perf(教师统计): 展开行的明细改成按需拉，统计响应不再背着 4.9 万行没人看的数据

上一版把明细收成「只取有 AC 的人、每人最近 50 条」，拿生产快照（12.4 万条提交）实测下来只从 105631 行降到 49108 行 —— 2.1 倍，不是一个数量级。原因是绝大多数人本来就不到 50 条，每人截断那道闸在真实分布上基本没咬到，最坏情况响应体仍有 ~2.4MB。真正的问题是形状不对：表格一次只展开一行（updateExpandedRowKeys 只留最后一个 key），却给 1900 个人各准备了一份。所以明细整个从统计响应里拿掉，改成展开时按需拉： - 新端点 `GET /submissions/statistics/items`，要用户名 + 同一套时间窗和题号。用户名这里是**精确匹配**，不是统计接口那种 ilike —— 那边填 ks251 要圈出整个班，这边是「点开的这一行是谁」。上限 200 条，多取一条来判断 truncated，被截断时展开行里说明「只显示最近 200 条」，免得老师以为这人就交了这么多。 - 时间窗和题号抽成共用的 statisticsScope，两个接口必须同一个范围，否则展开行看到的是另一个窗口的数据。 - 前端按人缓存，收起再展开不重拉；每次重新统计（含 15 秒自动刷新）清缓存，并把当前展开着的那一行重拉一遍 —— 展开行跟着一起活着，不然刷新之后上面的数变了、下面的明细还是老的。 - 去重放在 loadItems 里：点一行会同时走 rowProps 的 onClick 和表格的 update:expanded-row-keys，两边都想拉，改之前真发出了两条一模一样的请求。顺带把 submissionItems 从 submissionStatisticsUserSchema 里删掉。生产快照上的验证（12.4 万条提交 / 1956 用户 / 961 题，恢复进一次性容器跑完即删）： - 最坏情况（全部时段 + 不填条件）少搬 49108 行，约 2.4MB - 真实课堂量级（最忙的一小时：583 条提交 / 81 人）四条查询分别是主聚合 45ms、明细 6.5ms、语法未过 2.4ms、最近错因 <1ms - 「已解决」那条口径修正的实际影响：13.3% 的「人×题」有重复 AC，同一题最多 AC 45 次；按人看最夸张的是 419 条 AC 其实只有 38 道题 - 语法要求的题 15 道、result=10 共 57 条，其中「最后也没改对」的 18 个人×题 —— 角标会出现，但稀有浏览器实跑：展开前不发明细请求；展开后 1 条、12 个按钮；收起 +0、再展开 +0（走缓存）；自动刷新时统计与明细 1:1 配对、间隔 15 秒，没有重复请求。 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01KqjE6qPo67fqVDKn6Bx7yd
2026-09-08 05:43:32 -06:00
parent fdfb064d0c
commit 9c5a1d551d
4 changed files with 178 additions and 69 deletions
--- a/apps/api/src/routes/submission.ts
+++ b/apps/api/src/routes/submission.ts
@@ -8,6 +8,7 @@ import {
  submissionDetailSchema,
  submissionListItemSchema,
  submissionListSchema,
+  submissionStatisticsItemsSchema,
  submissionStatisticsSchema,
 } from "@oj2/contract"
 import { and, count, desc, eq, gt, ilike, inArray, isNull, or, sql, type SQL } from "drizzle-orm"
@@ -238,46 +239,13 @@ async function findPublicProblemsByDisplayIds(displayIds: string[]) {
 }

