- From: <bugzilla@jessica.w3.org>
- Date: Mon, 05 Dec 2011 20:33:22 +0000
- To: public-html-bugzilla@w3.org
https://www.w3.org/Bugs/Public/show_bug.cgi?id=14702
--- Comment #20 from Ian 'Hixie' Hickson <ian@hixie.ch> 2011-12-05 20:33:18 UTC ---
Here are some theoretical timing diagrams showing how page loads would progress
under various scenarios. In particular here I distinguish between the main page
having mixed data and structure, with a number of external resources critical
to the page load (the typical design these days), and the main page having just
the structure, with the data being one of the external resources. For
simplicity here I just assume we have styles, scripts, and images as the other
external resources. Also I assume here that the images and styles have Expires
headers, the data is always changing so cannot be cached, and the scripts have
ETag or If-Modified-Since caching but no Expires headers and thus have to be
checked every time in the normal (non-appcache) case, and the structure, when
provided separate from the data, can be cached, but that the user agent always
hits the network for the top-level load if it's not appcached.
Mixed data and structure, uncached:
[RTT][Structure+Data]
[RTT][Styles]
[RTT][Images]
[RTT][Scripts]
Mixed data and structure, cached:
[RTT][Structure+Data]
| (Styles)
| (Images)
[RTT] (Scripts)
Mixed data and structure, proposed appcache mechanism with manifest unchanged:
[RTT][Structure+Data]
[RTT] (Manifest)
| (Styles)
| (Images)
| (Scripts)
Mixed data and structure, proposed appcache mechanism with manifest changed but
most resources unchanged:
[RTT][Structure+Data]
[RTT][Manifest]
| (Styles)
| (Images)
[RTT] (Scripts)
Split data and structure, uncached:
[RTT][Structure]
[RTT][Styles]
[RTT][Images]
[RTT][Scripts]
[RTT][Data]
Split data and structure, cached:
[RTT] (Structure)
| (Styles)
| (Images)
[RTT] (Scripts)
[RTT][Data]
Split data and structure, appcached:
| (Structure)
| (Styles)
| (Images)
| (Scripts)
[RTT][Data]
It's really not clear to me, given this, why anyone would want to use the mixed
structure and data model these days. It's harder to maintain, is no faster than
the split model, and if you use appcache, is forcibly slower.
Given how many people are asking for this, it seems reasonable that we should
consider how to add the feature, but as far as I can tell it is never the right
solution from an authoring perspective.
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Received on Monday, 5 December 2011 20:33:25 UTC