feat(status): 启用 pg_stat_statements,运行状态页显示最慢 / 最频繁语句与各表死元组;PG 调低 random_page_cost

- docker-compose.yml 的 postgres 加 shared_preload_libraries=pg_stat_statements、pg_stat_statements.track=top;
  要重建 postgres 容器才生效(docs/runbook/storage.md)
- GET /system/storage 的 db.statements:平均最慢(调用 ≥ 10 次)与调用最多各 5 条;没装扩展 / 没预加载时
  enabled=false 并说明原因
- 运行状态页「存储」:体积最大的表加死元组列,新增「数据库语句统计」
- random_page_cost 4 → 1.1(PG_RANDOM_PAGE_COST):库整个在内存里,缺省值高估随机读

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Cxwgnn2pbzQ7rXv3rq7fei

apps/server/src/modules/system/storage.ts

@@ -248,10 +248,59 @@ export async function storageHealth(d: StorageDeps): Promise<{ level: HealthLeve
   return { level: l.level, alerts: l.alerts };
 }
 
+type Statements = SystemStorage["db"]["statements"];
+const STATEMENT_TOP = 5;
+/** 平均耗时排行只看调用过这么多次的语句(迁移、一次性维护语句不进榜) */
+const SLOW_MIN_CALLS = 10;
+
+/** pg_stat_statements 前几名;没装扩展或 postgres 没预加载时 enabled=false(不报错) */
+export async function statementStats(db: Kysely<DB>): Promise<Statements> {
+  const off = (note: string): Statements => ({ enabled: false, note, since: null, slowest: [], frequent: [] });
+  const has = await sql<{ r: string | null }>`select to_regclass('public.pg_stat_statements')::text as r`
+    .execute(db)
+    .catch(() => null);
+  if (!has?.rows[0]?.r) return off("没有安装 pg_stat_statements 扩展");
+  // 装了扩展但 postgres 没预加载时,查视图会报错
+  try {
+    await sql`select 1 from public.pg_stat_statements limit 1`.execute(db);
+  } catch {
+    return off("postgres 没有预加载 pg_stat_statements（shared_preload_libraries），重启数据库后生效");
+  }
+  type Row = { query: string; calls: string; total: number; mean: number; rows: string };
+  const top = async (order: "mean" | "calls") =>
+    (
+      await sql<Row>`
+        select left(regexp_replace(query, '[[:space:]]+', ' ', 'g'), 500) as query, calls::text,
+               total_exec_time as total, mean_exec_time as mean, rows::text
+          from public.pg_stat_statements
+         where dbid = (select oid from pg_database where datname = current_database())
+           and query not ilike '%pg_stat_statements%'
+           ${order === "mean" ? sql`and calls >= ${SLOW_MIN_CALLS} order by mean_exec_time desc` : sql`order by calls desc`}
+         limit ${STATEMENT_TOP}`.execute(db)
+    ).rows.map((r) => ({
+      query: r.query,
+      calls: Number(r.calls),
+      totalMs: Math.round(r.total * 100) / 100,
+      meanMs: Math.round(r.mean * 1000) / 1000,
+      rows: Number(r.rows),
+    }));
+  const info = await sql<{ since: Date | null }>`select stats_reset as since from public.pg_stat_statements_info`
+    .execute(db)
+    .catch(() => null);
+  const since = info?.rows[0]?.since;
+  return {
+    enabled: true,
+    note: null,
+    since: since ? new Date(since).toISOString() : null,
+    slowest: await top("mean"),
+    frequent: await top("calls"),
+  };
+}
+
 export async function buildStorage(
   d: StorageDeps & { engineSchema: string; refresh?: boolean },
 ): Promise<SystemStorage> {
-  const [bytes, scan, tables, kv, jobs] = await Promise.all([
+  const [bytes, scan, tables, kv, jobs, statements] = await Promise.all([
     dbSize(d.db).catch(() => null),
     dirScan(d.paths, { wait: true, force: d.refresh ?? false }).catch(() => null),
     sql<{
@@ -287,6 +336,7 @@ export async function buildStorage(
       .where("id", "in", Object.values(CLEANUP_JOB_IDS))
       .execute()
       .catch(() => []),
+    statementStats(d.db),
   ]);
   const lastSummaries = new Map<string, string | null>();
   if (jobs.length) {
@@ -324,6 +374,7 @@ export async function buildStorage(
         lastAutovacuumAt: iso(t.vac),
         lastAnalyzeAt: iso(t.ana),
       })),
+      statements,
     },
     kvCache: kv.rows.map((r) => ({ region: r.region, entries: r.entries, expired: r.expired, bytes: Number(r.bytes) })),
     images: { ...l.images, files: scan ? scan.images.files : null },

