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Fixed in 2020.2.X

Fixed in 2019.4.X, 2020.1.X



Found in





Issue ID




[Performance Regression] "EditorOnly [Prefabs.MergePrefabs]" process noticeably slower when opening a scene

Scene Management


Reproduction steps:
1. Import the attached .unitypackage ("1239162.unitypackage")
2. Open the Scene "Candy Trip 3"

Expected result: Scene is opened at the same speed as before
Actual result: Scene takes a lot longer to open than before

Reproducible with: 2019.3.0a1, 2019.3.12f1, 2020.1.0b8, 2020.2.0a9
Not reproducible with: 2018.4.22f1, 2019.2.0a14

- In the versions deemed not reproducible the same action would take about 90-100ms, while in the versions deemed reproducible it would take 25000-50000ms

  1. Resolution Note (fix version 2020.2):

    Fixed in 2020.2.0b1

  2. Resolution Note (fix version 2020.1):

    Fixed in 2020.1.8f1

  3. Resolution Note (fix version 2019.4):

    Fixed in 2019.4.24f1

Comments (2)

  1. JofreMP

    Nov 30, 2022 13:23

    It happens de same to me in the version 2020.3.11f1, so the bug is still not fixed on that version.

  2. Bastienre4

    Aug 19, 2020 15:24

    In my case, in some maps, it takes more than 60s to "Prefabs.MergePrefabs" on play mode exit.

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