<story><title>Why Prefetch Is Broken</title><url>https://www.jefftk.com/p/why-prefetch-is-broken</url></story><parent_chain><item><author>slver</author><text>If the cache is per domain, does that mean CDN-served dependencies like JQuery and React are in fact... useless in terms of cache reuse.</text></item></parent_chain><comment><author>pornel</author><text>Yes. Browsers and protocols have changed, and a lot of past performance best-practices have become actively harmful for performance.&lt;p&gt;A couple of related techniques are also useless: domain sharding and cookieless domains. HTTP&amp;#x2F;2 multiplexing and header compression made them obsolete, and now they&amp;#x27;re just an overhead for DNS+TLS, and often break HTTP&amp;#x2F;2 prioritization.&lt;p&gt;You should be careful with prefetch too. Thanks to preload scanners and HTTP&amp;#x2F;2 prioritization there are few situations where it is really beneficial. But there are many ways to screw it up and cause unnecessary or double downloads.</text></comment>
<story><title>Why Prefetch Is Broken</title><url>https://www.jefftk.com/p/why-prefetch-is-broken</url></story><parent_chain><item><author>slver</author><text>If the cache is per domain, does that mean CDN-served dependencies like JQuery and React are in fact... useless in terms of cache reuse.</text></item></parent_chain><comment><author>eli</author><text>Honestly cache reuse was never as high as anyone hoped. There were so many versions of jQuery and so many different CDNs that very few first time visitors already had the one you wanted.</text></comment>