Opened 3 years ago
Closed 13 months ago
#54423 closed enhancement (duplicate)
Add Site Health test for full page caching (advanced cache)
Reported by: | westonruter | Owned by: | |
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Milestone: | Priority: | normal | |
Severity: | normal | Version: | |
Component: | Site Health | Keywords: | needs-docs |
Focuses: | performance | Cc: |
Description
A best practice for performance is to enable full page caching for a WordPress site. Doing so reduces the time to first byte (TTFB) and thus directly impacts Core Web Vitals. This is especially important on shared hosts which have limited compute power, while also protecting a site from going down due to traffic spikes.
As with XML Sitemaps, it may make sense for WordPress core to include a basic full page caching solution out of the box which can be extended by the many plugins that provide page caching today. In the meantime, there should at least be a Site Health test with a low-severity recommended
status to point users to where to go to enable page caching. Since hosts often have built-in caching solutions in place, the Site Health test should be easily filterable so they can provide a link to their specific dashboard or documentation to enable caching which may not be a plugin at all but rather a reverse proxy like Varnish.
In the context of the AMP plugin for WordPress, we've already developed such a test which could be adapted for core. See amp-wp#6456. It's an async test which issues three loopback requests to the homepage, and the test will pass if responses include either of the following headers:
Cache-Control
with non-zeromax-age
.Expires
with a future time.Age
with a positive number (as is set via a proxy like Varnish).
Change History (6)
#1
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3 years ago
- Summary changed from Add Site Health test for page caching (advanced cache) to Add Site Health test for full page caching (advanced cache)
#2
in reply to:
↑ description
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3 years ago
#3
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3 years ago
- Keywords needs-docs added
I think this is a viable check to add in, both for page caches, but I could see other caching as well, perhaps a test for caching in general is the way to go, always on the "Recommended" level, but checks for both page and object caches, could even check if static assets have some form of cache headers?
The prerequisite for all of this is that we need user documentation ready on WordPress.org before any of this lands in core though (we probably should have for all of these things regardless of this enhancement landing, so flagging it down for the docs team to have a look at as well). There are some docs already at https://make.wordpress.org/hosting/handbook/performance/ but it is a bit of a catch-all, so perhaps it needs its own performance category and split out a little? (but that's for docs to know better than I how the users interact with these areas :) )
#4
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3 years ago
After releasing the page caching site health test in the AMP plugin v2.2, it came to light that the detection was not robust enough. A major improvement has just been merged which accounts for many more scenarios.
Cheers to Piotr Bak for discussing the additional scenarios in a WP Rocket issue.
#5
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3 years ago
Cross-posted in WordPress/performance#220.
Replying to westonruter:
Not the same as full page caching, but might be relevant for reference: persistent object caching was previously included in [3011] and removed in [6539] / #5570 due not not being actively maintained.