Using the cache count for acts_as_votable - ruby-on-rails

Question

I have a view that is iterating through a series of posts, and is running a count on the votes for each. I know how to do eager loading generally and how to use cache counters generally. But I can't figure out how to use the cache counter that comes with acts_as_votable (or I'm doing something else wrong.)
View:
<span class="votes">
<% if current_user.voted_for? link %>
<%= link_to like_link_path(link), class: "likes active", id: "link-#{link.id}", remote: true, method: :put do %>
<i class="fa fa-heart"></i> <%= link.cached_votes_total.to_s %>
<% end %>
<% else %>
<%= link_to like_link_path(link), class: "likes", id: "link-#{link.id}", remote: true, method: :put do %>
<i class="fa fa-heart-o"></i> <%= link.cached_votes_total.to_s %>
<% end %>
<% end %>
</span>
Terminal:
Link Load (0.4ms) SELECT "links".* FROM "links" ORDER BY "links"."score" DESC LIMIT 10 OFFSET 0
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" IN (1)
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT 1 [["id", 1]]
(0.2ms) SELECT COUNT(*) FROM "votes" WHERE "votes"."voter_id" = $1 AND "votes"."voter_type" = $2 AND "votes"."votable_id" = $3 AND "votes"."votable_type" = $4 AND "votes"."vote_scope" IS NULL [["voter_id", 1], ["voter_type", "User"], ["votable_id", 1], ["votable_type", "Link"]]
(0.2ms) SELECT COUNT(*) FROM "votes" WHERE "votes"."voter_id" = $1 AND "votes"."voter_type" = $2 AND "votes"."votable_id" = $3 AND "votes"."votable_type" = $4 AND "votes"."vote_scope" IS NULL [["voter_id", 1], ["voter_type", "User"], ["votable_id", 2], ["votable_type", "Link"]]
Rendered home/index.html.erb within layouts/application (24.6ms)
Completed 200 OK in 60ms (Views: 56.9ms | ActiveRecord: 1.6ms)
Thanks!

Answer 1

It looked nothing abnormal to me. The voted_for? method is alias of voted_on?. Keep on reading the code you will find this method calls a votes.size > 0, which will trigger following queries to database. (I guess you have 2 links on your page, right?) So it has nothing to do with the cached counts fields.
(0.2ms) SELECT COUNT(*) FROM "votes" WHERE "votes"."voter_id" = $1 AND "votes"."voter_type" = $2 AND "votes"."votable_id" = $3 AND "votes"."votable_type" = $4 AND "votes"."vote_scope" IS NULL [["voter_id", 1], ["voter_type", "User"], ["votable_id", 1], ["votable_type", "Link"]]
(0.2ms) SELECT COUNT(*) FROM "votes" WHERE "votes"."voter_id" = $1 AND "votes"."voter_type" = $2 AND "votes"."votable_id" = $3 AND "votes"."votable_type" = $4 AND "votes"."vote_scope" IS NULL [["voter_id", 1], ["voter_type", "User"], ["votable_id", 2], ["votable_type", "Link"]]
P.S. The code is here: github: voter.rb.

Answer 2

May be that is not the best way, but it could help to preload user's votes for links in single database hit:
Somewhere in backend (e.g. User model) you may define method like
# votable - records, which were voted by user, links in the case
def preloaded_votes(votable)
#preloaded_votes ||= Vote.where(voter: self, votable: votable).group(:votable_id).count
end
this method will return hash like {votable_id1 => count1, votable_id2 => count2 }, where votable_idN means id of an element from votable argument for the method.
Change current call current_user.voted_for? link to preloaded counts current_user.preloaded_votes.key?(link.id)
This solution adds one more database hit, but allow to avoid N+1 queries. Also, additional SQL does not contain any tables joins. One possible way to improve here - add special index for this kind of queries.