20 lines
1.0 KiB
Markdown
20 lines
1.0 KiB
Markdown
---
|
|
title: 坑：FastAPI async def 里阻塞 I/O 冻结事件循环
|
|
type: experience
|
|
permalink: main/projects/d5a7f581-c442-4554-87b9-ee723b8b0258/坑-fast-api-async-def-里阻塞-i-o-冻结事件循环
|
|
stable_id: df065dbf-85de-4f2b-bbb1-5d8b115de08c
|
|
scope: project
|
|
project_id: d5a7f581-c442-4554-87b9-ee723b8b0258
|
|
memory_type: experience
|
|
status: active
|
|
revision: 1
|
|
restored_from_commit: 6a6a895eafcca6052e81a14fca103a42635dd1c2
|
|
created_at: '2026-09-23T15:09:57.195425+00:00'
|
|
updated_at: '2026-09-23T15:09:57.195491+00:00'
|
|
tags:
|
|
- pitfall
|
|
- fastapi
|
|
- async
|
|
---
|
|
|
|
CapacityReport 大表导出把 /health 都卡死：async def 处理函数里直接调 pymysql/大文件/轮询等阻塞 I/O，事件循环被占满。修复：把这类处理函数改成普通 def，FastAPI 自动扔进线程池。通用经验：同步库（pymysql、paramiko、requests）的调用链不要包在 async def 接口里；另外重建线程池时旧池用 shutdown(wait=False) 非阻塞关闭（database/jobs.py、scripts/runs.py 的 _pool 模式）。 |