chore: update openapi specs

It's a new api so doesn't need to be backward compatible

conf/example.yaml

@@ -434,6 +434,17 @@ tracedetail:
     max_depth_to_auto_expand: 5
     # Threshold below which all spans are returned without windowing.
     max_limit_to_select_all_spans: 10000
+  flamegraph:
+    # Maximum number of BFS depth levels included in a windowed response.
+    max_selected_levels: 50
+    # Maximum spans per level before sampling is applied.
+    max_spans_per_level: 100
+    # Number of highest-latency spans always included when sampling a level.
+    sampling_top_latency_count: 5
+    # Number of timestamp buckets used for uniform sampling within a level.
+    sampling_bucket_count: 50
+    # Threshold below which all spans are returned without windowing or sampling.
+    select_all_spans_limit: 100000
 
 ##################### Authz #################################
 authz:

docs/api/openapi.yml

@@ -5663,6 +5663,58 @@ components:
       - attribute
       - resource
       type: string
+    SpantypesFlamegraphSpan:
+      properties:
+        attributes:
+          additionalProperties: {}
+          type: object
+        durationNano:
+          minimum: 0
+          type: integer
+        event:
+          items:
+            $ref: '#/components/schemas/SpantypesEvent'
+          nullable: true
+          type: array
+        hasError:
+          type: boolean
+        level:
+          format: int64
+          type: integer
+        name:
+          type: string
+        parentSpanId:
+          type: string
+        resource:
+          additionalProperties:
+            type: string
+          type: object
+        serviceName:
+          type: string
+        spanId:
+          type: string
+        timestamp:
+          minimum: 0
+          type: integer
+      type: object
+    SpantypesGettableFlamegraphTrace:
+      properties:
+        endTimestampMillis:
+          format: int64
+          type: integer
+        hasMore:
+          type: boolean
+        spans:
+          items:
+            items:
+              $ref: '#/components/schemas/SpantypesFlamegraphSpan'
+            type: array
+          nullable: true
+          type: array
+        startTimestampMillis:
+          format: int64
+          type: integer
+      type: object
     SpantypesGettableSpanMapperGroups:
       properties:
         items:
@@ -5710,6 +5762,15 @@ components:
           nullable: true
           type: array
       type: object
+    SpantypesPostableFlamegraph:
+      properties:
+        selectFields:
+          items:
+            $ref: '#/components/schemas/TelemetrytypesTelemetryFieldKey'
+          type: array
+        selectedSpanId:
+          type: string
+      type: object
     SpantypesPostableSpanMapper:
       properties:
         config:
@@ -18878,6 +18939,75 @@ paths:
       summary: Put profile in Zeus for a deployment.
       tags:
       - zeus
+  /api/v3/traces/{traceID}/flamegraph:
+    post:
+      deprecated: false
+      description: Returns the flamegraph view of spans for a given trace ID.
+      operationId: GetFlamegraph
+      parameters:
+      - in: path
+        name: traceID
+        required: true
+        schema:
+          type: string
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/SpantypesPostableFlamegraph'
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                properties:
+                  data:
+                    $ref: '#/components/schemas/SpantypesGettableFlamegraphTrace'
+                  status:
+                    type: string
+                required:
+                - status
+                - data
+                type: object
+          description: OK
+        "400":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Bad Request
+        "401":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Unauthorized
+        "403":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Forbidden
+        "404":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Not Found
+        "500":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Internal Server Error
+      security:
+      - api_key:
+        - VIEWER
+      - tokenizer:
+        - VIEWER
+      summary: Get flamegraph view for a trace
+      tags:
+      - tracedetail
   /api/v3/traces/{traceID}/waterfall:
     post:
       deprecated: false

