【发布时间】：2016-05-14 20:59:47
【问题描述】：
我在 Digital Ocean 上有一个 Rails 4.2 应用程序。部署 cmets 模型（带有迁移文件）后，它在开发中运行良好，但在生产中无法正常运行。 我一直在使用 Capistrano（根据本教程 - https://www.digitalocean.com/community/tutorials/deploying-a-rails-app-on-ubuntu-14-04-with-capistrano-nginx-and-puma）部署一直运行良好，直到现在。
这是我的迁移文件（在我的部署中丢失）。
class CreateComments < ActiveRecord::Migration
def change
create_table :comments do |t|
t.references :user, index: true, foreign_key: true
t.text :body
t.references :path, index: true, foreign_key: true
t.timestamps null: false
end
end
end
我检查并可以在生产和开发匹配中看到我的架构，并参考迁移文件中的最后一个引用。 但是当
当我使用rails控制台生产时，我可以看到cmets表不存在。这是我控制台中的消息。
Loading production environment (Rails 4.2.5)
2.2.1 :001 > Comment.all
ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR: relation "comments" does not exist
LINE 1: SELECT "comments".* FROM "comments"
^
: SELECT "comments".* FROM "comments"
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/postgresql_adapter.rb:592:in `async_exec'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/postgresql_adapter.rb:592:in `block in exec_no_cache'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/abstract_adapter.rb:472:in `block in log'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activesupport-4.2.5/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/abstract_adapter.rb:466:in `log'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/postgresql_adapter.rb:592:in `exec_no_cache'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/postgresql_adapter.rb:584:in `execute_and_clear'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/postgresql/database_statements.rb:160:in `exec_query'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/abstract/database_statements.rb:355:in `select'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/abstract/database_statements.rb:32:in `select_all'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/connection_adapters/abstract/query_cache.rb:70:in `select_all'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/querying.rb:39:in `find_by_sql'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/relation.rb:639:in `exec_queries'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/relation.rb:515:in `load'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/relation.rb:243:in `to_a'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/activerecord-4.2.5/lib/active_record/relation.rb:630:in `inspect'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/commands/console.rb:110:in `start'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/commands/console.rb:9:in `start'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:68:in `console'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/commands.rb:17:in `<top (required)>'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/app_rails_loader.rb:45:in `require'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/app_rails_loader.rb:45:in `block in exec_app_rails'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/app_rails_loader.rb:34:in `loop'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/app_rails_loader.rb:34:in `exec_app_rails'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/lib/rails/cli.rb:5:in `<top (required)>'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/bin/rails:9:in `require'
from /home/laurie/apps/friendlyroad-rails/shared/bundle/ruby/2.2.0/gems/railties-4.2.5/bin/rails:9:in `<top (required)>'
from /home/laurie/.rvm/gems/ruby-2.2.1/bin/rails:23:in `load'
from /home/laurie/.rvm/gems/ruby-2.2.1/bin/rails:23:in `<main>'
from /home/laurie/.rvm/gems/ruby-2.2.1/bin/ruby_executable_hooks:15:in `eval'
from /home/laurie/.rvm/gems/ruby-2.2.1/bin/ruby_executable_hooks:15:in `<main>'2.2.1 :002 >
我也尝试过 sudo-apt-get clean，我已经重置了我的数据库，添加了动作包缓存 gem，并多次重新启动了我的服务器。
我的生产日志列出了未呈现的 cmets 视图文件（因为没有 cmets 表）。
运行 rake db:migrate:status 显示“无文件”
up 20151224215110 Devise create users
up 20151231173736 Add first name last name to users
up 20160112022120 Add role to users
up 20160122204744 Create paths
up 20160123004558 Add attachment image to paths
up 20160124191428 Remove user id from paths
up 20160124191601 Add user id to paths
up 20160124212622 Remove bio from users
up 20160124213023 Add bio to users
up 20160124213311 Remove title from paths
up 20160124213624 Add title content to paths
up 20160204222816 ********** NO FILE **********
检查目录（生产服务器）我看到文件不存在。
另外，删除旧的迁移，检查我的服务器的内存等。出现空白？
【问题讨论】：
标签： ruby-on-rails postgresql caching dbmigrate