Understanding Ruby on Rails render times

Question

I am working on an "optimization" on my application and I am trying to understand the output that rails (version 2.2.2) gives at the end of the render.

Here is the "old" way:

Rendered user/_old_log (25.7ms)
Completed in 466ms (View: 195, DB: 8) | 200 OK

And the "new" way:

Rendered user/_new_log (48.6ms)
Completed in 337ms (View: 192, DB: 33) | 200 OK

These queries were exactly the same, the difference is the old way is parsing log files while the new way is querying the database log table.

The actual speed of the page is not the issue (the user understands that this is a slow request) ... but I would like the page to respond as quickly as possible even though it is a "slow" page.

So, my question is, what do the numbers represent/mean? In other words, which way was the faster method and why?

Answer 1

This:

Rendered user/_old_log (25.7ms)

is the time to render just the _old_log partial template, and comes from an ActiveSupport::Notification getting processed by ActionView::LogSubscriber

This:

Completed 200 OK in 466ms

Is the http status returned, as well as the total time for the entire request. It comes from ActionController::LogSubscriber.

Also, note those parenthetical items at the end:

(Views: 124.6ms | ActiveRecord: 10.8ms)

Those are the total times for rendering the entire view (partials & everything) and all database requests, respectively, and come from ActionController::LogSubscriber as well.

Answer 2

Jordan's answer is correct. To paraphrase, the first number is the time the page took to load. The second is how long the view took to generate. The last number is how long it took for your database to handle all queries you sent to it.

You can also get an estimation of how long your Controller and Model code took by subtracting the last two numbers from the first number, but a better way would be to use the Benchmark.measure method (http://www.ruby-doc.org/stdlib/libdoc/benchmark/rdoc/classes/Benchmark.html).

Your new way appears to have improved because code in the Controller/Model completes faster.

Answer 3

Your new way is spending less time overall but more time rendering the template.