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

@@ -6689,6 +6689,81 @@ export enum SpantypesFieldContextDTO {
 	attribute = 'attribute',
 	resource = 'resource',
 }
+export type SpantypesFlamegraphSpanDTOAttributes = { [key: string]: unknown };
+
+export type SpantypesFlamegraphSpanDTOResource = { [key: string]: string };
+
+export interface SpantypesFlamegraphSpanDTO {
+	/**
+	 * @type object
+	 */
+	attributes?: SpantypesFlamegraphSpanDTOAttributes;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	durationNano?: number;
+	/**
+	 * @type array,null
+	 */
+	event?: SpantypesEventDTO[] | null;
+	/**
+	 * @type boolean
+	 */
+	hasError?: boolean;
+	/**
+	 * @type integer
+	 * @format int64
+	 */
+	level?: number;
+	/**
+	 * @type string
+	 */
+	name?: string;
+	/**
+	 * @type string
+	 */
+	parentSpanId?: string;
+	/**
+	 * @type object
+	 */
+	resource?: SpantypesFlamegraphSpanDTOResource;
+	/**
+	 * @type string
+	 */
+	serviceName?: string;
+	/**
+	 * @type string
+	 */
+	spanId?: string;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	timestamp?: number;
+}
+
+export interface SpantypesGettableFlamegraphTraceDTO {
+	/**
+	 * @type integer
+	 * @format int64
+	 */
+	endTimestampMillis?: number;
+	/**
+	 * @type boolean
+	 */
+	hasMore?: boolean;
+	/**
+	 * @type array,null
+	 */
+	spans?: SpantypesFlamegraphSpanDTO[][] | null;
+	/**
+	 * @type integer
+	 * @format int64
+	 */
+	startTimestampMillis?: number;
+}
+
 export type SpantypesSpanMapperGroupConditionDTOAnyOf = {
 	/**
 	 * @type array,null
@@ -6964,6 +7039,17 @@ export interface SpantypesGettableWaterfallTraceDTO {
 	uncollapsedSpans?: string[] | null;
 }
 
+export interface SpantypesPostableFlamegraphDTO {
+	/**
+	 * @type array
+	 */
+	selectFields?: TelemetrytypesTelemetryFieldKeyDTO[];
+	/**
+	 * @type string
+	 */
+	selectedSpanId?: string;
+}
+
 export enum SpantypesSpanMapperOperationDTO {
 	move = 'move',
 	copy = 'copy',
@@ -9221,6 +9307,17 @@ export type GetHosts200 = {
 	status: string;
 };
 
+export type GetFlamegraphPathParameters = {
+	traceID: string;
+};
+export type GetFlamegraph200 = {
+	data: SpantypesGettableFlamegraphTraceDTO;
+	/**
+	 * @type string
+	 */
+	status: string;
+};
+
 export type GetWaterfallPathParameters = {
 	traceID: string;
 };

frontend/src/api/generated/services/tracedetail/index.ts

@@ -12,17 +12,119 @@ import type {
 } from 'react-query';
 
 import type {
+	GetFlamegraph200,
+	GetFlamegraphPathParameters,
 	GetWaterfall200,
 	GetWaterfallPathParameters,
 	GetWaterfallV4200,
 	GetWaterfallV4PathParameters,
 	RenderErrorResponseDTO,
+	SpantypesPostableFlamegraphDTO,
 	SpantypesPostableWaterfallDTO,
 } from '../sigNoz.schemas';
 
 import { GeneratedAPIInstance } from '../../../generatedAPIInstance';
 import type { ErrorType, BodyType } from '../../../generatedAPIInstance';
 
