diff --git a/app/components/CopyCom.vue b/app/components/CopyCom.vue
index c3044dc..bc2e2cb 100644
--- a/app/components/CopyCom.vue
+++ b/app/components/CopyCom.vue
@@ -58,7 +58,7 @@ defineExpose({ isCopied });
     :variant="variant"
     :size="size"
     :disabled="disabled"
-    :class="cn('relative overflow-hidden pl-8', className)"
+    :class="cn('relative overflow-hidden pl-7', className)"
     @click.prevent.stop="handleCopy"
   >
     <!-- 复制成功图标：未复制时向上移出，复制后滑入 -->
diff --git a/app/components/dashboard/QaRecordsTable.vue b/app/components/dashboard/QaRecordsTable.vue
index 4bffcd6..ccde928 100644
--- a/app/components/dashboard/QaRecordsTable.vue
+++ b/app/components/dashboard/QaRecordsTable.vue
@@ -14,8 +14,19 @@ import {
   CardHeader,
   CardTitle
 } from "@/components/ui/card";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue
+} from "@/components/ui/select";
 import type { IQaRecord } from "@/interfaces";
-import { QUESTION_TYPE_LABELS, useAnswerStore } from "@/stores/answer";
+import {
+  DASHBOARD_PAGE_SIZE_OPTIONS,
+  QUESTION_TYPE_LABELS,
+  useAnswerStore
+} from "@/stores/answer";
 
 const answerStore = useAnswerStore();
 const {
@@ -78,8 +89,29 @@ const displayOptions = (record: IQaRecord) => {
 <template>
   <Card>
     <CardHeader>
-      <CardTitle>最近问答记录</CardTitle>
-      <CardDescription>当前进程最多保留最近 100 条。</CardDescription>
+      <div class="flex items-center justify-between gap-4">
+        <div>
+          <CardTitle>最近问答记录</CardTitle>
+          <CardDescription>分页展示，按创建时间倒序</CardDescription>
+        </div>
+        <Select
+          :model-value="String(recordsPageSize)"
+          @update:model-value="(v) => answerStore.setRecordsPageSize(Number(v))"
+        >
+          <SelectTrigger class="w-28">
+            <SelectValue />
+          </SelectTrigger>
+          <SelectContent>
+            <SelectItem
+              v-for="size in DASHBOARD_PAGE_SIZE_OPTIONS"
+              :key="size"
+              :value="String(size)"
+            >
+              {{ size }} 条/页
+            </SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
     </CardHeader>
 
     <CardContent>
diff --git a/app/components/dashboard/StatsOverview.vue b/app/components/dashboard/StatsOverview.vue
index 4142f78..e58376a 100644
--- a/app/components/dashboard/StatsOverview.vue
+++ b/app/components/dashboard/StatsOverview.vue
@@ -3,10 +3,7 @@
 import { RefreshCw, Trash2 } from "lucide-vue-next";
 import { storeToRefs } from "pinia";
 
-import {
-  Alert,
-  AlertDescription
-} from "@/components/ui/alert";
+import { Alert, AlertDescription } from "@/components/ui/alert";
 import { Button } from "@/components/ui/button";
 import {
   Card,
@@ -39,13 +36,7 @@ const overviewItems = computed(() => [
   {
     label: "模型",
     value: stats.value?.model || health.value?.model || "-",
-    detail: stats.value?.cache_enabled ? "缓存已启用" : "缓存未启用",
-    loading: statsLoading.value && !stats.value
-  },
-  {
-    label: "缓存数量",
-    value: stats.value?.cache_size?.toString() ?? "0",
-    detail: "当前进程",
+    detail: "AI 模型",
     loading: statsLoading.value && !stats.value
   },
   {
@@ -59,7 +50,9 @@ const overviewItems = computed(() => [
 
