHook()(u);
+
+		expect(setSeries).toHaveBeenCalledWith(2, { focus: true });
+		expect(redraw).toHaveBeenCalledWith(true, false);
+	});
+
+	it('focuses the nearest group above the stack, dimming the rest', () => {
+		const { u, setSeries, redraw } = plotAt(1.5, 50);
+
+		setCursorHook()(u);
+
+		expect(setSeries).toHaveBeenCalledWith(2, { focus: true });
+		expect(redraw).toHaveBeenCalledWith(true, false);
+	});
+
+	it('keeps a tooltip over an empty bucket without dimming any group', () => {
+		const hook = setCursorHook();
+		const { u, setSeries, redraw } = plotAt(1.5, 8);
+		hook(u);
+		redraw.mockClear();
+
+		u.cursor.left = 2.5;
+		u.cursor.top = 1;
+		hook(u);
+
+		expect(setSeries).toHaveBeenLastCalledWith(1, { focus: true });
+		expect(redraw).toHaveBeenCalledWith(true, false);
+	});
+
+	it('focuses nothing off the plot', () => {
+		const hook = setCursorHook();
+		const { u, setSeries } = plotAt(1.5, 8);
+		hook(u);
+
+		u.cursor.left = -1;
+		hook(u);
+
+		expect(setSeries).toHaveBeenLastCalledWith(null, { focus: true });
+	});
+
+	it('focuses nothing over an empty bucket when every group is hidden', () => {
+		const { u, setSeries } = plotAt(2.5, 1);
+
+		setCursorHook([])(u);
+
+		expect(setSeries).not.toHaveBeenCalled();
+	});
+});

frontend/src/lib/visualization/charts/Distribution/__tests__/drawPercentileMarkers.test.ts

@@ -0,0 +1,58 @@
+import {
+	layoutMarkerLabels,
+	resolveHoveredMarker,
+} from '../drawPercentileMarkers';
+
+describe('resolveHoveredMarker', () => {
+	const areas = [
+		{
+			x: 100,
+			badges: [
+				{ left: 92, right: 108, top: 0, bottom: 16 },
+				{ left: 92, right: 108, top: 184, bottom: 200 },
+			],
+		},
+		{
+			x: 120,
+			badges: [{ left: 112, right: 128, top: 18, bottom: 34 }],
+		},
+	];
+
+	it('picks the line nearest x within the tolerance', () => {
+		expect(resolveHoveredMarker(areas, 103, 100, 4)).toBe(0);
+		expect(resolveHoveredMarker(areas, 117, 100, 4)).toBe(1);
+		expect(resolveHoveredMarker(areas, 110, 100, 4)).toBeNull();
+	});
+
+	it('picks the marker whose badge is under the cursor', () => {
+		expect(resolveHoveredMarker(areas, 107, 190, 4)).toBe(0);
+		expect(resolveHoveredMarker(areas, 126, 20, 4)).toBe(1);
+	});
+});
+
+describe('layoutMarkerLabels', () => {
+	it('keeps labels that fit on the first row', () => {
+		expect(
+			layoutMarkerLabels(
+				[
+					{ x: 0, width: 20 },
+					{ x: 40, width: 20 },
+				],
+				4,
+			),
+		).toStrictEqual([0, 0]);
+	});
+
+	it('drops a label that would overlap to the next free row', () => {
+		expect(
+			layoutMarkerLabels(
+				[
+					{ x: 30, width: 20 },
+					{ x: 0, width: 20 },
+					{ x: 10, width: 20 },
+				],
+				4,
+			),
+		).toStrictEqual([0, 0, 1]);
+	});
+});

frontend/src/lib/visualization/charts/Distribution/__tests__/layout.test.ts

@@ -0,0 +1,286 @@
+import { StackMode } from 'lib/uPlotV2/config/types';
+
+import {
+	clampDistributionXAxis,
+	cropDistributionXAxis,
+	LOG_Y_BASE,
+	resolveDistributionBars,
+	resolveDistributionXAxis,
+	resolveNearestSeries,
+	sumVisibleCounts,
+	thinLabelledSplits,
+} from '../layout';
+
+function widths(edges: number[]): number[] {
+	return edges.slice(1).map((edge, index) => edge - edges[index]);
+}
+
+describe('resolveDistributionXAxis', () => {
+	it('lays N bounds out as N + 1 buckets, overflow last', () => {
+		const axis = resolveDistributionXAxis([10, 20, 30]);
+
+		expect(axis.rows).toHaveLength(4);
+		expect(axis.rows[0].isUnderflow).toBe(true);
+		expect(axis.rows[3]).toMatchObject({ lower: 30, isOverflow: true });
+		expect(axis.edges).toHaveLength(5);
+	});
+
+	it('gives every bucket the same width, ticks on the bounds', () => {
+		const axis = resolveDistributionXAxis([0, 5, 10, 25, 1000]);
+
+		expect(widths(axis.edges)).toStrictEqual([1, 1, 1, 1, 1, 1]);
+		expect(axis.splits).toStrictEqual([1, 2, 3, 4, 5]);
+		expect(axis.overflowSplit).toBe(6);
+		expect(axis.toBucketValue(3.5)).toBe(17.5);
+	});
+});
+
+describe('cropDistributionXAxis', () => {
+	it('stops one bucket past the last occupied one', () => {
+		const axis = resolveDistributionXAxis([1, 2, 3, 4]);
+
+		const cropped = cropDistributionXAxis(axis, [1, 5, 0, 0, 0]);
+
+		expect(cropped.max).toBe(3);
+		expect(cropped.overflowSplit).toBeNull();
+	});
+});
+
+describe('clampDistributionXAxis', () => {
+	// Buckets ≤ 10, (10, 20], (20, 40], (40, 80], > 80 in slots [0, 1] … [4, 5].
+	const axis = resolveDistributionXAxis([10, 20, 40, 80]);
+
+	it('keeps every bucket without a range', () => {
+		expect(clampDistributionXAxis(axis)).toStrictEqual(axis);
+	});
+
+	it('hides buckets wholly outside the range, keeping straddling ones whole', () => {
+		const clamped = clampDistributionXAxis(axis, 20, 50);
+
+		expect([clamped.min, clamped.max]).toStrictEqual([2, 4]);
+		expect(clamped.overflowSplit).toBeNull();
+	});
+
+	it('keeps the overflow tick while the overflow bucket shows', () => {
+		const clamped = clampDistributionXAxis(axis, 15);
+
+		expect([clamped.min, clamped.max]).toStrictEqual([1, 5]);
+		expect(clamped.overflowSplit).toBe(5);
+	});
+
+	it('keeps one bucket when the range misses them all', () => {
+		const clamped = clampDistributionXAxis(axis, 1000);
+
+		expect([clamped.min, clamped.max]).toStrictEqual([4, 5]);
+	});
+
+	it('narrows an already cropped axis, never widening it', () => {
+		const cropped = cropDistributionXAxis(axis, [1, 5, 0, 0, 0]);
+
+		expect(clampDistributionXAxis(cropped, 15).max).toBe(cropped.max);
+	});
+});
+
+describe('sumVisibleCounts', () => {
+	it('adds only the visible series', () => {
+		expect(
+			sumVisibleCounts(
+				[
+					[1, 2],
+					[10, 20],
+					[100, 200],
+				],
+				[true, false, true],
+				2,
+			),
+		).toStrictEqual([101, 202]);
+	});
+});
+
+describe('resolveDistributionBars', () => {
+	const xAxis = resolveDistributionXAxis([1, 2]);
+	const counts = [
+		[4, 6, 0],
+		[1, 3, 2],
+	];
+
+	it('sizes the count axis by the buckets left in the window', () => {
+		// Buckets ≤ 1, (1, 2], > 2; a max of 1 keeps only the first.
+		const { yMax } = resolveDistributionBars({
+			xAxis: clampDistributionXAxis(xAxis, undefined, 1),
+			counts: [[4, 1000, 0]],
+			stack: StackMode.Normal,
+			isLogY: false,
+		});
+
+		expect(yMax).toBe(4);
+	});
+
+	it('stacks series in each bucket under normal', () => {
+		const { rects, yMax } = resolveDistributionBars({
+			xAxis,
+			counts,
+			stack: StackMode.Normal,
+			isLogY: false,
+		});
+
+		expect(rects[0].map(({ y0, y1 }) => [y0, y1])).toStrictEqual([
+			[0, 4],
+			[0, 6],
+		]);
+		expect(rects[1].map(({ y0, y1 }) => [y0, y1])).toStrictEqual([
+			[4, 5],
+			[6, 9],
+			[0, 2],
+		]);
+		expect(yMax).toBe(9);
+	});
+
+	it('marks the overflow bucket hatched', () => {
+		const { rects } = resolveDistributionBars({
+			xAxis,
+			counts,
+			stack: StackMode.Normal,
+			isLogY: false,
+		});
+
+		expect(rects[1].map(({ hatched }) => hatched)).toStrictEqual([
+			false,
+			false,
+			true,
+		]);
+	});
+
+	it('stacks shares of each bucket under percent', () => {
+		const { rects, yMax } = resolveDistributionBars({
+			xAxis,
+			counts,
+			stack: StackMode.Percent,
+			isLogY: false,
+		});
+
+		expect(rects[0][0]).toMatchObject({ y0: 0, y1: 80 });
+		expect(rects[1][0]).toMatchObject({ y0: 80, y1: 100 });
+		expect(yMax).toBe(100);
+	});
+
+	it('splits the bucket width between series under none', () => {
+		const { rects, yMax } = resolveDistributionBars({
+			xAxis,
+			counts,
+			stack: StackMode.None,
+			isLogY: false,
+		});
+
+		expect(rects[0][0]).toMatchObject({ x0: 0, x1: 0.5, y0: 0, y1: 4 });
+		expect(rects[1][0]).toMatchObject({ x0: 0.5, x1: 1, y0: 0, y1: 1 });
+		expect(yMax).toBe(6);
+	});
+
+	it('starts bars at the log base and skips zero counts', () => {
+		const { rects } = resolveDistributionBars({
+			xAxis,
+			counts,
+			stack: StackMode.Normal,
+			isLogY: true,
+		});
+
+		expect(rects[0].map(({ y0 }) => y0)).toStrictEqual([LOG_Y_BASE, LOG_Y_BASE]);
+		expect(rects[0].map(({ bucketIndex }) => bucketIndex)).toStrictEqual([0, 1]);
+	});
+
+	it('skips bars whose top stays under the log base, never inverting one', () => {
+		const fractional = [
+			[0.5, 3, 0],
+			[0.25, 0.5, 2],
+		];
+		const stacked = resolveDistributionBars({
+			xAxis,
+			counts: fractional,
+			stack: StackMode.Normal,
+			isLogY: true,
+		});
+		const sideBySide = resolveDistributionBars({
+			xAxis,
+			counts: fractional,
+			stack: StackMode.None,
+			isLogY: true,
+		});
+
+		expect(
+			stacked.rects.map((rects) => rects.map(({ y0, y1 }) => [y0, y1])),
+		).toStrictEqual([
+			[[LOG_Y_BASE, 3]],
+			[
+				[3, 3.5],
+				[LOG_Y_BASE, 2],
+			],
+		]);
+		expect(
+			sideBySide.rects.map((rects) => rects.map(({ bucketIndex }) => bucketIndex)),
+		).toStrictEqual([[1], [2]]);
+	});
+});
+
+describe('thinLabelledSplits', () => {
+	it('keeps labels that clear each other by the gap', () => {
+		expect(
+			thinLabelledSplits({
+				positions: [0, 50, 100],
+				widths: [20, 20, 20],
+				gap: 10,
+			}),
+		).toStrictEqual([0, 1, 2]);
+	});
+
+	it('drops a wide label that would touch its neighbour, keeping the rightmost', () => {
+		// 16.67 mins-wide labels 60 px apart: each needs 70 px of centre distance.
+		expect(
+			thinLabelledSplits({
+				positions: [0, 60, 120, 180],
+				widths: [60, 60, 60, 60],
+				gap: 10,
+			}),
+		).toStrictEqual([1, 3]);
+	});
+});
+
+describe('resolveNearestSeries', () => {
+	// Buckets ≤ 10, (10, 20], (20, 40], > 40 in slots [0, 1] … [3, 4].
+	const xAxis = resolveDistributionXAxis([10, 20, 40]);
+	const counts = [
+		[0, 4, 0, 0],
+		[0, 6, 0, 0],
+	];
+	const stacked = resolveDistributionBars({
+		xAxis,
+		counts,
+		stack: StackMode.Normal,
+		isLogY: false,
+	});
+
+	it('names the group whose bar is under the point', () => {
+		expect(resolveNearestSeries(stacked, 1, 1.5, 2)).toBe(0);
+		expect(resolveNearestSeries(stacked, 1, 1.5, 8)).toBe(1);
+	});
+
+	it('takes the vertically nearest group off the bars, as a bar chart does', () => {
+		expect(resolveNearestSeries(stacked, 1, 1.5, 50)).toBe(1);
+	});
+
+	it('is null over an empty bucket', () => {
+		expect(resolveNearestSeries(stacked, 2, 2.5, 1)).toBeNull();
+	});
+
+	it('picks the sub-bar under the cursor side by side', () => {
+		const sideBySide = resolveDistributionBars({
+			xAxis,
+			counts,
+			stack: StackMode.None,
+			isLogY: false,
+		});
+
+		expect(resolveNearestSeries(sideBySide, 1, 1.25, 50)).toBe(0);
+		expect(resolveNearestSeries(sideBySide, 1, 1.75, 1)).toBe(1);
+	});
+});

frontend/src/lib/visualization/charts/Distribution/__tests__/percentiles.test.ts

@@ -0,0 +1,97 @@
+import { resolveDistributionXAxis } from '../layout';
+import {
+	computeDistributionPercentiles,
+	formatPercentileBadge,
+	formatPercentileName,
+	formatPercentileValue,
+	groupPercentileMarkers,
+} from '../percentiles';
+
+// Buckets ≤ 10, (10, 20], (20, 40], > 40 in slots [0, 1] … [3, 4].
+const xAxis = resolveDistributionXAxis([10, 20, 40]);
+
+describe('computeDistributionPercentiles', () => {
+	it('interpolates inside the bucket holding the rank, as histogram_quantile does', () => {
+		const markers = computeDistributionPercentiles({
+			xAxis,
+			totals: [10, 20, 10, 0],
+			percentiles: [50, 90],
+		});
+
+		expect(markers.map(({ value }) => value)).toStrictEqual([15, 32]);
+		expect(markers.every(({ isOverflow }) => !isOverflow)).toBe(true);
+	});
+
+	it('places the marker the same fraction across the bucket on the axis', () => {
+		const [p50] = computeDistributionPercentiles({
+			xAxis,
+			totals: [10, 20, 10, 0],
+			percentiles: [50],
+		});
+
+		expect(p50.axisValue).toBe(1.5);
+	});
+
+	it('starts the lowest bucket at zero', () => {
+		const [p10] = computeDistributionPercentiles({
+			xAxis,
+			totals: [10, 20, 10, 0],
+			percentiles: [10],
+		});
+
+		expect(p10.value).toBe(4);
+	});
+
+	it('reports a percentile in overflow as above the last bound, at its left edge', () => {
+		const [p99] = computeDistributionPercentiles({
+			xAxis,
+			totals: [0, 0, 10, 10],
+			percentiles: [99],
+		});
+
+		expect(p99).toMatchObject({ value: 40, axisValue: 3, isOverflow: true });
+	});
+
+	it('marks nothing when every count is zero', () => {
+		expect(
+			computeDistributionPercentiles({
+				xAxis,
+				totals: [0, 0, 0, 0],
+				percentiles: [50],
+			}),
+		).toStrictEqual([]);
+	});
+});
+
+describe('formatPercentileName', () => {
+	it('keeps fractional percentile names short', () => {
+		expect(formatPercentileName(99.9)).toBe('p99.9');
+		expect(formatPercentileName(50)).toBe('p50');
+	});
+});
+
+describe('percentile marker groups', () => {
+	const formatBound = (value: number): string => `${value} ms`;
+	const p50 = { percentile: 50, value: 15, axisValue: 1.5, isOverflow: false };
+	const p99 = { percentile: 99, value: 40, axisValue: 3, isOverflow: true };
+	const p90 = { percentile: 90, value: 40, axisValue: 3, isOverflow: true };
+
+	it('groups markers on the same spot, lowest percentile first', () => {
+		expect(groupPercentileMarkers([p50, p99, p90])).toStrictEqual([
+			[p50],
+			[p90, p99],
+		]);
+	});
+
+	it('names a group by its lowest percentile', () => {
+		expect(formatPercentileBadge([p50])).toBe('p50');
+		expect(formatPercentileBadge([p90, p99])).toBe('p90+');
+	});
+
+	it('shows the estimate, or the overflow bound once for the group', () => {
+		expect(formatPercentileValue([p50], formatBound)).toBe('p50 ≈ 15 ms');
+		expect(formatPercentileValue([p90, p99], formatBound)).toBe(
+			'p90, p99 > 40 ms',
+		);
+	});
+});

frontend/src/lib/visualization/charts/Distribution/__tests__/topGroups.test.ts

@@ -0,0 +1,126 @@
+import { StackMode } from 'lib/uPlotV2/config/types';
+
+import { resolveDistributionXAxis } from '../layout';
+import {
+	groupIntoOther,
+	resolveClickedGroup,
+	MAX_STACKED_GROUPS,
+	OTHER_GROUP_LABEL,
+	resolveMaxDrawnGroups,
+} from '../topGroups';
+
+describe('resolveMaxDrawnGroups', () => {
+	// Four equal buckets plus underflow and overflow: six slots of one unit each.
+	const xAxis = resolveDistributionXAxis([1, 2, 3, 4, 5]);
+
+	it('caps stacked and percent at the fixed limit', () => {
+		expect(
+			resolveMaxDrawnGroups({ stack: StackMode.Normal, xAxis, plotWidth: 60 }),
+		).toBe(MAX_STACKED_GROUPS);
+		expect(
+			resolveMaxDrawnGroups({ stack: StackMode.Percent, xAxis, plotWidth: 60 }),
+		).toBe(MAX_STACKED_GROUPS);
+	});
+
+	it('fits side by side so the narrowest bar stays 3 px wide', () => {
+		// 120 px over six slots: 20 px a bucket, six 3 px bars.
+		expect(
+			resolveMaxDrawnGroups({ stack: StackMode.None, xAxis, plotWidth: 120 }),
+		).toBe(6);
+		expect(
+			resolveMaxDrawnGroups({ stack: StackMode.None, xAxis, plotWidth: 6 }),
+		).toBe(1);
+	});
+});
+
+describe('groupIntoOther', () => {
+	const args = {
+		labels: ['a', 'b', 'c', 'd'],
+		counts: [
+			[1, 1],
+			[5, 5],
+			[2, 0],
+			[3, 3],
+		],
+		colors: ['#a', '#b', '#c', '#d'],
+		visible: [true, true, true, true],
+		otherColor: '#999',
+	};
+
+	it('draws every visible group when they fit', () => {
+		const drawn = groupIntoOther({ ...args, maxGroups: 4 });
+
+		expect(drawn.labels).toStrictEqual(['a', 'b', 'c', 'd']);
+		expect(drawn.otherGroupCount).toBe(0);
+	});
+
+	it('keeps the largest, in legend order, and sums the rest exactly', () => {
+		const drawn = groupIntoOther({ ...args, maxGroups: 3 });
+
+		expect(drawn.labels).toStrictEqual(['b', 'd', OTHER_GROUP_LABEL]);
+		expect(drawn.sourceIndexes).toStrictEqual([1, 3, null]);
+		expect(drawn.counts[2]).toStrictEqual([3, 1]);
+		expect(drawn.colors[2]).toBe('#999');
+		expect(drawn).toMatchObject({ otherGroupCount: 2, visibleGroupCount: 4 });
+	});
+
+	it('re-ranks without hidden groups, which never reach Other', () => {
+		const drawn = groupIntoOther({
+			...args,
+			visible: [true, false, true, true],
+			maxGroups: 2,
+		});
+
+		expect(drawn.labels).toStrictEqual(['d', OTHER_GROUP_LABEL]);
+		expect(drawn.sourceIndexes).toStrictEqual([3, null]);
+		expect(drawn.counts[1]).toStrictEqual([3, 1]);
+		expect(drawn.visibleGroupCount).toBe(3);
+	});
+});
+
+describe('resolveClickedGroup', () => {
+	const series = ['a', 'b', 'c'].map((label) => ({
+		label,
+		counts: [label === 'a' ? 5 : 1],
+	}));
+	const drawn = groupIntoOther({
+		labels: ['a', 'b', 'c'],
+		counts: series.map(({ counts }) => counts),
+		colors: ['#a', '#b', '#c'],
+		visible: [true, true, true],
+		maxGroups: 2,
+		otherColor: '#999',
+	});
+
+	it('maps a drawn bar back to its source group and colour', () => {
+		expect(resolveClickedGroup(drawn, 0, series)).toStrictEqual({
+			series: series[0],
+			color: '#a',
+		});
+	});
+
+	it('refuses Other and empty space', () => {
+		expect(resolveClickedGroup(drawn, 1, series)).toBeNull();
+		expect(resolveClickedGroup(drawn, null, series)).toBeNull();
+	});
+
+	it('maps by source index, not label, when groups share a legend', () => {
+		const twins = [
+			{ label: 'Other', groupLabels: { pod: 'a' }, counts: [1] },
+			{ label: 'Other', groupLabels: { pod: 'b' }, counts: [2] },
+		];
+		const drawnTwins = groupIntoOther({
+			labels: twins.map(({ label }) => label),
+			counts: twins.map(({ counts }) => counts),
+			colors: ['#a', '#b'],
+			visible: [true, true],
+			maxGroups: 2,
+			otherColor: '#999',
+		});
+
+		expect(resolveClickedGroup(drawnTwins, 1, twins)).toStrictEqual({
+			series: twins[1],
+			color: '#b',
+		});
+	});
+});

frontend/src/lib/visualization/charts/Distribution/colors.ts

@@ -0,0 +1,29 @@
+import { Color } from '@signozhq/design-tokens';
+import { themeColors } from 'constants/theme';
+import { generateColor } from 'lib/uPlotLib/utils/generateColor';
+import { toAlphaHex } from 'lib/uPlotV2/utils/fillOpacity';
+
+const HEX_COLOR = /^#[0-9a-f]{6}$/i;
+
+export function withOpacity(color: string, opacity: number): string {
+	return HEX_COLOR.test(color) ? `${color}${toAlphaHex(opacity)}` : color;
+}
+
+/** Neutral, so the summed remainder never reads as one more group. */
+export function resolveOtherColor(isDarkMode: boolean): string {
+	return isDarkMode ? Color.BG_VANILLA_400 : Color.BG_SLATE_50;
+}
+
+export function resolveSeriesColor(
+	label: string,
+	isDarkMode: boolean,
+	customColors?: Record<string, string>,
+): string {
+	return (
+		customColors?.[label] ??
+		generateColor(
+			label,
+			isDarkMode ? themeColors.chartcolors : themeColors.lightModeColor,
+		)
+	);
+}

frontend/src/lib/visualization/charts/Distribution/components/DistributionTooltip/DistributionTooltip.module.scss