+/**
+ * Returns the flamegraph view of spans for a given trace ID.
+ * @summary Get flamegraph view for a trace
+ */
+export const getFlamegraph = (
+	{ traceID }: GetFlamegraphPathParameters,
+	spantypesPostableFlamegraphDTO?: BodyType<SpantypesPostableFlamegraphDTO>,
+	signal?: AbortSignal,
+) => {
+	return GeneratedAPIInstance<GetFlamegraph200>({
+		url: `/api/v3/traces/${traceID}/flamegraph`,
+		method: 'POST',
+		headers: { 'Content-Type': 'application/json' },
+		data: spantypesPostableFlamegraphDTO,
+		signal,
+	});
+};
+
+export const getGetFlamegraphMutationOptions = <
+	TError = ErrorType<RenderErrorResponseDTO>,
+	TContext = unknown,
+>(options?: {
+	mutation?: UseMutationOptions<
+		Awaited<ReturnType<typeof getFlamegraph>>,
+		TError,
+		{
+			pathParams: GetFlamegraphPathParameters;
+			data?: BodyType<SpantypesPostableFlamegraphDTO>;
+		},
+		TContext
+	>;
+}): UseMutationOptions<
+	Awaited<ReturnType<typeof getFlamegraph>>,
+	TError,
+	{
+		pathParams: GetFlamegraphPathParameters;
+		data?: BodyType<SpantypesPostableFlamegraphDTO>;
+	},
+	TContext
+> => {
+	const mutationKey = ['getFlamegraph'];
+	const { mutation: mutationOptions } = options
+		? options.mutation &&
+			'mutationKey' in options.mutation &&
+			options.mutation.mutationKey
+			? options
+			: { ...options, mutation: { ...options.mutation, mutationKey } }
+		: { mutation: { mutationKey } };
+
+	const mutationFn: MutationFunction<
+		Awaited<ReturnType<typeof getFlamegraph>>,
+		{
+			pathParams: GetFlamegraphPathParameters;
+			data?: BodyType<SpantypesPostableFlamegraphDTO>;
+		}
+	> = (props) => {
+		const { pathParams, data } = props ?? {};
+
+		return getFlamegraph(pathParams, data);
+	};
+
+	return { mutationFn, ...mutationOptions };
+};
+
+export type GetFlamegraphMutationResult = NonNullable<
+	Awaited<ReturnType<typeof getFlamegraph>>
+>;
+export type GetFlamegraphMutationBody =
+	| BodyType<SpantypesPostableFlamegraphDTO>
+	| undefined;
+export type GetFlamegraphMutationError = ErrorType<RenderErrorResponseDTO>;
+
+/**
+ * @summary Get flamegraph view for a trace
+ */
+export const useGetFlamegraph = <
+	TError = ErrorType<RenderErrorResponseDTO>,
+	TContext = unknown,
+>(options?: {
+	mutation?: UseMutationOptions<
+		Awaited<ReturnType<typeof getFlamegraph>>,
+		TError,
+		{
+			pathParams: GetFlamegraphPathParameters;
+			data?: BodyType<SpantypesPostableFlamegraphDTO>;
+		},
+		TContext
+	>;
+}): UseMutationResult<
+	Awaited<ReturnType<typeof getFlamegraph>>,
+	TError,
+	{
+		pathParams: GetFlamegraphPathParameters;
+		data?: BodyType<SpantypesPostableFlamegraphDTO>;
+	},
+	TContext
+> => {
+	return useMutation(getGetFlamegraphMutationOptions(options));
+};
 /**
  * Returns the waterfall view of spans for a given trace ID with tree structure, metadata, and windowed pagination
  * @summary Get waterfall view for a trace

pkg/apiserver/signozapiserver/tracedetail.go

@@ -48,5 +48,23 @@ func (provider *provider) addTraceDetailRoutes(router *mux.Router) error {
 		return err
 	}
 
+	if err := router.Handle("/api/v3/traces/{traceID}/flamegraph", handler.New(
+		provider.authzMiddleware.ViewAccess(provider.traceDetailHandler.GetFlamegraph),
+		handler.OpenAPIDef{
+			ID:                  "GetFlamegraph",
+			Tags:                []string{"tracedetail"},
+			Summary:             "Get flamegraph view for a trace",
+			Description:         "Returns the flamegraph view of spans for a given trace ID.",
+			Request:             new(spantypes.PostableFlamegraph),
+			RequestContentType:  "application/json",
+			Response:            new(spantypes.GettableFlamegraphTrace),
+			ResponseContentType: "application/json",
+			SuccessStatusCode:   http.StatusOK,
+			ErrorStatusCodes:    []int{http.StatusBadRequest, http.StatusNotFound},
+			SecuritySchemes:     newSecuritySchemes(types.RoleViewer),
+		},
+	)).Methods(http.MethodPost).GetError(); err != nil {
+		return err
+	}
 	return nil
 }