 <template>
   <section class="grid gap-4">
-    <div class="flex flex-col gap-3 md:flex-row md:items-center md:justify-between">
+    <div
+      class="flex flex-col gap-3 md:flex-row md:items-center md:justify-between"
+    >
       <div>
         <h1 class="text-xl font-semibold text-foreground">Dashboard</h1>
         <p class="mt-1 text-sm text-muted-foreground">
diff --git a/app/components/home/OcsConfigCard.vue b/app/components/home/OcsConfigCard.vue
index 2f0128b..eae0ea9 100644
--- a/app/components/home/OcsConfigCard.vue
+++ b/app/components/home/OcsConfigCard.vue
@@ -1,5 +1,8 @@
 <!-- app/components/home/OcsConfigCard.vue - OCS AnswererWrapper 配置片段 -->
 <script lang="ts" setup>
+import { RefreshCw } from "lucide-vue-next";
+
+import { Button } from "@/components/ui/button";
 import {
   Card,
   CardAction,
@@ -12,6 +15,14 @@ import { useAuthStore } from "@/stores/auth";
 const authStore = useAuthStore();
 const origin = ref("http://localhost:3000");
 
+const refreshing = ref(false);
+
+const handleRefreshToken = async () => {
+  refreshing.value = true;
+  await authStore.refreshApiToken();
+  refreshing.value = false;
+};
+
 /** 浏览器端读取当前站点地址，避免文档里写死 localhost 或生产域名 */
 onMounted(() => {
   origin.value = window.location.origin;
@@ -22,7 +33,8 @@ const configText = computed(() => {
   const data: Record<string, string> = {
     title: "${title}",
     type: "${type}",
-    options: "${options}"
+    options: "${options}",
+    token: ""
   };
 
   if (authStore.user?.apiToken) {
@@ -53,13 +65,25 @@ const configText = computed(() => {
     <CardHeader>
       <CardTitle>OCS 配置</CardTitle>
       <CardAction>
-        <CopyCom :text="configText" :timeout="1200" />
+        <div class="flex items-center gap-2">
+          <Button
+            v-if="authStore.user?.apiToken && authStore.isOnline"
+            variant="outline"
+            size="sm"
+            :disabled="refreshing"
+            @click="handleRefreshToken"
+          >
+            <RefreshCw :class="['size-4', refreshing ? 'animate-spin' : '']" />
+            刷新 Token
+          </Button>
+          <CopyCom :text="configText" :timeout="1200" :disabled="refreshing" />
+        </div>
       </CardAction>
     </CardHeader>
 
     <CardContent>
       <pre
-        class="max-h-120 overflow-auto rounded-2xl bg-muted p-4 text-xs leading-5 text-muted-foreground"
+        class="h-89.5 overflow-x-auto overflow-y-hidden rounded-2xl bg-muted p-4 text-xs leading-5 text-muted-foreground"
       ><code>{{ configText }}</code>
         </pre>
     </CardContent>
diff --git a/app/interfaces/answer.ts b/app/interfaces/answer.ts
index ff4d007..df2018b 100644
--- a/app/interfaces/answer.ts
+++ b/app/interfaces/answer.ts
@@ -47,13 +47,11 @@ export interface IHealthResponse {
   message: string;
   /** 服务版本 */
   version: string;
-  /** 当前是否启用内存缓存 */
-  cache_enabled: boolean;
   /** 当前模型名，不包含 API Key 或 baseURL */
   model: string;
 }
 
-/** 服务统计响应，来自当前 Nuxt 进程的内存状态 */
+/** 服务统计响应 */
 export interface IStatsResponse {
   /** 服务版本 */
   version: string;
@@ -61,11 +59,7 @@ export interface IStatsResponse {
   uptime: number;
   /** 当前模型名 */
   model: string;
-  /** 当前是否启用内存缓存 */
-  cache_enabled: boolean;
-  /** 当前有效缓存数量 */
-  cache_size: number;
-  /** 当前进程内问答记录数量 */
+  /** 当前用户的问答记录总数 */
   qa_records_count: number;
 }
 
