So I'm trying to delete a number of rows from a reasonably large mysql(innodb)table. 

The query i'm trying to use do this is as follows:

`delete from item where id in (select id from items_to_be_deleted);`

`item` is a 70'000'000 row table, and `items_to_be_deleted` is a 1'000'000 row table. 

My query just never seems to finish, even if i add an incredibly small limit to it. (`delete from item where id in (select id from items_to_be_deleted) LIMIT 10;`

If i run `select id from items_to_be_deleted` it returns nearly instantaneously, it is just a table with a primary key (id) and another varchar field. 

Whats wrong with my query that it is taking so long / never seems to finish?