@@ -0,0 +1,116 @@
+@use '../../../../../../styles/scrollbar' as *;
+
+// Same surface as the shared and heatmap tooltips.
+.container {
+	--gutter: 14px;
+	--row-inset: 6px;
+
+	font-family: 'Inter';
+	font-size: 12px;
+	background: var(--l2-background);
+	-webkit-font-smoothing: antialiased;
+	color: var(--l2-foreground);
+	border-radius: 6px;
+	border: 1px solid var(--l2-border);
+	display: flex;
+	flex-direction: column;
+	min-width: 240px;
+
+	&.pinned {
+		border-color: var(--ring);
+	}
+}
+
+.divider {
+	display: block;
+	width: 100%;
+	height: 1px;
+	background-color: var(--l2-border);
+}
+
+// Same as the heatmap tooltip's bucket row.
+.title {
+	display: flex;
+	align-items: center;
+	justify-content: space-between;
+	gap: var(--spacing-2);
+	padding: var(--spacing-6) var(--gutter);
+}
+
+.titleBucket,
+.titleCount {
+	font-family: var(--font-mono);
+	font-size: var(--font-size-xs);
+	font-weight: 700;
+	letter-spacing: -0.01em;
+	color: var(--popover-foreground);
+	white-space: nowrap;
+	font-variant-numeric: tabular-nums;
+}
+
+.titleSeparator {
+	flex: 1;
+	border-width: 0.5px;
+	border-style: dashed;
+	border-color: currentColor;
+	min-width: 24px;
+	opacity: 0.5;
+}
+
+// One grid for the heading and every row, so their columns line up.
+.rows {
+	display: grid;
+	grid-template-columns: 12px minmax(0, 1fr) repeat(3, auto);
+	column-gap: var(--spacing-6);
+	row-gap: var(--spacing-1);
+	align-content: start;
+	padding: var(--spacing-4) var(--spacing-4) var(--spacing-6);
+	max-height: 320px;
+	overflow-y: auto;
+
+	@include custom-scrollbar;
+}
+
+.columnHeader,
+.rows .row {
+	grid-column: 1 / -1;
+	display: grid;
+	grid-template-columns: subgrid;
+	// The shared item's own `gap` would otherwise shift the subgrid off the parent.
+	column-gap: var(--spacing-6);
+	align-items: center;
+}
+
+.columnHeader {
+	padding: 0 6px var(--spacing-2);
+	font-family: var(--font-mono);
+	font-size: 10px;
+	letter-spacing: 0.06em;
+	text-transform: uppercase;
+	color: var(--muted-foreground);
+
+	> span:nth-child(n + 2) {
+		text-align: right;
+	}
+}
+
+.columnLabel {
+	grid-column: 1 / 3;
+	min-width: 0;
+	overflow: hidden;
+	text-overflow: ellipsis;
+	white-space: nowrap;
+}
+
+.rows .row {
+	border-radius: var(--radius);
+	font-variant-numeric: tabular-nums;
+
+	&[data-is-active='true'] {
+		background: var(--l3-background);
+	}
+
+	> :nth-child(n + 3) {
+		text-align: right;
+	}
+}

frontend/src/lib/visualization/charts/Distribution/components/DistributionTooltip/DistributionTooltip.tsx

@@ -0,0 +1,154 @@
+import { useMemo } from 'react';
+import cx from 'classnames';
+import {
+	formatRowLabel,
+	resolveRowIndex,
+} from 'lib/uPlotV2/plugins/HeatmapPlugin/geometry';
+import TooltipPinnedBadge from 'lib/uPlotV2/components/Tooltip/components/TooltipPinnedBadge/TooltipPinnedBadge';
+import ItemStyles from 'lib/uPlotV2/components/Tooltip/components/TooltipItem/TooltipItem.module.scss';
+
+import { resolveNearestSeries } from '../../layout';
+import {
+	buildDistributionTooltipRows,
+	formatPercent,
+	resolveGroupColumn,
+} from './distributionTooltipContent';
+import { DistributionTooltipProps } from './types';
+
+import Styles from './DistributionTooltip.module.scss';
+
+/**
+ * The bucket comes from the live cursor, not uPlot's `cursor.idx`: that snaps to the
+ * nearest bucket centre, which on uneven widths is often the neighbour.
+ */
+export default function DistributionTooltip({
+	uPlotInstance,
+	xAxis,
+	layout,
+	labels,
+	colors,
+	counts,
+	formatBound,
+	isPinned,
+	dismiss,
+	renderTooltipFooter,
+}: DistributionTooltipProps): JSX.Element | null {
+	// Read outside the memo: uPlot mutates the same instance on every move.
+	const { left = -10, top = -10 } = uPlotInstance.cursor;
+
+	const hover = useMemo(() => {
+		if (left < 0 || top < 0) {
+			return null;
+		}
+		const x = uPlotInstance.posToVal(left, 'x');
+		const bucket = resolveRowIndex(xAxis.edges, x);
+		if (bucket === null) {
+			return null;
+		}
+		return {
+			bucket,
+			series: resolveNearestSeries(
+				layout,
+				bucket,
+				x,
+				uPlotInstance.posToVal(top, 'y'),
+			),
+		};
+	}, [left, top, uPlotInstance, xAxis, layout]);
+
+	const groupColumn = useMemo(() => resolveGroupColumn(labels), [labels]);
+
+	const rows = useMemo(
+		() =>
+			hover
+				? buildDistributionTooltipRows({
+						labels,
+						colors,
+						counts,
+						bucket: hover.bucket,
+						hoveredSeries: hover.series,
+						formatLabel: groupColumn.format,
+					})
+				: [],
+		[hover, labels, colors, counts, groupColumn],
+	);
+
+	if (!hover) {
+		return null;
+	}
+
+	const bucket = xAxis.rows[hover.bucket];
+	const bucketTotal = rows.reduce((sum, row) => sum + row.count, 0);
+
+	return (
+		<div
+			className={cx(Styles.container, { [Styles.pinned]: isPinned })}
+			data-pinned={isPinned}
+			data-testid="distribution-tooltip"
+		>
+			<div className={Styles.title}>
+				<span
+					className={Styles.titleBucket}
+					data-testid="distribution-tooltip-range"
+				>
+					{formatRowLabel(bucket, formatBound)}
+				</span>
+				<span className={Styles.titleSeparator} />
+				<span
+					className={Styles.titleCount}
+					data-testid="distribution-tooltip-total"
+				>
+					{bucketTotal.toLocaleString()}
+				</span>
+				{isPinned && <TooltipPinnedBadge />}
+			</div>
+
+			<span className={Styles.divider} />
+
+			<div className={Styles.rows}>
+				<div className={Styles.columnHeader}>
+					<span
+						className={Styles.columnLabel}
+						title={groupColumn.heading}
+						data-testid="distribution-tooltip-group-heading"
+					>
+						{groupColumn.heading}
+					</span>
+					<span>Count</span>
+					<span>% Total</span>
+					<span data-testid="distribution-tooltip-cumulative-heading">
+						{bucket.isOverflow ? 'All' : `≤ ${formatBound(bucket.upper)}`}
+					</span>
+				</div>
+				{rows.map((row) => (
+					<div
+						key={row.seriesIndex}
+						className={cx(ItemStyles.uplotTooltipItem, Styles.row)}
+						data-is-active={row.isHovered}
+						data-testid="distribution-tooltip-row"
+						data-hovered={row.isHovered}
+					>
+						<span
+							className={ItemStyles.uplotTooltipItemMarker}
+							style={{ borderColor: row.color, backgroundColor: row.color }}
+						/>
+						<span className={ItemStyles.uplotTooltipItemLabel} title={row.label}>
+							{row.label}
+						</span>
+						<span className={ItemStyles.uplotTooltipItemValue}>
+							{row.count.toLocaleString()}
+						</span>
+						<span className={ItemStyles.uplotTooltipItemValue}>
+							{formatPercent(row.share)}
+						</span>
+						<span className={ItemStyles.uplotTooltipItemValue}>
+							{formatPercent(row.cumulativeShare)}
+						</span>
+					</div>
+				))}
+			</div>
+
+			{renderTooltipFooter?.({ isPinned, dismiss })}
+		</div>
+	);
+}

frontend/src/lib/visualization/charts/Distribution/components/DistributionTooltip/__tests__/DistributionTooltip.test.tsx

@@ -0,0 +1,88 @@
+import { StackMode } from 'lib/uPlotV2/config/types';
+import {
+	resolveDistributionBars,
+	resolveDistributionXAxis,
+} from 'lib/visualization/charts/Distribution/layout';
+import { render, screen } from 'tests/test-utils';
+import type uPlot from 'uplot';
+
+import DistributionTooltip from '../DistributionTooltip';
+
+// Buckets ≤ 10, (10, 20], (20, 40], > 40 in slots [0, 1] … [3, 4].
+const xAxis = resolveDistributionXAxis([10, 20, 40]);
+const counts = [
+	[1, 4, 2, 0],
+	[0, 6, 1, 1],
+];
+const layout = resolveDistributionBars({
+	xAxis,
+	counts,
+	stack: StackMode.Normal,
+	isLogY: false,
+});
+
+/** Pixels are values: the cursor at (1.5, 2) is over the first group in (10, 20]. */
+function plotAt(left: number, top: number): uPlot {
+	const plot: Partial<uPlot> = {
+		cursor: { left, top },
+		posToVal: (position: number) => position,
+	};
+	return plot as uPlot;
+}
+
+function renderTooltip(uPlotInstance: uPlot): void {
+	render(
+		<DistributionTooltip
+			uPlotInstance={uPlotInstance}
+			isPinned={false}
+			dismiss={jest.fn()}
+			xAxis={xAxis}
+			layout={layout}
+			labels={['{service.name="cart"}', '{service.name="checkout"}']}
+			colors={['#f00', '#0f0']}
+			counts={counts}
+			formatBound={(value): string => `${value} ms`}
+		/>,
+	);
+}
+
+describe('DistributionTooltip', () => {
+	it('names the bucket under the cursor and its total', () => {
+		renderTooltip(plotAt(1.5, 2));
+
+		expect(screen.getByTestId('distribution-tooltip-range')).toHaveTextContent(
+			'10 ms – 20 ms',
+		);
+		expect(screen.getByTestId('distribution-tooltip-total')).toHaveTextContent(
+			'10',
+		);
+	});
+
+	it('heads the columns with the group-by key and the bucket bound', () => {
+		renderTooltip(plotAt(1.5, 2));
+
+		expect(
+			screen.getByTestId('distribution-tooltip-group-heading'),
+		).toHaveTextContent('service.name');
+		expect(
+			screen.getByTestId('distribution-tooltip-cumulative-heading'),
+		).toHaveTextContent('≤ 20 ms');
+	});
+
+	it('lists every group in legend order, the hovered one active', () => {
+		renderTooltip(plotAt(1.5, 2));
+
+		const rows = screen.getAllByTestId('distribution-tooltip-row');
+		expect(rows).toHaveLength(2);
+		expect(rows[0]).toHaveTextContent('cart457%71%');
+		expect(rows[0]).toHaveAttribute('data-is-active', 'true');
+		expect(rows[1]).toHaveTextContent('checkout675%75%');
+		expect(rows[1]).toHaveAttribute('data-is-active', 'false');
+	});
+
+	it('renders nothing off the plot', () => {
+		renderTooltip(plotAt(-1, -1));
+
+		expect(screen.queryByTestId('distribution-tooltip')).not.toBeInTheDocument();
+	});
+});

frontend/src/lib/visualization/charts/Distribution/components/DistributionTooltip/__tests__/distributionTooltipContent.test.ts

@@ -0,0 +1,73 @@
+import {
+	buildDistributionTooltipRows,
+	formatPercent,
+	resolveGroupColumn,
+} from '../distributionTooltipContent';
+
+describe('formatPercent', () => {
+	it('rounds, and never shows a real share as 0%', () => {
+		expect(formatPercent(0.256)).toBe('26%');
+		expect(formatPercent(0.004)).toBe('<1%');
+		expect(formatPercent(0)).toBe('0%');
+	});
+});
+
+describe('resolveGroupColumn', () => {
+	it('names the column after a shared single key and shows its values', () => {
+		const column = resolveGroupColumn([
+			'{service.name="cart"}',
+			'{service.name="checkout"}',
+		]);
+
+		expect(column.heading).toBe('service.name');
+		expect(column.format('{service.name="cart"}')).toBe('cart');
+	});
+
+	it('keeps full labels for several keys or mixed labels', () => {
+		const several = resolveGroupColumn(['{env="prod", service.name="cart"}']);
+		const mixed = resolveGroupColumn(['{service.name="cart"}', 'Other']);
+
+		expect(several.heading).toBe('Group');
+		expect(several.format('{env="prod", service.name="cart"}')).toBe(
+			'{env="prod", service.name="cart"}',
+		);
+		expect(mixed.heading).toBe('Group');
+	});
+});
+
+describe('buildDistributionTooltipRows', () => {
+	it('gives each drawn group, in legend order, its count, share and cumulative share', () => {
+		const rows = buildDistributionTooltipRows({
+			labels: ['cart', 'checkout'],
+			colors: ['#f00', '#0f0'],
+			counts: [
+				[2, 6, 2],
+				[5, 0, 5],
+			],
+			bucket: 1,
+			hoveredSeries: 0,
+			formatLabel: (label) => label.toUpperCase(),
+		});
+
+		expect(rows).toStrictEqual([
+			{
+				seriesIndex: 0,
+				label: 'CART',
+				color: '#f00',
+				count: 6,
+				share: 0.6,
+				cumulativeShare: 0.8,
+				isHovered: true,
+			},
+			{
+				seriesIndex: 1,
+				label: 'CHECKOUT',
+				color: '#0f0',
+				count: 0,
+				share: 0,
+				cumulativeShare: 0.5,
+				isHovered: false,
+			},
+		]);
+	});
+});

frontend/src/lib/visualization/charts/Distribution/components/DistributionTooltip/distributionTooltipContent.ts

@@ -0,0 +1,70 @@
+import { DistributionGroupColumn, DistributionTooltipRow } from './types';
+
+const SINGLE_LABEL = /^\{([^=,]+)="([^"]*)"\}$/;
+
+/** `<1%` rather than `0%`, so a share that exists never reads as none. */
+export function formatPercent(share: number): string {
+	if (share > 0 && share < 0.01) {
+		return '<1%';
+	}
+	return `${Math.round(share * 100)}%`;
+}
+
+/**
+ * Names the group column after the one group-by key every label shares, showing just
+ * its values; anything else (several keys, Other) keeps the full labels.
+ */
+export function resolveGroupColumn(labels: string[]): DistributionGroupColumn {
+	const keys = new Set<string>();
+	labels.forEach((label) => {
+		keys.add(SINGLE_LABEL.exec(label)?.[1] ?? '');
+	});
+	const [key] = [...keys];
+	if (keys.size !== 1 || !key) {
+		return { heading: 'Group', format: (label) => label };
+	}
+	return {
+		heading: key,
+		format: (label) => SINGLE_LABEL.exec(label)?.[2] ?? label,
+	};
+}
+
+/** One row per drawn group, in legend order, with its count in `bucket`. */
+export function buildDistributionTooltipRows({
+	labels,
+	colors,
+	counts,
+	bucket,
+	hoveredSeries,
+	formatLabel,
+}: {
+	labels: string[];
+	colors: string[];
+	/** `counts[series][bucket]`. */
+	counts: number[][];
+	bucket: number;
+	hoveredSeries: number | null;
+	formatLabel: (label: string) => string;
+}): DistributionTooltipRow[] {
+	return labels.map((label, series) => {
+		const seriesCounts = counts[series] ?? [];
+		let total = 0;
+		let atOrBelow = 0;
+		seriesCounts.forEach((count, index) => {
+			total += count;
+			if (index <= bucket) {
+				atOrBelow += count;
+			}
+		});
+		const count = seriesCounts[bucket] ?? 0;
+		return {
+			seriesIndex: series,
+			label: formatLabel(label),
+			color: colors[series],
+			count,
+			share: total > 0 ? count / total : 0,
+			cumulativeShare: total > 0 ? atOrBelow / total : 0,
+			isHovered: series === hoveredSeries,
+		};
+	});
+}

frontend/src/lib/visualization/charts/Distribution/components/DistributionTooltip/types.ts

@@ -0,0 +1,39 @@
+import type {
+	IRenderTooltipFooterArgs,
+	TooltipRenderArgs,
+} from 'lib/uPlotV2/components/types';
+
+import type { DistributionBarsLayout } from '../../layout';
+import type { DistributionXAxis } from '../../types';
+
+export interface DistributionTooltipRow {
+	/** Index among the drawn series. */
+	seriesIndex: number;
+	label: string;
+	color: string;
+	count: number;
+	/** Of the group's own total over the range. */
+	share: number;
+	/** Of the group's total, at or below this bucket. */
+	cumulativeShare: number;
+	isHovered: boolean;
+}
+
+export interface DistributionGroupColumn {
+	heading: string;
+	format: (label: string) => string;
+}
+
+export interface DistributionTooltipProps extends Pick<
+	TooltipRenderArgs,
+	'uPlotInstance' | 'isPinned' | 'dismiss'
+> {
+	xAxis: DistributionXAxis;
+	layout: DistributionBarsLayout;
+	labels: string[];
+	colors: string[];
+	/** `counts[series][bucket]`. */
+	counts: number[][];
+	formatBound: (value: number) => string;
+	renderTooltipFooter?: (args: IRenderTooltipFooterArgs) => React.ReactNode;
+}

frontend/src/lib/visualization/charts/Distribution/config.ts

@@ -0,0 +1,288 @@
+import { PrecisionOption } from 'components/Graph/types';
+import {
+	DistributionType,
+	DrawStyle,
+	StackMode,
+} from 'lib/uPlotV2/config/types';
+import { UPlotConfigBuilder } from 'lib/uPlotV2/config/UPlotConfigBuilder';
+import { createVariableWidthBarsPathBuilder } from 'lib/uPlotV2/paths/variableWidthBars';
+import { resolveRowIndex } from 'lib/uPlotV2/plugins/HeatmapPlugin/geometry';
+import { createHatchPattern } from 'lib/uPlotV2/plugins/HeatmapPlugin/paint';
+import uPlot from 'uplot';
+
+import { withOpacity } from './colors';
+import {
+	drawPercentileMarkers,
+	MARKER_HIT_PX,
+	PercentileMarkerHitArea,
+	resolveHoveredMarker,
+} from './drawPercentileMarkers';
+import {
+	DistributionBarsLayout,
+	LOG_Y_BASE,
+	resolveNearestSeries,
+	thinLabelledSplits,
+} from './layout';
+import { DistributionPercentile, groupPercentileMarkers } from './percentiles';
+import { DistributionXAxis } from './types';
+import { createBoundFormatter } from './utils';
+
+/** Minimum space between two x tick labels, in CSS pixels. */
+const X_LABEL_GAP_PX = 12;
+const BAR_GAP_PX = 1;
+const BAR_OPACITY = 0.85;
+const OVERFLOW_BAR_OPACITY = 0.4;
+/** Every group but the hovered one fades to this. */
+const DIMMED_BAR_OPACITY = 0.25;
+const DIMMED_OVERFLOW_BAR_OPACITY = 0.12;
+const OVERFLOW_AXIS_LABEL = '∞';
+/** Headroom above the tallest bar: a fraction on linear, a factor on log. Marker
+ *  labels sit at the top of the plot, so they take more. */
+const LINEAR_HEADROOM = 1.1;
+const LINEAR_HEADROOM_WITH_MARKERS = 1.3;
+const LOG_HEADROOM = 2;
+const LOG_HEADROOM_WITH_MARKERS = 6;
+
+function resolveYRange({
+	yMax,
+	isLogY,
+	stack,
+	hasMarkers,
+}: {
+	yMax: number;
+	isLogY: boolean;
+	stack: StackMode;
+	hasMarkers: boolean;
+}): [number, number] {
+	if (stack === StackMode.Percent) {
+		return [0, hasMarkers ? 100 * LINEAR_HEADROOM_WITH_MARKERS : 100];
+	}
+	if (isLogY) {
+		const headroom = hasMarkers ? LOG_HEADROOM_WITH_MARKERS : LOG_HEADROOM;
+		return [LOG_Y_BASE, Math.max(yMax, LOG_Y_BASE) * headroom];
+	}
+	const headroom = hasMarkers ? LINEAR_HEADROOM_WITH_MARKERS : LINEAR_HEADROOM;
+	return [0, yMax > 0 ? yMax * headroom : 1];
+}
+
+export interface BuildDistributionConfigArgs {
+	id: string;
+	xAxis: DistributionXAxis;
+	layout: DistributionBarsLayout;
+	labels: string[];
+	colors: string[];
+	stack: StackMode;
+	isLogY: boolean;
+	isDarkMode: boolean;
+	/** Drawn across the plot, labelled at the top. */
+	markers: DistributionPercentile[];
+	/** Unit of the bucket bounds; counts take none. */
+	xAxisUnit?: string;
+	decimalPrecision?: PrecisionOption;
+}
+
+export function buildDistributionConfig({
+	id,
+	xAxis,
+	layout,
+	labels,
+	colors,
+	stack,
+	isLogY,
+	isDarkMode,
+	markers,
+	xAxisUnit,
+	decimalPrecision,
+}: BuildDistributionConfigArgs): UPlotConfigBuilder {
+	const builder = new UPlotConfigBuilder({ id });
+	// uPlot's focus picks the series nearest in value, meaningless for stacked bars; the
+	// setCursor hook focuses the one under the cursor itself. Alpha 1 leaves the
+	// dimming to the bar fills.
+	builder.setFocus({ alpha: 1 });
+	// The x range is pinned to the buckets, so a drag-zoom would only flash a box.
+	builder.setCursor({
+		focus: { prox: -1 },
+		points: { show: false },
+		drag: { x: false, y: false },
+	});
+
+	const formatBound = createBoundFormatter(xAxisUnit, decimalPrecision);
+
+	builder.addScale({
+		scaleKey: 'x',
+		time: false,
+		auto: false,
+		range: (): [number, number] => [xAxis.min, xAxis.max],
+	});
+	const yRange = resolveYRange({
+		yMax: layout.yMax,
+		isLogY,
+		stack,
+		hasMarkers: markers.length > 0,
+	});
+	builder.addScale({
+		scaleKey: 'y',
+		time: false,
+		auto: false,
+		distribution: isLogY ? DistributionType.Logarithmic : DistributionType.Linear,
+		range: (): [number, number] => yRange,
+	});
+
+	const axisSplits =
+		xAxis.overflowSplit === null
+			? xAxis.splits
+			: [...xAxis.splits, xAxis.overflowSplit];
+	const splitLabels = new Map<number, string>();
+	xAxis.splits.forEach((split, index) => {
+		splitLabels.set(split, formatBound(xAxis.rows[index].upper));
+	});
+	if (xAxis.overflowSplit !== null) {
+		splitLabels.set(xAxis.overflowSplit, OVERFLOW_AXIS_LABEL);
+	}
+
+	const labelOf = (split: number): string =>
+		splitLabels.get(split) ?? formatBound(xAxis.toBucketValue(split));
+
+	builder.addAxis({
+		scaleKey: 'x',
+		side: 2,
+		isDarkMode,
+		// Thinned by each label's own width: bound labels run from `5 s` to
+		// `16.67 mins`, so no fixed spacing keeps them apart.
+		splits: (self, axisIdx): number[] => {
+			const visible = axisSplits.filter(
+				(split) => split >= xAxis.min && split <= xAxis.max,
+			);
+			const font = self.axes[axisIdx]?.font?.[0];
+			if (font) {
+				self.ctx.font = font;
+			}
+			const kept = thinLabelledSplits({
+				positions: visible.map((split) => self.valToPos(split, 'x')),
+				widths: visible.map(
+					(split) => self.ctx.measureText(labelOf(split)).width / uPlot.pxRatio,
+				),
+				gap: X_LABEL_GAP_PX,
+			});
+			return kept.map((index) => visible[index]);
+		},
+		values: (_, splits): string[] => splits.map(labelOf),
+	});
+	builder.addAxis({
+		scaleKey: 'y',
+		side: 3,
+		isDarkMode,
+		yAxisUnit: stack === StackMode.Percent ? 'percent' : 'short',
+		// The marker headroom runs a share axis past 100%, which labels nothing real.
+		...(stack === StackMode.Percent && {
+			filter: (_self: uPlot, splits: number[]): Array<number | null> =>
+				splits.map((split) => (split <= 100 ? split : null)),
+		}),
+	});
+
+	let hatchPattern: CanvasPattern | null | undefined;
+	const getHatchPattern = (
+		ctx: CanvasRenderingContext2D,
+	): CanvasPattern | null => {
+		hatchPattern ??= createHatchPattern(ctx, isDarkMode);
+		return hatchPattern;
+	};
+
+	// Read by every series' fill on each draw; a change redraws the paths.
+	const hover: {
+		series: number | null;
+		focused: number | null;
+		marker: number | null;
+	} = { series: null, focused: null, marker: null };
+	const plotMarkers = groupPercentileMarkers(
+		markers.filter(
+			({ axisValue }) => axisValue >= xAxis.min && axisValue <= xAxis.max,
+		),
+	);
+	let markerHitAreas: PercentileMarkerHitArea[] = [];
+	const isDimmed = (seriesIndex: number): boolean =>
+		hover.series !== null && hover.series !== seriesIndex;
+
+	labels.forEach((label, seriesIndex) => {
+		const color = colors[seriesIndex];
+		builder.addSeries({
+			scaleKey: 'y',
+			label,
+			drawStyle: DrawStyle.Bar,
+			pathBuilder: createVariableWidthBarsPathBuilder({
+				getBars: () => layout.rects[seriesIndex] ?? [],
+				fill: () =>
+					withOpacity(
+						color,
+						isDimmed(seriesIndex) ? DIMMED_BAR_OPACITY : BAR_OPACITY,
+					),
+				hatchedFill: () =>
+					withOpacity(
+						color,
+						isDimmed(seriesIndex)
+							? DIMMED_OVERFLOW_BAR_OPACITY
+							: OVERFLOW_BAR_OPACITY,
+					),
+				getHatchPattern,
+				gapPx: BAR_GAP_PX,
+			}),
+			lineColor: color,
+			lineWidth: 0,
+			colorMapping: {},
+			isDarkMode,
+			showPoints: false,
+			spanGaps: false,
+		});
+	});
+
+	builder.addHook('draw', (u: uPlot): void => {
+		markerHitAreas = drawPercentileMarkers(
+			u,
+			plotMarkers,
+			formatBound,
+			isDarkMode,
+			hover.marker,
+		);
+	});
+
+	// Registered as a hook, not a plugin, so it runs before TooltipPlugin's: the tooltip
+	// only shows for a focused series, and must find it focused when it positions.
+	builder.addHook('setCursor', (u: uPlot): void => {
+		const { left = -1, top = -1 } = u.cursor;
+		const isOnPlot = left >= 0 && top >= 0;
+		const x = isOnPlot ? u.posToVal(left, 'x') : Number.NaN;
+		const bucket = isOnPlot ? resolveRowIndex(xAxis.edges, x) : null;
+		const marker = isOnPlot
+			? resolveHoveredMarker(markerHitAreas, left, top, MARKER_HIT_PX)
+			: null;
+		// Over a marker, the bars neither dim nor show their tooltip.
+		const hovered =
+			bucket === null || marker !== null
+				? null
+				: resolveNearestSeries(layout, bucket, x, u.posToVal(top, 'y'));
+		// An empty bucket still gets a tooltip, as a bar chart's zero column does; with no
+		// nearest group to name, the first stands in.
+		const isEmptyBucket = bucket !== null && marker === null && hovered === null;
+		const focused = isEmptyBucket && labels.length > 0 ? 0 : hovered;
+
+		if (focused !== hover.focused) {
+			hover.focused = focused;
+			u.setSeries(focused === null ? null : focused + 1, { focus: true });
+		}
+		if (marker !== hover.marker) {
+			// The crosshair would cut through the marker's badges.
+			u.root
+				.querySelectorAll<HTMLElement>('.u-cursor-x, .u-cursor-y')
+				.forEach((line) => {
+					line.style.visibility = marker === null ? '' : 'hidden';
+				});
+		}
+		if (hovered !== hover.series || marker !== hover.marker) {
+			hover.series = hovered;
+			hover.marker = marker;
+			u.redraw(true, false);
+		}
+	});
+
+	return builder;
+}

