perf(analytics): analytics_event 活跃口径复合索引 (event,page,user_id,created_at)

active_event_condition 按 (event=show & page=home) ∪ 比价 ∪ 领券 过滤后 group by user_id、
max(created_at),是 worker 清零/预警 + admin 最近活跃的热点聚合;page 原无索引、show 又高频。
加覆盖索引 ix_analytics_event_active 让该聚合走 index-only。

⚠️ 分支迁移树既有多头(135e79414fd0 与 phone_rebind_log 同从 comparison_llm_cost 分叉,
`alembic upgrade head` 会多头报错)——既有问题、与本次无关。本迁移挂在 135e79414fd0 一侧,
dev 用 `alembic upgrade analytics_active_idx` 应用;集成 main 时需 alembic merge 合并 phone_rebind_log 头。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

alembic/versions/analytics_active_idx_active_composite_index.py

@@ -0,0 +1,36 @@
+"""analytics_event 活跃口径复合索引
+
+Revision ID: analytics_active_idx
+Revises: 135e79414fd0
+Create Date: 2026-07-18 17:35:00.000000
+
+给 analytics_event 加活跃口径热点复合索引 (event, page, user_id, created_at):
+activity.active_event_condition 按 (event=show & page=home) ∪ 比价 ∪ 领券 过滤后
+group by user_id、max(created_at)。覆盖索引让该聚合走 index-only,避免高频 show 事件全表扫。
+
+⚠️ 本分支迁移树有**既有多头**:135e79414fd0(不活跃两表)与 phone_rebind_log 同从
+comparison_llm_cost 分叉,`alembic upgrade head` 会多头报错。本迁移挂在 135e79414fd0
+一侧;集成到 main 时需 `alembic merge` 合并 phone_rebind_log 那个头(与本迁移无关的既有问题)。
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "analytics_active_idx"
+down_revision: Union[str, Sequence[str], None] = "135e79414fd0"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_index(
+        "ix_analytics_event_active",
+        "analytics_event",
+        ["event", "page", "user_id", "created_at"],
+        unique=False,
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_analytics_event_active", table_name="analytics_event")

app/models/analytics_event.py

@@ -15,7 +15,7 @@ from __future__ import annotations
 
 from datetime import datetime
 
-from sqlalchemy import JSON, BigInteger, DateTime, Integer, String, func
+from sqlalchemy import JSON, BigInteger, DateTime, Index, Integer, String, func
 from sqlalchemy.orm import Mapped, mapped_column
 
 from app.db.base import Base
@@ -23,6 +23,12 @@ from app.db.base import Base
 
 class AnalyticsEvent(Base):
     __tablename__ = "analytics_event"
+    __table_args__ = (
+        # 活跃口径聚合热点(activity.active_event_condition + last_active_subqueries):
+        # 按 (event,page) 过滤 首页可见(show/home)∪比价∪领券,再 group by user_id 取
+        # max(created_at)。覆盖索引 → 该聚合走 index-only,避免高频 show 事件全表扫。
+        Index("ix_analytics_event_active", "event", "page", "user_id", "created_at"),
+    )
 
     id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)