---
title: req.hash_ignore_busy
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/variables/client-request/req-hash-ignore-busy
---

**Type:** BOOL  
**Access:** can be read and set, but not unset

**Available in:** recv

When there is more than one simultaneous cache miss for an object, Fastly will normally put all but one of those requests in a queue. Thus, only one cache miss causes an origin fetch and the rest wait for that response, a process known as [request collapsing](https://www.fastly.com/documentation/guides/concepts/edge-state/cache/request-collapsing/).

`req.hash_ignore_busy` overrides this behavior and forces all requests to behave independently.  Enabling this may cause a large increase in origin traffic when objects are not in cache.

When enabled, this mode also makes [stale](https://www.fastly.com/documentation/guides/concepts/edge-state/cache/stale/) objects unusable, thereby disabling the effects of the `stale-while-revalidate` and `stale-if-error` `Cache-Control` directives.