perf: reduce graph load memory and clone overhead

2026-05-15 22:30:38 +08:00 · 2026-04-21 16:56:17 +08:00
parent 076618bc25
commit 4fd4786983
6 changed files with 238 additions and 105 deletions
--- a/index.js
+++ b/index.js
@@ -5423,11 +5423,8 @@ function applyShadowSnapshotToRuntime(

  let shadowGraph = null;
  try {
-    shadowGraph = cloneGraphForPersistence(
-      normalizeGraphRuntimeState(
-        deserializeGraph(shadowSnapshot.serializedGraph),
-        normalizedChatId,
-      ),
+    shadowGraph = normalizeGraphRuntimeState(
+      deserializeGraph(shadowSnapshot.serializedGraph),
      normalizedChatId,
    );
  } catch (error) {
@@ -5970,6 +5967,12 @@ function isIndexedDbSnapshotMeaningful(snapshot = null) {

  if (Array.isArray(snapshot.nodes) && snapshot.nodes.length > 0) return true;
  if (Array.isArray(snapshot.edges) && snapshot.edges.length > 0) return true;
+  if (
+    snapshot.__stBmeTombstonesOmitted === true &&
+    Number(snapshot?.meta?.tombstoneCount || 0) > 0
+  ) {
+    return true;
+  }
  if (Array.isArray(snapshot.tombstones) && snapshot.tombstones.length > 0)
    return true;

@@ -6017,6 +6020,7 @@ function isIndexedDbSnapshotMeaningful(snapshot = null) {
 function cacheIndexedDbSnapshot(chatId, snapshot = null) {
  const normalizedChatId = normalizeChatIdCandidate(chatId);
  if (!normalizedChatId || !snapshot || typeof snapshot !== "object") return;
+  if (snapshot.__stBmeTombstonesOmitted === true) return;
  const snapshotStore = resolveSnapshotGraphStorePresentation(snapshot);
  bmeIndexedDbSnapshotCacheByChatId.set(normalizedChatId, {
    chatId: normalizedChatId,
@@ -6311,10 +6315,7 @@ async function readLocalCacheSnapshotForChat(chatId, source = "luker-sidecar-loa
    const manager = ensureBmeChatManager();
    if (!manager) return null;
    const db = await manager.getCurrentDb(normalizedChatId);
-    const snapshot = await db.exportSnapshot();
-    if (snapshot) {
-      cacheIndexedDbSnapshot(normalizedChatId, snapshot);
-    }
+    const snapshot = await db.exportSnapshot({ includeTombstones: false });
    return snapshot;
  } catch (error) {
    console.warn("[ST-BME] 读取 Luker 本地缓存快照失败:", source, error);
@@ -6394,11 +6395,8 @@ function buildSnapshotFromLukerSidecarState(
  let snapshot = null;
  if (sidecar?.checkpoint?.serializedGraph) {
    try {
-      const checkpointGraph = cloneGraphForPersistence(
-        normalizeGraphRuntimeState(
-          deserializeGraph(sidecar.checkpoint.serializedGraph),
-          normalizedChatId,
-        ),
+      const checkpointGraph = normalizeGraphRuntimeState(
+        deserializeGraph(sidecar.checkpoint.serializedGraph),
        normalizedChatId,
      );
      snapshot = buildSnapshotFromGraph(checkpointGraph, {
@@ -6437,8 +6435,8 @@ function buildSnapshotFromLukerSidecarState(
      headRevision: Number(normalizedManifest.headRevision || 0),
    };
  } else {
-    const emptyGraph = cloneGraphForPersistence(
-      normalizeGraphRuntimeState(createEmptyGraph(), normalizedChatId),
+    const emptyGraph = normalizeGraphRuntimeState(
+      createEmptyGraph(),
      normalizedChatId,
    );
    snapshot = buildSnapshotFromGraph(emptyGraph, {
@@ -7659,11 +7657,8 @@ async function loadGraphFromChatState(

