Add foreign keys to todos table.

Fixes #32282.

2 files changed, 41 insertions, 0 deletions

diff --git a/db/migrate/20180201110056_add_foreign_keys_to_todos.rb b/db/migrate/20180201110056_add_foreign_keys_to_todos.rb
new file mode 100644
index 00000000000..b7c40f8c01a
--- /dev/null
+++ b/db/migrate/20180201110056_add_foreign_keys_to_todos.rb
@@ -0,0 +1,38 @@
+class AddForeignKeysToTodos < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  class Todo < ActiveRecord::Base
+    self.table_name = 'todos'
+    include EachBatch
+  end
+
+  BATCH_SIZE = 1000
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    Todo.where('NOT EXISTS ( SELECT true FROM users WHERE id=todos.user_id )').each_batch(of: BATCH_SIZE) do |batch|
+      batch.delete_all
+    end
+
+    Todo.where('NOT EXISTS ( SELECT true FROM users WHERE id=todos.author_id )').each_batch(of: BATCH_SIZE) do |batch|
+      batch.delete_all
+    end
+
+    Todo.where('note_id IS NOT NULL AND NOT EXISTS ( SELECT true FROM notes WHERE id=todos.note_id )').each_batch(of: BATCH_SIZE) do |batch|
+      batch.delete_all
+    end
+
+    add_concurrent_foreign_key :todos, :users, column: :user_id, on_delete: :cascade
+    add_concurrent_foreign_key :todos, :users, column: :author_id, on_delete: :cascade
+    add_concurrent_foreign_key :todos, :notes, column: :note_id, on_delete: :cascade
+  end
+
+  def down
+    remove_foreign_key :todos, :users
+    remove_foreign_key :todos, column: :author_id
+    remove_foreign_key :todos, :notes
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 14024164359..dd8d14fb401 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -2045,7 +2045,10 @@ ActiveRecord::Schema.define(version: 20180202111106) do
   add_foreign_key "system_note_metadata", "notes", name: "fk_d83a918cb1", on_delete: :cascade
   add_foreign_key "timelogs", "issues", name: "fk_timelogs_issues_issue_id", on_delete: :cascade
   add_foreign_key "timelogs", "merge_requests", name: "fk_timelogs_merge_requests_merge_request_id", on_delete: :cascade
+  add_foreign_key "todos", "notes", name: "fk_91d1f47b13", on_delete: :cascade
   add_foreign_key "todos", "projects", name: "fk_45054f9c45", on_delete: :cascade
+  add_foreign_key "todos", "users", column: "author_id", name: "fk_ccf0373936", on_delete: :cascade
+  add_foreign_key "todos", "users", name: "fk_d94154aa95", on_delete: :cascade
   add_foreign_key "trending_projects", "projects", on_delete: :cascade
   add_foreign_key "u2f_registrations", "users"
   add_foreign_key "user_callouts", "users", on_delete: :cascade