Home/ Questions/Q 9182931
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-17T18:40:53+00:00

I get an exception and I want to understand why. I’ve created a git

  • 0

I get an exception and I want to understand why. I’ve created a git repo so anyone can test it.

The rails app is fresh with Devise installed on it.

Running the app and this script that try to create the same user:

1000.times do
  fork do
    `curl -d "user[email]=your@mail.com&user[password]=pwd&user[password_confirmation]=pwd" localhost:3000/users`
  end
end

I get the follow exception:

An ActiveRecord::RecordNotUnique occurred in registrations#create:

Mysql2::Error: Duplicate entry 'your@mail.com' for key 'index_users_on_email': INSERT INTO `users` (`authentication_token`, `confirmation_sent_at`, `confirmation_token`, `confirmed_at`, `created_at`, `current_sign_in_at`, `current_sign_in_ip`, `email`, `encrypted_password`, `failed_attempts`, `last_sign_in_at`, `last_sign_in_ip`, `locked_at`, `remember_created_at`, `reset_password_sent_at`, `reset_password_token`, `sign_in_count`, `unconfirmed_email`, `unlock_token`, `updated_at`) VALUES (NULL, '2013-01-24 16:48:23', 'GQwbJzsawxRsbvhp1LkR', NULL, '2013-01-24 16:48:23', NULL, NULL, 'your@mail.com', '$2a$10$koMNiiZQuhkeWhmYV8PtcOUlvi6rZHTKMs82MGWNa2M/GsUQ0cIHO', 0, NULL, NULL, NULL, NULL, NULL, NULL, 0, NULL, NULL, '2013-01-24 16:48:23')
activerecord (3.2.11) lib/active_record/connection_adapters/abstract_mysql_adapter.rb:245:in `query'

Why I get this exception and not a validation error? If I try to create an user with an email that is already used from the web page “http://localhost:3000/users/sign_up” I dont get this exception but a validation error…

If I run the script without fork (request are sequential), I get no error.

Seems a race conditions problem.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    In your script you try to create 1000 users all with the email “your@mail.com”. You have a uniqueness constraint on your user email index (correctly – you only want one user per email address). The second time it tries to create a user with that email you will get the error.

    As you are forking your request the validates_uniqueness_of validation provided by devise may be succeeding because it queries for another record with the same email. But, by the time the record is actually written, another record may exist.

    For example,

    1. Request 1 checks for existing email “your@mail.com” – okay
    2. Request 2 checks for existing email “your@mail.com” – okay
    3. Request 1 writes record with email “your@mail.com” – okay
    4. Request 2 writes record with email “your@mail.com” – uniqueness violation.
    • 0