322 lines
9.4 KiB
Python
Executable File
322 lines
9.4 KiB
Python
Executable File
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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数据库连接池模块
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使用queue实现固定大小的连接池,防止连接泄漏
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"""
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import sqlite3
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import threading
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import time
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from queue import Empty, Full, Queue
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from app_config import get_config
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from app_logger import get_logger
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logger = get_logger("database")
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config = get_config()
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DB_CONNECT_TIMEOUT_SECONDS = max(1, int(getattr(config, "DB_CONNECT_TIMEOUT_SECONDS", 10)))
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DB_BUSY_TIMEOUT_MS = max(1000, int(getattr(config, "DB_BUSY_TIMEOUT_MS", 10000)))
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DB_CACHE_SIZE_KB = max(1024, int(getattr(config, "DB_CACHE_SIZE_KB", 8192)))
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DB_WAL_AUTOCHECKPOINT_PAGES = max(100, int(getattr(config, "DB_WAL_AUTOCHECKPOINT_PAGES", 1000)))
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DB_MMAP_SIZE_MB = max(0, int(getattr(config, "DB_MMAP_SIZE_MB", 256)))
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DB_LOCK_RETRY_COUNT = max(0, int(getattr(config, "DB_LOCK_RETRY_COUNT", 3)))
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DB_LOCK_RETRY_BASE_MS = max(10, int(getattr(config, "DB_LOCK_RETRY_BASE_MS", 50)))
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def _is_lock_conflict_error(error: sqlite3.OperationalError) -> bool:
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message = str(error or "").lower()
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return ("locked" in message) or ("busy" in message)
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class ConnectionPool:
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"""SQLite连接池"""
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def __init__(self, database, pool_size=5, timeout=30):
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"""
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初始化连接池
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Args:
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database: 数据库文件路径
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pool_size: 连接池大小(默认5)
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timeout: 获取连接超时时间(秒)
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"""
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self.database = database
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self.pool_size = pool_size
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self.timeout = timeout
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self._pool = Queue(maxsize=pool_size)
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self._lock = threading.Lock()
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self._created_connections = 0
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# 预创建连接
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self._initialize_pool()
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def _initialize_pool(self):
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"""预创建连接池中的连接"""
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for _ in range(self.pool_size):
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conn = self._create_connection()
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self._pool.put(conn)
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self._created_connections += 1
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def _create_connection(self):
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"""创建新的数据库连接"""
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conn = sqlite3.connect(
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self.database,
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check_same_thread=False,
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timeout=DB_CONNECT_TIMEOUT_SECONDS,
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)
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conn.row_factory = sqlite3.Row
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pragma_statements = [
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"PRAGMA foreign_keys=ON",
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"PRAGMA journal_mode=WAL",
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"PRAGMA synchronous=NORMAL",
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f"PRAGMA busy_timeout={DB_BUSY_TIMEOUT_MS}",
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"PRAGMA temp_store=MEMORY",
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f"PRAGMA cache_size={-DB_CACHE_SIZE_KB}",
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f"PRAGMA wal_autocheckpoint={DB_WAL_AUTOCHECKPOINT_PAGES}",
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]
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if DB_MMAP_SIZE_MB > 0:
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pragma_statements.append(f"PRAGMA mmap_size={DB_MMAP_SIZE_MB * 1024 * 1024}")
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for statement in pragma_statements:
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try:
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conn.execute(statement)
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except sqlite3.DatabaseError as e:
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logger.warning(f"设置数据库参数失败 ({statement}): {e}")
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return conn
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def _close_connection(self, conn) -> None:
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if conn is None:
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return
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try:
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conn.close()
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except Exception as e:
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logger.warning(f"关闭连接失败: {e}")
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def _is_connection_healthy(self, conn) -> bool:
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if conn is None:
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return False
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try:
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conn.rollback()
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conn.execute("SELECT 1")
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return True
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except sqlite3.Error as e:
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logger.warning(f"连接健康检查失败(数据库错误): {e}")
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except Exception as e:
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logger.warning(f"连接健康检查失败(未知错误): {e}")
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return False
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def _replenish_pool_if_needed(self) -> None:
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with self._lock:
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if self._pool.qsize() >= self.pool_size:
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return
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new_conn = None
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try:
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new_conn = self._create_connection()
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self._pool.put(new_conn, block=False)
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self._created_connections += 1
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except Full:
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if new_conn:
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self._close_connection(new_conn)
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except Exception as e:
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if new_conn:
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self._close_connection(new_conn)
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logger.warning(f"重建连接失败: {e}")
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def get_connection(self):
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"""
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从连接池获取连接
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Returns:
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PooledConnection: 连接包装对象
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"""
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try:
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conn = self._pool.get(timeout=self.timeout)
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return PooledConnection(conn, self)
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except Empty:
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raise RuntimeError(f"无法在{self.timeout}秒内获取数据库连接")
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def return_connection(self, conn):
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"""
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归还连接到连接池 [安全修复: 改进竞态条件处理]
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Args:
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conn: 要归还的连接
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"""
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if conn is None:
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return
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if self._is_connection_healthy(conn):
