Re: query too slow

[Patrick Matsumura]

Hi Rodrigo

You should try to omit the call to the where function, since you're not really filtering. Also set an index on the data_captura field like this:

db.mentions.ensureIndex({data_captura: -1})

This should solve the problem with your slow query.

Hope this helps.

Patrick

On Wednesday, November 7, 2012 7:17:29 PM UTC+1, Rodrigo Coutinho wrote:

Hi,

I have the fallowing model and when this query is executed, it takes 1.1 s.

Other app is using the same database and performs this query with 0.3 s(PHP) .

Don't know what else to do, i've tried to change this query many times and still slow, despite the 200k documents.

help please

class Mention

include MongoMapper::Document

        def all (options = {})

             mentions = Mention.where({}).sort(:data_captura.desc).paginate(:per_page => 15, :page => 2).all

        end

end

Here's the output of the explain method:

=> {"cursor"=>"BasicCursor", "nscanned"=>214618, "nscannedObjects"=>214618, "n"=>15, "scanAndOrder"=>true, "millis"=>557, "indexBounds"=>{}, "allPlans"=>[{"cursor"=>"BasicCursor", "indexBounds"=>{}}], "oldPlan"=>{"cursor"=>"BasicCursor", "indexBounds"=>{}}}