  let chatStateGraph = null;
  try {
-    chatStateGraph = cloneGraphForPersistence(
-      normalizeGraphRuntimeState(
-        deserializeGraph(payload.serializedGraph),
-        normalizedChatId,
-      ),
+    chatStateGraph = normalizeGraphRuntimeState(
+      deserializeGraph(payload.serializedGraph),
      normalizedChatId,
    );
  } catch (error) {
@@ -7953,13 +7948,9 @@ async function readPersistedGraphForChatStateTarget(
  });
  if (sidecarResult?.ok && sidecarResult?.snapshot) {
    try {
-      return cloneGraphForPersistence(
-        normalizeGraphRuntimeState(
-          buildGraphFromSnapshot(sidecarResult.snapshot),
-          targetChatId,
-        ),
-        targetChatId,
-      );
+      return buildGraphFromSnapshot(sidecarResult.snapshot, {
+        chatId: targetChatId,
+      });
    } catch (error) {
      console.warn("[ST-BME] 读取 Luker branch source snapshot 失败:", error);
    }
@@ -7971,11 +7962,8 @@ async function readPersistedGraphForChatStateTarget(
  });
  if (legacySnapshot?.serializedGraph) {
    try {
-      return cloneGraphForPersistence(
-        normalizeGraphRuntimeState(
-          deserializeGraph(legacySnapshot.serializedGraph),
-          targetChatId,
-        ),
+      return normalizeGraphRuntimeState(
+        deserializeGraph(legacySnapshot.serializedGraph),
        targetChatId,
      );
    } catch (error) {
@@ -8175,10 +8163,13 @@ function readLegacyGraphFromChatMetadata(chatId, context = getContext()) {
      typeof legacyGraph === "string"
        ? deserializeGraph(legacyGraph)
        : legacyGraph;
-    return cloneGraphForPersistence(
-      normalizeGraphRuntimeState(hydratedLegacyGraph, normalizedChatId),
+    const normalizedLegacyGraph = normalizeGraphRuntimeState(
+      hydratedLegacyGraph,
      normalizedChatId,
    );
+    return typeof legacyGraph === "string"
+      ? normalizedLegacyGraph
+      : cloneGraphForPersistence(normalizedLegacyGraph, normalizedChatId);
  } catch (error) {
    console.warn("[ST-BME] 读取 legacy chat_metadata 图谱失败:", error);
    return null;
@@ -9218,10 +9209,7 @@ function applyIndexedDbSnapshotToRuntime(
      attemptIndex,
    };
  }
-  currentGraph = cloneGraphForPersistence(
-    normalizeGraphRuntimeState(graphFromSnapshot, normalizedChatId),
-    normalizedChatId,
-  );
+  currentGraph = graphFromSnapshot;
  stampGraphPersistenceMeta(currentGraph, {
    revision,
    reason: `${reasonPrefix}:${String(source || reasonPrefix)}`,
@@ -9485,7 +9473,7 @@ async function loadGraphFromIndexedDb(
      identityRecoveryResult?.snapshot ||
      localStoreMigrationResult?.snapshot ||
      migrationResult?.snapshot ||
-      (await db.exportSnapshot());
+      (await db.exportSnapshot({ includeTombstones: false }));
    const shadowSnapshot = resolveCompatibleGraphShadowSnapshot(
      resolveCurrentChatIdentity(getContext()),
    );
@@ -10802,11 +10790,8 @@ function resolvePendingPersistGraphSource(chatId = "") {
    shadowSnapshot.serializedGraph
  ) {
    try {
-      const shadowGraph = cloneGraphForPersistence(
-        normalizeGraphRuntimeState(
-          deserializeGraph(shadowSnapshot.serializedGraph),
-          normalizedChatId,
-        ),
+      const shadowGraph = normalizeGraphRuntimeState(
+        deserializeGraph(shadowSnapshot.serializedGraph),
        normalizedChatId,
      );
      return {
@@ -11376,7 +11361,9 @@ async function persistExtractionBatchResult({
  const context = getContext();
  const persistGraph =
    graphSnapshot && typeof graphSnapshot === "object"
-      ? cloneGraphSnapshot(graphSnapshot)
+      ? graphSnapshot === currentGraph
+        ? cloneGraphSnapshot(graphSnapshot)
+        : graphSnapshot
      : currentGraph;
  if (!context || !persistGraph) {
    return buildGraphPersistResult({
@@ -12847,10 +12834,14 @@ function loadGraphFromChat(options = {}) {
    : undefined;
  if (savedData != null && savedData !== "") {
    try {
-      const officialGraph = cloneGraphForPersistence(
-        normalizeGraphRuntimeState(deserializeGraph(savedData), chatId),
+      const hydratedOfficialGraph = normalizeGraphRuntimeState(
+        deserializeGraph(savedData),
        chatId,
      );
+      const officialGraph =
+        typeof savedData === "string"
+          ? hydratedOfficialGraph
+          : cloneGraphForPersistence(hydratedOfficialGraph, chatId);
      const shadowDecision = shouldPreferShadowSnapshotOverOfficial(
        officialGraph,
        shadowSnapshot,
--- a/maintenance/extraction-controller.js
+++ b/maintenance/extraction-controller.js
@@ -297,7 +297,7 @@ function buildCommittedBatchPersistSnapshot(
      : null,
    rangeEnd,
  ];
-  const afterSnapshot = runtime.cloneGraphSnapshot(graph);
+  const afterSnapshot = graph;
  const effectiveArtifacts = Array.isArray(postProcessArtifacts)
    ? [...postProcessArtifacts]
    : [];
@@ -357,17 +357,12 @@ function buildCommittedBatchPersistSnapshot(
    persistGraphSnapshot: committedGraphSnapshot,
    committedBatchJournalEntry,
    afterSnapshot,
-    committedAfterSnapshot: runtime.cloneGraphSnapshot(committedGraphSnapshot),
+    committedAfterSnapshot: committedGraphSnapshot,
    postProcessArtifacts: effectiveArtifacts,
  };
 }