pkg/modules/tracedetail/config.go

@@ -6,7 +6,16 @@ import (
 )
 
 type Config struct {
-	Waterfall WaterfallConfig `mapstructure:"waterfall"`
+	Waterfall  WaterfallConfig  `mapstructure:"waterfall"`
+	Flamegraph FlamegraphConfig `mapstructure:"flamegraph"`
+}
+
+type FlamegraphConfig struct {
+	MaxSelectedLevels            int  `mapstructure:"max_selected_levels"`
+	MaxSpansPerLevel             int  `mapstructure:"max_spans_per_level"`
+	SamplingTopLatencySpansCount int  `mapstructure:"sampling_top_latency_count"`
+	SamplingBucketCount          int  `mapstructure:"sampling_bucket_count"`
+	SelectAllSpansLimit          uint `mapstructure:"select_all_spans_limit"`
 }
 
 type WaterfallConfig struct {
@@ -29,6 +38,13 @@ func newConfig() factory.Config {
 			MaxDepthToAutoExpand:     5,
 			MaxLimitToSelectAllSpans: 10_000,
 		},
+		Flamegraph: FlamegraphConfig{
+			MaxSelectedLevels:            50,
+			MaxSpansPerLevel:             100,
+			SamplingTopLatencySpansCount: 5,
+			SamplingBucketCount:          50,
+			SelectAllSpansLimit:          100_000,
+		},
 	}
 }
 
@@ -45,5 +61,25 @@ func (c Config) Validate() error {
 		return errors.NewInvalidInputf(errors.CodeInvalidInput,
 			"tracedetail.waterfall.max_limit_to_select_all_spans must be positive")
 	}
+	if c.Flamegraph.MaxSelectedLevels <= 0 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput,
+			"tracedetail.flamegraph.level_limit must be positive, got %d", c.Flamegraph.MaxSelectedLevels)
+	}
+	if c.Flamegraph.MaxSpansPerLevel <= 0 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput,
+			"tracedetail.flamegraph.spans_per_level must be positive, got %d", c.Flamegraph.MaxSpansPerLevel)
+	}
+	if c.Flamegraph.SamplingTopLatencySpansCount < 0 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput,
+			"tracedetail.flamegraph.top_latency_count cannot be negative, got %d", c.Flamegraph.SamplingTopLatencySpansCount)
+	}
+	if c.Flamegraph.SamplingBucketCount <= 0 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput,
+			"tracedetail.flamegraph.bucket_count must be positive, got %d", c.Flamegraph.SamplingBucketCount)
+	}
+	if c.Flamegraph.SelectAllSpansLimit == 0 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput,
+			"tracedetail.flamegraph.max_limit_to_select_all_spans must be positive")
+	}
 	return nil
 }

pkg/modules/tracedetail/impltracedetail/handler.go

@@ -59,3 +59,19 @@ func (h *handler) GetWaterfallV4(rw http.ResponseWriter, r *http.Request) {
 
 	render.Success(rw, http.StatusOK, result)
 }
+
+func (h *handler) GetFlamegraph(rw http.ResponseWriter, r *http.Request) {
+	req := new(spantypes.PostableFlamegraph)
+	if err := binding.JSON.BindBody(r.Body, req); err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	result, err := h.module.GetFlamegraph(r.Context(), mux.Vars(r)["traceID"], req)
+	if err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	render.Success(rw, http.StatusOK, result)
+}

pkg/modules/tracedetail/impltracedetail/module.go

@@ -46,6 +46,33 @@ func (m *module) GetWaterfall(ctx context.Context, traceID string, req *spantype
 	return spantypes.NewGettableWaterfallTrace(waterfallTrace, selectedSpans, uncollapsedSpans, selectedAllSpans, aggregationResults), nil
 }
 
