id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	post_tag_assn	ref	PRIMARY,tag_id,post_id	tag_id	4	const	16	Using index; Using temporary; Using filesort
1	SIMPLE	post	eq_ref	PRIMARY,idx-post-type,idx-post-is_public	PRIMARY	4	bsr.post_tag_assn.post_id	1	Using where