 function isPersistenceRevisionAccepted(runtime, persistence = null) {
-  if (!persistence || persistence.accepted === true) return true;
-  const graphPersistenceState = runtime?.getGraphPersistenceState?.() || {};
-  if (graphPersistenceState.pendingPersist === true) {
-    return false;
-  }
  const persistenceRevision = Number(persistence?.revision || 0);
  if (!Number.isFinite(persistenceRevision) || persistenceRevision <= 0) {
    return false;
@@ -645,7 +640,7 @@ export async function executeExtractionBatchController(
    processedRange: [startIdx, endIdx],
    postProcessArtifacts: runtime.computePostProcessArtifacts(
      beforeSnapshot,
-      runtime.cloneGraphSnapshot(runtime.getCurrentGraph()),
+      runtime.getCurrentGraph(),
      effects?.postProcessArtifacts || [],
    ),
    vectorHashesInserted: effects?.vectorHashesInserted || [],
--- a/sync/bme-db.js
+++ b/sync/bme-db.js
@@ -2013,6 +2013,14 @@ export function buildGraphFromSnapshot(snapshot, options = {}) {
    normalizeChatId(options.chatId) ||
    normalizeChatId(snapshotMeta?.chatId) ||
    normalizeChatId(snapshotState?.chatId);
+  const snapshotHistoryState = toPlainData(
+    snapshotMeta?.[BME_RUNTIME_HISTORY_META_KEY],
+    {},
+  );
+  const snapshotVectorState = toPlainData(
+    snapshotMeta?.[BME_RUNTIME_VECTOR_META_KEY],
+    {},
+  );

