Fast delete wordpress post_meta after delete post by using sql query

Get a list of orphaned post meta

SELECT * 
FROM wp_postmeta pm
LEFT JOIN wp_posts wp ON wp.ID = pm.post_id
WHERE wp.ID IS NULL

Delete orphaned post meta

DELETE pm
FROM wp_postmeta pm
LEFT JOIN wp_posts wp ON wp.ID = pm.post_id
WHERE wp.ID IS NULL