Question

I’m trying to seed about 100,000 users using rake db:seed in my Rails 3 project and it is really slow!

Here’s the code sample:

# ...
User.create!(
  :display_name => "#{title} #{name} #{surname}",
  :email => "#{name}.#{surname}_#{num}@localtinkers.com",
  :password => '12341234'
)

It works, but it is really slow because for each user:

1. Devise issues a SELECT statement to find out if the email is already taken.
2. A separate INSERT statement is issued.

For other objects I use “ar-extensions” and “activerecord-import” gems as follows:

tags.each do |tag|
  all_tags << Tag.new(:name => tag)
end

Tag.import(all_tags, :validate => false, :ignore => true)

The above creates just one INSERT statement for all the tags and it works really fast, just like MySql database restore from the SQL dump.

But for users I cannot do this because I need Devise to generate encrypted password, salt, etc for each user. Is there a way to generate them on the SQL side or are there other efficient ways of seeding users?

Thank you.

Answer 1

How about:

u = User.new(
  :display_name => "#{title} #{name} #{surname}",
  :email => "#{name}.#{surname}_#{num}@localtinkers.com",
  :password => '12341234'
)
u.save!(:validate => false)

This should create and save the record without executing the validations, and therefore without checking for e-mail address uniqueness. Obviously the downside of this is that you’re not being protected by any other validations on the user too, so make sure you check your data first!