269 lines
8.9 KiB
Python
269 lines
8.9 KiB
Python
"""
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透明连接复用管理器
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在不改变原有API的情况下，实现数据库连接的智能复用
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"""
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import asyncio
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import time
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from contextlib import asynccontextmanager
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from typing import Any
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from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
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from src.common.logger import get_logger
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logger = get_logger("connection_pool_manager")
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class ConnectionInfo:
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"""连接信息包装器"""
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def __init__(self, session: AsyncSession, created_at: float):
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self.session = session
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self.created_at = created_at
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self.last_used = created_at
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self.in_use = False
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self.ref_count = 0
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def mark_used(self):
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"""标记连接被使用"""
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self.last_used = time.time()
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self.in_use = True
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self.ref_count += 1
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def mark_released(self):
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"""标记连接被释放"""
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self.in_use = False
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self.ref_count = max(0, self.ref_count - 1)
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def is_expired(self, max_lifetime: float = 300.0, max_idle: float = 60.0) -> bool:
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"""检查连接是否过期"""
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current_time = time.time()
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# 检查总生命周期
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if current_time - self.created_at > max_lifetime:
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return True
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# 检查空闲时间
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if not self.in_use and current_time - self.last_used > max_idle:
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return True
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return False
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async def close(self):
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"""关闭连接"""
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try:
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await self.session.close()
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logger.debug("连接已关闭")
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except Exception as e:
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logger.warning(f"关闭连接时出错: {e}")
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class ConnectionPoolManager:
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"""透明的连接池管理器"""
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def __init__(self, max_pool_size: int = 10, max_lifetime: float = 300.0, max_idle: float = 60.0):
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self.max_pool_size = max_pool_size
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self.max_lifetime = max_lifetime
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self.max_idle = max_idle
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# 连接池
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self._connections: set[ConnectionInfo] = set()
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self._lock = asyncio.Lock()
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# 统计信息
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self._stats = {
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"total_created": 0,
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"total_reused": 0,
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"total_expired": 0,
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"active_connections": 0,
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"pool_hits": 0,
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"pool_misses": 0,
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}
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# 后台清理任务
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self._cleanup_task: asyncio.Task | None = None
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self._should_cleanup = False
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logger.info(f"连接池管理器初始化完成 (最大池大小: {max_pool_size})")
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async def start(self):
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"""启动连接池管理器"""
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if self._cleanup_task is None:
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self._should_cleanup = True
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self._cleanup_task = asyncio.create_task(self._cleanup_loop())
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logger.info("连接池管理器已启动")
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async def stop(self):
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"""停止连接池管理器"""
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self._should_cleanup = False
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if self._cleanup_task:
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self._cleanup_task.cancel()
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try:
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await self._cleanup_task
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except asyncio.CancelledError:
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pass
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self._cleanup_task = None
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# 关闭所有连接
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await self._close_all_connections()
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logger.info("连接池管理器已停止")
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@asynccontextmanager
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async def get_session(self, session_factory: async_sessionmaker[AsyncSession]):
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"""
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获取数据库会话的透明包装器
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如果有可用连接则复用，否则创建新连接
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"""
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connection_info = None
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try:
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# 尝试获取现有连接
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connection_info = await self._get_reusable_connection(session_factory)
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if connection_info:
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# 复用现有连接
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connection_info.mark_used()
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self._stats["total_reused"] += 1
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self._stats["pool_hits"] += 1
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logger.debug(f"复用现有连接 (活跃连接数: {len(self._connections)})")
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else:
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# 创建新连接
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session = session_factory()
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connection_info = ConnectionInfo(session, time.time())
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async with self._lock:
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self._connections.add(connection_info)
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connection_info.mark_used()
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self._stats["total_created"] += 1
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self._stats["pool_misses"] += 1
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logger.debug(f"创建新连接 (活跃连接数: {len(self._connections)})")
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yield connection_info.session
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except Exception:
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# 发生错误时回滚连接
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if connection_info and connection_info.session:
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try:
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await connection_info.session.rollback()
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except Exception as rollback_error:
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logger.warning(f"回滚连接时出错: {rollback_error}")
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raise
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finally:
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# 释放连接回池中
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if connection_info:
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connection_info.mark_released()
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async def _get_reusable_connection(
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self, session_factory: async_sessionmaker[AsyncSession]
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) -> ConnectionInfo | None:
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"""获取可复用的连接"""
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async with self._lock:
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# 清理过期连接
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await self._cleanup_expired_connections_locked()
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# 查找可复用的连接
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for connection_info in list(self._connections):
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if not connection_info.in_use and not connection_info.is_expired(self.max_lifetime, self.max_idle):
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# 验证连接是否仍然有效
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try:
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# 执行一个简单的查询来验证连接
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await connection_info.session.execute("SELECT 1")
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return connection_info
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except Exception as e:
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logger.debug(f"连接验证失败，将移除: {e}")
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await connection_info.close()
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self._connections.remove(connection_info)
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self._stats["total_expired"] += 1
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# 检查是否可以创建新连接
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if len(self._connections) >= self.max_pool_size:
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logger.warning(f"连接池已满 ({len(self._connections)}/{self.max_pool_size})，等待复用")
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return None
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return None
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async def _cleanup_expired_connections_locked(self):
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"""清理过期连接（需要在锁内调用）"""
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time.time()
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expired_connections = []
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for connection_info in list(self._connections):
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if connection_info.is_expired(self.max_lifetime, self.max_idle) and not connection_info.in_use:
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expired_connections.append(connection_info)
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for connection_info in expired_connections:
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await connection_info.close()
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self._connections.remove(connection_info)
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self._stats["total_expired"] += 1
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if expired_connections:
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logger.debug(f"清理了 {len(expired_connections)} 个过期连接")
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async def _cleanup_loop(self):
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"""后台清理循环"""
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while self._should_cleanup:
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try:
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await asyncio.sleep(30.0) # 每30秒清理一次
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async with self._lock:
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await self._cleanup_expired_connections_locked()
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# 更新统计信息
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self._stats["active_connections"] = len(self._connections)
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except asyncio.CancelledError:
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break
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except Exception as e:
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logger.error(f"连接池清理循环出错: {e}")
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await asyncio.sleep(10.0)
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async def _close_all_connections(self):
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"""关闭所有连接"""
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async with self._lock:
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for connection_info in list(self._connections):
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await connection_info.close()
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self._connections.clear()
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logger.info("所有连接已关闭")
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def get_stats(self) -> dict[str, Any]:
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"""获取连接池统计信息"""
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return {
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**self._stats,
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"active_connections": len(self._connections),
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"max_pool_size": self.max_pool_size,
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"pool_efficiency": (
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self._stats["pool_hits"] / max(1, self._stats["pool_hits"] + self._stats["pool_misses"])
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)
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* 100,
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}
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# 全局连接池管理器实例
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_connection_pool_manager: ConnectionPoolManager | None = None
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def get_connection_pool_manager() -> ConnectionPoolManager:
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"""获取全局连接池管理器实例"""
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global _connection_pool_manager
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if _connection_pool_manager is None:
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_connection_pool_manager = ConnectionPoolManager()
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return _connection_pool_manager
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async def start_connection_pool():
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"""启动连接池"""
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manager = get_connection_pool_manager()
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await manager.start()
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async def stop_connection_pool():
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"""停止连接池"""
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global _connection_pool_manager
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if _connection_pool_manager:
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await _connection_pool_manager.stop()
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_connection_pool_manager = None
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