diff --git a/docs/architecture/iot-data-platform-principles.md b/docs/architecture/iot-data-platform-principles.md
index 583c51d2..d9a8dd30 100644
--- a/docs/architecture/iot-data-platform-principles.md
+++ b/docs/architecture/iot-data-platform-principles.md
@@ -52,7 +52,7 @@ flowchart LR
 | MySQL | `vehicle_daily_mileage` | Queryable daily mileage | vin, date, protocol, daily mileage, source mileage | temporary vehicle keys, generic metric key/value rows, per-frame raw details |
 | MySQL | `vehicle_identity_binding` | Manual identity mapping | vin, plate, phone, device id | registration history |
 | MySQL | `jt808_registration` | JT808 registration and auth trace | phone, device id, plate, auth code, vin match state, first/latest seen | GB32960 or MQTT records |
-| Redis | `vehicle:latest:{vehicleKey}` | Latest merged realtime state | cross-protocol latest fields | historical data |
+| Redis | `vehicle:latest:{vehicleKey}` | Latest merged realtime state | cross-protocol latest fields only | full parsed payloads and historical data |
 | Redis | `vehicle:realtime-raw:{protocol}:{vehicleKey}` | Latest full realtime protocol state | latest protocol parsed payload | historical data |
 
 ## Event Envelope Rules
diff --git a/docs/architecture/production-data-plane-inventory.md b/docs/architecture/production-data-plane-inventory.md
index 074c7249..0a675304 100644
--- a/docs/architecture/production-data-plane-inventory.md
+++ b/docs/architecture/production-data-plane-inventory.md
@@ -81,9 +81,9 @@ Redis 使用 DB 50，定位为实时缓存，不作为历史事实来源。
 
 | Key 族 | 用途 |
 | --- | --- |
-| `vehicle:latest:{vehicleKey}` | 跨协议合并后的最新实时快照 |
+| `vehicle:latest:{vehicleKey}` | 跨协议合并后的最新核心字段快照，不重复保存完整 parsed |
 | `vehicle:latest:{vehicleKey}:{protocol}` | 单协议最新快照 |
-| `vehicle:realtime-raw:{protocol}:{vehicleKey}` | 单协议最新完整 parsed 状态 |
+| `vehicle:realtime-raw:{protocol}:{vehicleKey}` | 单协议最新完整 parsed 状态，是实时完整协议字段的唯一 Redis 副本 |
 | `vehicle:online:{vehicleKey}` | 在线状态和 TTL |
 | `vehicle:protocols:{vehicleKey}` | 当前车辆最近出现过的协议集合 |
 | `vehicle:last_seen` | 最近活跃车辆排序集合 |
diff --git a/docs/go-version-data-flow.html b/docs/go-version-data-flow.html
index 27d738eb..91133eb3 100644
--- a/docs/go-version-data-flow.html
+++ b/docs/go-version-data-flow.html
@@ -638,7 +638,7 @@
             <thead><tr><th>接口类型</th><th>数据源</th><th>说明</th></tr></thead>
             <tbody>
               <tr><td>VIN 是否在线</td><td>Redis online key</td><td>TTL 内有数据即在线，默认 TTL 600 秒。</td></tr>
-              <tr><td>VIN 实时数据</td><td>Redis merged snapshot</td><td>跨协议合并 fields，并保留各协议 ProtocolData。</td></tr>
+              <tr><td>VIN 实时数据</td><td>Redis latest snapshot</td><td>跨协议合并核心 fields；完整协议字段通过 realtime-raw 查询。</td></tr>
               <tr><td>单协议实时 RAW</td><td>Redis realtime-raw</td><td>查看某 VIN/phone 在某协议下最新 parsed 全量字段。</td></tr>
             </tbody>
           </table>
@@ -722,7 +722,7 @@
         </div>
         <div class="ok">
           <strong>实时多协议合并</strong><br>
-          Redis 同时保留 latest snapshot、protocol snapshot、realtime-raw，既能看统一实时，也能追单协议原始字段。
+          Redis latest snapshot 只保留统一实时核心字段；完整协议 parsed 只放 realtime-raw，避免重复缓存大 JSON。
         </div>
         <div class="ok">
           <strong>身份解析降级</strong><br>
diff --git a/go/vehicle-gateway/internal/realtime/model.go b/go/vehicle-gateway/internal/realtime/model.go
index 3474f4af..342280d3 100644
--- a/go/vehicle-gateway/internal/realtime/model.go
+++ b/go/vehicle-gateway/internal/realtime/model.go
@@ -7,19 +7,18 @@ import (
 )
 