diff --git a/app/pages/dashboard.vue b/app/pages/dashboard.vue
index aebc1a7..9f9a6f7 100644
--- a/app/pages/dashboard.vue
+++ b/app/pages/dashboard.vue
@@ -1,25 +1,13 @@
 <!-- app/pages/dashboard.vue - 运行状态与最近问答记录页面 -->
 <script lang="ts" setup>
-import { RefreshCw } from "lucide-vue-next";
-
 import QaRecordDetail from "@/components/dashboard/QaRecordDetail.vue";
 import QaRecordsTable from "@/components/dashboard/QaRecordsTable.vue";
 import StatsOverview from "@/components/dashboard/StatsOverview.vue";
-import { Button } from "@/components/ui/button";
-import {
-  Card,
-  CardContent,
-  CardDescription,
-  CardHeader,
-  CardTitle
-} from "@/components/ui/card";
 import { useAnswerStore } from "@/stores/answer";
-import { useAuthStore } from "@/stores/auth";
 
 definePageMeta({ middleware: "auth" });
 
 const answerStore = useAnswerStore();
-const authStore = useAuthStore();
 
 useHead({
   title: "Dashboard - OCS AI 答题服务"
@@ -36,50 +24,10 @@ if (import.meta.client) {
     void answerStore.loadDashboard();
   });
 }
-
-const refreshing = ref(false);
-
-const handleRefreshToken = async () => {
-  refreshing.value = true;
-  await authStore.refreshApiToken();
-  refreshing.value = false;
-};
 </script>
 
 <template>
   <div class="grid gap-6">
-    <!-- OCS 油猴脚本 API token 配置卡片 -->
-    <Card v-if="authStore.user?.apiToken">
-      <CardHeader>
-        <CardTitle>OCS 脚本 Token</CardTitle>
-        <CardDescription>
-          在 OCS 油猴脚本的服务器配置中填入此
-          token，脚本将以你的账号身份调用答题接口。
-        </CardDescription>
-      </CardHeader>
-      <CardContent>
-        <div class="flex items-center gap-2">
-          <code
-            class="flex-1 overflow-x-auto bg-muted px-3 py-2 font-mono text-sm rounded-full"
-          >
-            {{ authStore.user.apiToken }}
-          </code>
-          <CopyCom :text="authStore.user.apiToken" :disabled="refreshing" />
-          <Button
-            variant="outline"
-            size="icon"
-            :disabled="refreshing"
-            title="刷新 Token"
-            class="flex items-center gap-1 w-fit px-2.5"
-            @click="handleRefreshToken"
-          >
-            <RefreshCw :class="['size-4', refreshing ? 'animate-spin' : '']" />
-            <span>刷新 Token</span>
-          </Button>
-        </div>
-      </CardContent>
-    </Card>
-
     <StatsOverview />
     <QaRecordsTable />
     <QaRecordDetail />
diff --git a/app/stores/answer.ts b/app/stores/answer.ts
index fca7854..91eefab 100644
--- a/app/stores/answer.ts
+++ b/app/stores/answer.ts
@@ -13,6 +13,9 @@ import { AnswerService } from "@/services";
 /** Dashboard 最近记录表格每页数量，组件直接复用，避免多个地方写死 */
 export const DASHBOARD_RECORD_PAGE_SIZE = 10;
 
+/** 分页大小可选列表，与后端白名单保持一致 */
+export const DASHBOARD_PAGE_SIZE_OPTIONS = [10, 50, 100] as const;
+
 /** 题型下拉选项，value 保持 OCS / 旧 Python 服务使用的英文值 */
 export const QUESTION_TYPE_OPTIONS: Array<{
   label: string;
@@ -104,6 +107,13 @@ export const useAnswerStore = defineStore("answer", () => {
     await getRecords(page);
   };
 
