Memory usage bump after upgrading to the latest version

[filipebarros]

After upgrading to the latest version I've noticed the memory consumption keeps going up so I created a dummy application to check if the same happened with the previous version:

require 'grape'

class API < Grape::API
  get :heartbeat do
    'OK'
  end
end

run API

Here's the memory usage with both 1.2.1 version and 1.1.0 at the start of the process and after 1000 and 10000 calls:

	1.2.1 - 1000	1.1.0 - 1000	1.2.1 - 10000	1.1.0 - 10000
Start	25.4Mb	26.4Mb	25.2Mb	25.1Mb
Finish	45.0Mb	29.0Mb	198.5Mb	29.7Mb

Here's the script I used to run the API calls.

for run in {1..1000} do
  curl -s "http://localhost:9292/heartbeat"
done

[dblock]

Let's debug this more thoroughly?

Check out #665 where we debugged a memory leak successfully for next steps.

cc: @myxoh

[nijikon]

We are experiencing this as well, reverting to 1.1.0 fixed this issue for us.

[myxoh]

Interesting, I wouldn't have thought the changes I've implemented should have impacted the memory consumption other than ever so slightly at load time. I'll take a look into this somewhere between late today and early tomorrow

[myxoh]

oh wow. I think I've found the issue. This is unique to mounting the API directly on Rack I believe. call and call! are being called on the base instance, and hence continously added ot the setup of the application.
I already have a fix in place that passes all specs. I'll be creating a PR in a minute now.

Thanks for realizing this!

[myxoh]

As a colour note, on my local testing this fix puts the memory footprint of 1.2.2 in the same values as the 1.1.0 .

[dblock]

@nijikon @filipebarros Please do try the code from #1836, which I just merged on master, and confirm whether the problem is fixed?

[myxoh]

Setup:

# configu.ru
require 'grape'

class API < Grape::API
  get :heartbeat do
    'OK'
  end
end

run API

tab 1:
> rackup
tab 2:
> irb

> 1_000.times { `curl http://localhost:9292/heartbeat` }

Results:
master:
1,000 requests
32.8 MB
10,000 requests
32.9 MB

1.2.1
1,000 requests
46.5 MB
10,000 requests
214 MB

1.1.0
1,000 requests
32.0 MB
10,000 requests
32.1 MB

EDIT: 1.1.0 has been updated with the correct test results

[myxoh]

Also, benchmarking the time for 1,000 calls gives me similar results for both 1.1.0 and master

[dblock]

Good. I say cut a release.

[myxoh]

Agreed with the release. Could you look at #1833 before it please? 👍
Thanks

[filipebarros]

Tested against 34610f56ef99dbc1d9bd1efd6fa564482020e7d2 and memory usage is steady around 29Mb for 10000 calls 👍