+// GetWaterfallV4 is the OOM-safe V4 waterfall.
+// For large traces (NumSpans > effectiveLimit) it uses a two-step fetch:
+// minimal fields for all spans to build the tree, then full fields for the
+// visible window only. Aggregations are not returned.
+func (m *module) GetWaterfallV4(ctx context.Context, traceID string, selectedSpanID string, uncollapsedSpans []string, selectAllLimit uint) (*spantypes.GettableWaterfallTrace, error) {
+	summary, err := m.store.GetTraceSummary(ctx, traceID)
+	if err != nil {
+		return nil, err
+	}
+	effectiveLimit := min(selectAllLimit, m.config.Waterfall.MaxLimitToSelectAllSpans)
+	if summary.NumSpans > uint64(effectiveLimit) {
+		return m.getWindowedWaterfall(ctx, traceID, selectedSpanID, uncollapsedSpans, summary.Start, summary.End)
+	}
+	return m.getFullWaterfall(ctx, traceID, summary)
+}
+
+func (m *module) GetFlamegraph(ctx context.Context, traceID string, req *spantypes.PostableFlamegraph) (*spantypes.GettableFlamegraphTrace, error) {
+	summary, err := m.store.GetTraceSummary(ctx, traceID)
+	if err != nil {
+		return nil, err
+	}
+	if summary.NumSpans <= uint64(m.config.Flamegraph.SelectAllSpansLimit) {
+		return m.getFullFlamegraph(ctx, traceID, summary)
+	}
+	return m.getWindowedFlamegraph(ctx, traceID, req.SelectedSpanID, summary)
+}
+
 // getTraceData fetches all spans for a trace and builds the WaterfallTrace.
 func (m *module) getTraceData(ctx context.Context, traceID string) (*spantypes.WaterfallTrace, error) {
 	summary, err := m.store.GetTraceSummary(ctx, traceID)
@@ -69,22 +96,6 @@ func (m *module) getTraceData(ctx context.Context, traceID string) (*spantypes.W
 	return spantypes.NewWaterfallTraceFromSpans(nodes), nil
 }
 
