> For the complete documentation index, see [llms.txt](https://www.axisnow.io/zh/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.axisnow.io/zh/docs/edge/policies/cache/purge-and-warming.md).
# 缓存清理与预热
缓存清理的匹配方式与生效时间以及预热的执行方式
清理和预热是策略下的两个独立入口，不走规则集；提交后分发到全部边缘节点，各节点独立执行，洞察页可查看每次任务的状态和明细。
## 清理
每次最多提交 1000 条。
清理是标记失效而不是删除文件：节点收到任务后，早于任务时间的副本在下一次被请求时视为过期，重新回源校验，响应状态为 `EXPIRED`，源站确认内容未变时为 `REVALIDATED`。任务到达节点后 3 秒内生效，验证方法是再请求一次：`X-Cache` 不再是 `HIT`，且响应带 `X-Timestamp`。分片缓存的大文件所有分片一起失效。
先在源站发布新内容再清理：清理后的第一次请求回源校验，源站内容未变、返回 304 时旧副本续期。清理只作用于边缘，浏览器已缓存的副本要等它自己过期，所以会频繁更新的内容不要给浏览器设长时长。
## 预热
提交完整 URL（含协议），每次最多 1000 条，也可上传 CSV。每个节点每 10 秒领取一次任务，各自向本机发起请求把内容拉进自己的缓存；节点之间不共享，新增节点需要重新预热。http 与 https 是两份副本，只预热提交的那个协议。
* 是否写入缓存仍由缓存控制的规则决定，URL 没有命中可缓存规则就不会被缓存。
* 返回 200 或 206 视为成功；跟随一次 301、302 或 307 重定向；5xx 共尝试 3 次。
* 可压缩的内容（文本、脚本、样式、字体等）会按 gzip、br、deflate 各预热一份，与客户端不同的压缩协商对应。
* 预热请求不经过[通用访问控制](/zh/docs/edge/policies/access-control.md)。
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