  const runtimeGraph = createEmptyGraph();
  runtimeGraph.version = Number.isFinite(
@@ -2020,21 +2028,17 @@ export function buildGraphFromSnapshot(snapshot, options = {}) {
  )
    ? Number(snapshotMeta[BME_RUNTIME_GRAPH_VERSION_META_KEY])
    : runtimeGraph.version;
-  runtimeGraph.nodes = toArray(snapshotView.nodes).map((node) => ({
-    ...(node || {}),
-  }));
-  runtimeGraph.edges = toArray(snapshotView.edges).map((edge) => ({
-    ...(edge || {}),
-  }));
+  runtimeGraph.nodes = toArray(toPlainData(snapshotView.nodes, []));
+  runtimeGraph.edges = toArray(toPlainData(snapshotView.edges, []));
  runtimeGraph.batchJournal = toArray(
-    snapshotMeta?.[BME_RUNTIME_BATCH_JOURNAL_META_KEY],
+    toPlainData(snapshotMeta?.[BME_RUNTIME_BATCH_JOURNAL_META_KEY], []),
  );
  runtimeGraph.lastRecallResult = toPlainData(
    snapshotMeta?.[BME_RUNTIME_LAST_RECALL_META_KEY],
    null,
  );
  runtimeGraph.maintenanceJournal = toArray(
-    snapshotMeta?.[BME_RUNTIME_MAINTENANCE_JOURNAL_META_KEY],
+    toPlainData(snapshotMeta?.[BME_RUNTIME_MAINTENANCE_JOURNAL_META_KEY], []),
  );
  runtimeGraph.knowledgeState = toPlainData(
    snapshotMeta?.[BME_RUNTIME_KNOWLEDGE_STATE_META_KEY],
@@ -2073,22 +2077,21 @@ export function buildGraphFromSnapshot(snapshot, options = {}) {

  runtimeGraph.historyState = {
    ...(runtimeGraph.historyState || {}),
-    ...(snapshotMeta?.[BME_RUNTIME_HISTORY_META_KEY] || {}),
+    ...snapshotHistoryState,
    lastProcessedAssistantFloor: Number.isFinite(
      Number(snapshotState?.lastProcessedFloor),
    )
      ? Number(snapshotState.lastProcessedFloor)
      : Number(
-          snapshotMeta?.[BME_RUNTIME_HISTORY_META_KEY]
-            ?.lastProcessedAssistantFloor ?? META_DEFAULT_LAST_PROCESSED_FLOOR,
+          snapshotHistoryState?.lastProcessedAssistantFloor ??
+            META_DEFAULT_LAST_PROCESSED_FLOOR,
        ),
    extractionCount: Number.isFinite(
      Number(snapshotState?.extractionCount),
    )
      ? Number(snapshotState.extractionCount)
      : Number(
-          snapshotMeta?.[BME_RUNTIME_HISTORY_META_KEY]
-            ?.extractionCount ?? META_DEFAULT_EXTRACTION_COUNT,
+          snapshotHistoryState?.extractionCount ?? META_DEFAULT_EXTRACTION_COUNT,
        ),
  };
  if (
@@ -2146,10 +2149,10 @@ export function buildGraphFromSnapshot(snapshot, options = {}) {
  }
  runtimeGraph.vectorIndexState = {
    ...(runtimeGraph.vectorIndexState || {}),
-    ...(snapshotMeta?.[BME_RUNTIME_VECTOR_META_KEY] || {}),
+    ...snapshotVectorState,
    collectionId: buildVectorCollectionId(
      chatId ||
-        snapshotMeta?.[BME_RUNTIME_HISTORY_META_KEY]?.chatId ||
+        snapshotHistoryState?.chatId ||
        runtimeGraph.historyState?.chatId ||
        "",
    ),
@@ -3032,23 +3035,47 @@ export class BmeDatabase {
    };
  }

-  async exportSnapshot() {
+  async exportSnapshot(options = {}) {
    const db = await this.open();

-    const [nodes, edges, tombstones, metaRows] = await db.transaction(
-      "r",
-      db.table("nodes"),
-      db.table("edges"),
-      db.table("tombstones"),
-      db.table("meta"),
-      async () =>
-        await Promise.all([
-          db.table("nodes").toArray(),
-          db.table("edges").toArray(),
-          db.table("tombstones").toArray(),
-          db.table("meta").toArray(),
-        ]),
-    );
+    const includeTombstones =
+      options && typeof options === "object"
+        ? options.includeTombstones !== false
+        : options !== false;
+    let nodes = [];
+    let edges = [];
+    let tombstones = [];
+    let metaRows = [];
+
+    if (includeTombstones) {
+      [nodes, edges, tombstones, metaRows] = await db.transaction(
+        "r",
+        db.table("nodes"),
+        db.table("edges"),
+        db.table("tombstones"),
+        db.table("meta"),
+        async () =>
+          await Promise.all([
+            db.table("nodes").toArray(),
+            db.table("edges").toArray(),
+            db.table("tombstones").toArray(),
+            db.table("meta").toArray(),
+          ]),
+      );
+    } else {
+      [nodes, edges, metaRows] = await db.transaction(
+        "r",
+        db.table("nodes"),
+        db.table("edges"),
+        db.table("meta"),
+        async () =>
+          await Promise.all([
+            db.table("nodes").toArray(),
+            db.table("edges").toArray(),
+            db.table("meta").toArray(),
+          ]),
+      );
+    }