+  /** 切换分页大小，重置到第 1 页后重新请求 */
+  const setRecordsPageSize = async (size: number) => {
+    if (recordsLoading.value || size === recordsPageSize.value) return;
+    recordsPageSize.value = size;
+    await getRecords(1);
+  };
+
   /** 调用答题 API，返回 OCS 兼容结构但只在 store 中维护 UI 状态 */
   const searchAnswer = async () => {
     const title = question.value.trim();
@@ -245,6 +255,7 @@ export const useAnswerStore = defineStore("answer", () => {
     loadDashboard,
     clearCache,
     selectRecord,
-    setRecordsPage
+    setRecordsPage,
+    setRecordsPageSize
   };
 });
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 80ea996..997689c 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -13,17 +13,19 @@ datasource db {
 // Better Auth 标准用户表
 // apiToken 由服务端注册 hook 生成，供 OCS 油猴脚本跨域身份验证
 model User {
-  id            String     @id
-  name          String
-  email         String     @unique
-  emailVerified Boolean
-  image         String?
-  createdAt     DateTime
-  updatedAt     DateTime
-  apiToken      String?    @unique
-  sessions      Session[]
-  accounts      Account[]
-  qaRecords     QaRecord[]
+  id             String     @id
+  name           String
+  email          String     @unique
+  emailVerified  Boolean
+  image          String?
+  createdAt      DateTime
+  updatedAt      DateTime
+  apiToken       String?    @unique
+  /// 用户最近一次清缓存的时间；只有在此时间之后写入的记录才算缓存命中
+  cacheClearedAt DateTime?
+  sessions       Session[]
+  accounts       Account[]
+  qaRecords      QaRecord[]
 
   @@map("user")
 }
@@ -85,7 +87,10 @@ model QaRecord {
   type      String
   options   String?  @db.Text
   answer    String?  @db.Text
+  /// 题目+题型+选项的 MD5，用于 DB 缓存查询；老记录为 null
+  hash      String?  @db.Char(32)
   createdAt DateTime @default(now())
 
+  @@index([userId, hash])
   @@map("qa_record")
 }
diff --git a/server/api/cache/clear.post.ts b/server/api/cache/clear.post.ts
index 9cd27d3..1ece541 100644
--- a/server/api/cache/clear.post.ts
+++ b/server/api/cache/clear.post.ts
@@ -1,27 +1,22 @@
-// server/api/cache/clear.post.ts - 清空答题缓存接口
-import { answerCache } from "~~/server/utils/cache";
-import { serverEnv } from "~~/server/utils/env";
+// server/api/cache/clear.post.ts - 清空当前用户 DB 缓存接口
+import { prisma } from "~~/server/utils/db";
 import { createApiLogger } from "~~/server/utils/logging";
 
 /**
- * 清空内存缓存
+ * 清缓存：将当前用户的 cacheClearedAt 更新为当前时间
  *
- * 这是一个管理类接口，必须携带有效 session cookie（由 api-auth middleware 统一鉴权）
- * 清理的是当前 Nuxt 进程内缓存；多实例部署时，每个实例都有自己的内存缓存
+ * 之后查 DB 缓存时只命中该时间之后写入的记录，历史记录全部保留。
+ * 必须携带有效 session cookie（由 api-auth middleware 统一鉴权）
  */
-export default defineEventHandler((event) => {
+export default defineEventHandler(async (event) => {
   const logger = createApiLogger(event, "api.cache.clear");
+  const userId = event.context.auth!.user.id;
 
-  // 缓存被关闭时不报错，只明确告诉调用方当前没有缓存可清
-  if (!serverEnv.enableCache || !answerCache) {
-    return {
-      success: false,
-      message: "缓存未启用"
-    };
-  }
+  await prisma.user.update({
+    where: { id: userId },
+    data: { cacheClearedAt: new Date() }
+  });
 
-  // 清空当前进程内缓存，DB 记录不受影响
-  answerCache.clear();
   logger.info("finish_success");
 
   return {
diff --git a/server/api/health.get.ts b/server/api/health.get.ts
index 841320f..a468456 100644
--- a/server/api/health.get.ts
+++ b/server/api/health.get.ts
@@ -6,14 +6,13 @@ import { SERVICE_VERSION } from "~~/server/utils/runtimeState";
  * 健康检查不需要鉴权
  *
  * 这个接口用于部署平台、Docker healthcheck 或人工确认服务是否启动；
- * 返回模型名和缓存开关，但不返回 API Key、baseURL 或其他敏感配置
+ * 返回模型名，但不返回 API Key、baseURL 或其他敏感配置
  */
 export default defineEventHandler(() => {
   return {
     status: "ok",
     message: "AI题库服务运行正常",
     version: SERVICE_VERSION,
-    cache_enabled: serverEnv.enableCache,
     model: serverEnv.openAiModel
   };
 });
diff --git a/server/api/records.get.ts b/server/api/records.get.ts
index eaf1fb3..eec392c 100644
--- a/server/api/records.get.ts
+++ b/server/api/records.get.ts
@@ -18,9 +18,9 @@ export default defineEventHandler(async (event) => {
   const query = getQuery(event);
   const rawPage = Number.parseInt(query.page?.toString() || "1", 10);
   const rawSize = Number.parseInt(query.size?.toString() || "10", 10);
-  const size = Number.isFinite(rawSize)
-    ? Math.min(Math.max(rawSize, 1), 100)
-    : 10;
+  // size 只允许 10 / 50 / 100；传入其他值（含超出上限）一律退回 10
+  const ALLOWED_SIZES = new Set([10, 50, 100]);
+  const size = ALLOWED_SIZES.has(rawSize) ? rawSize : 10;
   const page = Number.isFinite(rawPage) ? Math.max(rawPage, 1) : 1;
 
