Merge branch 'dm-reset-event-pk-sequence' into 'master'

Reset `events` table primary key sequence to make sure it’s correct

Closes #42667

See merge request gitlab-org/gitlab-ce!16960

db/migrate/20180206200543_reset_events_primary_key_sequence.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class ResetEventsPrimaryKeySequence < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  class Event < ActiveRecord::Base
+    self.table_name = 'events'
+  end
+
+  def up
+    if Gitlab::Database.postgresql?
+      reset_primary_key_for_postgresql
+    else
+      reset_primary_key_for_mysql
+    end
+  end
+
+  def down
+    # No-op
+  end
+
+  def reset_primary_key_for_postgresql
+    reset_pk_sequence!(Event.table_name)
+  end
+
+  def reset_primary_key_for_mysql
+    amount = Event.pluck('COALESCE(MAX(id), 1)').first
+
+    execute "ALTER TABLE #{Event.table_name} AUTO_INCREMENT = #{amount}"
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180204200836) do
+ActiveRecord::Schema.define(version: 20180206200543) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"