sql performance

Hi all.
I have a sql performance problem. Would be great to get some inspiration.

model hour: id, week_id, :user_id, project_id, hour

@hours = Hour.project(@project.id)

if params[:booking_user_ids]
params[:booking_user_ids].each do
Hour.update(params[:booking_user].keys, params[:booking_user].values).reject { |p| p.errors.empty? }

<% @hours.group_by(&:user_id).sort.each do |user, hours| %>

<%= simple_form_for @hour, :url => hour_path, :remote => true, :method => :put do %>
<%= render ‘form_user’, :hours => hours %>

<% hours.each do |week|%>

<%= fields_for "booking_user[]", week do |w| %>
<%= w.text_field :hour, :class => 'submittable' %>
<%= hidden_field_tag "booking_user_ids[]", w %>

Form entries are stored but on reload it gives me tons of:
CACHE (0.0ms) SELECT hours.* FROM hours WHERE hours.id = 189 LIMIT 1
(1.0ms) BEGIN
(0.9ms) COMMIT
and takes 11 seconds

on the second reload is fine 300 milsec.
Any idea to improve that?

That sounds like you could benefit from a .includes on your initial
load. Google "N + 1 queries problem".


I don't think so. The CACHE entries mean that the op did the same fetch as he had recently done and the data was still around and was used with no db access.


Should also note that the cache only hangs around as long as the request does.