Hi, I seem to have a related issue.
When clicking on featured image of a post to select an image from the library. I’ve noticed it takes around 30 seconds to load the media library. This only started after activating the w3tc extension.
Upon logging the queries I see this (with the query time in parens):
SELECT SQL_CALC_FOUND_ROWS wp_posts.id
FROM wp_posts
LEFT JOIN wp_postmeta
ON ( wp_posts.id = wp_postmeta.post_id
AND wp_postmeta.meta_key = 'w3tc_imageservice_file' )
WHERE 1 = 1
AND ( wp_posts.post_mime_type LIKE 'image/%' )
AND ( wp_postmeta.post_id IS NULL )
AND wp_posts.post_type = 'attachment'
AND (( wp_posts.post_status = 'inherit'
OR wp_posts.post_status = 'private' ))
GROUP BY wp_posts.id
ORDER BY wp_posts.post_date DESC
LIMIT 0, 80 - (33.225322008133 s)
When I tested this query directly and removing the left join it only takes 500ms (we have over 400k rows).
I don’t have the Image Service active (which I understand will be fixed in the next update). But even if I did have it active, it seems to be greatly slowing down the query.
