CODEWITHSUNDEEP
sqlruby-on-railsruby-on-rails-3activerecordquery-optimization
Mohit Jain
Mohit Jain

Reputation: 43959

Need help in optimizing the query in ruby on rails

I have some 30,000 records in my Raw_deals table and some raw_cities table has some 30 records and each deal is linked with some 5-8 cities.

Now i want to fetch any random deal within some specific cities.

List of those cities can be fetched like this:

@raw_cities = RawCity.where('disabled = ?', 0).map(&:id)

Now i need a deal. I wrote a query but its taking too much time.

@raw_deal = RawDeal.order("RAND()").find(:first,:joins=>[:raw_cities], :conditions=>["raw_cities.id IN (?)",@raw_cities])

Upvotes: 1

Views: 110

Answers (1)

Frost
Frost

Reputation: 11987

The order("RAND()") is probably what's slowing your query down, and since you're only looking for one single deal, you can use a combination of limit and offset to simulate a random order.

Try something like this:

@raw_deal = RawDeal.offset(rand(RawDeal.count)).
                    joins(:raw_cities).
                    where(raw_cities: @raw_cities).
                    first

Upvotes: 3

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