frontend/src/lib/visualization/charts/Distribution/drawPercentileMarkers.ts

@@ -0,0 +1,242 @@
+import { Color } from '@signozhq/design-tokens';
+import { themeColors } from 'constants/theme';
+import uPlot from 'uplot';
+
+import {
+	DistributionPercentile,
+	formatPercentileBadge,
+	formatPercentileValue,
+} from './percentiles';
+
+const MARKER_DASH: [number, number] = [3, 3];
+const MARKER_FONT_SIZE_PX = 9;
+/** Space between a badge's name and its diamond's edges. */
+const MARKER_BADGE_PADDING_PX = 2;
+const MARKER_BADGE_GAP_PX = 2;
+const MARKER_VALUE_FONT_SIZE_PX = 11;
+/** How far from a marker line the cursor still hovers it, in CSS pixels. */
+export const MARKER_HIT_PX = 4;
+const MARKER_PILL_PADDING_X_PX = 6;
+const MARKER_PILL_PADDING_Y_PX = 3;
+const MARKER_PILL_RADIUS_PX = 4;
+/** Height of the pill's notch pointing up at the line; also its gap from the axis. */
+const MARKER_PILL_POINTER_PX = 4;
+
+interface HitRect {
+	left: number;
+	right: number;
+	top: number;
+	bottom: number;
+}
+
+/** A drawn marker's hover targets, in CSS pixels relative to the plot. */
+export interface PercentileMarkerHitArea {
+	x: number;
+	badges: HitRect[];
+}
+
+/**
+ * The marker under `(x, y)`: one whose badge it is over, else the line nearest
+ * `x` within `tolerance`. `null` when none is.
+ */
+export function resolveHoveredMarker(
+	areas: PercentileMarkerHitArea[],
+	x: number,
+	y: number,
+	tolerance: number,
+): number | null {
+	const overBadge = areas.findIndex(({ badges }) =>
+		badges.some(
+			(badge) =>
+				x >= badge.left && x <= badge.right && y >= badge.top && y <= badge.bottom,
+		),
+	);
+	if (overBadge !== -1) {
+		return overBadge;
+	}
+	let nearest: number | null = null;
+	let nearestDistance = tolerance;
+	areas.forEach((area, index) => {
+		const distance = Math.abs(area.x - x);
+		if (distance <= nearestDistance) {
+			nearest = index;
+			nearestDistance = distance;
+		}
+	});
+	return nearest;
+}
+
+/**
+ * Stacks marker badges into rows so none overlap: each goes in the first row whose
+ * last badge ends before it starts. Input and output are in the same pixel space.
+ */
+export function layoutMarkerLabels(
+	labels: Array<{ x: number; width: number }>,
+	gap: number,
+): number[] {
+	const rowEnds: number[] = [];
+	const order = labels
+		.map((label, index) => ({ ...label, index }))
+		.sort((a, b) => a.x - b.x);
+	const rows = new Array<number>(labels.length).fill(0);
+
+	order.forEach(({ x, width, index }) => {
+		let row = rowEnds.findIndex((end) => x >= end + gap);
+		if (row === -1) {
+			row = rowEnds.length;
+			rowEnds.push(0);
+		}
+		rowEnds[row] = x + width;
+		rows[index] = row;
+	});
+
+	return rows;
+}
+
+/** A square diamond centred on `(x, y)` with half-diagonal `r`, filled then outlined. */
+function drawDiamond(
+	ctx: CanvasRenderingContext2D,
+	x: number,
+	y: number,
+	r: number,
+	fill: string,
+	stroke: string,
+): void {
+	ctx.beginPath();
+	ctx.moveTo(x, y - r);
+	ctx.lineTo(x + r, y);
+	ctx.lineTo(x, y + r);
+	ctx.lineTo(x - r, y);
+	ctx.closePath();
+	ctx.fillStyle = fill;
+	ctx.fill();
+	ctx.strokeStyle = stroke;
+	ctx.stroke();
+}
+
+/**
+ * Dashed lines across the plot with a diamond badge at each end naming the
+ * percentile, one per group on the same spot; badges stack into rows so none overlap. The hovered marker is
+ * emphasised and shows its value on the x axis. Returns each marker's hover targets.
+ */
+export function drawPercentileMarkers(
+	u: uPlot,
+	markers: DistributionPercentile[][],
+	formatBound: (value: number) => string,
+	isDarkMode: boolean,
+	hovered: number | null,
+): PercentileMarkerHitArea[] {
+	if (markers.length === 0) {
+		return [];
+	}
+	const { ctx, bbox } = u;
+	const { pxRatio } = uPlot;
+	const color = isDarkMode ? themeColors.white : themeColors.black;
+	const background = isDarkMode ? Color.BG_INK_400 : Color.BG_VANILLA_100;
+	const bottom = bbox.top + bbox.height;
+
+	ctx.save();
+	ctx.font = `600 ${MARKER_FONT_SIZE_PX * pxRatio}px Inter, sans-serif`;
+	ctx.textAlign = 'center';
+	ctx.textBaseline = 'middle';
+
+	const named = markers.map((group) => {
+		const text = formatPercentileBadge(group);
+		return { text, width: ctx.measureText(text).width };
+	});
+	// One square diamond for all, fitting the widest name's box: |dx| + |dy| ≤ r at
+	// its corners. Cap height stands in for the text's height.
+	const r =
+		(Math.max(...named.map(({ width }) => width)) +
+			MARKER_FONT_SIZE_PX * pxRatio * 0.7) /
+			2 +
+		MARKER_BADGE_PADDING_PX * pxRatio;
+	const badges = markers.map((group, index) => ({
+		text: named[index].text,
+		x: u.valToPos(group[0].axisValue, 'x', true),
+	}));
+	const rows = layoutMarkerLabels(
+		badges.map(({ x }) => ({ x: x - r, width: 2 * r })),
+		MARKER_BADGE_GAP_PX * pxRatio,
+	);
+	const rowStep = 2 * r + MARKER_BADGE_GAP_PX * pxRatio;
+	const badgeCentres = (index: number): [number, number] => {
+		const offset = r + rows[index] * rowStep;
+		return [bbox.top + offset, bottom - offset];
+	};
+
+	const drawMarker = (index: number): void => {
+		const { text, x } = badges[index];
+		const isHovered = index === hovered;
+
+		ctx.globalAlpha = isHovered ? 1 : 0.55;
+		ctx.strokeStyle = color;
+		ctx.lineWidth = pxRatio;
+		ctx.setLineDash(MARKER_DASH.map((dash) => dash * pxRatio));
+		ctx.beginPath();
+		ctx.moveTo(x, bbox.top);
+		ctx.lineTo(x, bottom);
+		ctx.stroke();
+
+		ctx.globalAlpha = 1;
+		ctx.setLineDash([]);
+		badgeCentres(index).forEach((y) => {
+			drawDiamond(ctx, x, y, r, isHovered ? color : background, color);
+			ctx.fillStyle = isHovered ? background : color;
+			ctx.fillText(text, x, y);
+		});
+
+		if (!isHovered) {
+			return;
+		}
+		// The value sits on the x axis under the line, over the tick labels, in a pill
+		// whose notch points up at the line.
+		ctx.font = `500 ${MARKER_VALUE_FONT_SIZE_PX * pxRatio}px Inter, sans-serif`;
+		const value = formatPercentileValue(markers[index], formatBound);
+		const padX = MARKER_PILL_PADDING_X_PX * pxRatio;
+		const padY = MARKER_PILL_PADDING_Y_PX * pxRatio;
+		const pointer = MARKER_PILL_POINTER_PX * pxRatio;
+		const width = ctx.measureText(value).width + 2 * padX;
+		const height = MARKER_VALUE_FONT_SIZE_PX * pxRatio + 2 * padY;
+		const left = Math.min(Math.max(x - width / 2, 0), ctx.canvas.width - width);
+		const top = bottom + 2 * pointer;
+		const notchX = Math.min(
+			Math.max(x, left + pointer + MARKER_PILL_RADIUS_PX * pxRatio),
+			left + width - pointer - MARKER_PILL_RADIUS_PX * pxRatio,
+		);
+		// A halo in the chart's background hides the tick labels it overlaps.
+		ctx.fillStyle = background;
+		ctx.fillRect(left - padX, top, width + 2 * padX, height + 2 * padY);
+		ctx.fillStyle = isDarkMode ? Color.BG_SLATE_400 : Color.BG_INK_400;
+		ctx.beginPath();
+		ctx.roundRect(left, top, width, height, MARKER_PILL_RADIUS_PX * pxRatio);
+		ctx.moveTo(notchX - pointer, top);
+		ctx.lineTo(notchX, top - pointer);
+		ctx.lineTo(notchX + pointer, top);
+		ctx.closePath();
+		ctx.fill();
+		ctx.fillStyle = Color.BG_VANILLA_100;
+		ctx.fillText(value, left + width / 2, top + height / 2);
+	};
+
+	// The hovered one last, so it draws over its neighbours.
+	badges.forEach((_, index) => index !== hovered && drawMarker(index));
+	if (hovered !== null && hovered < badges.length) {
+		drawMarker(hovered);
+	}
+	ctx.restore();
+
+	return badges.map(({ x }, index) => {
+		const toPlot = (value: number, origin: number): number =>
+			(value - origin) / pxRatio;
+		return {
+			x: toPlot(x, bbox.left),
+			badges: badgeCentres(index).map((y) => ({
+				left: toPlot(x - r, bbox.left),
+				right: toPlot(x + r, bbox.left),
+				top: toPlot(y - r, bbox.top),
+				bottom: toPlot(y + r, bbox.top),
+			})),
+		};
+	});
+}

frontend/src/lib/visualization/charts/Distribution/layout.ts

@@ -0,0 +1,232 @@
+import { StackMode } from 'lib/uPlotV2/config/types';
+import {
+	cropHeatmapYAxis,
+	resolveHeatmapYAxis,
+} from 'lib/uPlotV2/plugins/HeatmapPlugin/geometry';
+import { HeatmapAxisScale } from 'lib/uPlotV2/plugins/HeatmapPlugin/types';
+
+import { DistributionBarRect, DistributionXAxis } from './types';
+
+/** Bottom of a log count axis: a bar has to start somewhere above zero. */
+export const LOG_Y_BASE = 1;
+
+/**
+ * N bounds give N + 1 buckets: `≤ first`, the finite ones, and `> last`. Every bucket
+ * is equally wide: bucket `i` spans `[i, i + 1]`, and ticks still name the bounds.
+ */
+export function resolveDistributionXAxis(buckets: number[]): DistributionXAxis {
+	const { rows, overflowSplit } = resolveHeatmapYAxis(
+		buckets,
+		HeatmapAxisScale.Linear,
+	);
+	const edges = rows.map((_, index) => index).concat(rows.length);
+	return {
+		rows,
+		edges,
+		splits: rows.slice(0, -1).map((_, index) => index + 1),
+		overflowSplit: overflowSplit === null ? null : rows.length,
+		toBucketValue: (axisValue: number): number => {
+			const index = Math.min(rows.length - 1, Math.max(0, Math.floor(axisValue)));
+			const row = rows[index];
+			return row.lower + (axisValue - index) * (row.upper - row.lower);
+		},
+		min: 0,
+		max: rows.length,
+	};
+}
+
+/** Sum of each bucket across the visible series. */
+export function sumVisibleCounts(
+	counts: number[][],
+	visible: boolean[],
+	bucketCount: number,
+): number[] {
+	const totals = new Array<number>(bucketCount).fill(0);
+	counts.forEach((seriesCounts, seriesIndex) => {
+		if (!visible[seriesIndex]) {
+			return;
+		}
+		for (let bucket = 0; bucket < bucketCount; bucket += 1) {
+			totals[bucket] += seriesCounts[bucket] ?? 0;
+		}
+	});
+	return totals;
+}
+
+/** Drops empty buckets past the last occupied one, as the heatmap does. */
+export function cropDistributionXAxis(
+	axis: DistributionXAxis,
+	totals: number[],
+): DistributionXAxis {
+	return cropHeatmapYAxis(
+		axis,
+		totals.map((total) => [total]),
+	);
+}
+
+/**
+ * Narrows the axis window to the buckets overlapping `[min, max]`, never below one.
+ * A bucket straddling a bound stays whole: cutting it would misstate its count.
+ */
+export function clampDistributionXAxis(
+	axis: DistributionXAxis,
+	min?: number,
+	max?: number,
+): DistributionXAxis {
+	const { rows, edges } = axis;
+	let first = edges.indexOf(axis.min);
+	let last = edges.indexOf(axis.max) - 1;
+	while (min !== undefined && first < last && rows[first].upper <= min) {
+		first += 1;
+	}
+	while (max !== undefined && last > first && rows[last].lower >= max) {
+		last -= 1;
+	}
+	return {
+		...axis,
+		overflowSplit: rows[last].isOverflow ? axis.overflowSplit : null,
+		min: edges[first],
+		max: edges[last + 1],
+	};
+}
+
+export interface DistributionBarsLayout {
+	/** One list per series, in series order. */
+	rects: DistributionBarRect[][];
+	/** Top of the tallest bar inside the axis window, for the count axis range. */
+	yMax: number;
+}
+
+/**
+ * Every bar, in scale space. `normal` stacks the series in each bucket, `percent`
+ * stacks their shares of it, `none` splits the bucket width between them.
+ */
+export function resolveDistributionBars({
+	xAxis,
+	counts,
+	stack,
+	isLogY,
+}: {
+	xAxis: DistributionXAxis;
+	/** `counts[series][bucket]`. */
+	counts: number[][];
+	stack: StackMode;
+	isLogY: boolean;
+}): DistributionBarsLayout {
+	const { rows, edges } = xAxis;
+	const rects: DistributionBarRect[][] = counts.map(() => []);
+	const base = isLogY ? LOG_Y_BASE : 0;
+	let yMax = 0;
+
+	rows.forEach((row, bucketIndex) => {
+		const x0 = edges[bucketIndex];
+		const x1 = edges[bucketIndex + 1];
+		// Buckets outside the window are off the plot and mustn't set its height.
+		const isInWindow = x0 >= xAxis.min && x1 <= xAxis.max;
+		const total = counts.reduce(
+			(sum, seriesCounts) => sum + (seriesCounts[bucketIndex] ?? 0),
+			0,
+		);
+		let cumulative = 0;
+
+		counts.forEach((seriesCounts, seriesIndex) => {
+			const count = seriesCounts[bucketIndex] ?? 0;
+			if (count <= 0) {
+				return;
+			}
+			const bar = { bucketIndex, hatched: row.isOverflow };
+
+			if (stack === StackMode.None) {
+				// Below the log base a bar would draw downwards from the axis.
+				if (count <= base) {
+					return;
+				}
+				const width = (x1 - x0) / counts.length;
+				rects[seriesIndex].push({
+					...bar,
+					x0: x0 + seriesIndex * width,
+					x1: x0 + (seriesIndex + 1) * width,
+					y0: base,
+					y1: count,
+				});
+				if (isInWindow) {
+					yMax = Math.max(yMax, count);
+				}
+				return;
+			}
+
+			const scale = stack === StackMode.Percent ? 100 / total : 1;
+			const y0 = cumulative * scale;
+			cumulative += count;
+			const y1 = cumulative * scale;
+			if (y1 <= base) {
+				return;
+			}
+			rects[seriesIndex].push({
+				...bar,
+				x0,
+				x1,
+				y0: Math.max(y0, base),
+				y1,
+			});
+			if (isInWindow) {
+				yMax = Math.max(yMax, y1);
+			}
+		});
+	});
+
+	return { rects, yMax };
+}
+
+/**
+ * The group nearest `(x, y)` vertically in `bucket`, as uPlot focuses bar series;
+ * side by side, only the sub-bar under `x` competes. `null` over an empty bucket.
+ */
+export function resolveNearestSeries(
+	layout: DistributionBarsLayout,
+	bucket: number,
+	x: number,
+	y: number,
+): number | null {
+	const candidates = layout.rects.flatMap((rects, series) =>
+		rects
+			.filter((rect) => rect.bucketIndex === bucket)
+			.map((rect) => ({ rect, series })),
+	);
+	const underX = candidates.filter(({ rect }) => x >= rect.x0 && x < rect.x1);
+	let nearest: number | null = null;
+	let nearestDistance = Number.POSITIVE_INFINITY;
+	(underX.length > 0 ? underX : candidates).forEach(({ rect, series }) => {
+		const distance = Math.max(rect.y0 - y, y - rect.y1, 0);
+		if (distance < nearestDistance) {
+			nearest = series;
+			nearestDistance = distance;
+		}
+	});
+	return nearest;
+}
+
+/**
+ * Indexes of the ticks whose centred labels fit without touching, walking from the
+ * right so the `∞` edge survives. Positions and widths share one pixel space.
+ */
+export function thinLabelledSplits({
+	positions,
+	widths,
+	gap,
+}: {
+	positions: number[];
+	widths: number[];
+	gap: number;
+}): number[] {
+	const kept: number[] = [];
+	let leftEdge = Number.POSITIVE_INFINITY;
+	for (let index = positions.length - 1; index >= 0; index -= 1) {
+		const half = widths[index] / 2;
+		if (positions[index] + half + gap <= leftEdge) {
+			kept.push(index);
+			leftEdge = positions[index] - half;
+		}
+	}
+	return kept.reverse();
+}

frontend/src/lib/visualization/charts/Distribution/percentiles.ts

@@ -0,0 +1,110 @@
+import { DistributionXAxis } from './types';
+
+export interface DistributionPercentile {
+	/** 0–100, as configured. */
+	percentile: number;
+	/** The estimate; in overflow, the last finite bound it is known to exceed. */
+	value: number;
+	/** Where the marker is drawn, in x-scale space. */
+	axisValue: number;
+	isOverflow: boolean;
+}
+
+/**
+ * Percentiles of the summed counts, by `histogram_quantile`'s method: find the bucket
+ * holding the target rank and interpolate linearly inside it, with the lowest bucket
+ * starting at zero. So the values match a time-series panel's percentiles.
+ */
+export function computeDistributionPercentiles({
+	xAxis,
+	totals,
+	percentiles,
+}: {
+	xAxis: DistributionXAxis;
+	/** Summed visible counts per bucket. */
+	totals: number[];
+	percentiles: readonly number[];
+}): DistributionPercentile[] {
+	const { rows, edges } = xAxis;
+	const total = totals.reduce((sum, count) => sum + count, 0);
+	if (total <= 0 || rows.length === 0) {
+		return [];
+	}
+
+	return percentiles.flatMap<DistributionPercentile>((percentile) => {
+		const rank = (percentile / 100) * total;
+		let below = 0;
+		for (let index = 0; index < rows.length; index += 1) {
+			const count = totals[index] ?? 0;
+			if (count > 0 && below + count >= rank) {
+				const row = rows[index];
+				if (row.isOverflow) {
+					return [
+						{
+							percentile,
+							value: row.lower,
+							axisValue: edges[index],
+							isOverflow: true,
+						},
+					];
+				}
+				const fraction = (rank - below) / count;
+				const lower = row.isUnderflow ? Math.min(0, row.upper) : row.lower;
+				return [
+					{
+						percentile,
+						value: lower + fraction * (row.upper - lower),
+						axisValue: edges[index] + fraction * (edges[index + 1] - edges[index]),
+						isOverflow: false,
+					},
+				];
+			}
+			below += count;
+		}
+		return [];
+	});
+}
+
+export function formatPercentileName(percentile: number): string {
+	return `p${Number(percentile.toFixed(3))}`;
+}
+
+/**
+ * Markers that fall on the same spot, sharing one badge: the percentiles landing
+ * in overflow all sit on its edge. Each group is in ascending percentile order.
+ */
+export function groupPercentileMarkers(
+	markers: DistributionPercentile[],
+): DistributionPercentile[][] {
+	const groups = new Map<number, DistributionPercentile[]>();
+	markers.forEach((marker) => {
+		groups.set(marker.axisValue, [
+			...(groups.get(marker.axisValue) ?? []),
+			marker,
+		]);
+	});
+	return [...groups.values()].map((group) =>
+		[...group].sort((a, b) => a.percentile - b.percentile),
+	);
+}
+
+/** `p90` for one marker; `p90+` for a group, starting at its lowest percentile. */
+export function formatPercentileBadge(group: DistributionPercentile[]): string {
+	const name = formatPercentileName(group[0].percentile);
+	return group.length > 1 ? `${name}+` : name;
+}
+
+/**
+ * `p99 ≈ 412 ms` for an estimate; `p90, p99 > 5 s` where only the overflow bound is
+ * known. A group shares one spot, so one value and overflow flag.
+ */
+export function formatPercentileValue(
+	group: DistributionPercentile[],
+	formatBound: (value: number) => string,
+): string {
+	const names = group
+		.map(({ percentile }) => formatPercentileName(percentile))
+		.join(', ');
+	const [{ value, isOverflow }] = group;
+	return `${names} ${isOverflow ? '>' : '≈'} ${formatBound(value)}`;
+}

