I'm working on a Rails 3 app, and we recently realized we have a duplicate index:
我正在开发一个Rails 3应用程序，我们最近意识到我们有一个重复的索引：
# from schema.rb
add_index "dogs", ["owner_id"], :name => "index_dogs_on_owner"
add_index "dogs", ["owner_id"], :name => "index_dogs_on_owner_id"
How can I check which index ActiveRecord is using for relevant queries? Or do I even need to? If one of the indices is removed will ActiveRecord happily just use the other?
如何检查ActiveRecord用于相关查询的索引？或者我甚至需要？如果其中一个索引被删除，ActiveRecord会愉快地使用另一个吗？
I can play around with it locally, but I'm not sure our production environment behaves exactly the same at the DB level.
我可以在本地使用它，但我不确定我们的生产环境在数据库级别上的行为是否完全相同。
1 个解决方案
#1
1
The name of the index is arbitrary. The database engine will look at the indexes based on the column name, not the human name. The index will not affect ActiveRecord. I recommend removing whichever index is least obvious, in this case index_dogs_on_owner, because the other index is clearly on the owner_id column.
索引的名称是任意的。数据库引擎将根据列名而不是人名查看索引。索引不会影响ActiveRecord。我建议删除哪个索引最不明显，在本例中为index_dogs_on_owner，因为另一个索引显然在owner_id列上。
remove_index :dogs, :name => 'index_dogs_on_owner'
Cite: http://apidock.com/rails/ActiveRecord/ConnectionAdapters/SchemaStatements/remove_index
引用：http：//apidock.com/rails/ActiveRecord/ConnectionAdapters/SchemaStatements/remove_index
#1
1
The name of the index is arbitrary. The database engine will look at the indexes based on the column name, not the human name. The index will not affect ActiveRecord. I recommend removing whichever index is least obvious, in this case index_dogs_on_owner, because the other index is clearly on the owner_id column.
索引的名称是任意的。数据库引擎将根据列名而不是人名查看索引。索引不会影响ActiveRecord。我建议删除哪个索引最不明显，在本例中为index_dogs_on_owner，因为另一个索引显然在owner_id列上。
remove_index :dogs, :name => 'index_dogs_on_owner'
Cite: http://apidock.com/rails/ActiveRecord/ConnectionAdapters/SchemaStatements/remove_index
引用：http：//apidock.com/rails/ActiveRecord/ConnectionAdapters/SchemaStatements/remove_index