chore(backend): add session start time attribute to events and spans

Author: abhaysood

backend/api/event/attribute.go

@@ -4,6 +4,7 @@ import (
 	"backend/api/opsys"
 	"fmt"
 	"slices"
+	"time"
 
 	"github.com/google/uuid"
 )
@@ -118,6 +119,10 @@ type Attribute struct {
 	// - 5g
 	// - unknown
 	NetworkGeneration string `json:"network_generation"`
+
+	// SessionStartTime is the time when the session
+	// containing this event started at.
+	SessionStartTime *time.Time `json:"session_start_time"`
 }
 
 // Validate validates an event's attributes.

backend/api/measure/event.go

@@ -1016,6 +1016,11 @@ func (e eventreq) ingestEvents(ctx context.Context) error {
 			attachments = string(marshalledAttachments)
 		}
 
+		var sessionStartTime interface{}
+		if e.events[i].Attribute.SessionStartTime != nil {
+			sessionStartTime = e.events[i].Attribute.SessionStartTime.Format(chrono.MSTimeFormat)
+		}
+
 		row := stmt.NewRow().
 			Set(`id`, e.events[i].ID).
 			Set(`team_id`, e.teamId).
@@ -1057,6 +1062,7 @@ func (e eventreq) ingestEvents(ctx context.Context) error {
 			Set(`attribute.network_type`, e.events[i].Attribute.NetworkType).
 			Set(`attribute.network_generation`, e.events[i].Attribute.NetworkGeneration).
 			Set(`attribute.network_provider`, e.events[i].Attribute.NetworkProvider).
+			Set(`attribute.session_start_time`, sessionStartTime).
 
 			// user defined attribute
 			Set(`user_defined_attribute`, e.events[i].UserDefinedAttribute.Parameterize()).
@@ -1543,6 +1549,11 @@ func (e eventreq) ingestSpans(ctx context.Context) error {
 		b.WriteString("]")
 		formattedCheckpoints := b.String()
 
+		var spanSessionStartTime interface{}
+		if e.spans[i].Attributes.SessionStartTime != nil {
+			spanSessionStartTime = e.spans[i].Attributes.SessionStartTime.Format(chrono.MSTimeFormat)
+		}
+
 		stmt.NewRow().
 			Set(`team_id`, e.teamId).
 			Set(`app_id`, e.spans[i].AppID).
@@ -1573,6 +1584,7 @@ func (e eventreq) ingestSpans(ctx context.Context) error {
 			Set(`attribute.device_locale`, e.spans[i].Attributes.DeviceLocale).
 			Set(`attribute.device_low_power_mode`, e.spans[i].Attributes.LowPowerModeEnabled).
 			Set(`attribute.device_thermal_throttling_enabled`, e.spans[i].Attributes.ThermalThrottlingEnabled).
+			Set(`attribute.session_start_time`, spanSessionStartTime).
 			// user defined attribute
 			Set(`user_defined_attribute`, e.spans[i].UserDefinedAttribute.Parameterize())
 	}

backend/api/span/span.go

@@ -99,6 +99,7 @@ type SpanAttributes struct {
 	DeviceLocale             string    `json:"device_locale"`
 	LowPowerModeEnabled      bool      `json:"device_low_power_mode"`
 	ThermalThrottlingEnabled bool      `json:"device_thermal_throttling_enabled"`
+	SessionStartTime         *time.Time `json:"session_start_time"`
 }
 
 type RootSpanDisplay struct {

self-host/clickhouse/20260226113936_alter_events_table.sql

@@ -0,0 +1,7 @@
+-- migrate:up
+alter table events
+  add column if not exists `attribute.session_start_time` Nullable(DateTime64(3, 'UTC')) comment 'time when session this event belongs to started' CODEC(DoubleDelta, ZSTD(3)) after `attribute.network_provider`;
+
+-- migrate:down
+alter table events
+drop column if exists `attribute.session_start_time`;

self-host/clickhouse/20260227164651_alter_spans_table.sql

@@ -0,0 +1,7 @@
+-- migrate:up
+alter table spans
+  add column if not exists `attribute.session_start_time` Nullable(DateTime64(3, 'UTC')) comment 'time when session this span belongs to started' CODEC(DoubleDelta, ZSTD(3)) after `attribute.network_provider`;
+
+-- migrate:down
+alter table spans
+	drop column if exists `attribute.session_start_time`;