-// GetWaterfallV4 is the OOM-safe V4 waterfall.
-// For large traces (NumSpans > effectiveLimit) it uses a two-step fetch:
-// minimal fields for all spans to build the tree, then full fields for the
-// visible window only. Aggregations are not returned.
-func (m *module) GetWaterfallV4(ctx context.Context, traceID string, selectedSpanID string, uncollapsedSpans []string, selectAllLimit uint) (*spantypes.GettableWaterfallTrace, error) {
-	summary, err := m.store.GetTraceSummary(ctx, traceID)
-	if err != nil {
-		return nil, err
-	}
-	effectiveLimit := min(selectAllLimit, m.config.Waterfall.MaxLimitToSelectAllSpans)
-	if summary.NumSpans > uint64(effectiveLimit) {
-		return m.getWindowedWaterfall(ctx, traceID, selectedSpanID, uncollapsedSpans, summary.Start, summary.End)
-	}
-	return m.getFullWaterfall(ctx, traceID, summary)
-}
-
 func (m *module) getFullWaterfall(ctx context.Context, traceID string, summary *spantypes.TraceSummary) (*spantypes.GettableWaterfallTrace, error) {
 	spanItems, err := m.store.GetTraceSpans(ctx, traceID, summary)
 	if err != nil {
@@ -145,3 +156,50 @@ func (m *module) getWindowedWaterfall(ctx context.Context, traceID, selectedSpan
 		waterfallTrace, selectedSpans, uncollapsedSpans, false, nil,
 	), nil
 }
+
+func (m *module) getFullFlamegraph(ctx context.Context, traceID string, summary *spantypes.TraceSummary) (*spantypes.GettableFlamegraphTrace, error) {
+	fullSpans, err := m.store.GetTraceSpans(ctx, traceID, summary)
+	if err != nil {
+		return nil, err
+	}
+	if len(fullSpans) == 0 {
+		return nil, spantypes.ErrTraceNotFound
+	}
+	flamegraphTrace := spantypes.NewFlamegraphTraceFromStorable(fullSpans)
+	return spantypes.NewGettableFlamegraphTrace(
+		flamegraphTrace.GetAllLevels(),
+		summary.Start.UnixMilli(), summary.End.UnixMilli(), false,
+	), nil
+}
+
+// getWindowedFlamegraph returns a window of a max levels and max sampled spans per level around the selected span.
+func (m *module) getWindowedFlamegraph(ctx context.Context, traceID, selectedSpanID string, summary *spantypes.TraceSummary) (*spantypes.GettableFlamegraphTrace, error) {
+	minimalSpans, err := m.store.GetMinimalSpans(ctx, traceID, summary.Start, summary.End)
+	if err != nil {
+		return nil, err
+	}
+	if len(minimalSpans) == 0 {
+		return nil, spantypes.ErrTraceNotFound
+	}
+
+	flamegraphTrace := spantypes.NewFlamegraphTraceFromMinimal(minimalSpans)
+	minimalSpans = nil //nolint:ineffassign,wastedassign // release backing array before further db calls
+
+	cfg := m.config.Flamegraph
+	selectedSpans := flamegraphTrace.GetSelectedLevels(selectedSpanID,
+		cfg.MaxSelectedLevels, cfg.MaxSpansPerLevel, cfg.SamplingTopLatencySpansCount, cfg.SamplingBucketCount)
+	if len(selectedSpans) == 0 {
+		return nil, spantypes.ErrTraceNotFound
+	}
+
+	fullSpans, err := m.store.GetTraceSpansByIDs(ctx, traceID, summary.Start, summary.End,
+		spantypes.FlamegraphWindowSpanIDs(selectedSpans))
+	if err != nil {
+		return nil, err
+	}
+
+	return spantypes.NewGettableFlamegraphTrace(
+		flamegraphTrace.EnrichSelectedSpans(selectedSpans, fullSpans),
+		summary.Start.UnixMilli(), summary.End.UnixMilli(), true,
+	), nil
+}

pkg/modules/tracedetail/tracedetail.go

@@ -11,10 +11,12 @@ import (
 type Handler interface {
 	GetWaterfall(http.ResponseWriter, *http.Request)
 	GetWaterfallV4(http.ResponseWriter, *http.Request)
+	GetFlamegraph(http.ResponseWriter, *http.Request)
 }
 
 // Module defines the business logic for trace detail operations.
 type Module interface {
 	GetWaterfall(ctx context.Context, traceID string, req *spantypes.PostableWaterfall) (*spantypes.GettableWaterfallTrace, error)
 	GetWaterfallV4(ctx context.Context, traceID string, selectedSpanID string, uncollapsedSpans []string, selectAllLimit uint) (*spantypes.GettableWaterfallTrace, error)
+	GetFlamegraph(ctx context.Context, traceID string, req *spantypes.PostableFlamegraph) (*spantypes.GettableFlamegraphTrace, error)
 }

