I recently changed the theme and added https//: to a blog I'm managing. Since then I have found that when I click on a link going to a blog Post, the website takes about 10+ seconds to begin loading the Post which then only takes a few seconds to finish. When I click on one of the static pages the website responds immediately and takes the same couple seconds to load.
I rolled the theme back to the previous one but was still experiencing the same delay on Posts but still none on Pages. Tested on multiple browsers and on different machines with the same results.
I recently changed the theme and added https//: to a blog I'm managing. Since then I have found that when I click on a link going to a blog Post, the website takes about 10+ seconds to begin loading the Post which then only takes a few seconds to finish. When I click on one of the static pages the website responds immediately and takes the same couple seconds to load.
I rolled the theme back to the previous one but was still experiencing the same delay on Posts but still none on Pages. Tested on multiple browsers and on different machines with the same results.
It could be that the posts in the database have too many revisions, so the posts table is a bit large. And it could be inefficiencies in your hosting server's database service.
I'd first try a 'database optimizer' program to get rid of revisions: I've used this one with success: https://wordpress.org/plugins/wp-optimize/ ; there are others available.
It is also possible that your theme is not 'efficient'. You could quickly test this by doing a temporary change to one of the 'twenty' themes. Although you mentioned that you rolled back to a previous theme version, that won't verify that it is not a theme issue. Changing to a 'twenty' theme temporarily as a test might provide useful information.