frontend/src/lib/visualization/charts/Distribution/topGroups.ts

@@ -0,0 +1,133 @@
+import { StackMode } from 'lib/uPlotV2/config/types';
+
+import { DistributionSeries, DistributionXAxis } from './types';
+
+/** Colours stop being told apart past this many stacked groups. */
+export const MAX_STACKED_GROUPS = 10;
+/** Narrowest a side-by-side bar may get, in CSS pixels. */
+const MIN_SIDE_BY_SIDE_BAR_PX = 3;
+export const OTHER_GROUP_LABEL = 'Other';
+
+/**
+ * How many series fit: a fixed cap when stacked, and side by side as many as keep
+ * every bar in the narrowest bucket at least `MIN_SIDE_BY_SIDE_BAR_PX` wide.
+ */
+export function resolveMaxDrawnGroups({
+	stack,
+	xAxis,
+	plotWidth,
+}: {
+	stack: StackMode;
+	xAxis: DistributionXAxis;
+	/** Approximate width of the plotting area, in CSS pixels. */
+	plotWidth: number;
+}): number {
+	if (stack !== StackMode.None) {
+		return MAX_STACKED_GROUPS;
+	}
+	const span = xAxis.max - xAxis.min;
+	let narrowest = Number.POSITIVE_INFINITY;
+	for (let index = 0; index + 1 < xAxis.edges.length; index += 1) {
+		if (xAxis.edges[index] < xAxis.max) {
+			narrowest = Math.min(narrowest, xAxis.edges[index + 1] - xAxis.edges[index]);
+		}
+	}
+	if (!(span > 0) || !Number.isFinite(narrowest)) {
+		return MAX_STACKED_GROUPS;
+	}
+	const narrowestPx = (plotWidth * narrowest) / span;
+	return Math.min(
+		MAX_STACKED_GROUPS,
+		Math.max(1, Math.floor(narrowestPx / MIN_SIDE_BY_SIDE_BAR_PX)),
+	);
+}
+
+export interface DrawnGroups {
+	labels: string[];
+	counts: number[][];
+	colors: string[];
+	/** Each drawn group's index among the source series; `null` for Other. */
+	sourceIndexes: (number | null)[];
+	/** Visible groups summed into the Other series; 0 when none were. */
+	otherGroupCount: number;
+	/** Visible groups in all, drawn or folded. */
+	visibleGroupCount: number;
+}
+
+function sum(counts: number[]): number {
+	return counts.reduce((total, count) => total + count, 0);
+}
+
+/**
+ * The visible groups to draw: all of them when they fit, else the largest by total
+ * and one Other series summing the rest. Exact, because bucket counts add. Drawn
+ * groups keep legend order.
+ */
+export function groupIntoOther({
+	labels,
+	counts,
+	colors,
+	visible,
+	maxGroups,
+	otherColor,
+}: {
+	labels: string[];
+	counts: number[][];
+	colors: string[];
+	visible: boolean[];
+	maxGroups: number;
+	otherColor: string;
+}): DrawnGroups {
+	const visibleIndexes = labels
+		.map((_, index) => index)
+		.filter((index) => visible[index]);
+
+	if (visibleIndexes.length <= maxGroups) {
+		return {
+			labels: visibleIndexes.map((index) => labels[index]),
+			counts: visibleIndexes.map((index) => counts[index]),
+			colors: visibleIndexes.map((index) => colors[index]),
+			sourceIndexes: visibleIndexes,
+			otherGroupCount: 0,
+			visibleGroupCount: visibleIndexes.length,
+		};
+	}
+
+	const keep = new Set(
+		[...visibleIndexes]
+			.sort((a, b) => sum(counts[b]) - sum(counts[a]) || a - b)
+			.slice(0, Math.max(0, maxGroups - 1)),
+	);
+	const kept = visibleIndexes.filter((index) => keep.has(index));
+	const folded = visibleIndexes.filter((index) => !keep.has(index));
+	const bucketCount = Math.max(...folded.map((index) => counts[index].length));
+	const other = Array.from({ length: bucketCount }, (_, bucket) =>
+		folded.reduce((total, index) => total + (counts[index][bucket] ?? 0), 0),
+	);
+
+	return {
+		labels: [...kept.map((index) => labels[index]), OTHER_GROUP_LABEL],
+		counts: [...kept.map((index) => counts[index]), other],
+		colors: [...kept.map((index) => colors[index]), otherColor],
+		sourceIndexes: [...kept, null],
+		otherGroupCount: folded.length,
+		visibleGroupCount: visibleIndexes.length,
+	};
+}
+
+/**
+ * The drawn group at `drawnIndex` as a source series and its colour; `null` for Other,
+ * which sums several groups no single filter can name.
+ */
+export function resolveClickedGroup(
+	drawn: DrawnGroups,
+	drawnIndex: number | null,
+	series: DistributionSeries[],
+): { series: DistributionSeries; color: string } | null {
+	const source =
+		drawnIndex === null ? null : (drawn.sourceIndexes[drawnIndex] ?? null);
+	if (drawnIndex === null || source === null) {
+		return null;
+	}
+	return { series: series[source], color: drawn.colors[drawnIndex] };
+}

frontend/src/lib/visualization/charts/Distribution/types.ts

@@ -0,0 +1,31 @@
+import type { VariableWidthBar } from 'lib/uPlotV2/paths/variableWidthBars';
+import type { HeatmapYAxis } from 'lib/uPlotV2/plugins/HeatmapPlugin/types';
+
+export interface DistributionSeries {
+	label: string;
+	/** Group-by key → value, for drilling into this group. Empty when ungrouped. */
+	groupLabels?: Record<string, string>;
+	/** One count per bucket bound plus the trailing overflow, summed over the range. */
+	counts: number[];
+}
+
+/** A click on a group's bar; never on Other, which no filter can name. */
+export interface DistributionBarClick {
+	series: DistributionSeries;
+	color: string;
+	/** Viewport coordinates of the click. */
+	coordinates: { x: number; y: number };
+}
+
+export enum DistributionYScale {
+	Linear = 'linear',
+	Log = 'log',
+}
+
+/** The bucket axis in x-scale space. The heatmap's row axis, laid sideways. */
+export type DistributionXAxis = HeatmapYAxis;
+
+/** `x` in bucket-axis units, `y` in counts (or percent); the overflow bucket is hatched. */
+export interface DistributionBarRect extends VariableWidthBar {
+	bucketIndex: number;
+}

frontend/src/lib/visualization/charts/Distribution/useDistributionBarClick.ts

@@ -0,0 +1,56 @@
+import { useCallback, useRef } from 'react';
+import { resolveRowIndex } from 'lib/uPlotV2/plugins/HeatmapPlugin/geometry';
+import type { ChartClickData } from 'lib/uPlotV2/plugins/TooltipPlugin/types';
+
+import { type DistributionBarsLayout, resolveNearestSeries } from './layout';
+import { type DrawnGroups, resolveClickedGroup } from './topGroups';
+import type {
+	DistributionBarClick,
+	DistributionSeries,
+	DistributionXAxis,
+} from './types';
+
+/** Resolves a plot click to the group under it; Other and empty buckets report none. */
+export function useDistributionBarClick({
+	xAxis,
+	layout,
+	drawn,
+	series,
+	onBarClick,
+}: {
+	xAxis: DistributionXAxis;
+	layout: DistributionBarsLayout;
+	drawn: DrawnGroups;
+	series: DistributionSeries[];
+	onBarClick?: (click: DistributionBarClick) => void;
+}): ((data: ChartClickData) => void) | undefined {
+	const onBarClickRef = useRef(onBarClick);
+	onBarClickRef.current = onBarClick;
+
+	const handleClick = useCallback(
+		({
+			xValue,
+			yValue,
+			absoluteMouseX,
+			absoluteMouseY,
+		}: ChartClickData): void => {
+			const bucket = resolveRowIndex(xAxis.edges, xValue);
+			const clicked = resolveClickedGroup(
+				drawn,
+				bucket === null
+					? null
+					: resolveNearestSeries(layout, bucket, xValue, yValue),
+				series,
+			);
+			if (clicked) {
+				onBarClickRef.current?.({
+					...clicked,
+					coordinates: { x: absoluteMouseX, y: absoluteMouseY },
+				});
+			}
+		},
+		[xAxis, layout, drawn, series],
+	);
+
+	return onBarClick ? handleClick : undefined;
+}

frontend/src/lib/visualization/charts/Distribution/utils.ts

@@ -0,0 +1,32 @@
+import { PrecisionOption } from 'components/Graph/types';
+import { getToolTipValue } from 'components/Graph/yAxisConfig';
+import uPlot from 'uplot';
+
+import { DistributionXAxis } from './types';
+
+export function createBoundFormatter(
+	unit?: string,
+	decimalPrecision?: PrecisionOption,
+): (value: number) => string {
+	return (value: number): string =>
+		getToolTipValue(String(value), unit, decimalPrecision);
+}
+
+/**
+ * `[bucket centres, ...counts per series]`. The series draw from the layout, so the
+ * data only feeds uPlot's cursor and tooltip.
+ */
+export function prepareDistributionChartData(
+	xAxis: DistributionXAxis,
+	counts: number[][],
+): uPlot.AlignedData {
+	const centres = xAxis.rows.map(
+		(_, index) => (xAxis.edges[index] + xAxis.edges[index + 1]) / 2,
+	);
+	return [
+		centres,
+		...counts.map((seriesCounts) =>
+			centres.map((_, index) => seriesCounts[index] ?? 0),
+		),
+	] as unknown as uPlot.AlignedData;
+}

frontend/src/lib/visualization/charts/types.ts

@@ -26,6 +26,11 @@ import {
 } from 'lib/uPlotV2/plugins/TooltipPlugin/types';
 import { BaseAutocompleteData } from 'types/api/queryBuilder/queryAutocompleteResponse';
 import type { StackMode } from 'lib/uPlotV2/config/types';
+import type {
+	DistributionBarClick,
+	DistributionSeries,
+	DistributionYScale,
+} from 'lib/visualization/charts/Distribution/types';
 
 interface BaseChartProps {
 	width: number;
@@ -167,6 +172,48 @@ export interface HeatmapChartProps {
 	'data-testid'?: string;
 }
 
+/**
+ * Whole-range bucket counts, one series per group, drawn as bars whose widths follow
+ * the bucket bounds. Builds its own config, since `buckets` fully determines the x
+ * axis. `buckets` and `series` must be referentially stable: a new identity rebuilds
+ * the plot.
+ */
+export interface DistributionChartProps {
+	/** Widget id; the group selection persists under it. */
+	id: string;
+	/** Ascending. N boundaries describe N+1 buckets, the last one overflow. */
+	buckets: number[];
+	series: DistributionSeries[];
+	width: number;
+	height: number;
+	isDarkMode: boolean;
+	/** Buckets wholly below it are hidden. */
+	xMin?: number;
+	/** Buckets wholly above it are hidden; unset crops trailing empty buckets. */
+	xMax?: number;
+	/** Default linear. Ignored under `percent`, whose axis is a share. */
+	yScale?: DistributionYScale;
+	/** Default normal. `none` draws the groups side by side. */
+	stack?: StackMode;
+	/** Unit of the bucket bounds; counts are always plain numbers. */
+	xAxisUnit?: string;
+	decimalPrecision?: PrecisionOption;
+	/** Hex colours keyed by group label, overriding the automatic palette. */
+	customColors?: Record<string, string>;
+	/** 0–100. Marked across the plot, over the visible groups combined. */
+	percentiles?: readonly number[];
+	/** Fires for a click on a group's bar; not on Other or empty space. */
+	onBarClick?: (click: DistributionBarClick) => void;
+	showLegend?: boolean;
+	legendPosition?: LegendPosition;
+	showTooltip?: boolean;
+	canPinTooltip?: boolean;
+	renderTooltipFooter?: (args: IRenderTooltipFooterArgs) => React.ReactNode;
+	tooltipPortalRoot?: HTMLElement | null;
+	layoutChildren?: React.ReactNode;
+	'data-testid'?: string;
+}
+
 /**
  * One resolved pie/donut slice: a display label, its (already parsed) positive
  * numeric value, and the colour used for the arc + legend swatch.

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/PanelTypeSwitcher/PanelTypeSwitcher.tsx

@@ -45,11 +45,12 @@ function PanelTypeSwitcher({
 		(kind: PanelKind): string | undefined =>
 			getPanelTypeDisabledReason({
 				kind,
+				fromKind: panelKind,
 				queryType,
 				signal,
 				label: getPanelDefinition(kind).displayName,
 			}),
-		[queryType, signal],
+		[panelKind, queryType, signal],
 	);
 
 	const canRevert = !!originalPanelKind && originalPanelKind !== panelKind;

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/PanelTypeSwitcher/__tests__/utils.test.ts

@@ -25,6 +25,39 @@ describe('getPanelTypeDisabledReason', () => {
 		).toBeUndefined();
 	});
 
+	it('blocks Histogram and Distribution switching into each other, both ways', () => {
+		expect(
+			getPanelTypeDisabledReason({
+				kind: 'signoz/DistributionPanel',
+				fromKind: 'signoz/HistogramPanel',
+				queryType: QUERY_BUILDER,
+				signal: metrics,
+				label: 'Distribution',
+			}),
+		).toMatch(/can't switch between them/);
+		expect(
+			getPanelTypeDisabledReason({
+				kind: 'signoz/HistogramPanel',
+				fromKind: 'signoz/DistributionPanel',
+				queryType: QUERY_BUILDER,
+				signal: metrics,
+				label: 'Histogram',
+			}),
+		).toMatch(/can't switch between them/);
+	});
+
+	it('lets Distribution switch to other kinds', () => {
+		expect(
+			getPanelTypeDisabledReason({
+				kind: 'signoz/HeatmapPanel',
+				fromKind: 'signoz/DistributionPanel',
+				queryType: QUERY_BUILDER,
+				signal: metrics,
+				label: 'Heatmap',
+			}),
+		).toBeUndefined();
+	});
+
 	it('explains an unsupported query type', () => {
 		expect(
 			getPanelTypeDisabledReason({

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/PanelTypeSwitcher/usePanelTypeSelectItems.tsx

@@ -9,6 +9,8 @@ import type { ConfigSelectItem } from '../controls/ConfigSelect/ConfigSelect';
 import { getPanelTypeDisabledReason } from './utils';
 
 interface UsePanelTypeSelectItemsArgs {
+	/** The panel's current kind, which some kinds can't be switched to from. */
+	fromKind?: PanelKind;
 	/** Active query type — a kind that can't be authored in it is disabled. */
 	queryType: EQueryType;
 	/** Current datasource — also gates the disabled rule (List needs logs/traces, not metrics). */
@@ -21,6 +23,7 @@ interface UsePanelTypeSelectItemsArgs {
  * the capabilities guard, the same rule the editor's `PanelTypeSwitcher` applies.
  */
 export function usePanelTypeSelectItems({
+	fromKind,
 	queryType,
 	signal,
 }: UsePanelTypeSelectItemsArgs): ConfigSelectItem<PanelKind>[] {
@@ -30,6 +33,7 @@ export function usePanelTypeSelectItems({
 				// One reason drives both the disabled flag and the tooltip, so they can't disagree.
 				const disabledReason = getPanelTypeDisabledReason({
 					kind,
+					fromKind,
 					queryType,
 					signal,
 					label: displayName,
@@ -42,6 +46,6 @@ export function usePanelTypeSelectItems({
 					tooltip: disabledReason,
 				};
 			}),
-		[queryType, signal],
+		[fromKind, queryType, signal],
 	);
 }

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/PanelTypeSwitcher/utils.ts

@@ -8,6 +8,12 @@ import {
 } from '../../../Panels/capabilities';
 import type { PanelKind } from '../../../Panels/types/panelKind';
 
+/** Their queries differ in shape, so neither converts into the other. */
+const UNSWITCHABLE_KINDS = new Set<PanelKind>([
+	'signoz/HistogramPanel',
+	'signoz/DistributionPanel',
+]);
+
 const QUERY_TYPE_LABEL: Record<EQueryType, string> = {
 	[EQueryType.QUERY_BUILDER]: 'Query Builder',
 	[EQueryType.CLICKHOUSE]: 'ClickHouse',
@@ -29,15 +35,26 @@ const SIGNAL_LABEL: Record<TelemetrytypesSignalDTO, string> = {
  */
 export function getPanelTypeDisabledReason({
 	kind,
+	fromKind,
 	queryType,
 	signal,
 	label,
 }: {
 	kind: PanelKind;
+	/** The panel's current kind; some pairs can't switch into each other. */
+	fromKind?: PanelKind;
 	queryType: EQueryType;
 	signal?: TelemetrytypesSignalDTO;
 	label: string;
 }): string | undefined {
+	if (
+		fromKind !== undefined &&
+		fromKind !== kind &&
+		UNSWITCHABLE_KINDS.has(fromKind) &&
+		UNSWITCHABLE_KINDS.has(kind)
+	) {
+		return "Histogram and Distribution query differently, so a panel can't switch between them";
+	}
 	// A kind that renders without a query pairs with anything — it declares no
 	// query types or signals, and the checks below would read that as "supports
 	// nothing" and disable it everywhere.

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/controls/drawings/switchSketches.tsx

@@ -26,6 +26,13 @@ export const SWITCH_SKETCHES = {
 			))}
 		</SketchSvg>
 	),
+	percentiles: (
+		<SketchSvg>
+			<path d="M3 19 L9 13 L15 7 L21 9 L27 14 L33 17 L37 19" />
+			<path d="M15 3 V20" strokeDasharray="2 2" />
+			<path d="M29 3 V20" strokeDasharray="2 2" />
+		</SketchSvg>
+	),
 	combine: (
 		<SketchSvg>
 			<rect x={4} y={10} width={6} height={10} />

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/controls/drawings/tileDrawings.tsx

@@ -180,6 +180,22 @@ export const TILE_DRAWINGS = {
 			<rect x={38} y={8} width={11} height={6} {...FILLED} />
 		</TileSvg>
 	),
+	barsSideBySide: (
+		<TileSvg>
+			<rect x={10} y={8} width={7} height={14} {...FILLED} opacity={0.5} />
+			<rect x={18} y={12} width={7} height={10} {...FILLED} />
+			<rect x={36} y={11} width={7} height={11} {...FILLED} opacity={0.5} />
+			<rect x={44} y={6} width={7} height={16} {...FILLED} />
+		</TileSvg>
+	),
+	barsPercent: (
+		<TileSvg>
+			<rect x={14} y={12} width={11} height={10} {...FILLED} opacity={0.5} />
+			<rect x={14} y={2} width={11} height={9} {...FILLED} />
+			<rect x={38} y={8} width={11} height={14} {...FILLED} opacity={0.5} />
+			<rect x={38} y={2} width={11} height={5} {...FILLED} />
+		</TileSvg>
+	),
 	areaOverlap: (
 		<TileSvg>
 			<path d="M4 15 L18 9 L32 13 L46 6 L60 9" />

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sectionRegistry.tsx

@@ -1,5 +1,6 @@
 import type { ComponentType } from 'react';
 import type {
+	DashboardtypesDistributionAxesDTO,
 	DashboardtypesLinkDTO,
 	DashboardtypesHistogramBucketsDTO,
 	DashboardtypesLegendDTO,
@@ -25,6 +26,7 @@ import BucketsSection from './sections/BucketsSection/BucketsSection';
 import ChartAppearanceSection from './sections/ChartAppearanceSection/ChartAppearanceSection';
 import ContextLinksSection from './sections/ContextLinksSection/ContextLinksSection';
 import DimensionsSection from './sections/DimensionsSection/DimensionsSection';
+import DistributionAxesSection from './sections/DistributionAxesSection/DistributionAxesSection';
 import FormattingSection from './sections/FormattingSection/FormattingSection';
 import LegendSection from './sections/LegendSection/LegendSection';
 import PanelHeaderSection from './sections/PanelHeaderSection/PanelHeaderSection';
@@ -97,6 +99,13 @@ export const SECTION_REGISTRY: {
 			getPluginSlice<DashboardtypesScatterPlotAxesDTO>(spec, 'axes'),
 		update: (spec, axes): PanelSpec => updatePluginSlice(spec, 'axes', axes),
 	},
+	// Same `axes` key again, in Distribution's bucket-range/count-scale shape.
+	[SectionKind.DistributionAxes]: {
+		Component: DistributionAxesSection,
+		get: (spec): DashboardtypesDistributionAxesDTO | undefined =>
+			getPluginSlice<DashboardtypesDistributionAxesDTO>(spec, 'axes'),
+		update: (spec, axes): PanelSpec => updatePluginSlice(spec, 'axes', axes),
+	},
 	[SectionKind.Dimensions]: {
 		Component: DimensionsSection,
 		get: (spec): DashboardtypesScatterPlotDimensionsDTO | undefined =>

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/ChartAppearanceSection/ChartAppearanceSection.tsx

@@ -1,4 +1,5 @@
 import cx from 'classnames';
+import { DashboardtypesStackModeDTO } from 'api/generated/services/sigNoz.schemas';
 import { resolveFillOpacity } from 'lib/uPlotV2/utils/fillOpacity';
 import type {
 	SectionEditorProps,
@@ -13,9 +14,12 @@ import { SWITCH_SKETCHES } from '../../controls/drawings/switchSketches';
 import type { SectionEditorContext } from '../../sectionContext';
 import { createFieldResetter } from '../../utils/changes';
 import DisconnectValuesField from './DisconnectValuesField';
+import DistributionPercentilesField from './DistributionPercentilesField';
 import HeatmapColorsField from './HeatmapColorsField';
 import PointsFields from './PointsFields';
 import {
+	BUCKET_STACK_HELP,
+	BUCKET_STACK_OPTIONS,
 	FILL_MODE_OPTIONS,
 	FILLED_FILL_MODE_OPTIONS,
 	LINE_INTERPOLATION_HELP,
@@ -45,9 +49,34 @@ function ChartAppearanceSection({
 	Pick<SectionEditorContext, 'stepInterval' | 'sizeColumnLabel'>): JSX.Element {
 	const reset = createFieldResetter(value, savedValue, onChange);
 	const interpolation = value?.lineInterpolation;
+	const stack = value?.stack ?? DashboardtypesStackModeDTO.normal;
 
 	return (
 		<>
+			{controls.stack && (
+				<ConfigField
+					label="Groups in a bucket"
+					help={BUCKET_STACK_HELP[stack]}
+					{...reset('stack')}
+				>
+					<ConfigTiles
+						testId="panel-editor-v2-bucket-stack"
+						aria-label="Groups in a bucket"
+						value={stack}
+						items={BUCKET_STACK_OPTIONS}
+						onChange={(next): void => onChange({ ...value, stack: next })}
+					/>
+				</ConfigField>
+			)}
+
+			{controls.percentiles && (
+				<DistributionPercentilesField
+					value={value?.percentiles}
+					savedValue={savedValue?.percentiles}
+					onChange={(percentiles): void => onChange({ ...value, percentiles })}
+				/>
+			)}
+
 			{controls.lineStyle && (
 				<ConfigField label="Line" {...reset('lineStyle')}>
 					<ConfigTiles

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/ChartAppearanceSection/DistributionPercentilesField.tsx