pkg/types/spantypes/flamegraph_span.go

@@ -0,0 +1,81 @@
+package spantypes
+
+import (
+	"maps"
+
+	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
+)
+
+type FlamegraphSpan struct {
+	SpanID       string            `json:"spanId"`
+	ParentSpanID string            `json:"parentSpanId"`
+	Timestamp    uint64            `json:"timestamp"`
+	DurationNano uint64            `json:"durationNano"`
+	HasError     bool              `json:"hasError"`
+	ServiceName  string            `json:"serviceName"`
+	Name         string            `json:"name"`
+	Level        int64             `json:"level"`
+	Events       []Event           `json:"event"`
+	Attributes   map[string]any    `json:"attributes,omitempty"`
+	Resource     map[string]string `json:"resource,omitempty"`
+	Children     []*FlamegraphSpan `json:"-"` // internal tree use only
+}
+
+// FlamegraphLevel groups span IDs at a single level within the selected window.
+type FlamegraphLevel struct {
+	Level   int64
+	SpanIDs []string
+}
+
+type PostableFlamegraph struct {
+	SelectedSpanID string                             `json:"selectedSpanId"`
+	SelectFields   []telemetrytypes.TelemetryFieldKey `json:"selectFields,omitempty"`
+}
+
+// GettableFlamegraphTrace is the response for the v3 flamegraph API.
+type GettableFlamegraphTrace struct {
+	Spans                [][]*FlamegraphSpan `json:"spans"`
+	StartTimestampMillis int64               `json:"startTimestampMillis"`
+	EndTimestampMillis   int64               `json:"endTimestampMillis"`
+	HasMore              bool                `json:"hasMore"`
+}
+
+func NewGettableFlamegraphTrace(spans [][]*FlamegraphSpan, startMs, endMs int64, hasMore bool) *GettableFlamegraphTrace {
+	return &GettableFlamegraphTrace{
+		Spans:                spans,
+		StartTimestampMillis: startMs,
+		EndTimestampMillis:   endMs,
+		HasMore:              hasMore,
+	}
+}
+
+func NewFlamegraphSpanFromStorable(s *StorableSpan, level int64) *FlamegraphSpan {
+	resources := make(map[string]string, len(s.ResourcesString))
+	maps.Copy(resources, s.ResourcesString)
+	return &FlamegraphSpan{
+		SpanID:       s.SpanID,
+		ParentSpanID: s.ParentSpanID,
+		Timestamp:    uint64(s.StartTime.UnixNano()),
+		DurationNano: s.DurationNano,
+		HasError:     s.HasError,
+		ServiceName:  s.ServiceName,
+		Name:         s.Name,
+		Level:        level,
+		Events:       s.UnmarshalledEvents(),
+		Attributes:   s.Attributes(),
+		Resource:     resources,
+	}
+}
+
+// FlamegraphWindowSpanIDs collects all span IDs from a level window into a flat slice.
+func FlamegraphWindowSpanIDs(window []FlamegraphLevel) []string {
+	total := 0
+	for _, lvl := range window {
+		total += len(lvl.SpanIDs)
+	}
+	ids := make([]string, 0, total)
+	for _, lvl := range window {
+		ids = append(ids, lvl.SpanIDs...)
+	}
+	return ids
+}

