Active record query issues in Rails 3.2 - nginx

Question

I have category model and category has many postings.
Problem: Sometimes postings are not visible under category in web even records are present in database
I investigated the query for the action in production enviroment by enabling config.log_level = :debug and restarted the
nginx passenger server. Now I can see the records under the category. I was unable to reproduce the same issue again and it occurs rarely.
Note:
I didn't change any code in the project. The same code behave differently.
Rails is 3.2.22. Nginx passenger(5.1.1)
Model are as follows
class Category < ActiveRecord::Base
has_many :postings, conditions: ['paid = ? AND start_date <= ? AND end_date >= ?', true, Date.current, Date.current]
end
class Posting < ActiveRecord::Base
searchkick
belongs_to :category
class << self
def payed
where paid: true
end
def activated
where :code => ""
end
def starts_on(date)
where "start_date <= ?", date
end
def ends_after(date)
where "end_date >= ?", date
end
def in_location(state,city)
where(stateid: state.id, cityid: city.id)
end
def not_deleted
where "active != false"
end
end
Postings controller
def index
#category = Category.find(params[:category_id])
postings = #category.postings.payed.activated.not_deleted.starts_on(Date.current).ends_after(Date.current).order(:created_at)
#postings = postings.in_location(current_state, current_city).page(params[:page])
end
From production.log, when accessing postings page /postings?category_id=25
Category Load (0.2ms) SELECT categories.* FROM categories
WHERE categories.id = 25 LIMIT 1
(0.4ms) SELECT COUNT(*) FROM postings WHERE
postings.category_id = 25 AND postings.paid = 1 AND
postings.code = '' AND postings.stateid = 44 AND
postings.cityid = 14823 AND (active != false) AND (paid = 1 AND
listing_start_date <= '2017-03-13' AND listing_end_date >=
'2017-03-13') AND (listing_start_date <= '2017-03-13') AND
(listing_end_date >= '2017-03-13')
CACHE (0. SELECT COUNT(*) FROM postings WHERE
postings.category_id = 25 AND postings.paid = 1 AND
postings.code = '' AND postings.stateid = 44 AND
postings.cityid = 14823 AND (active != false) AND (paid = 1 AND
listing_start_date <= '2017-03-13' AND listing_end_date >=
'2017-03-13') AND (listing_start_date <= '2017-03-13') AND
(listing_end_date >= '2017-03-13')
Posting Load (0.4ms) SELECT postings.* FROM postings WHERE
postings.category_id = 25 AND postings.paid = 1 AND
postings.code = '' AND postings.stateid = 44 AND
postings.cityid = 14823 AND (active != false) AND (paid = 1 AND
listing_start_date <= '2017-03-13' AND listing_end_date >=
'2017-03-13') AND (listing_start_date <= '2017-03-13') AND
(listing_end_date >= '2017-03-13') ORDER BY created_at LIMIT 10 OFFSET
0
The above set of queries did not pick any records; and after enabling debug mode and restart/touch the nginx server the same query fetched available records
Is the problem caused by active record query/ Nginx/ cache?
Please help me to resolve this issue.

Answer 1

Fixed the problem using Proc for association condition like
has_many :postings, conditions: proc { "payed = 1 AND start_date <= '#{Date.current.to_s(:db)}' AND end_date >= '#{Date.current.to_s(:db)}'"}
If you would have done association with dynamic condition like has_many :postings, conditions: ['paid = ? AND start_date <= ? AND end_date >= ?', true, Date.current, Date.current], there will be cases when the results you’ll get are not expected since the condition will have the day you started the Rails application and Date.current won’t be called again.
Thanks to Jose M.Gilgado. Reference: http://josemdev.com/articles/dynamic-conditions-associations-rails-3/