@@ -0,0 +1,70 @@
+import type { DashboardtypesDistributionPercentilesDTO } from 'api/generated/services/sigNoz.schemas';
+import { DEFAULT_DISTRIBUTION_PERCENTILES } from 'pages/DashboardPage/DashboardContainer/Panels/utils/chartAppearance/resolvers';
+
+import ConfigField from '../../controls/ConfigField/ConfigField';
+import ConfigMultiSelect from '../../controls/ConfigMultiSelect/ConfigMultiSelect';
+import ConfigSwitch from '../../controls/ConfigSwitch/ConfigSwitch';
+import { SWITCH_SKETCHES } from '../../controls/drawings/switchSketches';
+import { createFieldResetter } from '../../utils/changes';
+import {
+	MAX_PERCENTILE_MARKERS,
+	resolvePercentileItems,
+} from './percentileOptions';
+
+interface DistributionPercentilesFieldProps {
+	value: DashboardtypesDistributionPercentilesDTO | undefined;
+	savedValue?: DashboardtypesDistributionPercentilesDTO;
+	onChange: (next: DashboardtypesDistributionPercentilesDTO) => void;
+}
+
+/** Edits `chartAppearance.percentiles`; unset reads as on, at p50/p90/p99. */
+function DistributionPercentilesField({
+	value,
+	savedValue,
+	onChange,
+}: DistributionPercentilesFieldProps): JSX.Element {
+	const reset = createFieldResetter(value, savedValue, onChange);
+	const enabled = value?.enabled ?? true;
+	const values = value?.values ?? DEFAULT_DISTRIBUTION_PERCENTILES;
+
+	return (
+		<>
+			<ConfigSwitch
+				testId="panel-editor-v2-percentile-markers"
+				title="Percentile markers"
+				description="Dashed lines at percentiles estimated from the bucket counts."
+				sketch={SWITCH_SKETCHES.percentiles}
+				changed={reset('enabled').changed}
+				value={enabled}
+				onChange={(next): void => onChange({ enabled: next, values })}
+			/>
+
+			{enabled && (
+				<ConfigField
+					label="Percentiles"
+					help={
+						<span data-testid="panel-editor-v2-percentile-limit">
+							{values.length >= MAX_PERCENTILE_MARKERS
+								? `Limit of ${MAX_PERCENTILE_MARKERS} reached; remove one to pick another.`
+								: `Up to ${MAX_PERCENTILE_MARKERS}.`}
+						</span>
+					}
+					{...reset('values')}
+				>
+					<ConfigMultiSelect
+						testId="panel-editor-v2-percentile-values"
+						value={values.map(String)}
+						items={resolvePercentileItems(values)}
+						onChange={(picked): void => {
+							if (picked.length <= MAX_PERCENTILE_MARKERS) {
+								onChange({ enabled, values: picked.map(Number) });
+							}
+						}}
+					/>
+				</ConfigField>
+			)}
+		</>
+	);
+}
+
+export default DistributionPercentilesField;

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/ChartAppearanceSection/__tests__/ChartAppearanceSection.test.tsx

@@ -125,6 +125,41 @@ describe('ChartAppearanceSection', () => {
 		});
 	});
 
+	it('opens the bucket stack on stacked, where a distribution starts', () => {
+		render(
+			<ChartAppearanceSection
+				value={undefined}
+				controls={{ stack: true }}
+				onChange={jest.fn()}
+			/>,
+		);
+
+		expect(
+			screen.getByTestId('panel-editor-v2-bucket-stack'),
+		).toBeInTheDocument();
+		expect(
+			screen.getByText(
+				'Groups sit on top of each other, so the height shows the bucket total.',
+			),
+		).toBeInTheDocument();
+	});
+
+	it('writes the chosen bucket stack', async () => {
+		const user = userEvent.setup();
+		const onChange = jest.fn();
+		render(
+			<ChartAppearanceSection
+				value={undefined}
+				controls={{ stack: true }}
+				onChange={onChange}
+			/>,
+		);
+
+		await user.click(screen.getByText('Side by side'));
+
+		expect(onChange).toHaveBeenCalledWith({ stack: 'none' });
+	});
+
 	it('shows the fill opacity at the chart default when the spec omits it', () => {
 		render(
 			<ChartAppearanceSection

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/ChartAppearanceSection/__tests__/DistributionPercentilesField.test.tsx

@@ -0,0 +1,83 @@
+import { render, screen, userEvent } from 'tests/test-utils';
+
+import DistributionPercentilesField from '../DistributionPercentilesField';
+import { resolvePercentileItems } from '../percentileOptions';
+
+describe('DistributionPercentilesField', () => {
+	it('opens on, with the values picker shown', () => {
+		render(
+			<DistributionPercentilesField value={undefined} onChange={jest.fn()} />,
+		);
+
+		expect(
+			screen.getByTestId('panel-editor-v2-percentile-values'),
+		).toBeInTheDocument();
+	});
+
+	it('turns markers off, keeping the values for when they come back', async () => {
+		const onChange = jest.fn();
+		render(
+			<DistributionPercentilesField
+				value={{ enabled: true, values: [75] }}
+				onChange={onChange}
+			/>,
+		);
+
+		await userEvent
+			.setup({ pointerEventsCheck: 0 })
+			.click(screen.getByTestId('panel-editor-v2-percentile-markers'));
+
+		expect(onChange).toHaveBeenCalledWith({ enabled: false, values: [75] });
+	});
+
+	it('hides the values picker while markers are off', () => {
+		render(
+			<DistributionPercentilesField
+				value={{ enabled: false, values: [75] }}
+				onChange={jest.fn()}
+			/>,
+		);
+
+		expect(
+			screen.queryByTestId('panel-editor-v2-percentile-values'),
+		).not.toBeInTheDocument();
+	});
+});
+
+describe('DistributionPercentilesField limit', () => {
+	it('says when the limit is reached', () => {
+		const { rerender } = render(
+			<DistributionPercentilesField
+				value={{ enabled: true, values: [50, 90, 99] }}
+				onChange={jest.fn()}
+			/>,
+		);
+		expect(
+			screen.getByTestId('panel-editor-v2-percentile-limit'),
+		).toHaveTextContent('Up to 5.');
+
+		rerender(
+			<DistributionPercentilesField
+				value={{ enabled: true, values: [50, 75, 90, 95, 99] }}
+				onChange={jest.fn()}
+			/>,
+		);
+		expect(
+			screen.getByTestId('panel-editor-v2-percentile-limit'),
+		).toHaveTextContent('Limit of 5 reached; remove one to pick another.');
+	});
+});
+
+describe('resolvePercentileItems', () => {
+	it('adds a saved value missing from the presets, in order', () => {
+		expect(resolvePercentileItems([97]).map(({ label }) => label)).toStrictEqual([
+			'p50',
+			'p75',
+			'p90',
+			'p95',
+			'p97',
+			'p99',
+			'p99.9',
+		]);
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/ChartAppearanceSection/options.ts

@@ -1,4 +1,5 @@
 import {
+	DashboardtypesStackModeDTO,
 	DashboardtypesFillModeDTO,
 	DashboardtypesLineInterpolationDTO,
 	DashboardtypesLineStyleDTO,
@@ -99,3 +100,32 @@ export const DISCONNECT_MODE_OPTIONS: ConfigTileItem<DisconnectValuesMode>[] = [
 		drawing: TILE_DRAWINGS.gapsBreak,
 	},
 ];
+
+/** Distribution's layout of groups within a bucket. */
+export const BUCKET_STACK_OPTIONS: ConfigTileItem<DashboardtypesStackModeDTO>[] =
+	[
+		{
+			value: DashboardtypesStackModeDTO.normal,
+			label: 'Stacked',
+			drawing: TILE_DRAWINGS.barsStacked,
+		},
+		{
+			value: DashboardtypesStackModeDTO.none,
+			label: 'Side by side',
+			drawing: TILE_DRAWINGS.barsSideBySide,
+		},
+		{
+			value: DashboardtypesStackModeDTO.percent,
+			label: '100%',
+			drawing: TILE_DRAWINGS.barsPercent,
+		},
+	];
+
+export const BUCKET_STACK_HELP: Record<DashboardtypesStackModeDTO, string> = {
+	[DashboardtypesStackModeDTO.normal]:
+		'Groups sit on top of each other, so the height shows the bucket total.',
+	[DashboardtypesStackModeDTO.none]:
+		'Groups share each bucket side by side; hard to read past a few groups.',
+	[DashboardtypesStackModeDTO.percent]:
+		"Each group's share of the bucket; the y axis becomes a percentage.",
+};

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/ChartAppearanceSection/percentileOptions.ts

@@ -0,0 +1,18 @@
+import type { ConfigMultiSelectItem } from '../../controls/ConfigMultiSelect/ConfigMultiSelect';
+
+/** The save API rejects more. */
+export const MAX_PERCENTILE_MARKERS = 5;
+
+const PRESET_PERCENTILES = [50, 75, 90, 95, 99, 99.9];
+
+/** The presets plus any saved value outside them, ascending, so nothing saved is hidden. */
+export function resolvePercentileItems(
+	values: number[],
+): ConfigMultiSelectItem[] {
+	return [...new Set([...PRESET_PERCENTILES, ...values])]
+		.sort((a, b) => a - b)
+		.map((percentile) => ({
+			value: String(percentile),
+			label: `p${percentile}`,
+		}));
+}

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/DistributionAxesSection/DistributionAxesSection.module.scss

@@ -0,0 +1,10 @@
+.axes {
+	display: flex;
+	flex-direction: column;
+	gap: 24px;
+}
+
+.axis + .axis {
+	padding-top: 24px;
+	border-top: 1px solid var(--l1-border);
+}

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/DistributionAxesSection/DistributionAxesSection.tsx

@@ -0,0 +1,76 @@
+import { Callout } from '@signozhq/ui/callout';
+import type {
+	SectionEditorProps,
+	SectionKind,
+} from 'pages/DashboardPage/DashboardContainer/Panels/types/sections';
+import { DashboardtypesDistributionYScaleDTO } from 'api/generated/services/sigNoz.schemas';
+
+import ConfigField from '../../controls/ConfigField/ConfigField';
+import ConfigRangeInput from '../../controls/ConfigRangeInput/ConfigRangeInput';
+import { isRangeInverted } from '../../controls/ConfigRangeInput/utils';
+import ConfigTiles from '../../controls/ConfigTiles/ConfigTiles';
+import { createFieldResetter } from '../../utils/changes';
+import { Y_SCALE_HELP, Y_SCALE_OPTIONS } from './options';
+
+import styles from './DistributionAxesSection.module.scss';
+
+function DistributionAxesSection({
+	value,
+	savedValue,
+	onChange,
+}: SectionEditorProps<SectionKind.DistributionAxes>): JSX.Element {
+	const reset = createFieldResetter(value, savedValue, onChange);
+	const xMin = value?.x?.min;
+	const xMax = value?.x?.max;
+	const yScale = value?.y?.scale ?? DashboardtypesDistributionYScaleDTO.linear;
+
+	return (
+		<div className={styles.axes}>
+			<div className={styles.axis}>
+				<ConfigField
+					label="X-axis range"
+					help={
+						isRangeInverted(xMin, xMax) ? (
+							<Callout type="error" size="small" showIcon>
+								Min can&apos;t be greater than max.
+							</Callout>
+						) : (
+							'Hides buckets outside the range. Leave empty to show them all.'
+						)
+					}
+					{...reset('x')}
+				>
+					<ConfigRangeInput
+						minTestId="panel-editor-v2-distribution-x-min"
+						maxTestId="panel-editor-v2-distribution-x-max"
+						min={xMin}
+						max={xMax}
+						onChangeMin={(min): void =>
+							onChange({ ...value, x: { ...value?.x, min } })
+						}
+						onChangeMax={(max): void =>
+							onChange({ ...value, x: { ...value?.x, max } })
+						}
+					/>
+				</ConfigField>
+			</div>
+			<div className={styles.axis}>
+				<ConfigField
+					label="Y-axis scale"
+					help={Y_SCALE_HELP[yScale]}
+					{...reset('y')}
+				>
+					<ConfigTiles
+						testId="panel-editor-v2-distribution-y-scale"
+						aria-label="Y-axis scale"
+						value={yScale}
+						items={Y_SCALE_OPTIONS}
+						onChange={(scale): void => onChange({ ...value, y: { scale } })}
+					/>
+				</ConfigField>
+			</div>
+		</div>
+	);
+}
+
+export default DistributionAxesSection;

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/DistributionAxesSection/__tests__/DistributionAxesSection.test.tsx

@@ -0,0 +1,66 @@
+import { DashboardtypesDistributionYScaleDTO } from 'api/generated/services/sigNoz.schemas';
+import { render, screen, userEvent } from 'tests/test-utils';
+
+import DistributionAxesSection from '../DistributionAxesSection';
+
+describe('DistributionAxesSection', () => {
+	it('opens on the defaults the chart draws: every bucket, linear counts', () => {
+		render(<DistributionAxesSection value={undefined} onChange={jest.fn()} />);
+
+		expect(
+			screen.getByText(
+				'Hides buckets outside the range. Leave empty to show them all.',
+			),
+		).toBeInTheDocument();
+		expect(
+			screen.getByText('Bar heights proportional to counts.'),
+		).toBeInTheDocument();
+	});
+
+	it('writes the x min without dropping the max or the y scale', async () => {
+		const user = userEvent.setup({ pointerEventsCheck: 0 });
+		const onChange = jest.fn();
+		render(
+			<DistributionAxesSection
+				value={{
+					x: { max: 100 },
+					y: { scale: DashboardtypesDistributionYScaleDTO.log },
+				}}
+				onChange={onChange}
+			/>,
+		);
+
+		await user.click(screen.getByTestId('panel-editor-v2-distribution-x-min'));
+		await user.paste('10');
+
+		expect(onChange).toHaveBeenCalledWith({
+			x: { min: 10, max: 100 },
+			y: { scale: DashboardtypesDistributionYScaleDTO.log },
+		});
+	});
+
+	it('flags a min above the max', () => {
+		render(
+			<DistributionAxesSection
+				value={{ x: { min: 100, max: 10 } }}
+				onChange={jest.fn()}
+			/>,
+		);
+
+		expect(
+			screen.getByText("Min can't be greater than max."),
+		).toBeInTheDocument();
+	});
+
+	it('writes the y scale', async () => {
+		const user = userEvent.setup({ pointerEventsCheck: 0 });
+		const onChange = jest.fn();
+		render(<DistributionAxesSection value={undefined} onChange={onChange} />);
+
+		await user.click(screen.getByText('Logarithmic'));
+
+		expect(onChange).toHaveBeenCalledWith({
+			y: { scale: DashboardtypesDistributionYScaleDTO.log },
+		});
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/ConfigPane/sections/DistributionAxesSection/options.ts

@@ -0,0 +1,14 @@
+import { DashboardtypesDistributionYScaleDTO } from 'api/generated/services/sigNoz.schemas';
+
+import { pickScaleOptions } from '../AxesSection/options';
+
+export const Y_SCALE_OPTIONS = pickScaleOptions([
+	DashboardtypesDistributionYScaleDTO.linear,
+	DashboardtypesDistributionYScaleDTO.log,
+] as const);
+
+export const Y_SCALE_HELP: Record<DashboardtypesDistributionYScaleDTO, string> =
+	{
+		linear: 'Bar heights proportional to counts.',
+		log: 'Keeps small tail buckets visible next to the bulk.',
+	};

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/PanelEditorQueryBuilder/PanelEditorQueryBuilder.tsx

@@ -45,6 +45,8 @@ interface PanelEditorQueryBuilderProps {
 	onStageRunQuery: () => void;
 	/** Abort the in-flight preview fetch (the button's cancel action). */
 	onCancelQuery: () => void;
+	/** Optional content above the tabs (e.g. Histogram's pointer to Distribution). */
+	banner?: ReactNode;
 	/** Optional content pinned below the builder (e.g. the List columns editor). */
 	footer?: ReactNode;
 	/** Pin the tabs + Run Query row to the top of the scroll area. Off in the View modal, which shares a scroll area with its own header. */
@@ -62,6 +64,7 @@ function PanelEditorQueryBuilder({
 	isLoadingQueries,
 	onStageRunQuery,
 	onCancelQuery,
+	banner,
 	footer,
 	stickyHeader = true,
 }: PanelEditorQueryBuilderProps): JSX.Element {
@@ -188,6 +191,7 @@ function PanelEditorQueryBuilder({
 			role="presentation"
 		>
 			<div className={styles.scrollArea}>
+				{banner}
 				<Tabs
 					type="card"
 					className={cx(styles.tabsContainer, {

frontend/src/pages/DashboardPage/DashboardContainer/PanelEditor/hooks/usePanelKindAndQueryModeSwitch.ts

@@ -7,6 +7,7 @@ import type {
 	TelemetrytypesSignalDTO,
 } from 'api/generated/services/sigNoz.schemas';
 import type { PANEL_TYPES } from 'constants/queryBuilder';
+import { isBucketCountingPanelType } from 'lib/query/bucketCountingPanelTypes';
 import { handleQueryChange } from 'lib/query/panelQuery';
 import type { PartialPanelTypes } from 'lib/query/panelTypeDataSourceFormValuesMap';
 import { useQueryBuilder } from 'hooks/queryBuilder/useQueryBuilder';
@@ -183,7 +184,7 @@ export function usePanelKindAndQueryModeSwitch({
 					newKind === 'signoz/ListPanel'
 						? withDefaultListOrder(transformed)
 						: transformed;
-				return newKind === 'signoz/HeatmapPanel'
+				return isBucketCountingPanelType(newPanelType)
 					? withSingleHeatmapQuery(ordered)
 					: withPercentileHistogramAggregation(ordered);
 			};

frontend/src/pages/DashboardPage/DashboardContainer/Panels/__tests__/capabilities.test.ts

@@ -24,7 +24,8 @@ import type { PanelKind } from '../types/panelKind';
 
 const { QUERY_BUILDER, CLICKHOUSE, PROM } = EQueryType;
 const { logs, traces, metrics } = TelemetrytypesSignalDTO;
-const { time_series, scalar, raw, heatmap } = Querybuildertypesv5RequestTypeDTO;
+const { time_series, scalar, raw, heatmap, distribution } =
+	Querybuildertypesv5RequestTypeDTO;
 
 const EXPECTED_QUERY_TYPES: Record<PanelKind, EQueryType[]> = {
 	'signoz/TimeSeriesPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
@@ -33,6 +34,7 @@ const EXPECTED_QUERY_TYPES: Record<PanelKind, EQueryType[]> = {
 	'signoz/NumberPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
 	'signoz/HistogramPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
 	'signoz/HeatmapPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
+	'signoz/DistributionPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
 	'signoz/PieChartPanel': [QUERY_BUILDER, CLICKHOUSE],
 	'signoz/TablePanel': [QUERY_BUILDER, CLICKHOUSE],
 	'signoz/ListPanel': [QUERY_BUILDER],
@@ -73,6 +75,7 @@ const EXPECTED_QUERY_MODES: Record<PanelKind, QueryMode[]> = {
 		QueryMode.AI_QUERY_BUILDER,
 	],
 	'signoz/HeatmapPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
+	'signoz/DistributionPanel': [QUERY_BUILDER, CLICKHOUSE, PROM],
 	'signoz/PieChartPanel': [
 		QUERY_BUILDER,
 		CLICKHOUSE,
@@ -92,6 +95,7 @@ const EXPECTED_SIGNALS: Record<PanelKind, TelemetrytypesSignalDTO[]> = {
 	'signoz/HistogramPanel': [metrics, logs, traces],
 	// A heatmap needs a bucket axis, which only a metric carries.
 	'signoz/HeatmapPanel': [metrics],
+	'signoz/DistributionPanel': [metrics],
 	'signoz/PieChartPanel': [metrics, logs, traces],
 	'signoz/TablePanel': [metrics, logs, traces],
 	// List renders raw rows; metrics produce no row data.
@@ -145,6 +149,13 @@ const EXPECTED_QUERY_CAPABILITIES: Partial<
 		orderTiebreaker: false,
 		serverPaginated: false,
 	},
+	'signoz/DistributionPanel': {
+		requestType: distribution,
+		formatTableResultForUI: false,
+		bucketedStepInterval: false,
+		orderTiebreaker: false,
+		serverPaginated: false,
+	},
 	'signoz/NumberPanel': {
 		requestType: scalar,
 		formatTableResultForUI: false,

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/Renderer.tsx

@@ -0,0 +1,136 @@
+import { useCallback, useMemo, useRef } from 'react';
+import type { DashboardtypesDistributionPanelSpecDTO } from 'api/generated/services/sigNoz.schemas';
+import Distribution from 'lib/visualization/charts/Distribution/Distribution';
+import type { DistributionBarClick } from 'lib/visualization/charts/Distribution/types';
+import { IRenderTooltipFooterArgs } from 'lib/uPlotV2/components/types';
+import TooltipFooter from 'lib/visualization/panels/components/TooltipFooter';
+import { useIsDarkMode } from 'hooks/useDarkMode';
+import { useResizeObserver } from 'hooks/useDimensions';
+import { getDistributionResults } from 'pages/DashboardPage/DashboardContainer/queryV5/v5ResponseData';
+
+import NoData from '../../components/NoData/NoData';
+import PanelStyles from '../../panel.module.scss';
+import { PanelRendererProps } from '../../types/rendererProps';
+import {
+	resolveDecimalPrecision,
+	resolveDistributionPercentiles,
+	resolveDistributionStackMode,
+	resolveDistributionYScale,
+	resolveLegendPosition,
+} from '../../utils/chartAppearance/resolvers';
+import { enrichDistributionClick } from '../../utils/drilldown/enrichDistributionClick';
+import { getBuilderQueries } from '../../utils/getBuilderQueries';
+import { getPanelTimeRange } from '../../utils/getPanelTimeRange';
+
+import { prepareDistributionData } from './prepareData';
+
+function DistributionPanelRenderer({
+	panelId,
+	panel,
+	data,
+	isFetching,
+	refetch,
+	onClick,
+	enableDrillDown,
+}: PanelRendererProps<'signoz/DistributionPanel'>): JSX.Element {
+	const graphRef = useRef<HTMLDivElement>(null);
+	const containerDimensions = useResizeObserver(graphRef);
+	const isDarkMode = useIsDarkMode();
+
+	const spec = useMemo<DashboardtypesDistributionPanelSpecDTO>(
+		() => panel.spec.plugin.spec,
+		[panel.spec.plugin.spec],
+	);
+
+	const { buckets, series, queryName } = useMemo(
+		() =>
+			prepareDistributionData({
+				results: getDistributionResults(data.response),
+				legendMap: data.legendMap ?? {},
+			}),
+		[data.response, data.legendMap],
+	);
+
+	const percentiles = useMemo(
+		() => resolveDistributionPercentiles(spec.chartAppearance?.percentiles),
+		[spec.chartAppearance?.percentiles],
+	);
+
+	const decimalPrecision = useMemo(
+		() => resolveDecimalPrecision(spec.formatting?.decimalPrecision),
+		[spec.formatting?.decimalPrecision],
+	);
+
+	const builderQueries = useMemo(
+		() => getBuilderQueries(panel.spec.queries),
+		[panel.spec.queries],
+	);
+
+	const handleBarClick = useCallback(
+		(click: DistributionBarClick): void => {
+			const payload = enrichDistributionClick({
+				click,
+				queryName,
+				builderQueries,
+				timeRange: getPanelTimeRange(data.requestPayload),
+			});
+			if (payload) {
+				onClick?.(payload);
+			}
+		},
+		[onClick, queryName, builderQueries, data.requestPayload],
+	);
+
+	const renderTooltipFooter = useCallback(
+		({ isPinned, dismiss }: IRenderTooltipFooterArgs) => (
+			<TooltipFooter
+				id={panelId}
+				isPinned={isPinned}
+				canDrilldown={!!enableDrillDown}
+				dismiss={dismiss}
+			/>
+		),
+		[panelId, enableDrillDown],
+	);
+
+	const hasBars = buckets.length > 0 && series.length > 0;
+
+	return (
+		<div
+			ref={graphRef}
+			data-testid="distribution-panel-renderer"
+			className={PanelStyles.panelContainer}
+		>
+			{!hasBars && (
+				<NoData isFetching={isFetching} onRetry={refetch} panel={panel} />
+			)}
+			{hasBars &&
+				containerDimensions.width > 0 &&
+				containerDimensions.height > 0 && (
+					<Distribution
+						key={panelId}
+						id={panelId}
+						buckets={buckets}
+						series={series}
+						xMin={spec.axes?.x?.min ?? undefined}
+						xMax={spec.axes?.x?.max ?? undefined}
+						yScale={resolveDistributionYScale(spec.axes?.y?.scale)}
+						stack={resolveDistributionStackMode(spec.chartAppearance?.stack)}
+						xAxisUnit={spec.formatting?.unit}
+						decimalPrecision={decimalPrecision}
+						customColors={spec.legend?.customColors ?? undefined}
+						percentiles={percentiles}
+						canPinTooltip
+						renderTooltipFooter={renderTooltipFooter}
+						onBarClick={enableDrillDown && onClick ? handleBarClick : undefined}
+						legendPosition={resolveLegendPosition(spec.legend?.position)}
+						isDarkMode={isDarkMode}
+						width={containerDimensions.width}
+						height={containerDimensions.height}
+					/>
+				)}
+		</div>
+	);
+}
+
+export default DistributionPanelRenderer;