 /**
- * 表格展开行要看的「这个人交了哪几次」。两道闸都是为了不让「全部时段 + 不填条件」
- * 把十几万条提交整个搬进响应体：
+ * 展开行一次只看一个人（表格的 updateExpandedRowKeys 只留最后一个 key），所以明细
+ * **按需拉**，不再随统计一起下发。
 *
- * - **只取有 AC 的人**。明细只挂在 `data` 里，而 `data` 本来就只留有 AC 的人，
- *   原来给「一次没对的人」也捞一份明细，捞完直接扔掉。
- * - **每人只留最近 50 条**。展开行是一排 120px 的按钮，几十个就已经翻不动了。
- *   表格「提交数」那一列走的是 perUser 的 count，仍然是真实总数，不受这里截断影响。
+ * 原来是随 data 一起给所有人各带一份：生产快照实测，「全部时段 + 不填条件」要搬
+ * 49108 行（最早那版不截断是 105631 行），而其中真正被人看到的最多一个人的那几十条。
 */
-const STATISTICS_ITEMS_PER_USER = 50
-
-async function submissionItemsByUser(where: SQL | undefined, usernames: string[]) {
-  const byUser = new Map<string, { id: string; result: number }[]>()
-  if (!usernames.length) return byUser
-
-  // 走窗口函数而不是「查全量再在 JS 里截断」：截断要发生在数据库那边才省得下来。
-  const rows = await db.execute<{ username: string; id: string; result: number }>(sql`
-    select username, id, result from (
-      select
-        ${schema.submission.username} as username,
-        ${schema.submission.id} as id,
-        ${schema.submission.result} as result,
-        row_number() over (
-          partition by ${schema.submission.username}
-          order by ${schema.submission.createTime} desc
-        ) as rn
-      from ${schema.submission}
-      where ${and(where, inArray(schema.submission.username, usernames))}
-    ) t
-    where rn <= ${STATISTICS_ITEMS_PER_USER}
-    -- rn 就是「这个人的第几新」，外层不排的话展开行里的按钮是乱序的
-    order by username, rn
-  `)
-
-  for (const row of rows) {
-    const bucket = byUser.get(row.username)
-    if (bucket) bucket.push({ id: row.id, result: row.result })
-    else byUser.set(row.username, [{ id: row.id, result: row.result }])
-  }
-  return byUser
-}
+const STATISTICS_ITEMS_LIMIT = 200

 /** 错误摘要截断长度。编译错误能刷几十行，弹层里放不下，也没必要 */
 const FAILURE_MESSAGE_LIMIT = 400
@@ -381,9 +349,21 @@ async function matchedStudents(username: string) {
    )
 }

-submissionRoutes.get("/submissions/statistics", requireTeacher, async (c) => {
+/**
+ * 两个统计接口共用的范围：时间窗 + 题号。**用户名不在里面** —— 统计那边是
+ * ilike 模糊匹配（填 ks251 要匹配整个班），明细那边必须精确到人，口径不同。
+ */
+type StatisticsScope =
+  | { ok: true; filters: SQL[]; problemCount: number }
+  | { ok: false; status: 400 | 404; code: string; message: string }
+
+async function statisticsScope(c: {
+  req: { query(name: string): string | undefined }
+}): Promise<StatisticsScope> {
  const range = statisticsRange(c)
-  if (!range) return failure(c, 400, "invalid-request", "end is required")
+  if (!range) {
+    return { ok: false, status: 400, code: "invalid-request", message: "end is required" }
+  }

  const filters = [
    isNull(schema.submission.contestId),
@@ -393,16 +373,34 @@ submissionRoutes.get("/submissions/statistics", requireTeacher, async (c) => {

  const displayIds = parseDisplayIds(c.req.query("problemId") ?? "")
  if (displayIds.length > STATISTICS_MAX_PROBLEMS) {
-    return failure(c, 400, "invalid-request", `At most ${STATISTICS_MAX_PROBLEMS} problems`)
+    return {
+      ok: false,
+      status: 400,
+      code: "invalid-request",
+      message: `At most ${STATISTICS_MAX_PROBLEMS} problems`,
+    }
  }
  if (displayIds.length) {
    const { ids, missing } = await findPublicProblemsByDisplayIds(displayIds)
    if (missing) {
-      return failure(c, 404, "problem-not-found", `Problem ${missing} does not exist`)
+      return {
+        ok: false,
+        status: 404,
+        code: "problem-not-found",
+        message: `Problem ${missing} does not exist`,
+      }
    }
    filters.push(inArray(schema.submission.problemId, ids))
  }

