Nested documents boolean query doubt/problem

[miguelm]

Hi,

Sorry if this is the wrong place to post this, but i have searched for a while in other issues and documentation and didn't find the answer to my problem.

I'm using mongoid and i have a base class Venue:

class Venue
  include Mongoid::Document
  include Mongoid::Timestamps
  include Tire::Model::Search
  include Tire::Model::Callbacks

  # alot of fields
  field :name, type: String

  embeds_many :weekdays, :cascade_callbacks => true
  accepts_nested_attributes_for :weekdays, :allow_destroy => true

   mapping do
     indexes :weekdays do
       indexes :type, :type => "string"
       indexes :hours, :type => "string", :analyzer => 'keyword'
     end
   end

And my embedded document Weekday:

class Weekday
  include Mongoid::Document
  include Mongoid::Timestamps

  embedded_in :venue

  field :type
  field :hours, type: Array
end

In the hours field of my Weekday embedded documents i have an array with data like this:

["10:00", "11:00,"12:00", "12:30","14:30"]

What i'm trying to accomplish here is obtaining Venue documents given a specific type of weekday and between a range of hours.

I.e. I want documents with weekdays.type = 1 and an hours between 11:00 and 12:00.

For that i'v built this query:

tire.search do
  query do
   boolean do
       must { string "weekdays.type:1 AND weekdays.hours:[11\:00 TO 12\:00]" }
   end
  end
end

Unfortunately every-time all documents are returned, perhaps because there is weekdays with other type where the array has the 11:00 to 12:00 or even because since i'm trying to do a lexicographical comparison something might get borked (also used the \ to try to escape the : special character but also tested without it and same problem, even tried to change my model to have an integer 1100 instead of a string "11:00" but had the same problem).

So my question is, in this scenario what would be the best way to accomplish a query similar to this? and what am i doing wrong?

Thank you for your attention!

[karmi]

Hi, for solving this "cross matching" issue, you need to use the special nested type in Elasticsearch.

See:

• http://euphonious-intuition.com/2013/02/managing-relations-in-elasticsearch/ and http://www.spacevatican.org/2012/6/3/fun-with-elasticsearch-s-children-and-nested-documents/ for background
• https://github.com/karmi/tire/blob/master/test/integration/nested_query_test.rb Tire integration for working code to try it out

Ping me back with more questions if you need.

(Also, better use the match query instead of the error-prone query_string query...)

[miguelm]

You are awesome!

After i did your links i did another mapping structure like this:

mapping do
  indexes :weekdays, :type => "nested" do 
    indexes :type, :type => "string"
    indexes :hours, :type => "string", :analyzer => 'keyword'
  end
end

and a query construction like in your nested query test:

    s = Tire.search @index.name do
      query do
        boolean do
          must do
            match 'name', 'Duck'
          end
          must do
            nested path: 'weekdays' do
              query do
                boolean do
                  must { match 'weekdays.type',  '0' }
                  must { range 'weekdays.hours', { gt: "12:00" }}
                end
              end
            end
          end
        end
      end
    end

It all worked out.

Another last question if i may, since i will be returning an array a set of Venue results something similar to this:

<Item (Venue) _id: "xxxid", name: "xxx", weekdays: [<Item _id: "anotherid", type: 0, hours: ["14:30", "15:00"]>,<Item _id: "anotherid", type: 1, hours: ["14:30", "15:00"]>]>

With this result i only want to retrieve the items of weekdays that match my boolean query (type = 0) is that possible?

Since it's a nested document ideally i could do something like this:

 s.results.first.weekdays 

Where the only weekdays items are there are the ones who match type = 0
Is it possible without having to write the code to iterate over all the weekdays?

Let me know if i didn't explain myself properly.

Once again awesome tips and love your work!

[karmi]

Hi, thanks, you're very welcome :)

I know what you're after -- but Elasticsearch will return the whole document _source , so unfortunately you have to iterate over the venue.weekdays yourself to display just the matching ones...

[karmi]

@miguelm It's on the Elasticsearch roadmap though to return matching nested documents, elastic/elasticsearch#3022

[miguelm]

Nice catch, will follow up that issue elastic/elasticsearch#3022

For now i will do a venue.weekdays.select{...} over it and extract the values.

The most difficult part is solved, do you want to keep this issue as it links to the elastic search issue or should i close it so it doesn't take up more space on your backlog?

Once again thank you very much and hope i can repay it sometime in the future :)

[karmi]

@miguelm I think we can close it here. Thanks!