    const metaMap = toMetaMap(metaRows);
    const meta = {
@@ -3058,7 +3085,10 @@ export class BmeDatabase {
      revision: normalizeRevision(metaMap?.revision),
      nodeCount: nodes.length,
      edgeCount: edges.length,
-      tombstoneCount: tombstones.length,
+      tombstoneCount: normalizeNonNegativeInteger(
+        metaMap?.tombstoneCount,
+        tombstones.length,
+      ),
    };

    const state = {
@@ -3070,13 +3100,19 @@ export class BmeDatabase {
        : META_DEFAULT_EXTRACTION_COUNT,
    };

-    return {
+    const snapshot = {
      meta,
      nodes,
      edges,
-      tombstones,
+      tombstones: includeTombstones ? tombstones : [],
      state,
    };
+
+    if (!includeTombstones) {
+      snapshot.__stBmeTombstonesOmitted = true;
+    }
+
+    return snapshot;
  }

  async importSnapshot(snapshot, options = {}) {
--- a/sync/bme-opfs-store.js
+++ b/sync/bme-opfs-store.js
@@ -1345,15 +1345,23 @@ class LegacyOpfsGraphStore {
    };
  }

-  async exportSnapshot() {
-    const snapshot = await this._loadSnapshot();
-    return {
+  async exportSnapshot(options = {}) {
+    const includeTombstones =
+      options && typeof options === "object"
+        ? options.includeTombstones !== false
+        : options !== false;
+    const snapshot = await this._loadSnapshot({ includeTombstones });
+    const exported = {
      meta: toPlainData(snapshot.meta, {}),
      nodes: toPlainData(snapshot.nodes, []),
      edges: toPlainData(snapshot.edges, []),
-      tombstones: toPlainData(snapshot.tombstones, []),
+      tombstones: includeTombstones ? toPlainData(snapshot.tombstones, []) : [],
      state: toPlainData(snapshot.state, {}),
    };
+    if (!includeTombstones) {
+      exported.__stBmeTombstonesOmitted = true;
+    }
+    return exported;
  }

  async importSnapshot(snapshot, options = {}) {
@@ -2643,15 +2651,23 @@ export class OpfsGraphStore {
    };
  }

-  async exportSnapshot() {
-    const snapshot = await this._loadSnapshot();
-    return {
+  async exportSnapshot(options = {}) {
+    const includeTombstones =
+      options && typeof options === "object"
+        ? options.includeTombstones !== false
+        : options !== false;
+    const snapshot = await this._loadSnapshot({ includeTombstones });
+    const exported = {
      meta: toPlainData(snapshot.meta, {}),
      nodes: toPlainData(snapshot.nodes, []),
      edges: toPlainData(snapshot.edges, []),
-      tombstones: toPlainData(snapshot.tombstones, []),
+      tombstones: includeTombstones ? toPlainData(snapshot.tombstones, []) : [],
      state: toPlainData(snapshot.state, {}),
    };
+    if (!includeTombstones) {
+      exported.__stBmeTombstonesOmitted = true;
+    }
+    return exported;
  }

  async importSnapshot(snapshot, options = {}) {
@@ -3263,7 +3279,7 @@ export class OpfsGraphStore {
    return records;
  }