+  return { ok: true, filters, problemCount: displayIds.length }
+}
+
+submissionRoutes.get("/submissions/statistics", requireTeacher, async (c) => {
+  const scope = await statisticsScope(c)
+  if (!scope.ok) return failure(c, scope.status, scope.code, scope.message)
+  const filters = scope.filters
+
  const username = c.req.query("username")?.trim()
  if (username) filters.push(ilike(schema.submission.username, `%${username}%`))
  const where = and(...filters)
@@ -456,18 +454,17 @@ submissionRoutes.get("/submissions/statistics", requireTeacher, async (c) => {
   * 只填一道题时 `solvedCount >= 1` 和原来的 `acceptedCount > 0` 完全等价；
   * 不填题号时无所谓「全部」，退回「至少做出一道」。
   */
-  const requiredSolved = displayIds.length
+  const requiredSolved = scope.problemCount
  const isDone = (row: { solvedCount: number; acceptedCount: number }) =>
    requiredSolved > 0 ? row.solvedCount >= requiredSolved : row.acceptedCount > 0

  // 表格列的是做完了的人。没做完的（一条没交 / 交了没全对）在「未完成」那一栏
  const acceptedUsers = perUser.filter(isDone)
-  // 这两个都要等 acceptedUsers 定下来才能查，所以进不了上面那个 Promise.all
-  const acceptedNames = acceptedUsers.map((row) => row.username)
-  const [itemsByUser, astOnlyByUserMap] = await Promise.all([
-    submissionItemsByUser(where, acceptedNames),
-    astOnlyByUser(where, acceptedNames),
-  ])
+  // 要等 acceptedUsers 定下来才能查，所以进不了上面那个 Promise.all
+  const astOnlyByUserMap = await astOnlyByUser(
+    where,
+    acceptedUsers.map((row) => row.username),
+  )

  const submittedUsernames = new Set(perUser.map((row) => row.username))
  const classNames = new Map<string, string | null>()
@@ -488,7 +485,6 @@ submissionRoutes.get("/submissions/statistics", requireTeacher, async (c) => {
    astOnlyCount: astOnlyByUserMap.get(row.username) ?? 0,
    judgingCount: row.judgingCount,
    correctRate: judgedRate(row.acceptedCount, row.submissionCount - row.judgingCount),
-    submissionItems: itemsByUser.get(row.username) ?? [],
  }))

  const dataUnaccepted = rosterRows
@@ -538,6 +534,38 @@ submissionRoutes.get("/submissions/statistics", requireTeacher, async (c) => {
  )
 })

+/**
+ * 统计面板展开一行时拉这个人的提交明细。
+ *
+ * 用户名这里是**精确匹配**，不是统计接口那种 ilike —— 那边填 `ks251` 要圈出整个班，
+ * 这边是「点开的这一行是谁」。时间窗和题号沿用同一个 scope，不然展开行看到的
+ * 会是另一个范围的数据。
+ */
+submissionRoutes.get("/submissions/statistics/items", requireTeacher, async (c) => {
+  const username = c.req.query("username")?.trim()
+  if (!username) return failure(c, 400, "invalid-request", "username is required")
+
+  const scope = await statisticsScope(c)
+  if (!scope.ok) return failure(c, scope.status, scope.code, scope.message)
+
+  // 多取一条，好知道是不是被截断了
+  const rows = await db
+    .select({ id: schema.submission.id, result: schema.submission.result })
+    .from(schema.submission)
+    .where(and(...scope.filters, eq(schema.submission.username, username)))
+    .orderBy(desc(schema.submission.createTime), desc(schema.submission.id))
+    .limit(STATISTICS_ITEMS_LIMIT + 1)
+
+  const truncated = rows.length > STATISTICS_ITEMS_LIMIT
+  return success(
+    c,
+    submissionStatisticsItemsSchema.parse({
+      items: rows.slice(0, STATISTICS_ITEMS_LIMIT),
+      truncated,
+    }),
+  )
+})
+
 submissionRoutes.post("/submissions/:id/rejudge", requireSuperAdmin, async (c) => {
  const [row] = await db
    .select({ id: schema.submission.id, problemId: schema.submission.problemId })
--- a/apps/web/src/oj/api.ts
+++ b/apps/web/src/oj/api.ts
@@ -37,6 +37,7 @@ import {
  submissionDetailSchema,
  type FlowchartStatistics,
  type SubmissionStatistics,
+  type SubmissionStatisticsItems,
 } from "@oj2/contract"
 import api from "utils/api"
 import { filterResult } from "oj/transforms"
@@ -159,6 +160,20 @@ export function adminRejudge(id: string) {
  )
 }

