feat: 日聚合服务与命令 + 索引迁移打包（Task3 审查结论）

- refresh_daily：按上海自然日聚合 pv/uv/sessions/new_visitors，update_or_create 幂等
- refresh_stats 管理命令：回刷近 N 天（生产由 1Panel 每日 00:10 调度，见 Task 22）
- 索引打包（0002）：Event/VisitSession 增加 (site, 时间) 日聚合索引；
  删 5 个冗余单列 FK 索引（Event.site/session、VisitSession.site/visitor、DailyStat.site），
  保留 Event.visitor/Visitor.site；sqlite PRAGMA 实证级联索引完整、EXPLAIN 走新索引
- test_models：IntegrityError 断言收紧 + Site 级联删除测试

Co-Authored-By: Claude Code <noreply@anthropic.com>

server/tracker/management/commands/refresh_stats.py

@@ -0,0 +1,24 @@
+from datetime import timedelta
+from django.core.management.base import BaseCommand
+from django.utils import timezone
+from tracker.models import Site
+from tracker.services.stats import refresh_daily
+
+
+class Command(BaseCommand):
+    # 生产调度：1Panel 计划任务每日 00:10 执行
+    #   docker exec <web容器> python manage.py refresh_stats --days 2
+    # （回刷含今天在内的近 N 天，详见 Task 22 README）
+    help = "回刷近 N 天日聚合（含今天）"
+
+    def add_arguments(self, parser):
+        parser.add_argument("--days", type=int, default=2)
+
+    def handle(self, *args, **opts):
+        today = timezone.localdate()
+        total = 0
+        for site in Site.objects.filter(is_active=True):
+            for i in range(opts["days"]):
+                stat = refresh_daily(site, today - timedelta(days=i))
+                total += 1
+        self.stdout.write(f"refreshed {total} site-days")

server/tracker/migrations/0002_alter_dailystat_site_alter_event_session_and_more.py

@@ -0,0 +1,47 @@
+# Generated by Django 5.2.17 on 2026-09-15 05:36
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tracker', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='dailystat',
+            name='site',
+            field=models.ForeignKey(db_index=False, on_delete=django.db.models.deletion.CASCADE, related_name='daily_stats', to='tracker.site'),
+        ),
+        migrations.AlterField(
+            model_name='event',
+            name='session',
+            field=models.ForeignKey(db_index=False, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='events', to='tracker.visitsession'),
+        ),
+        migrations.AlterField(
+            model_name='event',
+            name='site',
+            field=models.ForeignKey(db_index=False, on_delete=django.db.models.deletion.CASCADE, related_name='events', to='tracker.site'),
+        ),
+        migrations.AlterField(
+            model_name='visitsession',
+            name='site',
+            field=models.ForeignKey(db_index=False, on_delete=django.db.models.deletion.CASCADE, related_name='sessions', to='tracker.site'),
+        ),
+        migrations.AlterField(
+            model_name='visitsession',
+            name='visitor',
+            field=models.ForeignKey(db_index=False, on_delete=django.db.models.deletion.CASCADE, related_name='sessions', to='tracker.visitor'),
+        ),
+        migrations.AddIndex(
+            model_name='event',
+            index=models.Index(fields=['site', 'occurred_at'], name='event_site_id_f158ab_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='visitsession',
+            index=models.Index(fields=['site', 'started_at'], name='visit_sessi_site_id_73fae1_idx'),
+        ),
+    ]

server/tracker/models.py

@@ -53,8 +53,9 @@ class Visitor(models.Model):
 
 
 class VisitSession(models.Model):
-    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="sessions")
-    visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="sessions")
+    # db_index=False：单列 FK 索引冗余——site 由 (site, started_at)、visitor 由 (visitor, -started_at) 复合索引前缀覆盖
+    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="sessions", db_index=False)
+    visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="sessions", db_index=False)
     session_id = models.CharField(max_length=64)
     started_at = models.DateTimeField()
     ended_at = models.DateTimeField()
@@ -68,13 +69,19 @@ class VisitSession(models.Model):
     class Meta:
         db_table = "visit_session"
         constraints = [models.UniqueConstraint(fields=["site", "session_id"], name="uq_site_session")]
-        indexes = [models.Index(fields=["visitor", "-started_at"])]
+        indexes = [
+            models.Index(fields=["visitor", "-started_at"]),
+            models.Index(fields=["site", "started_at"]),   # 按日聚合/时间线查询
+        ]
 
 
 class Event(models.Model):
-    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="events")
+    # site/session 的单列 FK 索引冗余：site 由 (site, visitor/-occurred_at)、(site, event_name, -occurred_at)、
+    # (site, occurred_at) 前缀覆盖，session 由 (session, occurred_at) 前缀覆盖，故 db_index=False。
+    # visitor 保留默认索引：无其他以 visitor 打头的索引，级联删除（visitor 反向删 events）需要它。
+    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="events", db_index=False)
     visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="events")
-    session = models.ForeignKey(VisitSession, on_delete=models.CASCADE, related_name="events", null=True)
+    session = models.ForeignKey(VisitSession, on_delete=models.CASCADE, related_name="events", null=True, db_index=False)
     event_id = models.CharField(max_length=64)
     event_name = models.CharField(max_length=50)
     occurred_at = models.DateTimeField()
@@ -96,11 +103,12 @@ class Event(models.Model):
             models.Index(fields=["site", "visitor", "-occurred_at"]),
             models.Index(fields=["session", "occurred_at"]),
             models.Index(fields=["site", "event_name", "-occurred_at"]),
+            models.Index(fields=["site", "occurred_at"]),   # refresh_daily 按日聚合扫描
         ]
 