   const { records, total } = await getQaRecords(event.context.auth!.user.id, {
diff --git a/server/api/search.ts b/server/api/search.ts
index e9b1632..10f5e32 100644
--- a/server/api/search.ts
+++ b/server/api/search.ts
@@ -1,4 +1,6 @@
 // server/api/search.ts - OCS AnswererWrapper 兼容搜索接口
+import { createHash } from "node:crypto";
+
 import {
   getQuery,
   type H3Event,
@@ -16,11 +18,10 @@ import {
   type SearchParams
 } from "~~/server/utils/answer";
 import { getAuthSession } from "~~/server/utils/auth";
-import { answerCache } from "~~/server/utils/cache";
 import { prisma } from "~~/server/utils/db";
 import { createApiLogger, toSafeLogError } from "~~/server/utils/logging";
 import { askAnswerStream } from "~~/server/utils/openai";
-import { addQaRecord } from "~~/server/utils/runtimeState";
+import { addQaRecord, lookupCachedAnswer } from "~~/server/utils/runtimeState";
 
 /**
  * 把 query/body/form 中的值统一转成字符串
@@ -138,17 +139,25 @@ export default defineEventHandler(async (event) => {
 
     // 鉴权：优先 session（浏览器登录），无 session 则用 body.token 查 apiToken
     // OCS 油猴脚本跨域无法携带 cookie，需在 body 中传入用户自己的 apiToken
+    // 同时取出 cacheClearedAt，用于 DB 缓存过滤
     let userId: string | null = null;
+    let cacheClearedAt: Date | null = null;
 
     const session = await getAuthSession(event);
     if (session) {
       userId = session.user.id;
+      const userData = await prisma.user.findUnique({
+        where: { id: userId },
+        select: { cacheClearedAt: true }
+      });
+      cacheClearedAt = userData?.cacheClearedAt ?? null;
     } else if (params.token) {
       const user = await prisma.user.findUnique({
         where: { apiToken: params.token },
-        select: { id: true }
+        select: { id: true, cacheClearedAt: true }
       });
       userId = user?.id ?? null;
+      cacheClearedAt = user?.cacheClearedAt ?? null;
     }
 
     if (!userId) {
@@ -167,12 +176,12 @@ export default defineEventHandler(async (event) => {
       return createOcsErrorResponse("未提供问题内容");
     }
 
-    // 缓存 key 包含题目、题型和选项；同题不同选项不能共用答案
-    const cachedAnswer = answerCache?.get(
-      params.title,
-      params.type,
-      params.options
-    );
+    // 计算缓存 key：题目+题型+选项的 MD5；同题不同选项不能共用答案
+    const hash = createHash("md5")
+      .update(`${params.title}|${params.type}|${params.options}`, "utf8")
+      .digest("hex");
+
+    const cachedAnswer = await lookupCachedAnswer(userId, hash, cacheClearedAt);
 
     if (cachedAnswer) {
       logger.info("cache_hit");
@@ -191,19 +200,14 @@ export default defineEventHandler(async (event) => {
     });
     const processedAnswer = extractAnswer(streamResult.answer, params.type);
 