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/__tests__/prepareData.test.ts

@@ -0,0 +1,152 @@
+import type {
+	Querybuildertypesv5DistributionDataDTO,
+	Querybuildertypesv5DistributionDTO,
+} from 'api/generated/services/sigNoz.schemas';
+
+import { prepareDistributionData } from '../prepareData';
+
+function result({
+	queryName = 'A',
+	buckets = [1, 2, 4],
+	distributions = [],
+}: {
+	queryName?: string;
+	buckets?: number[];
+	distributions?: Querybuildertypesv5DistributionDTO[];
+} = {}): Querybuildertypesv5DistributionDataDTO {
+	return {
+		queryName,
+		aggregations: [
+			{ alias: '__result_0', index: 0, meta: { buckets }, distributions },
+		],
+	};
+}
+
+describe('prepareDistributionData', () => {
+	it('reads the bucket bounds and one count array per group', () => {
+		const { buckets, series, queryName } = prepareDistributionData({
+			results: [
+				result({
+					distributions: [
+						{
+							labels: [{ key: { name: 'service' }, value: 'redis' }],
+							counts: [5, 12, 3, 1],
+						},
+						{
+							labels: [{ key: { name: 'service' }, value: 'cart' }],
+							counts: [0, 4, 8, 0],
+						},
+					],
+				}),
+			],
+			legendMap: {},
+		});
+
+		expect(buckets).toStrictEqual([1, 2, 4]);
+		expect(queryName).toBe('A');
+		expect(series).toStrictEqual([
+			{
+				label: '{service="redis"}',
+				groupLabels: { service: 'redis' },
+				counts: [5, 12, 3, 1],
+			},
+			{
+				label: '{service="cart"}',
+				groupLabels: { service: 'cart' },
+				counts: [0, 4, 8, 0],
+			},
+		]);
+	});
+
+	it('names an ungrouped distribution after its query', () => {
+		const { series } = prepareDistributionData({
+			results: [result({ distributions: [{ counts: [1, 0, 0, 0] }] })],
+			legendMap: { A: '' },
+		});
+
+		expect(series).toHaveLength(1);
+		expect(series[0].label).toBe('A');
+	});
+
+	it('applies the query legend as the group label template', () => {
+		const { series } = prepareDistributionData({
+			results: [
+				result({
+					distributions: [
+						{
+							labels: [{ key: { name: 'service' }, value: 'redis' }],
+							counts: [1, 0, 0, 0],
+						},
+					],
+				}),
+			],
+			legendMap: { A: '{{service}} latency' },
+		});
+
+		expect(series[0].label).toBe('redis latency');
+	});
+
+	it('pads missing counts with zero and trims extras, keeping the overflow slot', () => {
+		const { series } = prepareDistributionData({
+			results: [
+				result({
+					distributions: [
+						{ counts: [1, 2] },
+						{ counts: [1, 2, 3, 4, 5] },
+						{ counts: null },
+					],
+				}),
+			],
+			legendMap: {},
+		});
+
+		expect(series.map(({ counts }) => counts)).toStrictEqual([
+			[1, 2, 0, 0],
+			[1, 2, 3, 4],
+			[0, 0, 0, 0],
+		]);
+	});
+
+	it('skips aggregations without bounds and reads the first that has them', () => {
+		const { buckets } = prepareDistributionData({
+			results: [
+				{
+					queryName: 'A',
+					aggregations: [
+						{
+							alias: '__result_0',
+							index: 0,
+							meta: {},
+							distributions: [{ counts: [1] }],
+						},
+						{
+							alias: '__result_1',
+							index: 1,
+							meta: { buckets: [10, 20] },
+							distributions: [],
+						},
+					],
+				},
+			],
+			legendMap: {},
+		});
+
+		expect(buckets).toStrictEqual([10, 20]);
+	});
+
+	it('returns no buckets when nothing carries bounds', () => {
+		expect(
+			prepareDistributionData({
+				results: [result({ buckets: [] })],
+				legendMap: {},
+			}),
+		).toStrictEqual({ buckets: [], series: [], queryName: '' });
+		expect(prepareDistributionData({ results: [], legendMap: {} })).toStrictEqual(
+			{
+				buckets: [],
+				series: [],
+				queryName: '',
+			},
+		);
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/__tests__/warning.test.ts

@@ -0,0 +1,70 @@
+import {
+	DashboardtypesPanelKindDTO,
+	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTOKind as DistributionKind,
+	type DashboardtypesDistributionPanelSpecDTO,
+	type Querybuildertypesv5DistributionDataDTO,
+	Querybuildertypesv5RequestTypeDTO,
+} from 'api/generated/services/sigNoz.schemas';
+import type { PanelQueryData } from 'pages/DashboardPage/DashboardContainer/queryV5/types';
+
+import type { PanelOfKind } from '../../../types/rendererProps';
+import { getDistributionDataWarning } from '../warning';
+
+function dataWith(buckets: number[], counts: number[][]): PanelQueryData {
+	const result: Querybuildertypesv5DistributionDataDTO = {
+		queryName: 'A',
+		aggregations: [
+			{
+				alias: '__result_0',
+				index: 0,
+				meta: { buckets },
+				distributions: counts.map((entry) => ({ counts: entry })),
+			},
+		],
+	};
+	return {
+		response: {
+			status: 'success',
+			data: {
+				type: Querybuildertypesv5RequestTypeDTO.distribution,
+				data: { results: [result] },
+			},
+		},
+		requestPayload: undefined,
+		legendMap: {},
+	};
+}
+
+function panelWith(
+	spec: Partial<DashboardtypesDistributionPanelSpecDTO> = {},
+): PanelOfKind<'signoz/DistributionPanel'> {
+	return {
+		kind: DashboardtypesPanelKindDTO.Panel,
+		spec: {
+			display: { name: '' },
+			plugin: { kind: DistributionKind['signoz/DistributionPanel'], spec },
+			queries: [],
+		},
+	};
+}
+
+describe('getDistributionDataWarning', () => {
+	it('warns when more than 10% of observations overflow', () => {
+		const warning = getDistributionDataWarning(
+			panelWith({ formatting: { unit: 's' } }),
+			dataWith([1, 10], [[10, 50, 40]]),
+		);
+
+		expect(warning?.message).toMatch(/^40% of observations are above 10/);
+	});
+
+	it('says nothing at or under 10%', () => {
+		expect(
+			getDistributionDataWarning(panelWith(), dataWith([1, 10], [[40, 50, 10]])),
+		).toBeNull();
+	});
+
+	it('says nothing without bounds', () => {
+		expect(getDistributionDataWarning(panelWith(), dataWith([], []))).toBeNull();
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/definition.ts

@@ -0,0 +1,58 @@
+import { ChartColumnBig } from '@signozhq/icons';
+
+import { QueryBuilderField } from 'components/QueryBuilderV2/queryBuilderFields.types';
+
+import type { PanelDefinition } from '../../types/panelDefinition';
+import { QueryModeKind } from '../../types/panelCapabilities';
+import QueryBuilderEditorPane from 'pages/DashboardPage/DashboardContainer/PanelEditor/PanelEditorQueryBuilder/QueryBuilderEditorPane';
+import Renderer from './Renderer';
+import { sections } from './sections';
+import { getDistributionDataWarning } from './warning';
+import {
+	Querybuildertypesv5RequestTypeDTO,
+	TelemetrytypesSignalDTO,
+} from 'api/generated/services/sigNoz.schemas';
+import { QueryMode } from 'types/api/queryBuilder/queryBuilderData';
+
+export const definition: PanelDefinition<'signoz/DistributionPanel'> = {
+	kind: 'signoz/DistributionPanel',
+	displayName: 'Distribution',
+	mode: 'query',
+	icon: ChartColumnBig,
+	Renderer,
+	EditorPane: QueryBuilderEditorPane,
+	sections,
+	supportedQueryModesKindMap: {
+		// Only metrics carry a bucket axis; the request rejects the other signals.
+		[QueryMode.QUERY_BUILDER]: {
+			kind: QueryModeKind.SIGNAL,
+			signals: [TelemetrytypesSignalDTO.metrics],
+		},
+		[QueryMode.CLICKHOUSE]: { kind: QueryModeKind.SIGNAL_LESS },
+		[QueryMode.PROM]: { kind: QueryModeKind.SIGNAL_LESS },
+	},
+	// The request rejects both, as for heatmap: a point is a count per bucket.
+	queryBuilderFields: {
+		[QueryBuilderField.Functions]: { state: 'hidden' },
+		[QueryBuilderField.Having]: { state: 'hidden' },
+	},
+	// No width-derived step: there is no time axis, and a histogram's counts do not
+	// depend on the step.
+	queryCapabilities: {
+		requestType: Querybuildertypesv5RequestTypeDTO.distribution,
+		formatTableResultForUI: false,
+		bucketedStepInterval: false,
+		orderTiebreaker: false,
+		serverPaginated: false,
+	},
+	getDataWarning: getDistributionDataWarning,
+	actions: {
+		view: true,
+		edit: true,
+		clone: true,
+		download: { csv: false, png: true, svg: true },
+		createAlert: false,
+		search: false,
+		drilldown: true,
+	},
+};

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/prepareData.ts

@@ -0,0 +1,82 @@
+import type {
+	Querybuildertypesv5DistributionDataDTO,
+	Querybuildertypesv5DistributionDTO,
+} from 'api/generated/services/sigNoz.schemas';
+import getLabelName from 'lib/getLabelName';
+import type { DistributionSeries } from 'lib/visualization/charts/Distribution/types';
+
+export interface DistributionPanelData {
+	/** Ascending bucket upper bounds shared by every group; empty means no chart. */
+	buckets: number[];
+	series: DistributionSeries[];
+	/** The query the series came from, for drilldown. */
+	queryName: string;
+}
+
+const EMPTY_DATA: DistributionPanelData = {
+	buckets: [],
+	series: [],
+	queryName: '',
+};
+
+/**
+ * V5 distribution results → the chart's `buckets` + `series`. Only the first
+ * aggregation carrying bounds is read: each has its own bucket axis, and the chart
+ * has one.
+ */
+export function prepareDistributionData({
+	results,
+	legendMap,
+}: {
+	results: Querybuildertypesv5DistributionDataDTO[];
+	legendMap: Record<string, string>;
+}): DistributionPanelData {
+	for (const result of results) {
+		const queryName = result.queryName ?? '';
+		for (const aggregation of result.aggregations ?? []) {
+			const buckets = aggregation.meta?.buckets;
+			if (!buckets?.length) {
+				continue;
+			}
+			return {
+				buckets,
+				queryName,
+				series: (aggregation.distributions ?? []).map((distribution) =>
+					toDistributionSeries(
+						distribution,
+						buckets.length + 1,
+						queryName,
+						legendMap[queryName] ?? '',
+					),
+				),
+			};
+		}
+	}
+
+	return EMPTY_DATA;
+}
+
+/** Pads or trims to `length` so every series lines up with the bucket axis. */
+function toDistributionSeries(
+	distribution: Querybuildertypesv5DistributionDTO,
+	length: number,
+	queryName: string,
+	legend: string,
+): DistributionSeries {
+	const record: Record<string, string> = {};
+	(distribution.labels ?? []).forEach((label) => {
+		if (label.key?.name) {
+			record[label.key.name] = String(label.value);
+		}
+	});
+
+	const counts = distribution.counts ?? [];
+	return {
+		label: getLabelName(record, queryName, legend),
+		groupLabels: record,
+		counts: Array.from({ length }, (_, index) => {
+			const count = counts[index];
+			return Number.isFinite(count) ? count : 0;
+		}),
+	};
+}

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/sections.ts

@@ -0,0 +1,20 @@
+import { SectionKind, type SectionConfig } from '../../types/sections';
+import { resolveDistributionLegendSeries } from '../../utils/legendSeries';
+
+export const sections: SectionConfig[] = [
+	{
+		kind: SectionKind.Visualization,
+		controls: { switchPanelKind: true, timePreference: true },
+	},
+	{
+		kind: SectionKind.ChartAppearance,
+		controls: { stack: true, percentiles: true },
+	},
+	// Formats the bucket bounds; counts are plain integers and take no unit.
+	{ kind: SectionKind.Formatting, controls: { unit: true, decimals: true } },
+	{ kind: SectionKind.DistributionAxes },
+	{
+		kind: SectionKind.Legend,
+		controls: { position: true, colors: resolveDistributionLegendSeries },
+	},
+];

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/DistributionPanel/warning.ts

@@ -0,0 +1,48 @@
+import { getToolTipValue } from 'components/Graph/yAxisConfig';
+import type { PanelStatusDetail } from 'pages/DashboardPage/DashboardContainer/PanelsAndSectionsLayout/Panel/PanelStatus/types';
+import type { PanelQueryData } from 'pages/DashboardPage/DashboardContainer/queryV5/types';
+import { getDistributionResults } from 'pages/DashboardPage/DashboardContainer/queryV5/v5ResponseData';
+
+import type { PanelOfKind } from '../../types/rendererProps';
+import { prepareDistributionData } from './prepareData';
+
+/** Above this share in overflow, the bucket bounds probably stop short. */
+export const OVERFLOW_WARNING_SHARE = 0.1;
+
+/**
+ * Bounds that stop short, over every group regardless of the legend: too much
+ * landing in overflow.
+ */
+export function getDistributionDataWarning(
+	panel: PanelOfKind<'signoz/DistributionPanel'>,
+	data: PanelQueryData,
+): PanelStatusDetail | null {
+	const { buckets, series } = prepareDistributionData({
+		results: getDistributionResults(data.response),
+		legendMap: data.legendMap ?? {},
+	});
+	if (buckets.length === 0) {
+		return null;
+	}
+
+	const spec = panel.spec.plugin.spec;
+	const lastBound = buckets[buckets.length - 1];
+	let total = 0;
+	let overflow = 0;
+	series.forEach(({ counts }) => {
+		counts.forEach((count) => {
+			total += count;
+		});
+		overflow += counts[buckets.length] ?? 0;
+	});
+
+	const overflowShare = total > 0 ? overflow / total : 0;
+	if (overflowShare <= OVERFLOW_WARNING_SHARE) {
+		return null;
+	}
+	const bound = getToolTipValue(String(lastBound), spec.formatting?.unit);
+	return {
+		message: `${Math.round(overflowShare * 100)}% of observations are above ${bound}. The bucket bounds may be too low.`,
+		messages: [],
+	};
+}

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/HistogramPanel/HistogramEditorPane.module.scss

@@ -0,0 +1,3 @@
+.banner {
+	margin: var(--spacing-4) var(--spacing-6) 0;
+}

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/HistogramPanel/HistogramEditorPane.tsx

@@ -0,0 +1,49 @@
+import { Callout } from '@signozhq/ui/callout';
+import { useQueryBuilder } from 'hooks/queryBuilder/useQueryBuilder';
+
+import type { QueryEditorPaneProps } from '../../types/panelDefinition';
+import PanelEditorQueryBuilder from '../../../PanelEditor/PanelEditorQueryBuilder/PanelEditorQueryBuilder';
+import { isMetricQuery } from './isMetricQuery';
+
+import styles from './HistogramEditorPane.module.scss';
+
+/**
+ * Histogram bins the query's values in the browser, which for a histogram metric
+ * means percentiles or rates, not its bucket counts. Distribution reads those, but
+ * not logs or traces yet, so the pointer shows for metric queries only.
+ */
+function HistogramEditorPane({
+	panelDefinition,
+	isLoadingQueries,
+	onChangeQueryMode,
+	onStageRunQuery,
+	onCancelQuery,
+	stickyHeader,
+}: QueryEditorPaneProps): JSX.Element {
+	const { currentQuery } = useQueryBuilder();
+
+	return (
+		<PanelEditorQueryBuilder
+			panelDefinition={panelDefinition}
+			isLoadingQueries={isLoadingQueries}
+			onChangeQueryMode={onChangeQueryMode}
+			onStageRunQuery={onStageRunQuery}
+			onCancelQuery={onCancelQuery}
+			stickyHeader={stickyHeader}
+			banner={
+				isMetricQuery(currentQuery) && (
+					<Callout
+						className={styles.banner}
+						type="info"
+						size="small"
+						showIcon
+						title="For bucket counts over the time range, use the Distribution panel."
+						testId="histogram-distribution-banner"
+					/>
+				)
+			}
+		/>
+	);
+}
+
+export default HistogramEditorPane;

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/HistogramPanel/__tests__/isMetricQuery.test.ts

@@ -0,0 +1,29 @@
+import { initialQueriesMap } from 'constants/queryBuilder';
+import type { Query } from 'types/api/queryBuilder/queryBuilderData';
+import { EQueryType } from 'types/common/dashboard';
+import { DataSource } from 'types/common/queryBuilder';
+
+import { isMetricQuery } from '../isMetricQuery';
+
+function builderOver(dataSource: DataSource): Query {
+	return initialQueriesMap[dataSource];
+}
+
+describe('isMetricQuery', () => {
+	it('is true for a metrics builder query', () => {
+		expect(isMetricQuery(builderOver(DataSource.METRICS))).toBe(true);
+	});
+
+	it('is false for logs and traces, which Distribution does not read yet', () => {
+		expect(isMetricQuery(builderOver(DataSource.LOGS))).toBe(false);
+		expect(isMetricQuery(builderOver(DataSource.TRACES))).toBe(false);
+	});
+
+	it('is true for PromQL and ClickHouse', () => {
+		const base = builderOver(DataSource.LOGS);
+		expect(isMetricQuery({ ...base, queryType: EQueryType.PROM })).toBe(true);
+		expect(isMetricQuery({ ...base, queryType: EQueryType.CLICKHOUSE })).toBe(
+			true,
+		);
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/HistogramPanel/definition.ts

@@ -2,7 +2,7 @@ import { BarChart } from '@signozhq/icons';
 
 import type { PanelDefinition } from '../../types/panelDefinition';
 import { QueryModeKind } from '../../types/panelCapabilities';
-import QueryBuilderEditorPane from 'pages/DashboardPage/DashboardContainer/PanelEditor/PanelEditorQueryBuilder/QueryBuilderEditorPane';
+import HistogramEditorPane from './HistogramEditorPane';
 import Renderer from './Renderer';
 import { sections } from './sections';
 import {
@@ -17,7 +17,7 @@ export const definition: PanelDefinition<'signoz/HistogramPanel'> = {
 	mode: 'query',
 	icon: BarChart,
 	Renderer,
-	EditorPane: QueryBuilderEditorPane,
+	EditorPane: HistogramEditorPane,
 	sections,
 	supportedQueryModesKindMap: {
 		[QueryMode.QUERY_BUILDER]: {

frontend/src/pages/DashboardPage/DashboardContainer/Panels/kinds/HistogramPanel/isMetricQuery.ts

@@ -0,0 +1,13 @@
+import type { Query } from 'types/api/queryBuilder/queryBuilderData';
+import { EQueryType } from 'types/common/dashboard';
+import { DataSource } from 'types/common/queryBuilder';
+
+/** PromQL and ClickHouse read metrics here; a builder query does when any of it does. */
+export function isMetricQuery(query: Query): boolean {
+	if (query.queryType !== EQueryType.QUERY_BUILDER) {
+		return true;
+	}
+	return query.builder.queryData.some(
+		(queryData) => queryData.dataSource === DataSource.METRICS,
+	);
+}

frontend/src/pages/DashboardPage/DashboardContainer/Panels/registry.ts

@@ -1,5 +1,6 @@
 import { definition as AreaChart } from './kinds/AreaChartPanel/definition';
 import { definition as BarChart } from './kinds/BarChartPanel/definition';
+import { definition as Distribution } from './kinds/DistributionPanel/definition';
 import { definition as Heatmap } from './kinds/HeatmapPanel/definition';
 import { definition as Histogram } from './kinds/HistogramPanel/definition';
 import { definition as NumberValue } from './kinds/NumberPanel/definition';
@@ -29,6 +30,7 @@ export const PANELS: PanelRegistry = {
 	[ScatterPlot.kind]: ScatterPlot,
 	[Histogram.kind]: Histogram,
 	[Heatmap.kind]: Heatmap,
+	[Distribution.kind]: Distribution,
 	[List.kind]: List,
 	[Text.kind]: Text,
 };

frontend/src/pages/DashboardPage/DashboardContainer/Panels/types/interactions.ts

@@ -37,6 +37,9 @@ export type PanelInteractionMap = Record<PanelKind, object> & {
 	'signoz/HeatmapPanel': { onDragSelect?: DragSelect };
 	'signoz/TablePanel': { onClick?: (event: DrilldownClickPayload) => void };
 	'signoz/PieChartPanel': { onClick?: (event: DrilldownClickPayload) => void };
+	'signoz/DistributionPanel': {
+		onClick?: (event: DrilldownClickPayload) => void;
+	};
 	'signoz/NumberPanel': { onClick?: (event: DrilldownClickPayload) => void };
 	'signoz/ScatterPlotPanel': {
 		onClick?: (event: DrilldownClickPayload) => void;

frontend/src/pages/DashboardPage/DashboardContainer/Panels/types/panelKind.ts

@@ -27,6 +27,7 @@ export const PANEL_KIND_TO_PANEL_TYPE: Record<PanelKind, PANEL_TYPES> = {
 	'signoz/HeatmapPanel': PANEL_TYPES.HEATMAP,
 	'signoz/TextPanel': PANEL_TYPES.TEXT,
 	'signoz/ScatterPlotPanel': PANEL_TYPES.SCATTER,
+	'signoz/DistributionPanel': PANEL_TYPES.DISTRIBUTION,
 };
 
 /**

frontend/src/pages/DashboardPage/DashboardContainer/Panels/types/sections.ts

@@ -2,6 +2,8 @@ import type {
 	DashboardtypesLinkDTO,
 	DashboardtypesAxesDTO,
 	DashboardtypesComparisonThresholdDTO,
+	DashboardtypesDistributionAxesDTO,
+	DashboardtypesDistributionPercentilesDTO,
 	DashboardtypesFillModeDTO,
 	DashboardtypesFillOpacityDTO,
 	DashboardtypesHeatmapAxesDTO,
@@ -72,6 +74,8 @@ export enum SectionKind {
 	Dimensions = 'dimensions',
 	/** Scatter Plot's per-axis `axes` shape; `Axes` is the single y-axis shape. */
 	ScatterAxes = 'scatterAxes',
+	/** Distribution's `axes` shape: the bucket-axis range and count-axis scale. */
+	DistributionAxes = 'distributionAxes',
 }
 