+/**
+ * 统计面板展开一行时拉这个人的明细。username 这里要**精确**到人，
+ * 和上面那个按班级模糊匹配的不是一回事。
+ */
+export function getSubmissionStatisticsItems(
+  duration: { start?: string; end: string },
+  username: string,
+  problemID?: string,
+) {
+  return api.get<SubmissionStatisticsItems>("submissions/statistics/items", {
+    params: { ...duration, problemId: problemID, username },
+  })
+}
+
 export function getSubmissionStatistics(
  duration: { start?: string; end: string },
  problemID?: string,
--- a/apps/web/src/shared/components/StatisticsPanel.vue
+++ b/apps/web/src/shared/components/StatisticsPanel.vue
@@ -192,7 +192,7 @@
 <script setup lang="ts">
 import { h } from "vue"
 import { formatISO, sub, type Duration } from "date-fns"
-import { getSubmissionStatistics } from "oj/api"
+import { getSubmissionStatistics, getSubmissionStatisticsItems } from "oj/api"
 import { DURATION_OPTIONS, STORAGE_KEY } from "utils/constants"
 import storage from "utils/storage"
 import { useConfigStore } from "../store/config"
@@ -202,6 +202,7 @@ import { NButton, NFlex, NText, type DataTableRowKey } from "naive-ui"
 import { JUDGE_STATUS } from "utils/constants"
 import type {
  AttemptedStudent,
+  SubmissionStatisticsItems,
  SubmissionStatisticsUser,
  UnacceptedStudent,
 } from "@oj2/contract"
@@ -232,24 +233,35 @@ const columns: DataTableColumn<SubmissionStatisticsUser>[] = [
  {
    type: "expand",
    renderExpand: (row) => {
-      return h(NFlex, { size: "small", wrap: true }, () =>
-        row.submissionItems.map((item) =>
-          h(
-            NButton,
-            {
-              size: "small",
-              tertiary: true,
-              type: JUDGE_STATUS[item.result]?.type ?? "default",
-              style: "width: 120px",
-              onClick: (event: MouseEvent) => {
-                event.stopPropagation()
-                openSubmission(item.id)
+      const loaded = items[row.username]
+      if (!loaded) return h(NText, { depth: 3 }, () => "加载中…")
+      return h(NFlex, { vertical: true, size: "small" }, () => [
+        h(NFlex, { size: "small", wrap: true }, () =>
+          loaded.items.map((item) =>
+            h(
+              NButton,
+              {
+                size: "small",
+                tertiary: true,
+                type: JUDGE_STATUS[item.result]?.type ?? "default",
+                style: "width: 120px",
+                onClick: (event: MouseEvent) => {
+                  event.stopPropagation()
+                  openSubmission(item.id)
+                },
              },
-            },
-            () => item.id.toString().slice(0, 12),
+              () => item.id.toString().slice(0, 12),
+            ),
          ),
        ),
-      )
+        loaded.truncated
+          ? h(
+              NText,
+              { depth: 3 },
+              () => `只显示最近 ${loaded.items.length} 条，上面「提交数」才是总数`,
+            )
+          : null,
+      ])
    },
  },
  { title: "用户", key: "username" },
@@ -325,6 +337,41 @@ const listUnaccepted = ref<UnacceptedStudent[]>([])
 const listAttempted = ref<AttemptedStudent[]>([])
 const expandedRowKeys = ref<DataTableRowKey[]>([])

