Very large page has stopped saving my changes

Have you considered NOT having all that content on one page? Put it on a series of blog posts (so there’s an order to them).

No: it’s a book, not a series of blogs, so it needs to be one document. Are you suggesting that WordPress has a hard page size limit that I can’t get around?

There is a max size put on by the database, though that’s very large (4GB). However, there’s lots of moving parts and you could be hitting memory limits, spam filters, web site limits, browser issues, etc.

It really doesn’t have to be one document. That’s what you want, but not necessarily the best solution. You could break it up into chapters, for example, using pages or posts.

If the site can’t add some images, maybe your hosting capacity have been exceed the storage limit. To make sure this issue, maybe you can contact your hosting provider. If you hosting reach the limit, you can upgrade for bigger capacity hosting plan.

Or to optimize your space, you can try to install “wp-optimize” plugin. Where is the function of this plugin is to delete cache database, spam comment, revision history, and other unnecessary files.

Thanks, Indoteguh, but I’ve got tons of available space, so that’s not the problem. The problem is that the page seems to have hit a hard limit on size. I can delete text and add new text, as long as it’s not more than what I deleted. So, I need to know how to remove that size restriction.

Errors like this may be logged. Check the error log on your server. If you can’t find the log, please contact your host.

Meantime, enable wp_debug and wp_debug_log and after an error, look at wp-content/debug.log to see if anything gets logged there. https://codex.www.ads-software.com/Debugging_in_WordPress

So, I need to know how to remove that size restriction.

You say that as if that is an easy thing to do.

WordPress has no such size restriction. The database has a very large size restriction, which you have not hit yet. Things like POST variables on servers, security addons to your webserver, suhosin, things like these all may have other size restrictions that interfere as well.

The bottom line: You’ll have a harder time finding where this restriction is than you probably expect. However, it’s not a WordPress specific problem you’re running into here. Websites were not made for posting 400 page documents to them on a regular basis.

I suggest either splitting your document in a sensible way, or consider using a word processing program instead.

If you must, however, the first thing I would check is the bytesize of the current document. If it’s about 1 megabyte, then you’re probably hitting the maximum size for SQL statements. You can increase the max_allowed_packet in the MySQL Server settings.

Thanks, Steve and Samuel. I’ll look into both of those suggestions.

Well, I finally found the problem. The file size limitation is in the Classic Editor plugin for WordPress. When I deactivate it and use the new editor, the problem goes away. Thanks everyone for your help with this.

I spoke too soon. Turning off the Classic Editor plugin only resolved the problem temporarily. I’ve paid a bunch of money to my host to see if the problem was in the server side, but they couldn’t find anything. It definitely seems to be a hard limit to the size of a WP post, which make WP useless for anyone writing a sizeable book. Others have said that the maximum size for a WP post is several gigabytes, but mine is only a small fraction of that, so there’s a limit elsewhere in the system.

Anyone have any other ideas?