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try:
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self._pool.put(conn, block=False)
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return
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except Full:
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logger.warning("连接池已满，关闭多余连接")
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self._close_connection(conn)
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return
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self._close_connection(conn)
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self._replenish_pool_if_needed()
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def close_all(self):
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"""关闭所有连接"""
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while not self._pool.empty():
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try:
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conn = self._pool.get(block=False)
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conn.close()
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except Exception as e:
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logger.warning(f"关闭连接失败: {e}")
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def get_stats(self):
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"""获取连接池统计信息"""
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return {
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"pool_size": self.pool_size,
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"available": self._pool.qsize(),
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"in_use": self.pool_size - self._pool.qsize(),
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"total_created": self._created_connections,
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}
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class PooledConnection:
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"""连接池连接包装器,支持with语句自动归还"""
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def __init__(self, conn, pool):
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"""
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初始化
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Args:
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conn: 实际的数据库连接
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pool: 连接池对象
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"""
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self._conn = conn
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self._pool = pool
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self._cursor = None
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def __enter__(self):
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"""支持with语句"""
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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"""with语句结束时自动归还连接 [已修复Bug#3]"""
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try:
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if exc_type is not None:
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# 发生异常,回滚事务
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self._conn.rollback()
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logger.warning(f"数据库事务已回滚: {exc_type.__name__}")
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# 注意: 不自动commit，要求用户显式调用conn.commit()
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if self._cursor:
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self._cursor.close()
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self._cursor = None
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except Exception as e:
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logger.warning(f"关闭游标失败: {e}")
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finally:
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# 归还连接
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self._pool.return_connection(self._conn)
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return False # 不抑制异常
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def cursor(self):
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"""获取游标"""
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if self._cursor is None:
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self._cursor = self._conn.cursor()
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return self._cursor
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def commit(self):
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"""提交事务"""
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for attempt in range(DB_LOCK_RETRY_COUNT + 1):
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try:
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self._conn.commit()
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return
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except sqlite3.OperationalError as e:
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if (not _is_lock_conflict_error(e)) or attempt >= DB_LOCK_RETRY_COUNT:
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raise
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sleep_seconds = (DB_LOCK_RETRY_BASE_MS * (2**attempt)) / 1000.0
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logger.warning(
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f"数据库提交遇到锁冲突，{sleep_seconds:.3f}s 后重试 "
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f"({attempt + 1}/{DB_LOCK_RETRY_COUNT})"
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)
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time.sleep(sleep_seconds)
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def rollback(self):
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"""回滚事务"""
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self._conn.rollback()
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def execute(self, sql, parameters=None):
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"""执行SQL"""
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cursor = self.cursor()
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if parameters:
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return cursor.execute(sql, parameters)
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return cursor.execute(sql)
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def fetchone(self):
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"""获取一行"""
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if self._cursor:
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return self._cursor.fetchone()
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return None
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def fetchall(self):
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"""获取所有行"""
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if self._cursor:
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return self._cursor.fetchall()
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return []
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@property
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def lastrowid(self):
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"""最后插入的行ID"""
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if self._cursor:
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return self._cursor.lastrowid
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return None
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@property
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def rowcount(self):
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"""影响的行数"""
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if self._cursor:
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return self._cursor.rowcount
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return 0
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# 全局连接池实例
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_pool = None
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_pool_lock = threading.Lock()
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def init_pool(database, pool_size=5):
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"""
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初始化全局连接池
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Args:
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database: 数据库文件路径
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pool_size: 连接池大小
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"""
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global _pool
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with _pool_lock:
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if _pool is None:
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_pool = ConnectionPool(database, pool_size)
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logger.info(f"[OK] 数据库连接池已初始化 (大小: {pool_size})")
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def get_db():
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"""
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获取数据库连接(替代原有的get_db函数)
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Returns:
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PooledConnection: 连接对象
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"""
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global _pool
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if _pool is None:
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raise RuntimeError("连接池未初始化,请先调用init_pool()")
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return _pool.get_connection()
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def get_pool_stats():
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"""获取连接池统计信息"""
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global _pool
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if _pool:
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return _pool.get_stats()
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return None
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