 /**
@@ -116,6 +120,10 @@ export interface PanelChartAppearanceSlice {
 	colors?: DashboardtypesHeatmapColorsDTO;
 	/** Scatter Plot's dot size and opacity. */
 	points?: DashboardtypesScatterPlotPointsDTO;
+	/** Distribution stacking, which lives here rather than under `visualization`. */
+	stack?: DashboardtypesStackModeDTO;
+	/** Distribution's percentile markers. */
+	percentiles?: DashboardtypesDistributionPercentilesDTO;
 }
 
 /** Superset spanning every kind's visualization DTO. */
@@ -148,6 +156,7 @@ export interface SectionSpecMap {
 	[SectionKind.PanelHeader]: DashboardtypesHeaderOptionsDTO; // spec.plugin.spec.headerOptions (Text)
 	[SectionKind.Dimensions]: DashboardtypesScatterPlotDimensionsDTO; // spec.plugin.spec.dimensions (Scatter Plot)
 	[SectionKind.ScatterAxes]: DashboardtypesScatterPlotAxesDTO; // spec.plugin.spec.axes (Scatter Plot)
+	[SectionKind.DistributionAxes]: DashboardtypesDistributionAxesDTO; // spec.plugin.spec.axes (Distribution)
 }
 
 /**
@@ -188,6 +197,10 @@ export interface SectionControls {
 		colors?: boolean;
 		/** Scatter Plot's dots: one size, or a min/max range when a size column is bound. */
 		points?: boolean;
+		/** Distribution's group layout in a bucket: stacked, side by side or 100%. */
+		stack?: boolean;
+		/** Distribution's percentile markers: on/off and which ones. */
+		percentiles?: boolean;
 	};
 	[SectionKind.Buckets]: {
 		count?: boolean;
@@ -218,7 +231,8 @@ export type AtomicSectionKind =
 	| SectionKind.TextLayout
 	| SectionKind.PanelHeader
 	| SectionKind.Dimensions
-	| SectionKind.ScatterAxes;
+	| SectionKind.ScatterAxes
+	| SectionKind.DistributionAxes;
 
 /** Predicate to hide a section from the current spec; returning true removes it. */
 export type SectionVisibilityPredicate = (
@@ -255,6 +269,7 @@ export const SECTION_METADATA = {
 	[SectionKind.PanelHeader]: { title: 'Panel header', icon: PanelTop },
 	[SectionKind.Dimensions]: { title: 'Dimensions', icon: Crosshair },
 	[SectionKind.ScatterAxes]: { title: 'Axes', icon: Scale3D },
+	[SectionKind.DistributionAxes]: { title: 'Axes', icon: Scale3D },
 } as const satisfies Record<SectionKind, SectionMetadata>;
 
 /**

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/__tests__/legendSeries.test.ts

@@ -0,0 +1,58 @@
+import {
+	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTOKind as DistributionKind,
+	type DashboardtypesPanelSpecDTO,
+	type Querybuildertypesv5DistributionDataDTO,
+	Querybuildertypesv5RequestTypeDTO,
+} from 'api/generated/services/sigNoz.schemas';
+import { resolveSeriesColor } from 'lib/visualization/charts/Distribution/colors';
+import type { PanelQueryData } from 'pages/DashboardPage/DashboardContainer/queryV5/types';
+
+import { resolveDistributionLegendSeries } from '../legendSeries';
+
+describe('resolveDistributionLegendSeries', () => {
+	it('keys each group by the label and default colour the chart draws it with', () => {
+		const result: Querybuildertypesv5DistributionDataDTO = {
+			queryName: 'A',
+			aggregations: [
+				{
+					alias: '__result_0',
+					index: 0,
+					meta: { buckets: [1] },
+					distributions: [
+						{
+							labels: [{ key: { name: 'service' }, value: 'cart' }],
+							counts: [1, 2],
+						},
+					],
+				},
+			],
+		};
+		const data: PanelQueryData = {
+			response: {
+				status: 'success',
+				data: {
+					type: Querybuildertypesv5RequestTypeDTO.distribution,
+					data: { results: [result] },
+				},
+			},
+			requestPayload: undefined,
+			legendMap: { A: '{{service}}' },
+		};
+		const spec: DashboardtypesPanelSpecDTO = {
+			display: { name: '' },
+			plugin: { kind: DistributionKind['signoz/DistributionPanel'], spec: {} },
+			queries: [],
+		};
+
+		expect(
+			resolveDistributionLegendSeries({
+				spec,
+				queries: [],
+				data,
+				isDarkMode: true,
+			}),
+		).toStrictEqual([
+			{ label: 'cart', defaultColor: resolveSeriesColor('cart', true) },
+		]);
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/chartAppearance/__tests__/resolvers.test.ts

@@ -1,5 +1,6 @@
 import {
 	DashboardtypesAreaFillModeDTO,
+	DashboardtypesDistributionYScaleDTO,
 	DashboardtypesHeatmapColorModeDTO,
 	DashboardtypesHeatmapColorScaleDTO,
 	DashboardtypesHeatmapPaletteDTO,
@@ -15,9 +16,13 @@ import {
 	HeatmapColorPalette,
 	HeatmapColorScale,
 } from 'lib/uPlotV2/plugins/HeatmapPlugin/types';
+import { DistributionYScale } from 'lib/visualization/charts/Distribution/types';
 
 import {
 	resolveAreaFillMode,
+	resolveDistributionPercentiles,
+	resolveDistributionStackMode,
+	resolveDistributionYScale,
 	resolveHeatmapAxisScale,
 	resolveHeatmapColors,
 	resolveSpanGaps,
@@ -190,3 +195,46 @@ describe('resolveHeatmapColors', () => {
 		expect(resolveHeatmapColors({ steps: 0 })).toStrictEqual({});
 	});
 });
+
+describe('resolveDistributionStackMode', () => {
+	it('defaults to normal, unlike the shared stack default', () => {
+		expect(resolveDistributionStackMode(undefined)).toBe(StackMode.Normal);
+		expect(resolveStackMode(undefined)).toBe(StackMode.None);
+	});
+
+	it('keeps an explicit mode', () => {
+		expect(resolveDistributionStackMode(DashboardtypesStackModeDTO.none)).toBe(
+			StackMode.None,
+		);
+		expect(resolveDistributionStackMode(DashboardtypesStackModeDTO.percent)).toBe(
+			StackMode.Percent,
+		);
+	});
+});
+
+describe('resolveDistributionYScale', () => {
+	it('defaults to linear', () => {
+		expect(resolveDistributionYScale(undefined)).toBe(DistributionYScale.Linear);
+		expect(
+			resolveDistributionYScale(DashboardtypesDistributionYScaleDTO.log),
+		).toBe(DistributionYScale.Log);
+	});
+});
+
+describe('resolveDistributionPercentiles', () => {
+	it('marks p50/p90/p99 unless the spec says otherwise', () => {
+		expect(resolveDistributionPercentiles(undefined)).toStrictEqual([50, 90, 99]);
+		expect(
+			resolveDistributionPercentiles({ enabled: true, values: null }),
+		).toStrictEqual([50, 90, 99]);
+	});
+
+	it('marks the configured percentiles, or none when turned off', () => {
+		expect(
+			resolveDistributionPercentiles({ enabled: true, values: [75, 99.9] }),
+		).toStrictEqual([75, 99.9]);
+		expect(
+			resolveDistributionPercentiles({ enabled: false, values: [75] }),
+		).toStrictEqual([]);
+	});
+});

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/chartAppearance/enumMaps.ts

@@ -1,5 +1,6 @@
 import {
 	DashboardtypesAreaFillModeDTO,
+	DashboardtypesDistributionYScaleDTO,
 	DashboardtypesFillModeDTO,
 	DashboardtypesHeatmapColorModeDTO,
 	DashboardtypesHeatmapColorScaleDTO,
@@ -24,6 +25,7 @@ import {
 	HeatmapColorPalette,
 	HeatmapColorScale,
 } from 'lib/uPlotV2/plugins/HeatmapPlugin/types';
+import { DistributionYScale } from 'lib/visualization/charts/Distribution/types';
 
 /**
  * Bridges the V2 wire-format enums to the uPlotV2 chart enums. String values
@@ -114,3 +116,11 @@ export const HEATMAP_Y_SCALE_MAP: Record<
 	[DashboardtypesHeatmapYScaleDTO.log]: HeatmapAxisScale.Log,
 	[DashboardtypesHeatmapYScaleDTO.symlog]: HeatmapAxisScale.Symlog,
 };
+
+export const DISTRIBUTION_Y_SCALE_MAP: Record<
+	DashboardtypesDistributionYScaleDTO,
+	DistributionYScale
+> = {
+	[DashboardtypesDistributionYScaleDTO.linear]: DistributionYScale.Linear,
+	[DashboardtypesDistributionYScaleDTO.log]: DistributionYScale.Log,
+};

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/chartAppearance/resolvers.ts

@@ -1,6 +1,8 @@
 import { rangeUtil } from '@grafana/data';
 import {
 	type DashboardtypesAreaFillModeDTO,
+	type DashboardtypesDistributionPercentilesDTO,
+	type DashboardtypesDistributionYScaleDTO,
 	DashboardtypesHeatmapYScaleDTO,
 	DashboardtypesLegendPositionDTO,
 	DashboardtypesPrecisionOptionDTO,
@@ -18,9 +20,11 @@ import {
 	HeatmapAxisScale,
 	type HeatmapColorOptions,
 } from 'lib/uPlotV2/plugins/HeatmapPlugin/types';
+import { DistributionYScale } from 'lib/visualization/charts/Distribution/types';
 
 import {
 	AREA_FILL_MODE_MAP,
+	DISTRIBUTION_Y_SCALE_MAP,
 	HEATMAP_COLOR_MODE_MAP,
 	HEATMAP_COLOR_SCALE_MAP,
 	HEATMAP_PALETTE_MAP,
@@ -106,6 +110,33 @@ export function resolveStackMode(
 	return StackMode.None;
 }
 
+/** Missing/unknown falls back to `Normal`, where Distribution's stacking starts. */
+export function resolveDistributionStackMode(
+	stack: DashboardtypesStackModeDTO | undefined,
+): StackMode {
+	return stack ? resolveStackMode(stack) : StackMode.Normal;
+}
+
+export const DEFAULT_DISTRIBUTION_PERCENTILES = [50, 90, 99];
+
+/** The percentiles to mark; on with p50/p90/p99 unless the spec turns them off. */
+export function resolveDistributionPercentiles(
+	percentiles: DashboardtypesDistributionPercentilesDTO | undefined,
+): number[] {
+	if (percentiles?.enabled === false) {
+		return [];
+	}
+	return percentiles?.values ?? DEFAULT_DISTRIBUTION_PERCENTILES;
+}
+
+export function resolveDistributionYScale(
+	scale: DashboardtypesDistributionYScaleDTO | undefined,
+): DistributionYScale {
+	return scale && scale in DISTRIBUTION_Y_SCALE_MAP
+		? DISTRIBUTION_Y_SCALE_MAP[scale]
+		: DistributionYScale.Linear;
+}
+
 /**
  * Row-height distribution of a heatmap's bucket axis. Missing/unknown resolves to
  * `auto`, the one option that reads the bucket bounds rather than overriding them.

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/drilldown/__tests__/drilldown.test.ts

@@ -11,6 +11,7 @@ import { buildAggregateData } from '../buildAggregateData';
 import { stepClickTimeRange } from '../chartClickTimeRange';
 import { enrichChartClick } from '../enrichChartClick';
 import { enrichNumberClick } from '../enrichNumberClick';
+import { enrichDistributionClick } from '../enrichDistributionClick';
 import { enrichPieClick } from '../enrichPieClick';
 import { enrichTableClick } from '../enrichTableClick';
 import { getDataLinks } from '../getDataLinks';
@@ -390,6 +391,53 @@ describe('enrichPieClick', () => {
 	});
 });
 
+describe('enrichDistributionClick', () => {
+	const click = {
+		series: {
+			label: 'cart',
+			groupLabels: { 'service.name': 'cart' },
+			counts: [1, 2],
+		},
+		color: '#abc',
+		coordinates: { x: 7, y: 8 },
+	};
+
+	it("filters to the clicked group over the panel's whole window", () => {
+		const payload = enrichDistributionClick({
+			click,
+			queryName: 'A',
+			builderQueries: [
+				builderQuery({
+					name: 'A',
+					signal: 'metrics',
+					groupBy: [{ name: 'service.name' }],
+				}),
+			],
+			timeRange: { startTime: 1, endTime: 2 },
+		});
+
+		expect(payload).toStrictEqual({
+			coordinates: { x: 7, y: 8 },
+			context: {
+				queryName: 'A',
+				signal: 'metrics',
+				filters: [
+					{ filterKey: 'service.name', filterValue: 'cart', operator: '=' },
+				],
+				timeRange: { startTime: 1, endTime: 2 },
+				label: 'cart',
+				seriesColor: '#abc',
+			},
+		});
+	});
+
+	it('returns null without a drillable query', () => {
+		expect(
+			enrichDistributionClick({ click, queryName: '', builderQueries: [] }),
+		).toBeNull();
+	});
+});
+
 describe('resolvePanelContextLinks', () => {
 	it('substitutes the clicked field value (_-prefixed) into the label and URL', () => {
 		const resolved = resolvePanelContextLinks(

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/drilldown/enrichDistributionClick.ts

@@ -0,0 +1,46 @@
+import { isValidQueryName } from 'container/QueryTable/Drilldown/drilldownUtils';
+import type { DistributionBarClick } from 'lib/visualization/charts/Distribution/types';
+import type { BuilderQuery } from 'types/api/v5/queryRange';
+
+import type { DrilldownClickPayload } from '../../types/drilldown';
+
+import { getGroupByFilters } from './getGroupByFilters';
+import { resolveDrilldownSignal } from './signal';
+
+interface EnrichDistributionClickArgs {
+	click: DistributionBarClick;
+	queryName: string;
+	builderQueries: BuilderQuery[];
+	/** The fetched window: a bar sums the whole range, not one step. */
+	timeRange?: { startTime: number; endTime: number };
+}
+
+/**
+ * Turns a bar click into a drilldown payload, filtered to the clicked group. `null`
+ * when the bar has no drillable query.
+ */
+export function enrichDistributionClick({
+	click,
+	queryName,
+	builderQueries,
+	timeRange,
+}: EnrichDistributionClickArgs): DrilldownClickPayload | null {
+	if (!isValidQueryName(queryName)) {
+		return null;
+	}
+	const builderQuery = builderQueries.find((query) => query.name === queryName);
+
+	return {
+		coordinates: click.coordinates,
+		context: {
+			queryName,
+			signal: resolveDrilldownSignal(builderQuery),
+			filters: builderQuery
+				? getGroupByFilters(click.series.groupLabels ?? {}, builderQuery)
+				: [],
+			timeRange,
+			label: click.series.label,
+			seriesColor: click.color,
+		},
+	};
+}

frontend/src/pages/DashboardPage/DashboardContainer/Panels/utils/legendSeries.ts

@@ -5,6 +5,8 @@ import type {
 import { themeColors } from 'constants/theme';
 import getLabelName from 'lib/getLabelName';
 import { generateColor } from 'lib/uPlotLib/utils/generateColor';
+import { resolveSeriesColor } from 'lib/visualization/charts/Distribution/colors';
+import { prepareDistributionData } from '../kinds/DistributionPanel/prepareData';
 import { preparePieData } from '../kinds/PieChartPanel/prepareData';
 import { getColorGroupLabels } from '../kinds/ScatterPlotPanel/utils/prepareData';
 import { getJoinedScalarTable } from './getJoinedScalarTable';
@@ -14,6 +16,7 @@ import { prepareScalarTables } from 'pages/DashboardPage/DashboardContainer/quer
 import type { PanelQueryData } from 'pages/DashboardPage/DashboardContainer/queryV5/types';
 import {
 	flattenTimeSeries,
+	getDistributionResults,
 	getScalarResults,
 	getTimeSeriesResults,
 } from 'pages/DashboardPage/DashboardContainer/queryV5/v5ResponseData';
@@ -59,6 +62,21 @@ function buildLegendSeries(
 	}));
 }
 
+/** One entry per group, labelled and coloured as the Distribution chart draws it. */
+export function resolveDistributionLegendSeries({
+	data,
+	isDarkMode,
+}: LegendSeriesArgs): LegendSeries[] {
+	const { series } = prepareDistributionData({
+		results: getDistributionResults(data.response),
+		legendMap: data.legendMap ?? {},
+	});
+	return buildLegendSeries(
+		series.map((entry) => entry.label),
+		(label) => resolveSeriesColor(label, isDarkMode),
+	);
+}
+
 /**
  * Pie is fed by scalar results, not time series. Reuse the exact slices the renderer
  * draws (without overrides, so their colors are the defaults) so the color control keys

frontend/src/pages/DashboardPage/DashboardContainer/PanelsAndSectionsLayout/Panel/PanelTypeSelectionModal/components/PanelTypeBrowser/panelTypeCatalog.ts

@@ -50,13 +50,18 @@ const PANEL_TYPE_META: Record<PanelKind, PanelTypeMeta> = {
 	},
 	'signoz/HistogramPanel': {
 		group: 'distributions',
-		description: 'Distribution of values into buckets',
+		description: 'Bins query results in the browser',
 	},
 	'signoz/HeatmapPanel': {
 		group: 'distributions',
 		description: 'Bucket density over time',
 		isNew: true,
 	},
+	'signoz/DistributionPanel': {
+		group: 'distributions',
+		description: 'Bucket counts over the time range',
+		isNew: true,
+	},
 	'signoz/NumberPanel': {
 		group: 'single',
 		description: 'One aggregate value, large',

frontend/src/pages/DashboardPage/DashboardContainer/PanelsAndSectionsLayout/Panel/PanelTypeSelectionModal/components/PanelTypePreview/panelTypePreviews.tsx

@@ -55,6 +55,23 @@ const HEATMAP_CELLS = [
 	[0.4, 0.85, 0.7, 0.2],
 	[0.3, 0.65, 0.9, 0.45],
 ];
+// `[lower, upper]` heights (0–44) of two stacked groups per bucket, skewed right.
+const DISTRIBUTION_STACKS = [
+	[6, 3],
+	[14, 6],
+	[26, 10],
+	[20, 12],
+	[12, 9],
+	[7, 6],
+	[4, 3],
+	[2, 2],
+];
+const DISTRIBUTION_UPPER = { fill: 'var(--bg-robin-400)', fillOpacity: 0.55 };
+const PERCENTILE_MARKER = {
+	stroke: 'var(--l1-foreground)',
+	strokeOpacity: 0.6,
+};
+
 const TEXT_ROWS = [45, 100, 92, 64].map((width, i) => [
 	{ ...(i === 0 ? HEAD : CELL), width },
 ]);
@@ -113,6 +130,39 @@ export const PANEL_TYPE_PREVIEWS: Record<PanelKind, JSX.Element> = {
 			)}
 		</svg>
 	),
+	'signoz/DistributionPanel': (
+		<svg viewBox="0 0 120 44" preserveAspectRatio="none" className={styles.svg}>
+			{DISTRIBUTION_STACKS.map(([lower, upper], i) => (
+				// eslint-disable-next-line react/no-array-index-key
+				<g key={i}>
+					<rect
+						x={i * 15 + 1}
+						y={44 - lower}
+						width={13}
+						height={lower}
+						style={AREA_FILL}
+					/>
+					<rect
+						x={i * 15 + 1}
+						y={44 - lower - upper}
+						width={13}
+						height={upper}
+						style={DISTRIBUTION_UPPER}
+					/>
+				</g>
+			))}
+			<line
+				x1={88}
+				x2={88}
+				y1={2}
+				y2={44}
+				strokeWidth={1}
+				strokeDasharray="3 2"
+				vectorEffect="non-scaling-stroke"
+				style={PERCENTILE_MARKER}
+			/>
+		</svg>
+	),
 	'signoz/ScatterPlotPanel': (
 		<svg viewBox="0 0 120 44" className={styles.svg}>
 			{SCATTER_DOTS.map(([cx, cy, r]) => (

frontend/src/pages/DashboardPage/DashboardContainer/PanelsAndSectionsLayout/Panel/ViewPanelModal/ViewPanelModalHeader.tsx

@@ -73,6 +73,7 @@ function ViewPanelModalHeader(props: ViewPanelModalHeaderProps): JSX.Element {
 	// Same capabilities-guarded options as the editor's PanelTypeSwitcher, so the two
 	// selectors disable the same kinds (e.g. List under PromQL, metrics-only kinds).
 	const panelTypeItems = usePanelTypeSelectItems({
+		fromKind: panelKind,
 		queryType: query?.queryType ?? EQueryType.QUERY_BUILDER,
 		signal: query?.signal,
 	});

frontend/src/pages/DashboardPage/DashboardContainer/queryV5/persesQueryAdapters.ts

@@ -112,6 +112,8 @@ export function panelTypeToRequestType(
 			return Querybuildertypesv5RequestTypeDTO.raw;
 		case PANEL_TYPES.HEATMAP:
 			return Querybuildertypesv5RequestTypeDTO.heatmap;
+		case PANEL_TYPES.DISTRIBUTION:
+			return Querybuildertypesv5RequestTypeDTO.distribution;
 		case PANEL_TYPES.TRACE:
 			return Querybuildertypesv5RequestTypeDTO.trace;
 		default:

frontend/src/pages/DashboardPage/DashboardContainer/queryV5/v5ResponseData.ts

@@ -1,5 +1,6 @@
 import type {
 	Querybuildertypesv5AggregationBucketDTO,
+	Querybuildertypesv5DistributionDataDTO,
 	Querybuildertypesv5ExecStatsDTO,
 	Querybuildertypesv5RawDataDTO,
 	Querybuildertypesv5RequestTypeDTO,
@@ -36,6 +37,17 @@ export function getHeatmapResults(
 		[]) as Querybuildertypesv5TimeSeriesDataDTO[];
 }
 