apps/server/test/system/storage.test.ts

@@ -287,6 +287,9 @@ describe.skipIf(!hasPg)("CACHE-2 存储(真实 PG)", () => {
     const obs = d.cleanup.find((c) => c.target === "observation")!;
     expect(obs).toMatchObject({ jobId: "storage.retention.observation", retention: "90 天" });
     expect(d.cleanup.find((c) => c.target === "heartbeat")?.retention).toBe("24 小时");
+    expect(d.cleanup.find((c) => c.target === "pipeline")).toMatchObject({ jobId: "storage.retention.pipeline" });
+    // 语句统计:测试库没有预加载 pg_stat_statements 时给出原因,不报错
+    if (!d.db.statements.enabled) expect(d.db.statements.note).toMatch(/pg_stat_statements/);
     expect(d.level).toBe("ok");
   });
 

apps/web/app/components/status/storage-section.tsx

@@ -200,6 +200,72 @@ function CleanupTable({ rows }: { rows: CleanupRow[] }) {
 }
 
 /** 运行状态页的「存储」节 */
+type Statements = SystemStorage["db"]["statements"];
+type StatementRow = Statements["slowest"][number];
+
+const fmtMs = (ms: number) =>
+  ms >= 1000 ? `${(ms / 1000).toFixed(1)} 秒` : `${ms < 10 ? ms.toFixed(2) : Math.round(ms)} 毫秒`;
+
+function StatementTable({ rows }: { rows: StatementRow[] }) {
+  return (
+    <DataTable<StatementRow>
+      rows={rows}
+      rowKey={(r) => r.query}
+      empty={{ title: "还没有统计" }}
+      columns={[
+        {
+          key: "query",
+          header: "语句",
+          cell: (r) => (
+            <span className="line-clamp-2 font-mono text-meta break-all" title={r.query}>
+              {r.query}
+            </span>
+          ),
+        },
+        {
+          key: "calls",
+          header: "次数",
+          align: "right",
+          cell: (r) => <span className="tabular-nums">{r.calls.toLocaleString("zh-CN")}</span>,
+        },
+        {
+          key: "mean",
+          header: "平均",
+          align: "right",
+          cell: (r) => <span className="whitespace-nowrap tabular-nums">{fmtMs(r.meanMs)}</span>,
+        },
+        {
+          key: "total",
+          header: "合计",
+          align: "right",
+          hideBelow: "sm",
+          cell: (r) => <span className="whitespace-nowrap tabular-nums text-muted-foreground">{fmtMs(r.totalMs)}</span>,
+        },
+      ]}
+    />
+  );
+}
+
+/** 数据库语句统计(pg_stat_statements,见 docs/runbook/storage.md「数据库性能」) */
+function StatementsInfo({ st }: { st: Statements }) {
+  return (
+    <TechInfo title="数据库语句统计" columns={1}>
+      {st.enabled ? (
+        <div className="grid gap-6 xl:grid-cols-2">
+          <Panel title="平均最慢" note={`调用 10 次以上${st.since ? ` · 统计自 ${formatDateTime(st.since)}` : ""}`}>
+            <StatementTable rows={st.slowest} />
+          </Panel>
+          <Panel title="调用最多">
+            <StatementTable rows={st.frequent} />
+          </Panel>
+        </div>
+      ) : (
+        <p className="text-caption text-muted-foreground">语句统计未启用：{st.note}</p>
+      )}
+    </TechInfo>
+  );
+}
+
 export function StorageSection({ health }: { health: SystemHealth }) {
   const q = useSystemStorage();
   const s = q.data;
@@ -305,6 +371,17 @@ export function StorageSection({ health }: { health: SystemHealth }) {
                         </span>
                       ),
                     },
+                    {
+                      key: "dead",
+                      header: "死元组",
+                      align: "right",
+                      hideBelow: "md",
+                      cell: (t) => (
+                        <span className="tabular-nums text-muted-foreground">
+                          {t.deadRows === null ? "—" : t.deadRows.toLocaleString("zh-CN")}
+                        </span>
+                      ),
+                    },
                   ]}
                 />
               </Panel>
@@ -391,6 +468,8 @@ export function StorageSection({ health }: { health: SystemHealth }) {
             </div>
           </div>
 
+          <StatementsInfo st={s.db.statements} />
+
           <Panel title="清理任务" note="立即清理会把对应的维护任务排入执行，结果看运行记录">
             <CleanupTable rows={s.cleanup} />
           </Panel>