CODEWITHSUNDEEP
rubyruby-on-rails-4
Leon
Leon

Reputation: 161

Best way to architect unique identifier generation

I have an API in rails that will handle a lot of requests. Lets say millions a day. I want to be able to assign a unique id to each of these requests. The way i am doing it is starting with a uid of 3 letters/numbers and continue up till 9 letters/numbers when the previous bracket is all taken.

One one i am doing it is generate the uid in real time when the request comes, so the app will try to find the first available uid and assign it. But after a while i have the impression that this will impact the performance of the app.

The second way I am thinking is to auto-generate all the possible uids in advance and have a flag assigned to them [free/taken] so that when a request comes in i assign the first free uid to it, which should be very fast if that filed is indexed.

Any suggestions are much appreciated. Thank you

Upvotes: 1

Views: 61

Answers (1)

DiegoSalazar
DiegoSalazar

Reputation: 13521

I would just generate a random string and assign it while it doesn't exist. Before I get into that let me just mention that SecureRandom.uuid is the best way to go. It generates random uuids whose chance of collision are mathematically improbable.

Anyway, here is a way to use your own custom random string generator that will only assign if it doesn't already exist:

def generate_random_uid
  begin
    uid = my_custom_random_string_method
    object.uid = uid
  end while ObjectModel.exists? uid: uid

  object.save
end

The do while block will execute once and set a variable called uid to be a random string you generate in the method my_custom_random_string_method, then in the while part it checks if a record exists whose uid attribute matches the random uid you just generated, if it does it runs the do block again, rinse and repeat until the expression in the while part returns false meaning the uid doesn't exists, then your object is saved and the uid written to the db. This guarantees that you will only ever save the object with a uid that doesn't exist in your db.

Upvotes: 2

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