+/** One summed count array per group, positional against each aggregation's `meta.buckets`. */
+export function getDistributionResults(
+	response: QueryRangeV5200 | undefined,
+): Querybuildertypesv5DistributionDataDTO[] {
+	if (response?.data?.type !== 'distribution') {
+		return [];
+	}
+	return (response.data.data?.results ??
+		[]) as Querybuildertypesv5DistributionDataDTO[];
+}
+
 export function getScalarResults(
 	response: QueryRangeV5200 | undefined,
 ): Querybuildertypesv5ScalarDataDTO[] {

frontend/src/pages/DashboardPage/stories/panels/Panels.stories.mocks.tsx

@@ -27,6 +27,8 @@ import { publicDashboardMeta } from '../__story_mockdata__/publicDashboard';
 
 import {
 	BUCKET_WIDTHS,
+	DISTRIBUTION_OVERFLOWS,
+	DISTRIBUTION_X_RANGES,
 	GAPS,
 	HEATMAP_COUNT_RANGES,
 	HEATMAP_FIXED_COUNTS,
@@ -34,7 +36,7 @@ import {
 	HEATMAP_Y_SCALES,
 	LEGEND_POSITIONS,
 	LINE_STYLES,
-	MAX_SERIES,
+	MAX_SERIES_CONTROL,
 	PANEL_KINDS,
 	PANEL_RESULTS,
 	PANELS_DASHBOARD_ID,
@@ -58,6 +60,8 @@ import {
 } from './__story_mockdata__/panelResponses';
 import type {
 	BucketWidth,
+	DistributionOverflow,
+	DistributionXRange,
 	Gaps,
 	HeatmapCountRange,
 	PanelArgs,
@@ -111,7 +115,7 @@ export const panelsMocks = defineStoryMocks({
 		stack: choiceControl<StackMode>('Stack', {
 			group: PANEL,
 			description:
-				'Area stacks `normal` or to `percent`; Bar stacks on anything but `none`. No effect on other kinds.',
+				'Area and Distribution stack `normal` or to `percent`, and Distribution draws `none` side by side; Bar stacks on anything but `none`. No effect on other kinds.',
 			options: STACK_MODES,
 			value: StackMode.none,
 		}),
@@ -133,6 +137,22 @@ export const panelsMocks = defineStoryMocks({
 			options: HEATMAP_COUNT_RANGES,
 			value: 'auto',
 		}),
+		distributionXRange: choiceControl<DistributionXRange>(
+			'Distribution x range',
+			{
+				group: PANEL,
+				description:
+					'Bucket axis range: `all` shows every bucket, `clamped` hides those outside 10–1000.',
+				options: DISTRIBUTION_X_RANGES,
+				value: 'all',
+			},
+		),
+		percentiles: toggleControl('Distribution percentiles', {
+			group: PANEL,
+			description:
+				'Dashed p50, p90 and p99 markers across the Distribution panel.',
+			value: true,
+		}),
 		bucketWidth: choiceControl<BucketWidth>('Histogram bucket width', {
 			group: PANEL,
 			description:
@@ -160,7 +180,8 @@ export const panelsMocks = defineStoryMocks({
 		}),
 		yScale: choiceControl<YScale>('Y scale', {
 			group: PANEL,
-			description: 'The y axis of Time Series, Bar and Area.',
+			description:
+				'The y axis of Time Series, Bar and Area, and the count axis of Distribution.',
 			options: Y_SCALES,
 			value: 'linear',
 		}),
@@ -197,9 +218,9 @@ export const panelsMocks = defineStoryMocks({
 		series: countControl('Series', {
 			group: DATA,
 			description:
-				'Series on the charts, groups on the heatmap, slices on the pie, rows on the table.',
+				'Series on the charts, groups on the heatmap and distribution, slices on the pie, rows on the table. A stacked distribution draws 10 and sums the rest into Other.',
 			value: 4,
-			max: MAX_SERIES,
+			max: MAX_SERIES_CONTROL,
 		}),
 		pieSlices: choiceControl<PieSlices>('Pie slices', {
 			group: DATA,
@@ -215,6 +236,13 @@ export const panelsMocks = defineStoryMocks({
 			options: GAPS,
 			value: 'none',
 		}),
+		overflow: choiceControl<DistributionOverflow>('Distribution overflow', {
+			group: DATA,
+			description:
+				'Observations past the last bucket bound: `low` 2%, `high` 25%, which the panel header flags.',
+			options: DISTRIBUTION_OVERFLOWS,
+			value: 'low',
+		}),
 		listRows: countControl('List rows', {
 			group: DATA,
 			description:
@@ -277,6 +305,7 @@ export const panelsMocks = defineStoryMocks({
 						listJsonBody: values.listJsonBody,
 						gaps: values.gaps,
 						pieSlices: values.pieSlices,
+						overflow: values.overflow,
 					});
 				}),
 			),

frontend/src/pages/DashboardPage/stories/panels/Panels.stories.tsx

@@ -16,6 +16,7 @@ import DashboardPage from '../../DashboardPage';
 
 import { panelsMocks } from './Panels.stories.mocks';
 import {
+	playDistributionTooltip,
 	playLegendRight,
 	playListJsonBody,
 	playListPaginated,
@@ -118,6 +119,71 @@ export const HeatmapCountRange: Story = {
 	play: playPanel,
 };
 
+/**
+ * Latency bucket counts over the whole range, one stacked bar per bucket on a log
+ * bucket axis, with p50, p90 and p99 marked and the overflow bucket hatched.
+ */
+export const Distribution: Story = {
+	args: { kind: 'Distribution', stack: StackMode.normal },
+	play: playPanel,
+};
+
+/** Each bucket split between the services, their bars side by side. */
+export const DistributionSideBySide: Story = {
+	args: { kind: 'Distribution', stack: StackMode.none },
+	play: playPanel,
+};
+
+/** Each bucket stacked to 100%, every band its service's share of that bucket. */
+export const DistributionPercent: Story = {
+	args: { kind: 'Distribution', stack: StackMode.percent },
+	play: playPanel,
+};
+
+/** Buckets outside 10–1000 hidden, counts on a log axis. */
+export const DistributionClampedLog: Story = {
+	args: {
+		kind: 'Distribution',
+		stack: StackMode.normal,
+		distributionXRange: 'clamped',
+		yScale: 'log',
+	},
+	play: playPanel,
+};
+
+/**
+ * The tooltip over a bucket: its total, then each service's count, share of its
+ * own total, and running share up to the bucket's upper bound.
+ */
+export const DistributionTooltip: Story = {
+	args: { kind: 'Distribution', stack: StackMode.normal },
+	play: playDistributionTooltip,
+};
+
+/** Fourteen services: the top nine drawn, the other five summed into Other. */
+export const DistributionOther: Story = {
+	args: { kind: 'Distribution', stack: StackMode.normal, series: 14 },
+	play: playPanel,
+};
+
+/**
+ * Fourteen services side by side: as many as keep every bar 3 px wide in the
+ * narrowest bucket are drawn, and the rest summed into Other.
+ */
+export const DistributionSideBySideOther: Story = {
+	args: { kind: 'Distribution', stack: StackMode.none, series: 14 },
+	play: playPanel,
+};
+
+/**
+ * A quarter of observations past the last bound: the overflow bar dominates, p99
+ * reads `> 5 s`, and the header warns that the bounds may be too low.
+ */
+export const DistributionOverflow: Story = {
+	args: { kind: 'Distribution', stack: StackMode.normal, overflow: 'high' },
+	play: playPanel,
+};
+
 /** Each service's share of traffic as a donut, with the total in the middle. */
 export const Pie: Story = {
 	args: { kind: 'Pie' },

frontend/src/pages/DashboardPage/stories/panels/__story_mockdata__/constants.ts

@@ -24,6 +24,7 @@ export const PANEL_KINDS = [
 	'Area',
 	'Histogram',
 	'Heatmap',
+	'Distribution',
 	'Pie',
 	'Number',
 	'Table',
@@ -83,6 +84,7 @@ export const PANEL_NAME: Record<PanelKind, string> = {
 	Area: 'Request rate by service',
 	Histogram: 'Latency distribution',
 	Heatmap: 'Latency heatmap',
+	Distribution: 'Latency buckets',
 	Pie: 'Traffic share',
 	Number: 'p99 latency',
 	Table: 'Calls by service',
@@ -122,6 +124,21 @@ export const HEATMAP_BUCKETS = [
 
 export const HEATMAP_COLUMNS = 30;
 
+/** Exponential, as a latency histogram's `le` bounds are, so `auto` picks log. */
+export const DISTRIBUTION_BUCKETS = [
+	5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000,
+];
+
+/** `clamped` hides buckets outside 10–1000. */
+export const DISTRIBUTION_X_RANGES = ['all', 'clamped'] as const;
+export const DISTRIBUTION_CLAMP = { min: 10, max: 1000 };
+
+/** `high` puts a quarter of each group past the last bound, over the warning's 10%. */
+export const DISTRIBUTION_OVERFLOWS = ['low', 'high'] as const;
+
+/** Groups the series control allows: past the 10 a stacked distribution draws. */
+export const MAX_SERIES_CONTROL = 14;
+
 export const SERVICES = [
 	'checkout',
 	'payments',

frontend/src/pages/DashboardPage/stories/panels/__story_mockdata__/panelPlugins.ts

@@ -6,6 +6,8 @@
 import {
 	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesAreaChartPanelSpecDTOKind as AreaChartKind,
 	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesBarChartPanelSpecDTOKind as BarChartKind,
+	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesDistributionPanelSpecDTOKind as DistributionKind,
+	DashboardtypesDistributionYScaleDTO as DistributionYScale,
 	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHeatmapPanelSpecDTOKind as HeatmapKind,
 	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesHistogramPanelSpecDTOKind as HistogramKind,
 	DashboardtypesPanelPluginVariantGithubComSigNozSignozPkgTypesDashboardtypesListPanelSpecDTOKind as ListKind,
@@ -22,6 +24,7 @@ import {
 } from 'api/generated/services/sigNoz.schemas';
 
 import {
+	DISTRIBUTION_CLAMP,
 	HEATMAP_FIXED_COUNTS,
 	TABLE_SECOND_COLUMN,
 	TABLE_VALUE_COLUMN,
@@ -131,6 +134,35 @@ export const panelShape = (args: PanelArgs): PanelShape => {
 					metricQuery(RequestType.heatmap, { grouped: true, heatmap: true }),
 				],
 			};
+		case 'Distribution':
+			return {
+				plugin: {
+					kind: DistributionKind['signoz/DistributionPanel'],
+					spec: {
+						formatting,
+						legend,
+						axes: {
+							x: args.distributionXRange === 'clamped' ? DISTRIBUTION_CLAMP : {},
+							y: {
+								scale:
+									args.yScale === 'log'
+										? DistributionYScale.log
+										: DistributionYScale.linear,
+							},
+						},
+						chartAppearance: {
+							stack: args.stack,
+							percentiles: { enabled: args.percentiles, values: [50, 90, 99] },
+						},
+					},
+				},
+				queries: [
+					metricQuery(RequestType.distribution, {
+						grouped: true,
+						histogram: true,
+					}),
+				],
+			};
 		case 'Pie':
 			return {
 				plugin: {

frontend/src/pages/DashboardPage/stories/panels/__story_mockdata__/panelQueries.ts

@@ -89,6 +89,8 @@ export const TEXT_BODIES: Record<TextSample, string> = {
 interface MetricQueryOptions {
 	grouped: boolean;
 	heatmap?: boolean;
+	/** A histogram metric, whose `le` bounds are the bucket axis: no bucket options. */
+	histogram?: boolean;
 	name?: string;
 	metricName?: string;
 }
@@ -98,6 +100,7 @@ export const metricQuery = (
 	{
 		grouped,
 		heatmap,
+		histogram,
 		name = QUERY_NAME,
 		metricName = 'signoz_latency',
 	}: MetricQueryOptions,
@@ -107,9 +110,10 @@ export const metricQuery = (
 		signal: MetricSignal.metrics,
 		aggregations: [
 			{
-				metricName: heatmap ? `${metricName}_bucket` : metricName,
-				spaceAggregation: heatmap ? undefined : SpaceAggregation.p99,
-				timeAggregation: heatmap ? TimeAggregation.increase : TimeAggregation.avg,
+				metricName: heatmap || histogram ? `${metricName}_bucket` : metricName,
+				spaceAggregation: heatmap || histogram ? undefined : SpaceAggregation.p99,
+				timeAggregation:
+					heatmap || histogram ? TimeAggregation.increase : TimeAggregation.avg,
 			},
 		],
 		groupBy: grouped ? [{ name: 'service.name' }] : undefined,

frontend/src/pages/DashboardPage/stories/panels/__story_mockdata__/panelResponses.ts

@@ -8,6 +8,7 @@ import type { Warning } from 'types/api';
 import type { MetricRangePayloadV5, RawRow } from 'types/api/v5/queryRange';
 
 import {
+	queryRangeV5DistributionResponse,
 	queryRangeV5EmptyResponse,
 	queryRangeV5HeatmapResponse,
 	queryRangeV5RawResponse,
@@ -23,6 +24,7 @@ import {
 } from '../../__story_mockdata__/panelData';
 
 import {
+	DISTRIBUTION_BUCKETS,
 	HEATMAP_BUCKETS,
 	HEATMAP_COLUMNS,
 	HOLE,
@@ -33,7 +35,13 @@ import {
 	SERVICES,
 	TABLE_SECOND_COLUMN,
 } from './constants';
-import type { Gaps, PanelRequest, PanelResponseArgs, PieSlices } from './types';
+import type {
+	DistributionOverflow,
+	Gaps,
+	PanelRequest,
+	PanelResponseArgs,
+	PieSlices,
+} from './types';
 
 export const serviceAt = (index: number): string =>
 	index < SERVICES.length
@@ -162,6 +170,38 @@ const logBodyAt = (index: number, line: string): Record<string, unknown> =>
 		? { message: line, service: serviceAt(index % MAX_SERIES), attempt: 1 }
 		: { message: line };
 
+/**
+ * A latency-shaped hump per group, peaking a bucket further right every third
+ * group, plus the overflow count `overflow` asks for.
+ */
+export const distributionCounts = (
+	group: number,
+	overflow: DistributionOverflow,
+): number[] => {
+	const peak = 3 + (group % 3);
+	const scale = 1 + (group % 4) * 0.4;
+	const finite = DISTRIBUTION_BUCKETS.map((_bound, index) =>
+		Math.round(scale * 120 * Math.exp(-((index - peak) ** 2) / 3)),
+	);
+	const total = finite.reduce((sum, count) => sum + count, 0);
+	const share = overflow === 'high' ? 0.25 : 0.02;
+	return [...finite, Math.round((total * share) / (1 - share))];
+};
+
+const distributionResponse = (
+	count: number,
+	overflow: DistributionOverflow,
+	warning: Warning | undefined,
+): QueryRangeV5200 =>
+	queryRangeV5DistributionResponse({
+		buckets: DISTRIBUTION_BUCKETS,
+		warning,
+		distributions: Array.from({ length: count }, (_unused, group) => ({
+			labels: [{ key: { name: 'service.name' }, value: serviceAt(group) }],
+			counts: distributionCounts(group, overflow),
+		})),
+	});
+
 /** Spaced by the window, newest first, as the `timestamp desc` order asks for. */
 const logRows = (
 	{ start, end }: PanelWindow,
@@ -202,6 +242,7 @@ export const panelQueryResponse = ({
 	listJsonBody,
 	gaps,
 	pieSlices,
+	overflow,
 	window,
 	offset,
 	limit,
@@ -215,6 +256,8 @@ export const panelQueryResponse = ({
 	switch (kind) {
 		case 'Heatmap':
 			return heatmapResponse(window, series, warning);
+		case 'Distribution':
+			return distributionResponse(series, overflow, warning);
 		case 'Pie':
 			return queryRangeV5ScalarTableResponse({
 				groupBy: ['service.name'],

frontend/src/pages/DashboardPage/stories/panels/__story_mockdata__/types.ts

@@ -16,6 +16,8 @@ import type { PanelWindow } from '../../__story_mockdata__/panelData';
 
 import type {
 	BUCKET_WIDTHS,
+	DISTRIBUTION_OVERFLOWS,
+	DISTRIBUTION_X_RANGES,
 	GAPS,
 	HEATMAP_COUNT_RANGES,
 	PANEL_KINDS,
@@ -46,6 +48,9 @@ export type Gaps = (typeof GAPS)[number];
 export type SpanGaps = (typeof SPAN_GAPS)[number];
 
 export type PieSlices = (typeof PIE_SLICES)[number];
+export type DistributionOverflow = (typeof DISTRIBUTION_OVERFLOWS)[number];
+
+export type DistributionXRange = (typeof DISTRIBUTION_X_RANGES)[number];
 
 /** The controls that shape the dashboard document. */
 export interface PanelArgs {
@@ -66,6 +71,8 @@ export interface PanelArgs {
 	showPoints: boolean;
 	spanGaps: SpanGaps;
 	columnUnits: boolean;
+	distributionXRange: DistributionXRange;
+	percentiles: boolean;
 }
 
 /** What one `query_range` call asked for, as the handler reads it. */
@@ -83,4 +90,5 @@ export interface PanelResponseArgs extends PanelRequest {
 	listJsonBody: boolean;
 	gaps: Gaps;
 	pieSlices: PieSlices;
+	overflow: DistributionOverflow;
 }

frontend/src/pages/DashboardPage/stories/panels/panelPlay/distributions.ts

@@ -1,16 +1,25 @@
-import { DashboardtypesHeatmapYScaleDTO as HeatmapYScale } from 'api/generated/services/sigNoz.schemas';
+import {
+	DashboardtypesHeatmapYScaleDTO as HeatmapYScale,
+	DashboardtypesStackModeDTO as StackMode,
+} from 'api/generated/services/sigNoz.schemas';
+import { MAX_STACKED_GROUPS } from 'lib/visualization/charts/Distribution/topGroups';
 import { getPaletteStops } from 'lib/uPlotV2/plugins/HeatmapPlugin/palettes';
 import { HEATMAP_PALETTE_MAP } from 'pages/DashboardPage/DashboardContainer/Panels/utils/chartAppearance/enumMaps';
 import { expect, waitFor, within } from 'storybook/test';
 import type uPlot from 'uplot';
 
 import {
+	DISTRIBUTION_BUCKETS,
 	HEATMAP_BUCKETS,
 	HEATMAP_FIXED_COUNTS,
 } from '../__story_mockdata__/constants';
-import { heatmapMaxCount } from '../__story_mockdata__/panelResponses';
+import {
+	distributionCounts,
+	heatmapMaxCount,
+	serviceAt,
+} from '../__story_mockdata__/panelResponses';
 
-import { PANEL_LOAD, type PanelPlayArgs } from './args';
+import { hasData, PANEL_LOAD, type PanelPlayArgs } from './args';
 import { findPlot, toRgb, waitForPlot } from './plot';
 
 const isMultipleOf = (value: number, width: number): boolean =>
@@ -89,3 +98,148 @@ export const expectHeatmap = async (
 		);
 	}
 };
+
+export const expectDistribution = async (
+	root: HTMLElement,
+	args: PanelPlayArgs,
+): Promise<void> => {
+	const isStacked = args.stack !== StackMode.none;
+	let plot: uPlot | undefined;
+	await waitFor(async () => {
+		plot = findPlot(root);
+		await expect(plot).toBeDefined();
+	}, PANEL_LOAD);
+	const drawn = plot as uPlot;
+
+	// Side by side fits as many groups as the panel's width allows, never more than a
+	// stack, so only a stack has an exact count to hold it to.
+	const notice = within(root).queryByTestId('distribution-other-notice');
+	if (args.series > MAX_STACKED_GROUPS) {
+		await expect(notice).toHaveTextContent(
+			isStacked
+				? `Showing top ${MAX_STACKED_GROUPS - 1} of ${args.series} groups`
+				: `of ${args.series} groups; the rest are summed into Other.`,
+		);
+	} else if (isStacked) {
+		await expect(notice).not.toBeInTheDocument();
+	}
+	if (isStacked) {
+		await expect(drawn.series.length - 1).toBe(
+			Math.min(args.series, MAX_STACKED_GROUPS),
+		);
+	} else {
+		await expect(drawn.series.length - 1).toBeLessThanOrEqual(MAX_STACKED_GROUPS);
+	}
+
+	// One slot a bucket. Clamped to 10–1000: (10, 25] is slot 2, (500, 1000] slot 7.
+	if (args.distributionXRange === 'clamped') {
+		await expect(drawn.scales.x.min).toBe(2);
+		await expect(drawn.scales.x.max).toBe(8);
+	} else {
+		await expect(drawn.scales.x.max ?? 0).toBeLessThanOrEqual(
+			DISTRIBUTION_BUCKETS.length + 1,
+		);
+	}
+
+	if (args.stack === StackMode.percent) {
+		await expect(drawn.scales.y.max ?? 0).toBeGreaterThanOrEqual(100);
+	} else {
+		await expect(drawn.scales.y.distr).toBe(args.yScale === 'log' ? 3 : 1);
+	}
+};
+
+/** Moves uPlot's cursor over `bucket`, low in its column, as a real pointer would. */
+const hoverBucket = (plot: uPlot, bucket: number): void => {
+	const rect = plot.over.getBoundingClientRect();
+	const init = {
+		bubbles: true,
+		clientX: rect.left + plot.valToPos(bucket + 0.5, 'x'),
+		clientY: rect.top + rect.height - 2,
+	};
+	plot.over.dispatchEvent(new MouseEvent('mouseenter', init));
+	plot.over.dispatchEvent(new MouseEvent('mousemove', init));
+};
+
+const bucketCounts = (args: PanelPlayArgs, bucket: number): number[] =>
+	Array.from(
+		{ length: args.series },
+		(_, group) => distributionCounts(group, args.overflow)[bucket],
+	);
+
+const expectTooltipFor = async (
+	plot: uPlot,
+	args: PanelPlayArgs,
+	bucket: number,
+	cumulativeHeading: string,
+): Promise<void> => {
+	const drawnGroups = plot.series.length - 1;
+	hoverBucket(plot, bucket);
+	const total = bucketCounts(args, bucket).reduce(
+		(sum, count) => sum + count,
+		0,
+	);
+
+	const tooltip = await within(document.body).findByTestId(
+		'distribution-tooltip',
+		{},
+		PANEL_LOAD,
+	);
+	await waitFor(
+		async () =>
+			expect(
+				within(tooltip).getByTestId('distribution-tooltip-total'),
+			).toHaveTextContent(total.toLocaleString()),
+		PANEL_LOAD,
+	);
+	await expect(
+		within(tooltip).getByTestId('distribution-tooltip-cumulative-heading'),
+	).toHaveTextContent(cumulativeHeading);
+
+	// One row a drawn group, named by its service alone; past the cap the rest sit in
+	// Other, so only an uncapped panel has every service in legend order.
+	const rows = within(tooltip).getAllByTestId('distribution-tooltip-row');
+	await expect(rows).toHaveLength(drawnGroups);
+	for (const [group, row] of rows.entries()) {
+		if (drawnGroups === args.series) {
+			await expect(row).toHaveTextContent(serviceAt(group));
+		}
+		await expect(row).not.toHaveTextContent('service.name');
+	}
+	await expect(
+		rows.filter((row) => row.dataset.isActive === 'true'),
+	).toHaveLength(1);
+};
+
+/**
+ * Hovers the (100 ms, 250 ms] bucket, then the overflow one, whose running share
+ * covers every observation. Only a drawn Distribution has a tooltip to check.
+ */
+export const expectDistributionTooltip = async (
+	root: HTMLElement,
+	args: PanelPlayArgs,
+): Promise<void> => {
+	if (
+		args.kind !== 'Distribution' ||
+		args.dataState !== 'loaded' ||
+		!hasData(args)
+	) {
+		return;
+	}
+	let plot: uPlot | undefined;
+	await waitFor(async () => {
+		plot = findPlot(root);
+		await expect(plot).toBeDefined();
+	}, PANEL_LOAD);
+	const drawn = plot as uPlot;
+
+	await expectTooltipFor(
+		drawn,
+		args,
+		DISTRIBUTION_BUCKETS.indexOf(250),
+		'≤ 250 ms',
+	);
+	// A clamped range ends at 1000 ms, before the overflow bucket.
+	if (args.distributionXRange !== 'clamped') {
+		await expectTooltipFor(drawn, args, DISTRIBUTION_BUCKETS.length, 'All');
+	}
+};

frontend/src/pages/DashboardPage/stories/panels/panelPlay/expectPanel.ts

@@ -3,7 +3,11 @@ import { expect, within } from 'storybook/test';
 import { PANEL_NAME } from '../__story_mockdata__/constants';
 
 import { hasData, PANEL_LOAD, type PanelPlayArgs } from './args';
-import { expectHeatmap, expectHistogram } from './distributions';
+import {
+	expectDistribution,
+	expectHeatmap,
+	expectHistogram,
+} from './distributions';
 import { expectLineChart } from './lineChart';
 import { expectListPage } from './list';
 import { findPlot } from './plot';
@@ -31,6 +35,7 @@ const KIND_EXPECTATIONS: Record<
 	Area: expectLineChart,
 	Histogram: expectHistogram,
 	Heatmap: expectHeatmap,
+	Distribution: expectDistribution,
 	Pie: expectPie,
 	Number: expectNumber,
 	Table: expectTable,
@@ -73,4 +78,12 @@ export const expectPanel = async (
 			within(root).queryByTestId('panel-status-warning'),
 		).not.toBeInTheDocument();
 	}
+
+	// The panel's own read of the data, apart from the response's warning.
+	const dataWarning = within(root).queryByTestId('panel-status-data-warning');
+	if (args.kind === 'Distribution' && args.overflow === 'high') {
+		await expect(dataWarning).toBeInTheDocument();
+	} else if (args.kind === 'Distribution') {
+		await expect(dataWarning).not.toBeInTheDocument();
+	}
 };