pkg/types/spantypes/flamegraph_trace.go

@@ -0,0 +1,118 @@
+package spantypes
+
+import (
+	"sort"
+)
+
+// FlamegraphTrace holds the level wise tree built from minimal spans.
+type FlamegraphTrace struct {
+	roots     []*FlamegraphSpan
+	nodeByID  map[string]*FlamegraphSpan
+	startTime uint64
+	endTime   uint64
+}
+
+func NewFlamegraphTraceFromMinimal(spans []MinimalSpan) *FlamegraphTrace {
+	t := &FlamegraphTrace{
+		nodeByID: make(map[string]*FlamegraphSpan, len(spans)),
+	}
+	for i := range spans {
+		node := spans[i].ToFlamegraphSpan()
+		t.updateTimeRange(node.Timestamp, node.DurationNano)
+		t.nodeByID[node.SpanID] = node
+	}
+	t.buildSpanTree()
+	return t
+}
+
+func NewFlamegraphTraceFromStorable(spans []StorableSpan) *FlamegraphTrace {
+	t := &FlamegraphTrace{
+		nodeByID: make(map[string]*FlamegraphSpan, len(spans)),
+	}
+	for i := range spans {
+		node := NewFlamegraphSpanFromStorable(&spans[i], 0) // level is set later by BFS
+		t.updateTimeRange(node.Timestamp, node.DurationNano)
+		t.nodeByID[node.SpanID] = node
+	}
+	t.buildSpanTree()
+	return t
+}
+
+func (t *FlamegraphTrace) GetAllLevels() [][]*FlamegraphSpan {
+	return nil
+}
+
+// GetSelectedLevels returns the window of levels around selectedSpanID with sampling applied to dense levels.
+func (t *FlamegraphTrace) GetSelectedLevels(
+	selectedSpanID string,
+	levelLimit, spansPerLevel, topLatencyCount, bucketCount int,
+) []FlamegraphLevel {
+	return nil
+}
+
+func (t *FlamegraphTrace) EnrichSelectedSpans(selectedSpans []FlamegraphLevel, fullSpans []StorableSpan) [][]*FlamegraphSpan {
+	fullByID := make(map[string]*StorableSpan, len(fullSpans))
+	for i := range fullSpans {
+		fullByID[fullSpans[i].SpanID] = &fullSpans[i]
+	}
+
+	result := make([][]*FlamegraphSpan, len(selectedSpans))
+	for i, lvl := range selectedSpans {
+		result[i] = make([]*FlamegraphSpan, 0, len(lvl.SpanIDs))
+		for _, spanID := range lvl.SpanIDs {
+			if full, ok := fullByID[spanID]; ok {
+				result[i] = append(result[i], NewFlamegraphSpanFromStorable(full, lvl.Level))
+			} else if lean, ok := t.nodeByID[spanID]; ok {
+				result[i] = append(result[i], lean)
+			}
+		}
+	}
+	return result
+}
+
+func (t *FlamegraphTrace) updateTimeRange(timestamp, durationNano uint64) {
+	if t.startTime == 0 || timestamp < t.startTime {
+		t.startTime = timestamp
+	}
+	if end := timestamp + durationNano; end > t.endTime {
+		t.endTime = end
+	}
+}
+
+func (t *FlamegraphTrace) buildSpanTree() {
+	for _, node := range t.nodeByID {
+		if node.ParentSpanID != "" {
+			if parent, ok := t.nodeByID[node.ParentSpanID]; ok {
+				parent.Children = append(parent.Children, node)
+			} else {
+				missing := &FlamegraphSpan{
+					SpanID:       node.ParentSpanID,
+					Name:         "Missing Span",
+					Timestamp:    node.Timestamp,
+					DurationNano: node.DurationNano,
+					Children:     []*FlamegraphSpan{node},
+				}
+				t.nodeByID[missing.SpanID] = missing
+				t.roots = append(t.roots, missing)
+			}
+		} else if flamegraphSpanIndex(t.roots, node.SpanID) == -1 {
+			t.roots = append(t.roots, node)
+		}
+	}
+
+	sort.Slice(t.roots, func(i, j int) bool {
+		if t.roots[i].Timestamp == t.roots[j].Timestamp {
+			return t.roots[i].SpanID < t.roots[j].SpanID
+		}
+		return t.roots[i].Timestamp < t.roots[j].Timestamp
+	})
+}
+
+func flamegraphSpanIndex(spans []*FlamegraphSpan, spanID string) int {
+	for i, s := range spans {
+		if s != nil && s.SpanID == spanID {
+			return i
+		}
+	}
+	return -1
+}

pkg/types/spantypes/waterfall_span.go

@@ -156,6 +156,18 @@ func (item *MinimalSpan) ToWaterfallSpan(traceID string) *WaterfallSpan {
 	}
 }
 
+func (item *MinimalSpan) ToFlamegraphSpan() *FlamegraphSpan {
+	return &FlamegraphSpan{
+		SpanID:       item.SpanID,
+		ParentSpanID: item.ParentSpanID,
+		Timestamp:    uint64(item.StartTime.UnixNano()),
+		DurationNano: item.DurationNano,
+		HasError:     item.HasError,
+		ServiceName:  item.ServiceName,
+		Children:     make([]*FlamegraphSpan, 0),
+	}
+}
+
 // NewMissingWaterfallSpan creates a synthetic placeholder span for a parent that has no recorded data.
 func NewMissingWaterfallSpan(spanID, traceID string, timeUnixNano, durationNano uint64) *WaterfallSpan {
 	return &WaterfallSpan{