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Issue 726773 link

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Issue metadata

Status: Fixed
Owner:
Closed: Jun 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: All
Pri: 1
Type: Bug



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DataReductionProxy Holdback Experiment is not holding back

Project Member Reported by ryansturm@chromium.org, May 26 2017

Issue description

When a user is in a holdback experiment (e.g. chrome --force-fieldtrials=DataCompressionProxyHoldback/Enabled/) they should not have traffic navigated through the data reduction proxy.

Expected:
WasEligibleWithoutHoldback should not DCHECK

Actual:
[101620:101656:0526/104900.500544:FATAL:data_reduction_proxy_network_delegate.cc(591)] Check failed: proxy_info.is_empty() || proxy_info.is_direct() || !data_reduction_proxy_config_->IsDataReductionProxy( proxy_info.proxy_server(), nullptr).

I started to investigate:
Added 

  LOG(WARNING)<< "Calling WasEligibleWithoutHoldback";
  LOG(WARNING) << proxy_info.is_empty();
  LOG(WARNING) << proxy_info.is_direct();
  LOG(WARNING) << data_reduction_proxy_config_->IsDataReductionProxy(
      proxy_info.proxy_server(), nullptr);
  LOG(WARNING)<<request.url().spec();

before the DCHECK 

[101620:101656:0526/104900.500353:WARNING:data_reduction_proxy_network_delegate.cc(583)] Calling WasEligibleWithoutHoldback
[101620:101656:0526/104900.500423:WARNING:data_reduction_proxy_network_delegate.cc(584)] 0
[101620:101656:0526/104900.500451:WARNING:data_reduction_proxy_network_delegate.cc(585)] 0
[101620:101656:0526/104900.500477:WARNING:data_reduction_proxy_network_delegate.cc(586)] 1
[101620:101656:0526/104900.500512:WARNING:data_reduction_proxy_network_delegate.cc(588)] http://aws1.mdw.la/fw/
[101620:101656:0526/104900.500544:FATAL:data_reduction_proxy_network_delegate.cc(591)] Check failed: proxy_info.is_empty() || proxy_info.is_direct() || !data_reduction_proxy_config_->IsDataReductionProxy( proxy_info.proxy_server(), nullptr).


This indicates that the DRP was used for the URL  http://aws1.mdw.la/fw/ despite being in the holdback experiment.


Based on UMA this appears to be broken starting in M58:
https://uma.googleplex.com/p/chrome/variations/?sid=76f3f7615ca5350d0e9bf98ce1e56795
 
Removing the DCHECK I see the image on the page indicating that DRP was in fact used.

Further, I am pretty sure that we are not adding the CP header in this case due to the early return after determining we are in the field trial.
From the dashboard (https://uma.googleplex.com/p/chrome/variations/?sid=6c276f613806a82cd50fac306951806f), it seems that Enabled group has ~7.5k 
(almost negligible) navigations while Control has ~5.4M. Seems like it is working?

It is possible that there is a DCHECK failure. If yes, we should update the DCHECK.
Status: Started (was: Assigned)
Labels: Merge-Request-60
Please tag with appropriate OSs.  Thanks.
Labels: OS-All
Project Member

Comment 8 by sheriffbot@chromium.org, Jun 1 2017

Labels: -Merge-Request-60 Hotlist-Merge-Approved Merge-Approved-60
Your change meets the bar and is auto-approved for M60. Please go ahead and merge the CL to branch 3112 manually. Please contact milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), josafat@(ChromeOS), bustamante@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Labels: Merge-Request-59
Project Member

Comment 11 by sheriffbot@chromium.org, Jun 1 2017

Labels: -Merge-Request-59 Merge-Review-59 Hotlist-Merge-Review
This bug requires manual review: We are only 4 days from stable.
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), gkihumba@(ChromeOS), Abdul Syed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
We are targeting M59 to stable promotion for next week. Can you please tell why this is urgent? Has this been tested and verified in Canary, and is this a safe merge? My recommendation is to wait until M60, unless this is absolutely critical. 
Labels: -M-59 -Merge-Review-59 M-60
Status: Fixed (was: Started)
OK, if it is less than a week out, then I will skip M-59.

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