The function attachment_url_to_postid in wp-includes/media.php causes a slow query for a huge database

[samvthom16]

We have close to 40k posts and equivalent number of items in the media library. Lot of plugins like Yoast Seo use the function attachment_url_to_postid() quite often. This causes a slow query because of the huge database.

Solution:
Since URLs don't change that often. The function can use transient variables instead of querying the posts table.

[birgire]

Thanks for your report @samvthom16

This has already been reported in #41281.

Please join in there, thanks.