DB migration failure during the last update

I tried to update our forum via the web UI (tests-passed branch) and Activerecord failed due to a DB migration error. There wasn’t a way to rollback, the button didn’t show up.

The error in the Rails console was:

: SELECT "javascript_caches".* FROM "javascript_caches" WHERE "javascript_caches"."theme_id" = 2)
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.0.2/lib/patches/db/pg.rb:69:in `async_exec_params'
Failed to handle exception in exception app middleware : PG::UndefinedColumn: ERROR:  column javascript_caches.theme_id does not exist

The migration was failing because of a foreign key violation:

DETAIL:  Key (theme_field_id)=(6) is not present in table "theme_fields".                                                    
: ALTER TABLE "javascript_caches" ADD CONSTRAINT "fk_rails_ed33506dbd"                                                       
FOREIGN KEY ("theme_field_id")                                                                                               
  REFERENCES "theme_fields" ("id")                                                                                           

We had to remove the offending row from javascript_caches for the migration to succeed:

  5 |              6 | da39a3ee5e6b4b0d3255bfef95601890afd80709 |         | 2018-10-18 10:03:26.069247 | 2018-10-18 10:03:26.069247

Our current version is https://github.com/discourse/discourse/compare/22abad415192b53b899ea6a98b8c7f73c85ca0c1...tests-passed

Our issue in GitLab https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/6844.


@david just fixed this, can you rebuild again?

The migration is atomic so there is no permanent damage or half rolled out migrations like you can get in MySQL