几个使用大型 JQuery 自动完成数据集的用户正在减慢整个 Ruby on Rails 应用程序

Question

Just wondering if I can get some suggestions from more senior programmers on perhaps a better way to load large quantities of data in our daycare app.

The app is very basic. When the user signs in, it loads all their kids so that they can schedule daycare appointments for them.

On the homepage, we have the appointment calendar. When you click a certain date, an appointment creation modal shows up. This modal utilizes JQuery Autocomplete so that the business owner can start typing the kid/parent name and then select them from the list. Because of this need for JQuery Autocomplete, every kid is loaded into a JSON string when the homepage is loaded.

kids_for_autocomplete = []
Kid.where(business_id: current_user.business_id).order_by_name.pluck(:id, :name, :parent_name, :archived).each do |kid_id, kid_name, parent_name, archived|
  kids_for_autocomplete << {:label => "#{kid_name} ( #{parent_name} )", :value => "#{kid_name} ( #{parent_name} )", :id => "#{kid_id}"} unless archived == true
end

@kids_for_autocomplete = kids_for_autocomplete.to_json

So, most users have between 100 and 300 kids in their database and the load time is only several hundred milliseconds. However, we have a couple users with over 3,000 kids in their database. When they visit the homepage, their loading time is usually over 5000 milliseconds. This slows down requests for everyone else on the same Heroku dyno.

A possible solution would be to load the Kids each time a calendar date is clicked and the modal appears. This will increase the amount of requests since most users stay on the homepage and click the calendar a lot. For small users, loading the kids once for Autocomplete makes sense, since then the kids are loaded on the homepage for future requests (as long as they don't navigate off the homepage). I hope that makes sense.

We're just trying to figure out a way to speed up the requests for these users that have several thousands kids.

Any ideas are appreciated!

Answer 1

Do you know exactly where your performance bottleneck is? Without knowing exactly what part of this is slow, a couple of things that I would try before changing the overall design of the feature would be to use #find_each instead of #each on your Active Record relation. So,

Kid.where(business_id: current_user.business_id).order_by_name.pluck(:id, :name, :parent_name, :archived).find_each do

That'll avoid loading thousands of records into memory all at once in order build up your JSON.

I'd also add a database index on kids.business_id if you don't have one already.