Rails select random record

user_103739 0
Viewed 12550

I don't know if I'm just looking in the wrong places here or what, but does active record have a method for retrieving a random object?

Something like?

@user = User.random

Or... well since that method doesn't exist is there some amazing "Rails Way" of doing this, I always seem to be to verbose. I'm using mysql as well.

ruby-on-rails ruby mysql
8 Answers

Strongly Recommend this gem for random records, which is specially designed for table with lots of data rows:

https://github.com/haopingfan/quick_random_records

Simple Usage:

@user = User.random_records(1).take

All other answers perform badly with large database, except this gem:

  1. quick_random_records only cost 4.6ms totally.

enter image description here

  1. the accepted answer User.order('RAND()').limit(10) cost 733.0ms.

enter image description here

  1. the offset approach cost 245.4ms totally.

enter image description here

  1. the User.all.sample(10) approach cost 573.4ms.

enter image description here

Note: My table only has 120,000 users. The more records you have, the more enormous the difference of performance will be.

UPDATE:

Perform on table with 550,000 rows

  1. Model.where(id: Model.pluck(:id).sample(10)) cost 1384.0ms

enter image description here

  1. gem: quick_random_records only cost 6.4ms totally

enter image description here

user_81786430
Related