主外键减慢InnoDB插入速度

Question

I'm importing a lot (only ~10,000) of employees and then making them all a user account at once. Inserting into my user_profile table is slowing everything down a ton because the primary key of the table is a foreign key as well, and not the usual autoincrement id.

Is there any way to speed this up? Or do I need to go back and add an autoincrement id to user_profile somehow?

Edit:

user:
  id
  username
  salt
  password

user_profile:
  user_id -> Primary Key and Foreign Key to user table
  first_name
  last_name
  email
  ...

Answer 1

My recommendation is to add a id field to the user_profile table, make it the primary key (unsigned and auto_increment). Then make the user_id field the foreign key to the user ( id ) table. I've never seen a field act as the primary key AND foreign key to another table.