react / react/react-native

Fetching large json data results in OutOfMemoryError

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🌐Networking Issue: Author Provided Repro
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Description

Description

Using fetch to get several Megabytes (currently happens for me at around 80Mb) of JSON data causes Android to panic and throw an OutOfMemoryError. This is due to the fact that the whole response is being read as bytes, quickly filling up the heap.

Stacktrace:

09-01 21:32:21.035  5480  5555 E AndroidRuntime: java.lang.OutOfMemoryError: Failed to allocate a 98836368 byte allocation with 25165824 free bytes and 88MB until OOM, target footprint 133385952, growth limit 201326592
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at okio.Buffer.readByteArray(Buffer.kt:1429)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at okio.Buffer.readByteArray(Buffer.kt:1424)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at okio.RealBufferedSource.readByteArray(RealBufferedSource.kt:238)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at okhttp3.ResponseBody.bytes(ResponseBody.kt:124)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at com.facebook.react.modules.blob.BlobModule$4.toResponseData(BlobModule.java:134)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at com.facebook.react.modules.network.NetworkingModule$2.onResponse(NetworkingModule.java:512)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:519)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
09-01 21:32:21.035  5480  5555 E AndroidRuntime: 	at java.lang.Thread.run(Thread.java:923)

React Native version:

System:
    OS: Linux 5.13 Solus 4.3
    CPU: (8) x64 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
    Memory: 1.39 GB / 15.52 GB
    Shell: 5.1.8 - /bin/bash
  Binaries:
    Node: 14.17.5 - /usr/bin/node
    Yarn: 1.22.10 - /usr/bin/yarn
    npm: 6.14.14 - /usr/bin/npm
    Watchman: Not Found
  SDKs:
    Android SDK: Not Found
  IDEs:
    Android Studio: Not Found
  Languages:
    Java: 1.8.0_302-solus - /usr/lib64/openjdk-8/bin/javac
  npmPackages:
    @react-native-community/cli: Not Found
    react: 17.0.2 => 17.0.2 
    react-native: 0.65.1 => 0.65.1 
  npmGlobalPackages:
    *react-native*: Not Found

Steps To Reproduce

I created a test repository that shows the aforementioned behaviour. It also includes a 100Mb JSON file for testing, that you can serve locally or access via GitHub directly.
Steps are as follows

  1. Tap on the load data button
  2. Wait for the app to crash

Expected Results

Getting an out of memory error shouldn't really happen with this size of data in my opinion. Sure 100Mb sounds a lot at first, but in enterprise-grade apps this is probably a common scenario. In any case I think there should be a possibility to dynamically switch to streaming the response since okhttp offers bytestream and charstream as well. I'm not that well versed in Java but it would probably help reduce all of the 150Mb landing on the heap at once?

Snack, code example, screenshot, or link to a repository:

https://github.com/curtisy1/ReactNativeFetchRepro

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the Android response handling shown in BlobModule.java and NetworkingModule.java, then run the linked ReactNativeFetchRepro repository with its 100MB data.json file. Compare the current fetch path with the OkHttp ResponseBody byteStream and charStream references in the issue; done means large JSON responses no longer trigger the reported OutOfMemoryError.

Written by the indexing model from the issue text.

Assessment

Tech stack
android, java, react-native
Domain
mobile, networking
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

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