CODEWITHSUNDEEP
ruby-on-railsactiverecordperformance
Swift
Swift

Reputation: 13188

Most efficient method of finding a model by ID with Model.find

I noticed that I can do a Model.find in a number of ways (assuming @user is an instance of the User model): 

User.find(2)
=> #<User id: 2, name: "Mike Swift", email: "[email protected]", ... etc ...

OR

User.find(@user)
=> #<User id: 2, name: "Mike Swift", email: "[email protected]", ... etc ...

OR

User.find(@user[:id])
=> #<User id: 2, name: "Mike Swift", email: "[email protected]", ... etc ...

OR

User.find(@user.id)
=> #<User id: 2, name: "Mike Swift", email: "[email protected]", ... etc ...

Is there any real difference between the later three of these methods? (I already know User.find(n) would be the fastest) I would imagine they all work in about the same time, but perhaps I'm wrong.

Upvotes: 1

Views: 91

Answers (2)

Sam 山
Sam 山

Reputation: 42863

In terms of sql they all do the same thing. 

User.find(2)

This will be the fastest because there is no conversion needed.

Then User.find(@user.id) and User.find(@user[:id]).

And finally User.find(@user because rails needs convert the user to an ID.

Upvotes: 4

LeakyBucket
LeakyBucket

Reputation: 160

User.find(2) should be faster as Rails doesn't have to do any work to figure out the id. The others require some level of message passing to get the id.

I doubt the difference is very significant though.

You could try all of them and look at your log to see how long it takes to get your response.

Upvotes: 0

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