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