{"action":"created","issue":{"url":"https://api.github.com/repos/puma/puma/issues/797","labels_url":"https://api.github.com/repos/puma/puma/issues/797/labels{/name}","comments_url":"https://api.github.com/repos/puma/puma/issues/797/comments","events_url":"https://api.github.com/repos/puma/puma/issues/797/events","html_url":"https://github.com/puma/puma/issues/797","id":111291041,"number":797,"title":"Still seeing occasional total outages on Heroku","user":{"login":"vincentwoo","id":613320,"avatar_url":"https://avatars.githubusercontent.com/u/613320?v=3","gravatar_id":"","url":"https://api.github.com/users/vincentwoo","html_url":"https://github.com/vincentwoo","followers_url":"https://api.github.com/users/vincentwoo/followers","following_url":"https://api.github.com/users/vincentwoo/following{/other_user}","gists_url":"https://api.github.com/users/vincentwoo/gists{/gist_id}","starred_url":"https://api.github.com/users/vincentwoo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vincentwoo/subscriptions","organizations_url":"https://api.github.com/users/vincentwoo/orgs","repos_url":"https://api.github.com/users/vincentwoo/repos","events_url":"https://api.github.com/users/vincentwoo/events{/privacy}","received_events_url":"https://api.github.com/users/vincentwoo/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":22,"created_at":"2015-10-13T23:17:12Z","updated_at":"2015-11-25T13:37:33Z","closed_at":null,"body":"I've been running puma on Heroku since they made it the officially sanctioned option, but have continuously run into situations were all requests, randomly, start `H12`ing. This results in my app being entirely offline.\r\n\r\nHow can I begin debugging this issue? I'm running the very latest in `puma` and `rack-timeout-puma`. Should I... not run the latter? Is there some debugging option I can turn on to get better logs? All I see now are all my requests mysteriously dying."},"comment":{"url":"https://api.github.com/repos/puma/puma/issues/comments/159610330","html_url":"https://github.com/puma/puma/issues/797#issuecomment-159610330","issue_url":"https://api.github.com/repos/puma/puma/issues/797","id":159610330,"user":{"login":"schneems","id":59744,"avatar_url":"https://avatars.githubusercontent.com/u/59744?v=3","gravatar_id":"","url":"https://api.github.com/users/schneems","html_url":"https://github.com/schneems","followers_url":"https://api.github.com/users/schneems/followers","following_url":"https://api.github.com/users/schneems/following{/other_user}","gists_url":"https://api.github.com/users/schneems/gists{/gist_id}","starred_url":"https://api.github.com/users/schneems/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/schneems/subscriptions","organizations_url":"https://api.github.com/users/schneems/orgs","repos_url":"https://api.github.com/users/schneems/repos","events_url":"https://api.github.com/users/schneems/events{/privacy}","received_events_url":"https://api.github.com/users/schneems/received_events","type":"User","site_admin":false},"created_at":"2015-11-25T13:37:33Z","updated_at":"2015-11-25T13:37:33Z","body":"With H12 you are seeing a request that is taking longer than 30 seconds. You need info on what your app is doing when that happens, the best way we have to do that for now is Rack::Timeout. When the timeout fires you'll get a backtrace, use that backtrace to see where in your code you are stuck. Is it the same place every time?  If you don't kill the request it will stay stuck and other requests will back up behind it and cause more H12s. \r\n\r\nIf you think you're hitting noisy neighbors, you can try performance dynos which are on a dedicated VPS instead of a shared runtime.\r\n"}}