-  async _loadBaseSnapshotFromV2(manifest = null) {
+  async _loadBaseSnapshotFromV2(manifest = null, { includeTombstones = true } = {}) {
    const normalizedManifest = manifest || (await this._ensureV2Ready());
    const runtimeMeta = await this._readRuntimeMetaEntries();
    const nodes = [];
@@ -3275,8 +3291,10 @@ export class OpfsGraphStore {
    for (let index = 0; index < OPFS_V2_EDGE_BUCKET_COUNT; index += 1) {
      edges.push(...(await this._readShardRecords("edges", index)));
    }
-    for (let index = 0; index < OPFS_V2_TOMBSTONE_BUCKET_COUNT; index += 1) {
-      tombstones.push(...(await this._readShardRecords("tombstones", index)));
+    if (includeTombstones) {
+      for (let index = 0; index < OPFS_V2_TOMBSTONE_BUCKET_COUNT; index += 1) {
+        tombstones.push(...(await this._readShardRecords("tombstones", index)));
+      }
    }
    const meta = {
      ...createDefaultMetaValues(this.chatId),
@@ -3311,7 +3329,7 @@ export class OpfsGraphStore {
    return snapshot;
  }

-  async _loadSnapshot({ awaitWrites = true } = {}) {
+  async _loadSnapshot({ awaitWrites = true, includeTombstones = true } = {}) {
    if (awaitWrites) {
      await this._awaitPendingWrites();
    }
@@ -3319,10 +3337,24 @@ export class OpfsGraphStore {
    const headRevision = normalizeRevision(
      manifest?.headRevision || manifest?.meta?.revision,
    );
-    if (this._snapshotCache && normalizeRevision(this._snapshotCache.meta?.revision) === headRevision) {
-      return this._snapshotCache;
+    if (
+      this._snapshotCache &&
+      normalizeRevision(this._snapshotCache.meta?.revision) === headRevision
+    ) {
+      if (includeTombstones) {
+        return this._snapshotCache;
+      }
+      return {
+        meta: this._snapshotCache.meta,
+        state: this._snapshotCache.state,
+        nodes: this._snapshotCache.nodes,
+        edges: this._snapshotCache.edges,
+        tombstones: [],
+      };
    }
-    const snapshot = await this._loadBaseSnapshotFromV2(manifest);
+    const snapshot = await this._loadBaseSnapshotFromV2(manifest, {
+      includeTombstones,
+    });
    const walRecords = await this._readWalRecords(manifest);
    for (const walRecord of walRecords) {
      const nextSnapshot = applyOpfsV2DeltaToSnapshot(snapshot, walRecord.delta, walRecord.committedAt);
@@ -3355,7 +3387,11 @@ export class OpfsGraphStore {
    snapshot.state = normalizeSnapshotState(snapshot);
    snapshot.meta.lastProcessedFloor = snapshot.state.lastProcessedFloor;
    snapshot.meta.extractionCount = snapshot.state.extractionCount;
-    this._snapshotCache = snapshot;
+    if (includeTombstones) {
+      this._snapshotCache = snapshot;
+      return snapshot;
+    }
+    snapshot.tombstones = [];
    return snapshot;
  }

--- a/tests/indexeddb-persistence.mjs
+++ b/tests/indexeddb-persistence.mjs
@@ -2,6 +2,9 @@ import assert from "node:assert/strict";

 import {
  BME_DB_SCHEMA_VERSION,
+  BME_RUNTIME_BATCH_JOURNAL_META_KEY,
+  BME_RUNTIME_HISTORY_META_KEY,
+  BME_RUNTIME_VECTOR_META_KEY,
  BME_TOMBSTONE_RETENTION_MS,
  BmeDatabase,
  buildBmeDbName,
@@ -20,6 +23,7 @@ const chatIdsForCleanup = new Set([
  "chat-manager-a",
  "chat-manager-b",
  "chat-manager-selector",
+  "chat-export-without-tombstones",
  "chat-replace-reset",
 ]);

@@ -196,6 +200,41 @@ async function testSnapshotExportImport() {
  await db.close();
 }

