WordPress page editor takes 60 seconds

We have 45,000 pages in our WP Admin. After around 20,000 we started noticing the time it takes to edit a page increased. What we’re seeing now is that it’s taking around 1 minute to fully open a page to edit. Now all other areas of the site are running just fine. Editing/creating posts is fast, it’s only when editing a page that it takes a long time to open. We noticed that the more pages we have the slower that open edit page takes. Has anyone seen this before?

• This topic was modified 6 years, 7 months ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not an Everything else WordPress topic