perf(analytics): 5表 updated_at 窄索引——health MAX 消除全表扫(128MB buffer pool)

Co-Authored-By: Claude Code <noreply@anthropic.com>
2026-09-04 16:40:01 +08:00
parent 5b6a9bd35b
commit af05e58976
3 changed files with 105 additions and 0 deletions
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+"""5 表 updated_at 窄索引——/api/analytics/health MAX 消除全表扫
+
+Revision ID: c3d4e5f6a7b8
+Revises: f0a1b2c3d4e5
+Create Date: 2026-09-04
+
+health 端点每页面加载对 6 表各 MAX 一次;5 表 updated_at 无索引时
+MySQL 全表扫(media 5万宽行在 128MB buffer pool 下最伤)。单列窄索引
+各几 MB,MAX 变 O(1) 索引定位。幂等:_has_index 先查。SQLite/MySQL 通用。
+模型侧 models.py 同步双声明,防 alembic autogenerate 反 DROP。
+"""
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "c3d4e5f6a7b8"
+down_revision: str | Sequence[str] | None = "f0a1b2c3d4e5"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+# (表名, 索引名) —— 与 models.py 各模型 __table_args__ 一字对应
+_INDEXES: tuple[tuple[str, str], ...] = (
+    ("customer", "ix_customer_updated_at"),
+    ("chat_group", "ix_chat_group_updated_at"),
+    ("phone_call", "ix_phone_call_updated_at"),
+    ("media", "ix_media_updated_at"),
+    ("moments_post", "ix_moments_post_updated_at"),
+)
+
+
+def _has_index(bind, table: str, index: str) -> bool:
+    insp = sa.inspect(bind)
+    if not insp.has_table(table):
+        return False
+    return index in {ix["name"] for ix in insp.get_indexes(table)}
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    for table, index in _INDEXES:
+        if not _has_index(bind, table, index):
+            op.create_index(index, table, ["updated_at"])
+
+
+def downgrade() -> None:
+    bind = op.get_bind()
+    for table, index in _INDEXES:
+        if _has_index(bind, table, index):
+            op.drop_index(index, table_name=table)