on a default wordpress installation, what actually happens when you click publish?
I know there’s a new entry added to the posts table, but what else happens – Is there anything else updated such as tables, automatically telling search engines about them, updating sitemaps etc?
Sorry if this is the wrong sort of question to ask!
save_post action is triggered whenever a post is created or updated, it means that any code inside core, themes, or plugins that is hooked with that action is launched.
Well, if you have google XML sitemap, a new entry makes changes in your sitemap xml file and during google bot’s next visit, your xml file automatically tells google about the new post you added. Something like this.