Archived
snowy-yang
9a34517454
为什么：同步层每次数据库操作都新建连接并执行 mkdir + PRAGMA journal_mode=WAL。实测拆解（各 100 次中位数）： mkdir(exist_ok) 190us sqlite3.connect 435us PRAGMA WAL(新连接首语句) ~1000us ← 大头 get_conn 合计 1641us → 501us 登录路径走同步层 4 次查询（身份解析/验证/位置/日志），每次请求 固定省 ~4.6ms；下载任务的 ledger/日志调用同样受益。 改动（对齐 core/db.py 既有模式——异步层早已做过同款优化并记录过 「并发 PRAGMA 争排他锁报 database is locked」的实测坑，同步层漏同步）： - _WAL_READY 按路径缓存：journal_mode 持久化在库文件头，设一次即可； _WAL_SETUP_LOCK 串行化首连切换（读路径不持 _DB_LOCK） - mkdir 移出 happy path：connect 失败才兜底补建（用 DB_PATH.parent， monkeypatch 场景下与 DATA_DIR 可能不同） - exists() 检查在 connect 之前（connect 会创建空文件，之后恒真）， 覆盖「删库重建后新文件回退 delete 模式」的边界 新增 tests/test_db_conn.py 6 例：WAL 首连生效、后续连接零 PRAGMA （set_trace_callback 实证）、换路径重设、目录缺失自动建、删库重建 恢复 WAL、8 线程并发首连无报错。 门禁：ruff 全过 · pyright 0/0 · pytest 382 passed（375→382）。
132 lines
4.2 KiB
Python
132 lines
4.2 KiB
Python
"""get_conn 连接策略契约：WAL 首连设置一次 + 目录自动创建。
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背景：get_conn 原实现每个连接都执行 mkdir + PRAGMA journal_mode=WAL，
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实测每次多付 ~1.2ms（mkdir 190us + 新连接上 PRAGMA ~1ms）。WAL 模式
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持久化在库文件头里，与 core/db.py 的 _WAL_READY_FOR 同款，按路径设一次即可。
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"""
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import sqlite3
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from pathlib import Path
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from auth_system import db
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def _point_db_to(monkeypatch, tmp_path: Path, conn_counter: list[int] | None = None):
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"""把 DB_PATH 指到临时库，并清空 WAL 已就绪缓存。"""
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new_path = tmp_path / 'site.db'
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monkeypatch.setattr(db, 'DB_PATH', new_path)
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monkeypatch.setattr(db, '_WAL_READY', set())
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if conn_counter is not None:
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real_connect = sqlite3.connect
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def counting_connect(*a, **k):
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conn_counter[0] += 1
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return real_connect(*a, **k)
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monkeypatch.setattr(db.sqlite3, 'connect', counting_connect)
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return new_path
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def test_wal_mode_active_on_fresh_db(monkeypatch, tmp_path):
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"""新路径首连：WAL 生效。"""
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_point_db_to(monkeypatch, tmp_path)
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conn = db.get_conn()
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try:
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mode = conn.execute('PRAGMA journal_mode').fetchone()[0]
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assert mode.lower() == 'wal'
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finally:
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conn.close()
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def test_wal_pragma_only_once_per_path(monkeypatch, tmp_path):
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"""同一路径第二次起不再执行 PRAGMA journal_mode=WAL（用 SQL 追踪器实证）。"""
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_point_db_to(monkeypatch, tmp_path)
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conn1 = db.get_conn()
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conn1.close()
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conn2 = db.get_conn()
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conn2.close()
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# 用 sqlite3 的 set_trace_callback 记录第三条连接上的语句（2 连接已建立缓存）
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statements: list[str] = []
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conn3 = db.get_conn()
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conn3.set_trace_callback(statements.append)
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conn3.execute('SELECT 1').fetchall()
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conn3.close()
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assert statements == ['SELECT 1'], f'第三条连接不应再跑 PRAGMA，实际: {statements}'
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def test_new_path_resets_wal_cache(monkeypatch, tmp_path):
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"""换库路径（测试隔离场景）：新路径重新设置 WAL。"""
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_point_db_to(monkeypatch, tmp_path / 'a')
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c = db.get_conn()
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c.close()
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monkeypatch.setattr(db, 'DB_PATH', tmp_path / 'b' / 'site.db')
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c = db.get_conn()
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try:
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mode = c.execute('PRAGMA journal_mode').fetchone()[0]
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assert mode.lower() == 'wal'
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finally:
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c.close()
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def test_missing_dir_auto_created(monkeypatch, tmp_path):
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"""目录不存在：connect 失败兜底 mkdir 重试，不经 init_db 也能用。"""
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deep = tmp_path / 'x' / 'y'
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_point_db_to(monkeypatch, deep)
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assert not deep.exists()
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conn = db.get_conn()
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try:
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conn.execute('CREATE TABLE t (v)').close()
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conn.commit()
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finally:
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conn.close()
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assert (deep / 'site.db').exists()
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def test_deleted_db_file_recovers(monkeypatch, tmp_path):
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"""库文件被删（目录还在）：重连自动重建且恢复 WAL 模式，不崩。"""
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_point_db_to(monkeypatch, tmp_path)
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c = db.get_conn()
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c.close()
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(tmp_path / 'site.db').unlink()
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conn = db.get_conn()
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try:
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conn.execute('SELECT 1').fetchall()
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mode = conn.execute('PRAGMA journal_mode').fetchone()[0]
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assert mode.lower() == 'wal', '重建的库文件必须恢复 WAL（journal_mode 不持久于新文件）'
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finally:
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conn.close()
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def test_concurrent_first_connect_no_lease_conflict(monkeypatch, tmp_path):
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"""多线程同时首连（读路径不持 _DB_LOCK）：WAL 设置正确、无连接报错。
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core/db.py 记录过并发 PRAGMA 争排他锁报 database is locked 的实测坑，
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同步层用专用锁 + 二次复查同款防护。
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"""
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import threading
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_point_db_to(monkeypatch, tmp_path)
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errors: list[Exception] = []
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def worker():
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try:
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for _ in range(5):
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c = db.get_conn()
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c.execute('SELECT 1').fetchall()
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c.close()
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except Exception as e: # 收集全部失败供断言
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errors.append(e)
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threads = [threading.Thread(target=worker) for _ in range(8)]
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for t in threads:
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t.start()
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for t in threads:
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t.join()
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assert errors == []
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