Arvados

if the index is already there, we should have some logic to avoid the upgrade of the package to fail. also in postgres we have different ways to doing depending on the version install
https://dba.stackexchange.com/questions/35616/create-index-if-it-does-not-exist

I'm referring to this:

services/api/db/migrate/20171027183824_add_index_to_containers.rb
class AddIndexToContainers < ActiveRecord::Migration
  def up
    ActiveRecord::Base.connection.execute("CREATE INDEX index_containers_on_modified_at_uuid ON containers USING btree (modified_at desc, uuid asc)")
    ActiveRecord::Base.connection.execute("CREATE INDEX index_container_requests_on_container_uuid on container_requests (container_uuid)")
  end

  def down
    ActiveRecord::Base.connection.execute("DROP INDEX IF EXISTS index_containers_on_modified_at_uuid")
    ActiveRecord::Base.connection.execute("DROP INDEX IF EXISTS index_container_requests_on_container_uuid")
  end
end