+/**
+ * 展开行的明细，按人缓存。**每次重新统计都清空** —— 时间窗滚过之后旧明细就不对了；
+ * 清完如果还有展开着的行，顺手把那一行重拉一遍，让它跟着自动刷新一起活着。
+ */
+const items = reactive<Record<string, SubmissionStatisticsItems>>({})
+
+// 点一行会同时走 rowProps 的 onClick 和表格的 update:expanded-row-keys，
+// 两边都想拉一次；去重放在这里，调用方不用各自判
+const itemsLoading = new Set<string>()
+
+async function loadItems(username: string) {
+  if (items[username] || itemsLoading.has(username)) return
+  itemsLoading.add(username)
+  const current = Date.now()
+  const duration =
+    query.duration === "all"
+      ? { end: formatISO(current) }
+      : {
+          start: formatISO(sub(current, subOptions.value)),
+          end: formatISO(current),
+        }
+  try {
+    items[username] = await getSubmissionStatisticsItems(
+      duration,
+      username,
+      query.problem,
+    )
+  } catch {
+    // 拉不到就当空的：展开行显示不出东西，但不该把整个面板带崩
+    items[username] = { items: [], truncated: false }
+  } finally {
+    itemsLoading.delete(username)
+  }
+}
+
 /**
 * 「查出东西了吗」。**不能只看提交数** —— 一节课刚开始时一条提交都没有，但后端
 * 已经把整份花名册当作「未完成」返回了，而那正是老师最想看名单的时刻。
@@ -624,6 +671,10 @@ async function fetchStatistics() {
  personCount.value = res.personCount
  // 查过的班级记下来，下次打开直接带上
  if (query.username) storage.set(STORAGE_KEY.STATISTICS_CLASS, query.username)
+
+  const expanded = expandedRowKeys.value[0]
+  for (const key of Object.keys(items)) delete items[key]
+  if (typeof expanded === "string") loadItems(expanded)
 }

 function rowKey(row: SubmissionStatisticsUser): DataTableRowKey {
@@ -632,6 +683,8 @@ function rowKey(row: SubmissionStatisticsUser): DataTableRowKey {

 function updateExpandedRowKeys(keys: DataTableRowKey[]) {
  expandedRowKeys.value = keys.slice(-1)
+  const opened = expandedRowKeys.value[0]
+  if (typeof opened === "string") loadItems(opened)
 }

 function rowProps(row: SubmissionStatisticsUser) {
@@ -641,6 +694,7 @@ function rowProps(row: SubmissionStatisticsUser) {
      const key = rowKey(row)
      const isExpanded = expandedRowKeys.value.includes(key)
      expandedRowKeys.value = isExpanded ? [] : [key]
+      if (!isExpanded) loadItems(row.username)
    },
  }
 }
--- a/packages/contract/src/submission.ts
+++ b/packages/contract/src/submission.ts
@@ -172,9 +172,18 @@ export const submissionStatisticsUserSchema = z.object({
  judgingCount: z.number().int(),
  // 百分比数值，不带 %。旧后端返回 "85.5%" 字符串，展示格式化交给前端。
  correctRate: z.number(),
-  submissionItems: z.array(
-    z.object({ id: z.string(), result: judgeStatusSchema }),
-  ),
+})
+
+/**
+ * 展开行的明细，**按需拉**（GET /submissions/statistics/items）。
+ *
+ * 原来是随统计一起给每个人各带一份，可表格一次只展开一行 —— 生产快照上那是
+ * 4.9 万行没人看的数据。`truncated` 为真时前端要说明「只显示最近 N 条」，
+ * 免得老师以为这人就交了这么多。
+ */
+export const submissionStatisticsItemsSchema = z.object({
+  items: z.array(z.object({ id: z.string(), result: judgeStatusSchema })),
+  truncated: z.boolean(),
 })

 export const submissionStatisticsSchema = z.object({
@@ -214,6 +223,9 @@ export type SubmissionStatistics = z.infer<typeof submissionStatisticsSchema>
 export type SubmissionStatisticsUser = z.infer<
  typeof submissionStatisticsUserSchema
 >
+export type SubmissionStatisticsItems = z.infer<
+  typeof submissionStatisticsItemsSchema
+>
 export type UnacceptedStudent = z.infer<typeof unacceptedStudentSchema>
 export type AttemptedStudent = z.infer<typeof attemptedStudentSchema>