+async function testSnapshotExportWithoutTombstones() {
+  const db = new BmeDatabase("chat-export-without-tombstones", {
+    dexieClass: globalThis.Dexie,
+  });
+  await db.open();
+
+  await db.bulkUpsertNodes([
+    {
+      id: "node-light-snapshot",
+      type: "event",
+      sourceFloor: 3,
+      archived: false,
+      updatedAt: Date.now(),
+    },
+  ]);
+  await db.bulkUpsertTombstones([
+    {
+      id: "tomb-light-snapshot",
+      kind: "node",
+      targetId: "node-deleted-light-snapshot",
+      deletedAt: Date.now(),
+      sourceDeviceId: "device-light-snapshot",
+    },
+  ]);
+
+  const exported = await db.exportSnapshot({ includeTombstones: false });
+  assert.equal(exported.__stBmeTombstonesOmitted, true);
+  assert.ok(Array.isArray(exported.nodes));
+  assert.ok(Array.isArray(exported.edges));
+  assert.deepEqual(exported.tombstones, []);
+  assert.equal(exported.meta.tombstoneCount, 1);
+
+  await db.close();
+}
+
 async function testReplaceImportResetsStaleMeta() {
  const chatId = "chat-replace-reset";
  const db = new BmeDatabase(chatId, { dexieClass: globalThis.Dexie });
@@ -532,6 +571,9 @@ async function testGraphSnapshotConverters() {
    id: "node-converter",
    type: "event",
    sourceFloor: 9,
+    fields: {
+      title: "Converter Node",
+    },
    updatedAt: Date.now(),
  });

@@ -583,6 +625,32 @@ async function testGraphSnapshotConverters() {
  assert.equal(rebuilt.regionState.activeRegion, "camp");
  assert.equal(rebuilt.timelineState.activeSegmentId, "segment-1");
  assert.equal(rebuilt.summaryState.entries[0].id, "summary-1");
+
+  rebuilt.nodes[0].fields.title = "Mutated Converter Node";
+  rebuilt.historyState.processedMessageHashes[1] = "mutated-hash";
+  rebuilt.vectorIndexState.hashToNodeId["vec-hash"] = "node-mutated";
+  rebuilt.batchJournal[0].processedRange[0] = 99;
+
+  assert.equal(
+    snapshot.nodes[0].fields.title,
+    "Converter Node",
+    "buildGraphFromSnapshot 不应复用 snapshot 节点的嵌套字段引用",
+  );
+  assert.equal(
+    snapshot.meta[BME_RUNTIME_HISTORY_META_KEY].processedMessageHashes[1],
+    "hash-1",
+    "buildGraphFromSnapshot 不应复用 snapshot historyState 的嵌套对象引用",
+  );
+  assert.equal(
+    snapshot.meta[BME_RUNTIME_VECTOR_META_KEY].hashToNodeId["vec-hash"],
+    "node-converter",
+    "buildGraphFromSnapshot 不应复用 snapshot vectorState 的嵌套对象引用",
+  );
+  assert.equal(
+    snapshot.meta[BME_RUNTIME_BATCH_JOURNAL_META_KEY][0].processedRange[0],
+    8,
+    "buildGraphFromSnapshot 不应复用 snapshot batchJournal 的嵌套数组引用",
+  );
 }

 async function main() {
@@ -593,6 +661,7 @@ async function main() {
  await testCrudAndMeta();
  await testTransactionRollback();
  await testSnapshotExportImport();
+  await testSnapshotExportWithoutTombstones();
  await testReplaceImportResetsStaleMeta();
  await testRevisionMonotonicity();
  await testTombstonePrune();
--- a/tests/opfs-persistence.mjs
+++ b/tests/opfs-persistence.mjs
@@ -311,6 +311,12 @@ async function testImportExportPersistenceAndFileRotation() {
  assert.equal(firstExportedSnapshot.state.extractionCount, 2);
  assert.equal(firstExportedSnapshot.meta.storagePrimary, "opfs");
  assert.equal(firstExportedSnapshot.meta.storageMode, "opfs-primary");
+  const lightweightSnapshot = await store.exportSnapshot({
+    includeTombstones: false,
+  });
+  assert.equal(lightweightSnapshot.__stBmeTombstonesOmitted, true);
+  assert.deepEqual(lightweightSnapshot.tombstones, []);
+  assert.equal(lightweightSnapshot.meta.tombstoneCount, 1);
  assert.deepEqual(firstExportedSnapshot.meta[BME_RUNTIME_BATCH_JOURNAL_META_KEY], {
    pending: ["job-1"],
  });