I have a highly-normalized user model called Respondent. It has many
join fields such as “ethnicity_id”, “education_id”, etc. that define
relational categories. Most of them are indexed. For reasons unknown,
Rails is hitting a huge number of the tables when accessing any
Respondent objects. For example, on a simple SHOW action:
==CONTROLLER== (from basic scaffold)
def show
@respondent = Respondent.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => @respondent }
end
end
==VIEW== (note - nothing is even being rendered!)
<%= notice %>
<%= link_to ‘Edit’, edit_respondent_path(@respondent) %> |
<%= link_to ‘Back’, respondents_path %>
==RESULTING SERVER LOG==
Started GET “/respondents” for 127.0.0.1 at 2011-03-25 14:12:50 -0400
Processing by RespondentsController#index as HTML
Geokit is using the domain: localhost
←[1m←[35mPostalCode Load (101.0ms)←[0m SELECT postal_codes
.* FROM
postal_codes
←[1m←[36mCountry Load (1.0ms)←[0m ←[1mSELECT countries
.* FROM
countries
←[0m
←[1m←[35mEthnicity Load (1.0ms)←[0m SELECT ethnicities
.* FROM
ethnicities
←[1m←[36mEducation Load (0.0ms)←[0m ←[1mSELECT educations
.* FROM
educations
←[0m
←[1m←[35mJobStatus Load (0.0ms)←[0m SELECT job_statuses
.* FROM
job_statuses
←[1m←[36mRespondent Load (0.0ms)←[0m ←[1mSELECT respondents
.* FROM
respondents
←[0m
Rendered layouts/_navigation.html.erb (1.0ms)
Rendered respondents/index.html.erb within layouts/application (190.0ms)
Completed 200 OK in 3809ms (Views: 205.0ms | ActiveRecord: 103.0ms)
==QUESTION==
Why in the world could the server need to hit these tables and why is it
taking so long? Some of these models are related – for example,
postal_code BELONGS_TO country, etc. It does not do this for any other
models. I have attached the model and migration file for reference since
they are so long.