 type Snapshot struct {
-	VehicleKey     string                               `json:"vehicle_key"`
-	VIN            string                               `json:"vin"`
-	Protocol       envelope.Protocol                    `json:"protocol,omitempty"`
-	Protocols      []envelope.Protocol                  `json:"protocols,omitempty"`
-	EventID        string                               `json:"event_id,omitempty"`
-	EventTimeMS    int64                                `json:"event_time_ms"`
-	ReceivedAtMS   int64                                `json:"received_at_ms"`
-	SourceEndpoint string                               `json:"source_endpoint,omitempty"`
-	Fields         map[string]any                       `json:"fields,omitempty"`
-	FieldTimesMS   map[string]int64                     `json:"field_times_ms,omitempty"`
-	Parsed         map[string]any                       `json:"parsed,omitempty"`
-	ProtocolData   map[envelope.Protocol]map[string]any `json:"protocol_data,omitempty"`
-	UpdatedAtMS    int64                                `json:"updated_at_ms"`
+	VehicleKey     string              `json:"vehicle_key"`
+	VIN            string              `json:"vin"`
+	Protocol       envelope.Protocol   `json:"protocol,omitempty"`
+	Protocols      []envelope.Protocol `json:"protocols,omitempty"`
+	EventID        string              `json:"event_id,omitempty"`
+	EventTimeMS    int64               `json:"event_time_ms"`
+	ReceivedAtMS   int64               `json:"received_at_ms"`
+	SourceEndpoint string              `json:"source_endpoint,omitempty"`
+	Fields         map[string]any      `json:"fields,omitempty"`
+	FieldTimesMS   map[string]int64    `json:"field_times_ms,omitempty"`
+	Parsed         map[string]any      `json:"parsed,omitempty"`
+	UpdatedAtMS    int64               `json:"updated_at_ms"`
 }
 
 type OnlineStatus struct {
diff --git a/go/vehicle-gateway/internal/realtime/repository.go b/go/vehicle-gateway/internal/realtime/repository.go
index db500266..4019026d 100644
--- a/go/vehicle-gateway/internal/realtime/repository.go
+++ b/go/vehicle-gateway/internal/realtime/repository.go
@@ -92,7 +92,6 @@ func (r *Repository) Update(ctx context.Context, env envelope.FrameEnvelope) err
 			VIN:          vin,
 			Fields:       map[string]any{},
 			FieldTimesMS: map[string]int64{},
-			ProtocolData: map[envelope.Protocol]map[string]any{},
 		}
 	} else if merged.VIN == "" && vin != "" {
 		merged.VIN = vin
@@ -105,10 +104,6 @@ func (r *Repository) Update(ctx context.Context, env envelope.FrameEnvelope) err
 		merged.SourceEndpoint = env.SourceEndpoint
 	}
 	merged.Protocols = protocols
-	if merged.ProtocolData == nil {
-		merged.ProtocolData = map[envelope.Protocol]map[string]any{}
-	}
-	merged.ProtocolData[env.Protocol] = cloneMap(protocolSnapshot.Parsed)
 	merged.UpdatedAtMS = nowMS
 	if err := r.setJSON(ctx, mergedKey(vehicleKey), merged, r.cfg.ttl()); err != nil {
 		return err
diff --git a/go/vehicle-gateway/internal/realtime/repository_test.go b/go/vehicle-gateway/internal/realtime/repository_test.go
index 0e1e4356..b807e94e 100644
--- a/go/vehicle-gateway/internal/realtime/repository_test.go
+++ b/go/vehicle-gateway/internal/realtime/repository_test.go
@@ -2,6 +2,7 @@ package realtime
 
 import (
 	"context"
+	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -120,12 +121,12 @@ func TestRepositoryStoresFullParsedProtocolSnapshotAndMergesGB32960Units(t *test
 	if err != nil {
 		t.Fatalf("GetMerged() error = %v", err)
 	}
-	gb, ok := merged.ProtocolData[envelope.ProtocolGB32960]
-	if !ok {
-		t.Fatalf("merged protocol data missing: %#v", merged.ProtocolData)
+	mergedJSON, err := json.Marshal(merged)
+	if err != nil {
+		t.Fatal(err)
 	}
-	if len(gb["data_units"].([]any)) != 2 {
-		t.Fatalf("merged protocol data did not keep full parsed fields: %#v", gb)
+	if strings.Contains(string(mergedJSON), "protocol_data") {
+		t.Fatalf("merged snapshot should not duplicate full protocol parsed data: %s", string(mergedJSON))
 	}
 }