奇怪的rake db：迁移输出

为什么rake db:migrate运行Execute db:schema:dump我的输出全部搞砸了（显示SQL）。

看起来像这样：

  ActiveRecord::SchemaMigration Load (0.5ms) SELECT "schema_migrations".* FROM "schema_migrations" (3.7ms) SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete FROM pg_constraint c JOIN pg_class t1 ON c.conrelid = t1.oid JOIN pg_class t2 ON c.confrelid = t2.oid JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid JOIN pg_namespace t3 ON c.connamespace = t3.oid WHERE c.contype = 'f' AND t1.relname = 'accounts' AND t3.nspname = ANY (current_schemas(false)) ORDER BY c.conname (3.2ms) SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete FROM pg_constraint c JOIN pg_class t1 ON c.conrelid = t1.oid JOIN pg_class t2 ON c.confrelid = t2.oid JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid JOIN pg_namespace t3 ON c.connamespace = t3.oid WHERE c.contype = 'f' AND t1.relname = 'deliveries' AND t3.nspname = ANY (current_schemas(false)) ORDER BY c.conname (3.2ms) SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete FROM pg_constraint c JOIN pg_class t1 ON c.conrelid = t1.oid JOIN pg_class t2 ON c.confrelid = t2.oid JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid JOIN pg_namespace t3 ON c.connamespace = t3.oid WHERE c.contype = 'f' AND t1.relname = 'posts' AND t3.nspname = ANY (current_schemas(false)) ORDER BY c.conname 

Trace显示了这个：

 ** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Invoke db:load_config (first_time) ** Execute db:load_config ** Execute db:migrate ** Invoke db:_dump (first_time) ** Execute db:_dump ** Invoke db:schema:dump (first_time) ** Invoke environment ** Invoke db:load_config ** Execute db:schema:dump 

这是在将rails 4.1.6升级到rails 4.2.0之后开始的。

为什么会这样？

Answer 1

我得到这个奇怪的神秘SQL’ish输出的原因是因为我在我的gemfile中有Heroku的rails_12factor gem而没有分组到：production。

解决方案是：

 group :production do gem 'rails_12factor' end 

并运行bundle

Answer 2

在升级到Rails 4.2.1之后我遇到了同样的问题，阻止我通过Codeship部署迁移，而Codeship希望rake db:migrate的非常特殊的输出可以考虑推送成功。

在config/environments/production.rb设置config.log_level = :info修复了我的问题，大概是因为日志级别在:debug级别太冗长了。

Answer 3

这个讨论解决了我的“奇怪”输出：
只需在您的环境配置中将dump_schema_after_migration设置为false ，如下所示：

/config/environments/development.rb

 Application.configure do ... dump_schema_after_migration = false ... end 

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编辑
在大多数情况下，这不是您想要做的，因为您需要在版本控制中schema.rb 。