feat(memory): 添加运行期索引以优化节点和边的访问性能

src/memory_graph/models.py

@@ -238,6 +238,10 @@ class Memory:
     decay_factor: float = 1.0  # 衰减因子（随时间变化）
     metadata: dict[str, Any] = field(default_factory=dict)  # 扩展元数据
 
+    # 运行期索引（不序列化）
+    _node_index: dict[str, "MemoryNode"] = field(default_factory=dict, init=False, repr=False, compare=False)
+    _edges_by_source: dict[str, list["MemoryEdge"]] = field(default_factory=dict, init=False, repr=False, compare=False)
+
     def __post_init__(self):
         """后初始化处理"""
         if not self.id:
@@ -247,6 +251,73 @@ class Memory:
         self.activation = max(0.0, min(1.0, self.activation))
         if not self.updated_at:
             self.updated_at = self.created_at
+        # 构建加速索引
+        self._rebuild_indexes()
+
+    # --------------------
+    # 索引与快速访问
+    # --------------------
+    def _rebuild_indexes(self) -> None:
+        """从当前 nodes/edges 重新构建运行期索引。"""
+        # 节点索引
+        self._node_index.clear()
+        for n in self.nodes:
+            self._node_index[n.id] = n
+
+        # 源端分组的边索引
+        self._edges_by_source.clear()
+        for e in self.edges:
+            self._edges_by_source.setdefault(e.source_id, []).append(e)
+
+    def add_node(self, node: "MemoryNode") -> None:
+        """添加节点并更新索引。"""
+        self.nodes.append(node)
+        self._node_index[node.id] = node
+
+    def remove_node(self, node_id: str) -> bool:
+        """按 ID 移除节点，并清理相关索引。返回是否移除成功。"""
+        node = self._node_index.pop(node_id, None)
+        if node is None:
+            return False
+        # 从列表移除（保持原有数据结构契合度）
+        for i, n in enumerate(self.nodes):
+            if n.id == node_id:
+                del self.nodes[i]
+                break
+        # 同时移除以该节点为源或目标的边
+        new_edges = []
+        affected_sources: set[str] = set()
+        for e in self.edges:
+            if e.source_id == node_id or e.target_id == node_id:
+                affected_sources.add(e.source_id)
+                continue
+            new_edges.append(e)
+        self.edges = new_edges
+        # 更新边索引
+        for sid in affected_sources:
+            if sid in self._edges_by_source:
+                self._edges_by_source[sid] = [e for e in self._edges_by_source[sid] if e.source_id != node_id and e.target_id != node_id]
+                if not self._edges_by_source[sid]:
+                    self._edges_by_source.pop(sid, None)
+        return True
+
+    def add_edge(self, edge: "MemoryEdge") -> None:
+        """添加边并更新索引。"""
+        self.edges.append(edge)
+        self._edges_by_source.setdefault(edge.source_id, []).append(edge)
+
+    def remove_edge(self, edge_id: str) -> bool:
+        """按 ID 移除边，并更新索引。返回是否移除成功。"""
+        for i, e in enumerate(self.edges):
+            if e.id == edge_id:
+                del self.edges[i]
+                src_list = self._edges_by_source.get(e.source_id)
+                if src_list is not None:
+                    self._edges_by_source[e.source_id] = [x for x in src_list if x.id != edge_id]
+                    if not self._edges_by_source[e.source_id]:
+                        self._edges_by_source.pop(e.source_id, None)
+                return True
+        return False
 
     def to_dict(self) -> dict[str, Any]:
         """转换为字典（用于序列化）"""
@@ -312,10 +383,13 @@ class Memory:
 
     def get_node_by_id(self, node_id: str) -> MemoryNode | None:
         """根据ID获取节点"""
-        for node in self.nodes:
+        # O(1) 访问，回退安全（极少情况下索引不同步可重建）
-            if node.id == node_id:
+        node = self._node_index.get(node_id)
+        if node is not None:
             return node
-        return None
+        # 回退：重建索引后再取，避免外部直接修改列表导致的不同步
+        self._rebuild_indexes()
+        return self._node_index.get(node_id)
 
     def get_subject_node(self) -> MemoryNode | None:
         """获取主体节点"""
@@ -330,21 +404,22 @@ class Memory:
         # 简单的文本生成逻辑
         parts = [f"{subject_node.content}"]
 
-        # 查找主题节点（通过记忆类型边连接）
+        # 查找主题节点（通过记忆类型边连接）——使用索引加速
-        topic_node = None
+        topic_node: MemoryNode | None = None
-        for edge in self.edges:
+        for edge in self._edges_by_source.get(self.subject_id, []):
-            if edge.edge_type == EdgeType.MEMORY_TYPE and edge.source_id == self.subject_id:
+            if edge.edge_type == EdgeType.MEMORY_TYPE:
                 topic_node = self.get_node_by_id(edge.target_id)
+                if topic_node is not None:
                     break
 
         if topic_node:
             parts.append(topic_node.content)
 
-            # 查找客体节点（通过核心关系边连接）
+            # 查找客体节点（通过核心关系边连接）——使用索引加速
-            for edge in self.edges:
+            for edge in self._edges_by_source.get(topic_node.id, []):
-                if edge.edge_type == EdgeType.CORE_RELATION and edge.source_id == topic_node.id:
+                if edge.edge_type == EdgeType.CORE_RELATION:
                     obj_node = self.get_node_by_id(edge.target_id)
-                    if obj_node:
+                    if obj_node is not None:
                         parts.append(f"{edge.relation} {obj_node.content}")
                         break