-    // 先缓存再记录；这两步失败风险很低，且都是内存操作，不会阻塞主链路
-    answerCache?.set(
-      params.title,
-      processedAnswer,
-      params.type,
-      params.options
-    );
+    // 写入 DB 记录（带 hash）；记录本身即为后续缓存查询的来源
     await addQaRecord({
       userId,
       question: params.title,
       type: params.type,
       options: params.options,
-      answer: processedAnswer
+      answer: processedAnswer,
+      hash
     });
 
     logger.info("finish_success", {
diff --git a/server/api/stats.get.ts b/server/api/stats.get.ts
index 6fde850..b7a379f 100644
--- a/server/api/stats.get.ts
+++ b/server/api/stats.get.ts
@@ -1,16 +1,23 @@
 // server/api/stats.get.ts - 服务运行统计接口
+import { prisma } from "~~/server/utils/db";
 import { createApiLogger } from "~~/server/utils/logging";
 import { getRuntimeStats } from "~~/server/utils/runtimeState";
 
 /**
  * 运行统计接口
  *
- * 统计信息包含 uptime、模型名、缓存数量、最近问答记录数量
+ * 返回进程 uptime、模型名以及当前用户的问答记录总数
  * 必须携带有效 session cookie（由 api-auth middleware 统一鉴权）
  */
-export default defineEventHandler((event) => {
+export default defineEventHandler(async (event) => {
   const logger = createApiLogger(event, "api.stats");
-  // getRuntimeStats 会实时清理过期缓存，再返回有效缓存数量
+  const userId = event.context.auth!.user.id;
+
+  const [runtimeStats, qa_records_count] = await Promise.all([
+    Promise.resolve(getRuntimeStats()),
+    prisma.qaRecord.count({ where: { userId } })
+  ]);
+
   logger.info("finish_success");
-  return getRuntimeStats();
+  return { ...runtimeStats, qa_records_count };
 });
diff --git a/server/utils/cache.ts b/server/utils/cache.ts
deleted file mode 100644
index e726667..0000000
--- a/server/utils/cache.ts
+++ /dev/null
@@ -1,100 +0,0 @@
-// server/utils/cache.ts - 简单内存缓存，按题目、题型和选项生成缓存键
-import { createHash } from "node:crypto";
-
-import { serverEnv } from "~~/server/utils/env";
-
-/**
- * 旧 Python 服务使用进程内字典缓存答案
- *
- * Nuxt 版保持同样的“内存缓存”语义：服务重启后缓存清空，不跨实例共享；
- * 这对个人题库服务足够简单，也避免为了缓存引入数据库或 Redis
- */
-export class SimpleCache {
-  /** Map key 是题目、题型和选项计算出的 md5；value 保存写入时间和答案 */
-  private readonly cache = new Map<
-    string,
-    {
-      timestamp: number;
-      value: string;
-    }
-  >();
-
-  constructor(private readonly expirationSeconds: number) {}
-
-  /**
-   * 根据题目、题型和选项生成缓存键
-   *
-   * 同一道题如果选项不同，不能复用旧答案，所以三个字段都参与计算
-   */
-  private generateKey(question: string, questionType = "", options = "") {
-    return createHash("md5")
-      .update(`${question}|${questionType}|${options}`, "utf8")
-      .digest("hex");
-  }
-
-  /**
-   * 读取缓存答案
-   *
-   * 命中过期项时会顺手删除，避免长时间运行后堆积无效缓存
-   */
-  get(question: string, questionType = "", options = "") {
-    const key = this.generateKey(question, questionType, options);
-    const item = this.cache.get(key);
-    if (!item) return undefined;
-
-    if (Date.now() - item.timestamp < this.expirationSeconds * 1000) {
-      return item.value;
-    }
-
-    this.cache.delete(key);
-    return undefined;
-  }
-
-  /** 写入答案缓存，时间戳使用当前进程时间即可 */
-  set(question: string, answer: string, questionType = "", options = "") {
-    const key = this.generateKey(question, questionType, options);
-    this.cache.set(key, {
-      timestamp: Date.now(),
-      value: answer
-    });
-  }
-
-  /** 清空全部缓存，对应 `/api/cache/clear` */
-  clear() {
-    this.cache.clear();
-  }
-
-  /**
-   * 批量移除过期项
-   *
-   * 目前在统计缓存大小时调用，避免 stats 返回已经过期的数量
-   */
-  removeExpired() {
-    const now = Date.now();
-    let removedCount = 0;
-
-    for (const [key, item] of this.cache.entries()) {
-      if (now - item.timestamp >= this.expirationSeconds * 1000) {
-        this.cache.delete(key);
-        removedCount += 1;
-      }
-    }
-
-    return removedCount;
-  }
-
-  /** 获取当前有效缓存数量 */
-  size() {
-    this.removeExpired();
-    return this.cache.size;
-  }
-}
-
-/**
- * 全局答案缓存实例
- *
- * 如果 `ENABLE_CACHE=false`，导出 undefined，调用处用可选链即可保持逻辑简洁
- */
-export const answerCache = serverEnv.enableCache
-  ? new SimpleCache(serverEnv.cacheExpiration)
-  : undefined;
diff --git a/server/utils/env.ts b/server/utils/env.ts
index 7afda2b..9936e24 100644
--- a/server/utils/env.ts
+++ b/server/utils/env.ts
@@ -73,10 +73,6 @@ export const serverEnv = {
   maxTokens: readInteger("MAX_TOKENS", 500),
   /** 模型采样温度，越低越稳定 */
   temperature: readNumber("TEMPERATURE", 0.7),
-  /** 是否启用内存缓存 */
-  enableCache: readBoolean("ENABLE_CACHE", true),
-  /** 缓存过期时间，单位秒 */
-  cacheExpiration: readInteger("CACHE_EXPIRATION", 86_400),
   /** 预留日志级别配置，目前日志工具只负责安全输出 */
   logLevel: readString("LOG_LEVEL", "INFO"),
   /** 单行 SSE data 的最大字节数，用于防止异常流无限堆内存 */
diff --git a/server/utils/runtimeState.ts b/server/utils/runtimeState.ts
index 57af582..6d9700d 100644
--- a/server/utils/runtimeState.ts
+++ b/server/utils/runtimeState.ts
@@ -1,5 +1,4 @@
 // server/utils/runtimeState.ts - 服务启动时间内存状态 + 问答记录 DB 读写
-import { answerCache } from "~~/server/utils/cache";
 import { prisma } from "~~/server/utils/db";
 import { serverEnv } from "~~/server/utils/env";
 
