After upgrading to 2.1.0 I got this error repeatedly for about 3 minutes. I'm not sure it's related to the 2.1.0 upgrade, but I thought I'd share it here in case it is more clear to anyone else.
ERROR 25006 (read_only_sql_transaction) cannot execute SELECT FOR UPDATE in a read-only transaction
lib/postgrex.ex:233 Postgrex.query!/4
lib/rihanna/job.ex:417 Rihanna.Job.lock/3
lib/rihanna/job_dispatcher.ex:37 Rihanna.JobDispatcher.handle_info/2
gen_server.erl:637 :gen_server.try_dispatch/4
gen_server.erl:711 :gen_server.handle_msg/6
proc_lib.erl:249 :proc_lib.init_p_do_apply/3
After upgrading to 2.1.0 I got this error repeatedly for about 3 minutes. I'm not sure it's related to the 2.1.0 upgrade, but I thought I'd share it here in case it is more clear to anyone else.