Bug 49238 - Link prefetch launches subresource requests too aggressively
Summary: Link prefetch launches subresource requests too aggressively
Alias: None
Product: WebKit
Classification: Unclassified
Component: DOM (show other bugs)
Version: 528+ (Nightly build)
Hardware: All All
: P2 Normal
Assignee: Nobody
URL: http://http://www.belshe.com/test/pre...
Keywords: InRadar
Depends on: 194539
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Reported: 2010-11-08 20:35 PST by Gavin Peters
Modified: 2023-01-25 05:02 PST (History)
7 users (show)

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Description Gavin Peters 2010-11-08 20:35:40 PST
Look at the linked URL, and see the resource loading order.  The launch of prefetch requests is occurring too early.  Prefetch requests should not be launched while, for instance, the onload is pending.

Comment 1 Andy Davies 2020-07-23 12:09:09 PDT
This issue still applies in iOS 13.5.1 and Safari 13.1 on mojave

It's particularly bad if the HTTP/2 server doesn't support effective prioritisation as Safari makes the requests at a low priority but the server ignores this and responds, potentially blocking higher priority responses. 

See  https://andydavies.me/blog/2020/07/08/rel-equals-prefetch-and-the-importance-of-effective-http-slash-2-prioritisation/
Comment 2 Radar WebKit Bug Importer 2020-07-23 13:36:50 PDT