Speed up / Optimize Admin Edit Post Page on Large Websites (50-150k posts, 50 custom fields per post)
I’m working with a set of large WordPress installs with 50-150k posts, each with 40-50 custom fields. The installs are very basic, with limited plugins (less than 5), and a default WordPress theme (i.e. twenty twelve, etc.). The sites are on 1-Core, 2GB RAM, SSD VPS servers.
These are all private installs, with no public front-end or web traffic. Automatic updater, auto-update core, and revisions are all disabled.
I have no featured images or other media on the edit post page; Only text. The sites are on WordPress 5.6 or later (I understand they could be updated to 5.9.3, but doubt that is the issue).
The admin edit post page hangs for 25-45 seconds when accessed, and then finally loads. Is there any way to fix or speed this up on a large, basic wordpress install? It appears to be a problem in loading a large amount of custom field data, with 50-100k+ posts.
Here’s what I’ve found:
- Most other wp-admin pages such as categories, tags, pages, users, settings, etc. load quickly in a few seconds (3 seconds or less). The “All Posts” page takes a little longer at about 8-10 seconds or so.
- If I don’t use the classic editor plugin, and don’t enable the custom fields section to load in the new block editor, the edit page will load quickly as well (3 seconds or less).
- Disabling any other (or even all plugins) has no effect.
- I can load the front-end post page, and display all of the custom fields with no problem, under 3 seconds.
Any ideas? Is there a problem with the core WordPress backend functions at this scale for post pages with many custom fields?