Sql performance

Rails
1

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

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

update:
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? }
end
end

view:
<% @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 %>

partial:
<% 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?
Thanks

2

On Tue, Jan 15, 2013 at 5:25 AM, Werner
[email protected] wrote:

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

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

-Dave

–
Dave A., the T. Rex of Codosaurus LLC,
secret-cleared freelance software developer
taking contracts in or near NoVa or remote.
See information at http://www.Codosaur.us/.

3

On 01/16/2013 02:04 PM, Dave A. wrote:

On Tue, Jan 15, 2013 at 5:25 AM, Werner [email protected] wrote:

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

-Dave

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.

Norm

4

On Wed, Jan 16, 2013 at 5:22 PM, Norm S.
[email protected] wrote:

load. Google “N + 1 queries problem”.

-Dave

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.