Question

In this case which pattern will be faster?
Obviously Pattern1 with helper looks much more sophisticated and looks clean.
But it send SQL every time when user_link method is called.
Here it calls up to 100times at one page loading.

Which way would be better for benchmark performance?

Pattern1. With helper

application_helper

def user_link(username)
    link_to User.find_by_username(username).user_profile.nickname, show_user_path(username)
end

view

<% @topics.order("updated_at DESC").limit(100).each do |topic| %>
    <%= user_link(topic.comment_threads.order("id").last.user.username) if topic.comment_threads.present? %>
<% end %>

Pattern2. Without helper. Just only view

<% @topics.order("updated_at DESC").limit(100).each do |topic| %>
    <%= link_to(topic.comment_threads.order("id").last.user.nickname, show_user_path(topic.comment_threads.order("id").last.user.username) ) if topic.comment_threads.present? %>
<% end %>

Answer 1

try

# Topics model
#via scope
scope :get_topic_list, lambda do
  order("updated_at DESC").joins(:comment_threads => :user).limit(100)
end

#via method
def self.get_topic_list
  Topic.order("updated_at DESC").joins(:comment_threads => :user).limit(100)
end

# in your controller or move to model itself (recommened)
@topics = Topic.get_topic_list

# in you view
<% @topics.each do |topic| %>
    <%= link_to(topic.comment_threads.order("id").last.user.nickname, show_user_path(topic.comment_threads.order("id").last.user.username) ) if topic.comment_threads.present? %>
<% end %>