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Firebase/Performance: unrealistic App Launch duration for "Unknown" connection type #934

nick130586 opened this issue Mar 16, 2018 · 9 comments


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@nick130586 nick130586 commented Mar 16, 2018

In some cases, device connection type is detected as "Unknown" for small percentage of users. App Launch Duration shows enormous numbers in such cases

screen shot 2018-01-06 at 12 06 58 am

  • Xcode version: 9.x
  • iOS: 10, 11
  • Firebase Component: Performance
  • Component version: 4.7

Steps to reproduce:


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@morganchen12 morganchen12 commented Mar 16, 2018

Filed b/75269150 internally, will keep this ticket updated.

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@eshiehz eshiehz commented Mar 16, 2018

App start is measured from when the objc runtime initializes to the time the application is active.

There's a couple potential reasons for the long app start time:

  1. Likely the user is backgrounding the app before it successfully becomes active.
  2. "Unknown" connection indicates the devices doesn't have networking. Verify your app doesn't have any blocking network calls in your app initialization.

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@morganchen12 morganchen12 commented Mar 19, 2018

Closing as this seems to be intended behavior.

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@eithan eithan commented Mar 19, 2018

Hi there, is there not a way to filter out timings in the case of a user backgrounding the app? It seems wrong to ever be recording timings like 7000 seconds. Unfortunately we even have a 90th percentile timing of 45000 seconds across all connection types. Can you consider reopening this and investigating a bit more if so? Thanks.

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@eithan eithan commented Jul 9, 2018

Curious if any progress has been made on this issue? In case it helps here is some data from the last 48 hours when looking at median timings by carrier:

Nextel (Telet) --> 6,180.97 s
Telemovil --> 4,252.30 s
T-Mobile/Mobimak --> 2,569.22 s
Swisscom --> 26,289.16 s
UNKNOWN [311530] --> 11,504.04 s
BSNL --> 66,080.97 s

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@morganchen12 morganchen12 commented Nov 7, 2018

@visumickey, can you take a look at this? It seems like it'd be best to just discard app launch traces if the user backgrounds mid-launch, since it just adds noise.

In the future we can revisit a way to include background-mid-launch traces in a less noisy way.

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@nikodurand nikodurand commented Sep 23, 2019

Hi there,
we also have this issue, the problem is that we don't know which is the real performance of our application because 10% of sessions are not realistic. Very strange that it's not fixed, that's a real pain point for firebase on ios. Any fix to come ?

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@visumickey visumickey commented Nov 19, 2019

This seems to be an issue with the backgrounding enabled apps and Firebase Performance would be rolling out a fix for this to make sure the app start times are rightly calculated when launching the app from background. Expecting to roll this out in the next release. (Early december 2019)

@morganchen12 morganchen12 added this to the M60.1 milestone Nov 19, 2019
@visumickey visumickey removed this from the M60.1 milestone Nov 27, 2019
@visumickey visumickey added this to the M61 milestone Nov 27, 2019
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@paulb777 paulb777 commented Dec 17, 2019

Fix released with Firebase 6.14.0

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