 
 class DailyStat(models.Model):
-    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="daily_stats")
+    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="daily_stats", db_index=False)   # uq_site_date 前缀覆盖
     date = models.DateField()
     pv = models.PositiveIntegerField(default=0)
     uv = models.PositiveIntegerField(default=0)

server/tracker/services/stats.py

@@ -0,0 +1,26 @@
+from datetime import datetime, time, timedelta
+from django.utils import timezone
+from tracker.models import DailyStat, Event, VisitSession, Visitor
+
+
+def refresh_daily(site, date) -> DailyStat:
+    """重算某站点某自然日的聚合（幂等，update_or_create）。
+
+    日界取 TIME_ZONE（Asia/Shanghai）自然日：make_aware(datetime.combine(date, time.min))。
+    口径：pv/uv 均从事件表统计（排除 is_bot），uv=distinct visitor，与 pv 同源；
+    sessions 按会话 started_at 落入当日且访客非爬虫；new_visitors 按 Visitor.first_seen_at 落入当日。
+    """
+    day_start = timezone.make_aware(datetime.combine(date, time.min))
+    day_end = day_start + timedelta(days=1)
+    pv = Event.objects.filter(site=site, is_bot=False,
+                              occurred_at__gte=day_start, occurred_at__lt=day_end).count()
+    uv = Event.objects.filter(site=site, is_bot=False, occurred_at__gte=day_start,
+                              occurred_at__lt=day_end).values("visitor").distinct().count()
+    sessions = VisitSession.objects.filter(site=site, visitor__is_bot=False,
+                                           started_at__gte=day_start,
+                                           started_at__lt=day_end).count()
+    new_v = Visitor.objects.filter(site=site, first_seen_at__gte=day_start,
+                                   first_seen_at__lt=day_end).count()
+    obj, _ = DailyStat.objects.update_or_create(site=site, date=date,
+        defaults={"pv": pv, "uv": uv, "sessions": sessions, "new_visitors": new_v})
+    return obj

server/tracker/tests/test_models.py

@@ -1,4 +1,5 @@
 import pytest
+from django.db import IntegrityError
 from tracker.models import Site, Visitor, VisitSession, Event
 
 pytestmark = pytest.mark.django_db
@@ -22,6 +23,16 @@ def test_event_unique_site_event_id():
         started_at="2026-09-15T10:00:00Z", ended_at="2026-09-15T10:01:00Z")
     Event.objects.create(site=site, visitor=v, session=s, event_id="e1",
         event_name="page_view", occurred_at="2026-09-15T10:00:00Z", path="/")
-    with pytest.raises(Exception):
+    with pytest.raises(IntegrityError):
         Event.objects.create(site=site, visitor=v, session=s, event_id="e1",
             event_name="page_view", occurred_at="2026-09-15T10:01:00Z", path="/")
+
+def test_site_cascade_deletes_children():
+    site = Site.objects.create(name="s", domains=["a.com"])
+    v = Visitor.objects.create(site=site, visitor_id="v")
+    s = VisitSession.objects.create(site=site, visitor=v, session_id="s",
+        started_at="2026-09-15T10:00:00Z", ended_at="2026-09-15T10:01:00Z")
+    Event.objects.create(site=site, visitor=v, session=s, event_id="e",
+        event_name="page_view", occurred_at="2026-09-15T10:00:00Z", path="/")
+    site.delete()
+    assert Visitor.objects.count() == 0 and VisitSession.objects.count() == 0 and Event.objects.count() == 0

server/tracker/tests/test_stats.py

@@ -0,0 +1,30 @@
+from datetime import timedelta
+from django.utils import timezone
+from tracker.models import Site, Visitor, VisitSession, Event
+from tracker.services.stats import refresh_daily
+
+# 用上海本地时刻做基准：refresh_daily 的日界是上海自然日（make_aware），
+# 若直接用 UTC 的 timezone.now()，在本地 00:00-08:00 之间跑测试时 NOW.date() 会错一天
+NOW = timezone.localtime(timezone.now())
+YESTERDAY = NOW - timedelta(days=1)
+
+def _mk(site, vid, sid, day, n_events, stay=0):
+    v, _ = Visitor.objects.get_or_create(site=site, visitor_id=vid)
+    sess = VisitSession.objects.create(site=site, visitor=v, session_id=sid,
+        started_at=day, ended_at=day + timedelta(minutes=5),
+        stay_ms=stay, event_count=n_events)
+    for i in range(n_events):
+        Event.objects.create(site=site, visitor=v, session=sess, event_id=f"{vid}-{sid}-{day:%Y%m%d}-{i}",
+            event_name="page_view", occurred_at=day + timedelta(seconds=i), path="/")
+
+def test_refresh_daily_two_days(db):
+    site = Site.objects.create(name="s", domains=["a.com"])
+    _mk(site, "v1", "s1", YESTERDAY, 3)          # v1 昨天 3 事件
+    _mk(site, "v1", "s2", NOW, 2, stay=8000)      # v1 今天 2 事件
+    _mk(site, "v2", "s3", NOW, 4)                 # v2 今天 4 事件
+    y = refresh_daily(site, YESTERDAY.date())
+    t = refresh_daily(site, NOW.date())
+    # new_visitors 口径 = first_seen_at 落入当日。测试里 v1 虽有昨日事件，但访客记录是测试运行时（今天）建档的
+    # （auto_now_add），故昨天 new=0、今天 new=2（v1+v2）——按 first_seen_at 真实语义断言
+    assert (y.pv, y.uv, y.sessions, y.new_visitors) == (3, 1, 1, 0)
+    assert (t.pv, t.uv, t.sessions, t.new_visitors) == (6, 2, 2, 2)   # 今天：pv=6 uv=2(v1+v2) sessions=2 new=2(v1+v2)