Site changes | Page 34 | Fab Forum | The Beatles Bible

Just to outline the plan, for anyone who’s interested (and for my own records). There are two things that I hope will be able to help with load times here: ESI and public/private caches.

A year or so ago my old host enabled caching without my permission. This caused no end of problems, the main one of which was that when Forum User A was logged in, it would cache pages and serve them up to Forum User B as if they were logged in as A – ie it would show their login name, inbox, unread count etc.

This – apparently – can now be mitigated against with something called ESI.

ESI is a markup language that allows you to designate parts of your dynamic page as separate fragments that are then assembled together to make the whole page. To put it more quaintly, ESI lets you “punch holes” in a publicly-cached page, and then fill those holes with privately-cached content.

There’s also the facility to have a public cache (which will be useful for the non-forum pages on the site) and private caches for each user. The latter should store pages and elements requested by individual logged-in users, which don’t get shared with others. I think this will use up more storage on my server but if it works well it’ll be worth it.

Public cache is cache that can be accessed by everyone. A single copy of a publicly-cached page is stored and served to everyone who requests it.

Private cache is only accessible to an individual visitor. It usually contains information that is only pertinent to that particular user (for instance, the wordpress admin bar). When a page is privately-cached, there is a separate copy stored for each user that requests it.

Until this most recent update, LiteSpeed Cache for WordPress only dealt in public cache, and so any page that has individualized data on it, would just not be cached at all. When a user is logged in, there is the potential for every page to have private data on it, and so pages were never cached for logged-in users.

As of v 1.1.6, LSCWP supports private cache. This means many of the pages that were once considered uncacheable may now be cached privately instead.

These only became available last summer, so weren’t around when caching was last attempted. I’m waiting for my hosts to enable a small add-on, and once that’s done I’ll start experimenting. It sounds, in theory, like it’ll work very well.

ESI allows you to disassemble a full page and treat the pieces differently from each other.

LiteSpeed Web Server allows you to store content in either the public cache or a private cache.

Combine these two elements and you get something very powerful. You get a system that can break apart a page into public and private pieces, cache each piece appropriately, and then re-compose the full-page content from the relevant caches and serve it to a user without ever hitting the PHP backend.

That is pretty amazing.

This combination allows you to cache content for logged-in WordPress users. With ESI enabled you can say, “Hey this page is mostly public. Let’s cache it, punch a few holes in it for the private content, and save that content in the private cache.”

The Hole Got Fixed said
I’m having problems loading as well. It loads most of it, but things like the report/thank/PM/quote buttons, avatars etc (probably the private cache stuff) take much longer than they did before the change last week. 

Edit: this is what I see commonly:

  

I think this is the lazy load feature, which only loads images once they’re being viewed. It does seem a little slow so I’ll disable it. Looking at the other issues too.