# sqlalchemy.exc.TimeoutError：QueuePool 大小限制 5，溢出 10 已达到，连接超时，超时时间 30

- **ID:** `python/sqlalchemy-connection-pool-exhausted`
- **领域:** python
- **类别:** system_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

并发连接过多，超出池限制。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 3.x | active | — | — |

## 解决方案

1. **Increase pool size and overflow appropriately.** (85% 成功率)
   ```
   engine = create_engine(url, pool_size=20, max_overflow=30)
   ```
2. **Use connection pooling middleware like PgBouncer.** (90% 成功率)
   ```
   # Configure PgBouncer to pool connections externally
   ```

## 无效尝试

- **Setting pool_size to 0 (no limit).** — May cause database server overload. (60% 失败率)
- **Disabling pool pre-ping.** — Does not address connection exhaustion. (70% 失败率)