@@ -29,6 +28,7 @@ export const addQaRecord = async (record: {
   type: string;
   options: string;
   answer: string;
+  hash: string;
 }) => {
   await prisma.qaRecord.create({
     data: {
@@ -36,11 +36,34 @@ export const addQaRecord = async (record: {
       question: record.question,
       type: record.type,
       options: record.options || null,
-      answer: record.answer || null
+      answer: record.answer || null,
+      hash: record.hash
     }
   });
 };
 
+/**
+ * 按用户 + hash 查找 DB 缓存答案
+ *
+ * 只返回 cacheClearedAt 之后写入的记录；未存入时间或 hash 为 null 的老记录不会命中
+ */
+export const lookupCachedAnswer = async (
+  userId: string,
+  hash: string,
+  cacheClearedAt: Date | null
+): Promise<string | null> => {
+  const record = await prisma.qaRecord.findFirst({
+    where: {
+      userId,
+      hash,
+      ...(cacheClearedAt ? { createdAt: { gt: cacheClearedAt } } : {})
+    },
+    orderBy: { createdAt: "desc" },
+    select: { answer: true }
+  });
+  return record?.answer ?? null;
+};
+
 /**
  * 从数据库分页读取指定用户的问答记录，按创建时间倒序
  */
@@ -76,13 +99,11 @@ export const getQaRecords = async (
   }));
   return { records, total };
 };
-/** 生成 `/api/stats` 响应，实时计算 uptime 和有效缓存数量 */
+/** 生成 `/api/stats` 的基础运行时信息，不包含用户相关数据 */
 export const getRuntimeStats = () => {
   return {
     version: SERVICE_VERSION,
     uptime: (Date.now() - startTime) / 1000,
-    model: serverEnv.openAiModel,
-    cache_enabled: serverEnv.enableCache,
-    cache_size: answerCache?.size() ?? 0
+    model: serverEnv.openAiModel
   };
 };