On Feb 15, 8:28 pm, bingo bob <[email protected]> wrote:
> The following method in my rails app is called very, very frequently on
> incoming requests and results in model objects being rendered as JSON.
> All is working fine, but this thing has to be as efficient and fast as
> possible. So far I've added an index to updated_at and I've enabled
> mod_deflate on the server so the JSON responses are compressed.
>
> I've heard that it's possible to optimise rails queries as raw SQL so to
> eek extra performance out of the app. Is this true and a good idea (if
> it's marginal I'd stay as I am) and given the code in my method; is it
> worth doing, I'm not so familiar with SQL syntax so if it is something
> that I should do I'd appreciate any tips as to the syntax.
>
> Here's the method as it stands, working fine - circa 5,000 records,
> growing I hope to 50,000 in a few weeks, maybe 100,000 records
> ultimately.
You might try connection.select_all (which will return an array of
hashes), the default to_json might be sufficient.
Also worth only selecting those columns you need in your output, and
(if applicable) create an index that includes those columns (known as
a covering index)
Fred
>
> def self.time_query(date_from,date_to,limit = 40)
> self.all(:conditions => { :updated_at => date_from..date_to }, :order
> => "updated_at DESC", :limit => limit)
> end
>
> Here's some output from the logs, I guess the SQL I could use directly
> is based on the
> "SELECT * FROM `apps` WHERE (`apps`.`updated_at` BETWEEN
> '2011-02-15T18:25:53Z' AND '2011-02-15T18:35:53Z') ORDER BY updated_at
> DESC, updated_at ASC LIMIT 40"
>
> Is this worth doing, are there significant performance gains to be had
> bypassing the AR layer.
> If it matters this is a rails 2.3.8 app.
>
> Processing AppsController#index to json (for 127.0.0.1 at 2011-02-15
> 18:35:53) [GET]
> Parameters: {"date_to"=>"2011-02-15T18:35:53Z",
> "date_from"=>"2011-02-15T18:25:53Z"}
> App Load (27.5ms) SELECT * FROM `apps` WHERE (`apps`.`updated_at`
> BETWEEN '2011-02-15T18:25:53Z' AND '2011-02-15T18:35:53Z') ORDER BY
> updated_at DESC, updated_at ASC LIMIT 40
> Completed in 34ms (View: 1, DB: 28) | 200 OK
> SQL (0.2ms) SET NAMES 'utf8'
> SQL (0.1ms) SET SQL_AUTO_IS_NULL=0
>
> --
> Posted viahttp://www.ruby-forum.com/.
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